source: vbox/trunk/src/VBox/VMM/VMMR0/HMVMXR0.cpp@ 97572

/* $Id: HMVMXR0.cpp 97562 2022-11-16 02:34:26Z vboxsync $ */
/** @file
 * HM VMX (Intel VT-x) - Host Context Ring-0.
 */

/*
 * Copyright (C) 2012-2022 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * SPDX-License-Identifier: GPL-3.0-only
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#define LOG_GROUP LOG_GROUP_HM
#define VMCPU_INCL_CPUM_GST_CTX
#include <iprt/x86.h>
#include <iprt/asm-amd64-x86.h>
#include <iprt/thread.h>
#include <iprt/mem.h>
#include <iprt/mp.h>

#include <VBox/vmm/pdmapi.h>
#include <VBox/vmm/dbgf.h>
#include <VBox/vmm/iem.h>
#include <VBox/vmm/iom.h>
#include <VBox/vmm/tm.h>
#include <VBox/vmm/em.h>
#include <VBox/vmm/gcm.h>
#include <VBox/vmm/gim.h>
#include <VBox/vmm/apic.h>
#include "HMInternal.h"
#include <VBox/vmm/vmcc.h>
#include <VBox/vmm/hmvmxinline.h>
#include "HMVMXR0.h"
#include "VMXInternal.h"
#include "dtrace/VBoxVMM.h"


/*********************************************************************************************************************************
*   Defined Constants And Macros                                                                                                 *
*********************************************************************************************************************************/
#ifdef DEBUG_ramshankar
# define HMVMX_ALWAYS_SAVE_GUEST_RFLAGS
# define HMVMX_ALWAYS_SAVE_RO_GUEST_STATE
# define HMVMX_ALWAYS_SAVE_FULL_GUEST_STATE
# define HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE
# define HMVMX_ALWAYS_CLEAN_TRANSIENT
# define HMVMX_ALWAYS_CHECK_GUEST_STATE
# define HMVMX_ALWAYS_TRAP_ALL_XCPTS
# define HMVMX_ALWAYS_TRAP_PF
# define HMVMX_ALWAYS_FLUSH_TLB
# define HMVMX_ALWAYS_SWAP_EFER
#endif

/** Enables the fAlwaysInterceptMovDRx related code. */
#define VMX_WITH_MAYBE_ALWAYS_INTERCEPT_MOV_DRX 1


/*********************************************************************************************************************************
*   Structures and Typedefs                                                                                                      *
*********************************************************************************************************************************/
/**
 * VMX page allocation information.
 */
typedef struct
{
    uint32_t    fValid;       /**< Whether to allocate this page (e.g, based on a CPU feature). */
    uint32_t    uPadding0;    /**< Padding to ensure array of these structs are aligned to a multiple of 8. */
    PRTHCPHYS   pHCPhys;      /**< Where to store the host-physical address of the allocation. */
    PRTR0PTR    ppVirt;       /**< Where to store the host-virtual address of the allocation. */
} VMXPAGEALLOCINFO;
/** Pointer to VMX page-allocation info. */
typedef VMXPAGEALLOCINFO *PVMXPAGEALLOCINFO;
/** Pointer to a const VMX page-allocation info. */
typedef const VMXPAGEALLOCINFO *PCVMXPAGEALLOCINFO;
AssertCompileSizeAlignment(VMXPAGEALLOCINFO, 8);


/*********************************************************************************************************************************
*   Internal Functions                                                                                                           *
*********************************************************************************************************************************/
static bool     hmR0VmxShouldSwapEferMsr(PCVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient);
static int      hmR0VmxExitHostNmi(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo);


/*********************************************************************************************************************************
*   Global Variables                                                                                                             *
*********************************************************************************************************************************/
/** The DR6 value after writing zero to the register.
 * Set by VMXR0GlobalInit(). */
static uint64_t g_fDr6Zeroed = 0;


/**
 * Checks if the given MSR is part of the lastbranch-from-IP MSR stack.
 * @returns @c true if it's part of LBR stack, @c false otherwise.
 *
 * @param   pVM         The cross context VM structure.
 * @param   idMsr       The MSR.
 * @param   pidxMsr     Where to store the index of the MSR in the LBR MSR array.
 *                      Optional, can be NULL.
 *
 * @remarks Must only be called when LBR is enabled.
 */
DECL_FORCE_INLINE(bool) hmR0VmxIsLbrBranchFromMsr(PCVMCC pVM, uint32_t idMsr, uint32_t *pidxMsr)
{
    Assert(pVM->hmr0.s.vmx.fLbr);
    Assert(pVM->hmr0.s.vmx.idLbrFromIpMsrFirst);
    uint32_t const cLbrStack = pVM->hmr0.s.vmx.idLbrFromIpMsrLast - pVM->hmr0.s.vmx.idLbrFromIpMsrFirst + 1;
    uint32_t const idxMsr    = idMsr - pVM->hmr0.s.vmx.idLbrFromIpMsrFirst;
    if (idxMsr < cLbrStack)
    {
        if (pidxMsr)
            *pidxMsr = idxMsr;
        return true;
    }
    return false;
}


/**
 * Checks if the given MSR is part of the lastbranch-to-IP MSR stack.
 * @returns @c true if it's part of LBR stack, @c false otherwise.
 *
 * @param   pVM         The cross context VM structure.
 * @param   idMsr       The MSR.
 * @param   pidxMsr     Where to store the index of the MSR in the LBR MSR array.
 *                      Optional, can be NULL.
 *
 * @remarks Must only be called when LBR is enabled and when lastbranch-to-IP MSRs
 *          are supported by the CPU (see hmR0VmxSetupLbrMsrRange).
 */
DECL_FORCE_INLINE(bool) hmR0VmxIsLbrBranchToMsr(PCVMCC pVM, uint32_t idMsr, uint32_t *pidxMsr)
{
    Assert(pVM->hmr0.s.vmx.fLbr);
    if (pVM->hmr0.s.vmx.idLbrToIpMsrFirst)
    {
        uint32_t const cLbrStack = pVM->hmr0.s.vmx.idLbrToIpMsrLast - pVM->hmr0.s.vmx.idLbrToIpMsrFirst + 1;
        uint32_t const idxMsr    = idMsr - pVM->hmr0.s.vmx.idLbrToIpMsrFirst;
        if (idxMsr < cLbrStack)
        {
            if (pidxMsr)
                *pidxMsr = idxMsr;
            return true;
        }
    }
    return false;
}


/**
 * Gets the active (in use) VMCS info. object for the specified VCPU.
 *
 * This is either the guest or nested-guest VMCS info. and need not necessarily
 * pertain to the "current" VMCS (in the VMX definition of the term). For instance,
 * if the VM-entry failed due to an invalid-guest state, we may have "cleared" the
 * current VMCS while returning to ring-3. However, the VMCS info. object for that
 * VMCS would still be active and returned here so that we could dump the VMCS
 * fields to ring-3 for diagnostics. This function is thus only used to
 * distinguish between the nested-guest or guest VMCS.
 *
 * @returns The active VMCS information.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @thread  EMT.
 * @remarks This function may be called with preemption or interrupts disabled!
 */
DECLINLINE(PVMXVMCSINFO) hmGetVmxActiveVmcsInfo(PVMCPUCC pVCpu)
{
    if (!pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs)
        return &pVCpu->hmr0.s.vmx.VmcsInfo;
    return &pVCpu->hmr0.s.vmx.VmcsInfoNstGst;
}


/**
 * Returns whether the VM-exit MSR-store area differs from the VM-exit MSR-load
 * area.
 *
 * @returns @c true if it's different, @c false otherwise.
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECL_FORCE_INLINE(bool) hmR0VmxIsSeparateExitMsrStoreAreaVmcs(PCVMXVMCSINFO pVmcsInfo)
{
    return RT_BOOL(   pVmcsInfo->pvGuestMsrStore != pVmcsInfo->pvGuestMsrLoad
                   && pVmcsInfo->pvGuestMsrStore);
}


/**
 * Sets the given Processor-based VM-execution controls.
 *
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   uProcCtls       The Processor-based VM-execution controls to set.
 */
static void hmR0VmxSetProcCtlsVmcs(PVMXTRANSIENT pVmxTransient, uint32_t uProcCtls)
{
    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if ((pVmcsInfo->u32ProcCtls & uProcCtls) != uProcCtls)
    {
        pVmcsInfo->u32ProcCtls |= uProcCtls;
        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, pVmcsInfo->u32ProcCtls);
        AssertRC(rc);
    }
}


/**
 * Removes the given Processor-based VM-execution controls.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   uProcCtls       The Processor-based VM-execution controls to remove.
 *
 * @remarks When executing a nested-guest, this will not remove any of the specified
 *          controls if the nested hypervisor has set any one of them.
 */
static void hmR0VmxRemoveProcCtlsVmcs(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, uint32_t uProcCtls)
{
    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if (pVmcsInfo->u32ProcCtls & uProcCtls)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        if (   !pVmxTransient->fIsNestedGuest
            || !CPUMIsGuestVmxProcCtlsSet(&pVCpu->cpum.GstCtx, uProcCtls))
#else
        NOREF(pVCpu);
        if (!pVmxTransient->fIsNestedGuest)
#endif
        {
            pVmcsInfo->u32ProcCtls &= ~uProcCtls;
            int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, pVmcsInfo->u32ProcCtls);
            AssertRC(rc);
        }
    }
}


/**
 * Sets the TSC offset for the current VMCS.
 *
 * @param   uTscOffset  The TSC offset to set.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static void hmR0VmxSetTscOffsetVmcs(PVMXVMCSINFO pVmcsInfo, uint64_t uTscOffset)
{
    if (pVmcsInfo->u64TscOffset != uTscOffset)
    {
        int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_TSC_OFFSET_FULL, uTscOffset);
        AssertRC(rc);
        pVmcsInfo->u64TscOffset = uTscOffset;
    }
}


/**
 * Loads the VMCS specified by the VMCS info. object.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo       The VMCS info. object.
 *
 * @remarks Can be called with interrupts disabled.
 */
static int hmR0VmxLoadVmcs(PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->HCPhysVmcs != 0 && pVmcsInfo->HCPhysVmcs != NIL_RTHCPHYS);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    int rc = VMXLoadVmcs(pVmcsInfo->HCPhysVmcs);
    if (RT_SUCCESS(rc))
        pVmcsInfo->fVmcsState |= VMX_V_VMCS_LAUNCH_STATE_CURRENT;
    return rc;
}


/**
 * Clears the VMCS specified by the VMCS info. object.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks Can be called with interrupts disabled.
 */
static int hmR0VmxClearVmcs(PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->HCPhysVmcs != 0 && pVmcsInfo->HCPhysVmcs != NIL_RTHCPHYS);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    int rc = VMXClearVmcs(pVmcsInfo->HCPhysVmcs);
    if (RT_SUCCESS(rc))
        pVmcsInfo->fVmcsState = VMX_V_VMCS_LAUNCH_STATE_CLEAR;
    return rc;
}


/**
 * Checks whether the MSR belongs to the set of guest MSRs that we restore
 * lazily while leaving VT-x.
 *
 * @returns true if it does, false otherwise.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   idMsr   The MSR to check.
 */
static bool hmR0VmxIsLazyGuestMsr(PCVMCPUCC pVCpu, uint32_t idMsr)
{
    if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
    {
        switch (idMsr)
        {
            case MSR_K8_LSTAR:
            case MSR_K6_STAR:
            case MSR_K8_SF_MASK:
            case MSR_K8_KERNEL_GS_BASE:
                return true;
        }
    }
    return false;
}


/**
 * Loads a set of guests MSRs to allow read/passthru to the guest.
 *
 * The name of this function is slightly confusing. This function does NOT
 * postpone loading, but loads the MSR right now. "hmR0VmxLazy" is simply a
 * common prefix for functions dealing with "lazy restoration" of the shared
 * MSRs.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxLazyLoadGuestMsrs(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    Assert(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_SAVED_HOST);
    if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
    {
        /*
         * If the guest MSRs are not loaded -and- if all the guest MSRs are identical
         * to the MSRs on the CPU (which are the saved host MSRs, see assertion above) then
         * we can skip a few MSR writes.
         *
         * Otherwise, it implies either 1. they're not loaded, or 2. they're loaded but the
         * guest MSR values in the guest-CPU context might be different to what's currently
         * loaded in the CPU. In either case, we need to write the new guest MSR values to the
         * CPU, see @bugref{8728}.
         */
        PCCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
        if (   !(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
            && pCtx->msrKERNELGSBASE == pVCpu->hmr0.s.vmx.u64HostMsrKernelGsBase
            && pCtx->msrLSTAR        == pVCpu->hmr0.s.vmx.u64HostMsrLStar
            && pCtx->msrSTAR         == pVCpu->hmr0.s.vmx.u64HostMsrStar
            && pCtx->msrSFMASK       == pVCpu->hmr0.s.vmx.u64HostMsrSfMask)
        {
#ifdef VBOX_STRICT
            Assert(ASMRdMsr(MSR_K8_KERNEL_GS_BASE) == pCtx->msrKERNELGSBASE);
            Assert(ASMRdMsr(MSR_K8_LSTAR)          == pCtx->msrLSTAR);
            Assert(ASMRdMsr(MSR_K6_STAR)           == pCtx->msrSTAR);
            Assert(ASMRdMsr(MSR_K8_SF_MASK)        == pCtx->msrSFMASK);
#endif
        }
        else
        {
            ASMWrMsr(MSR_K8_KERNEL_GS_BASE, pCtx->msrKERNELGSBASE);
            ASMWrMsr(MSR_K8_LSTAR,          pCtx->msrLSTAR);
            ASMWrMsr(MSR_K6_STAR,           pCtx->msrSTAR);
            /* The system call flag mask register isn't as benign and accepting of all
               values as the above, so mask it to avoid #GP'ing on corrupted input. */
            Assert(!(pCtx->msrSFMASK & ~(uint64_t)UINT32_MAX));
            ASMWrMsr(MSR_K8_SF_MASK,        pCtx->msrSFMASK & UINT32_MAX);
        }
    }
    pVCpu->hmr0.s.vmx.fLazyMsrs |= VMX_LAZY_MSRS_LOADED_GUEST;
}


/**
 * Checks if the specified guest MSR is part of the VM-entry MSR-load area.
 *
 * @returns @c true if found, @c false otherwise.
 * @param   pVmcsInfo   The VMCS info. object.
 * @param   idMsr       The MSR to find.
 */
static bool hmR0VmxIsAutoLoadGuestMsr(PCVMXVMCSINFO pVmcsInfo, uint32_t idMsr)
{
    PCVMXAUTOMSR   pMsrs = (PCVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    uint32_t const cMsrs = pVmcsInfo->cEntryMsrLoad;
    Assert(pMsrs);
    Assert(sizeof(*pMsrs) * cMsrs <= X86_PAGE_4K_SIZE);
    for (uint32_t i = 0; i < cMsrs; i++)
    {
        if (pMsrs[i].u32Msr == idMsr)
            return true;
    }
    return false;
}


/**
 * Performs lazy restoration of the set of host MSRs if they were previously
 * loaded with guest MSR values.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 * @remarks The guest MSRs should have been saved back into the guest-CPU
 *          context by hmR0VmxImportGuestState()!!!
 */
static void hmR0VmxLazyRestoreHostMsrs(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    if (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
    {
        Assert(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_SAVED_HOST);
        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
        {
            ASMWrMsr(MSR_K8_LSTAR,          pVCpu->hmr0.s.vmx.u64HostMsrLStar);
            ASMWrMsr(MSR_K6_STAR,           pVCpu->hmr0.s.vmx.u64HostMsrStar);
            ASMWrMsr(MSR_K8_SF_MASK,        pVCpu->hmr0.s.vmx.u64HostMsrSfMask);
            ASMWrMsr(MSR_K8_KERNEL_GS_BASE, pVCpu->hmr0.s.vmx.u64HostMsrKernelGsBase);
        }
    }
    pVCpu->hmr0.s.vmx.fLazyMsrs &= ~(VMX_LAZY_MSRS_LOADED_GUEST | VMX_LAZY_MSRS_SAVED_HOST);
}


/**
 * Sets pfnStartVm to the best suited variant.
 *
 * This must be called whenever anything changes relative to the hmR0VmXStartVm
 * variant selection:
 *      - pVCpu->hm.s.fLoadSaveGuestXcr0
 *      - HM_WSF_IBPB_ENTRY in pVCpu->hmr0.s.fWorldSwitcher
 *      - HM_WSF_IBPB_EXIT  in pVCpu->hmr0.s.fWorldSwitcher
 *      - Perhaps: CPUMIsGuestFPUStateActive() (windows only)
 *      - Perhaps: CPUMCTX.fXStateMask (windows only)
 *
 * We currently ASSUME that neither HM_WSF_IBPB_ENTRY nor HM_WSF_IBPB_EXIT
 * cannot be changed at runtime.
 */
static void hmR0VmxUpdateStartVmFunction(PVMCPUCC pVCpu)
{
    static const struct CLANGWORKAROUND { PFNHMVMXSTARTVM pfn; } s_aHmR0VmxStartVmFunctions[] =
    {
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
    };
    uintptr_t const idx = (pVCpu->hmr0.s.fLoadSaveGuestXcr0                 ?  1 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_IBPB_ENTRY ?  2 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_L1D_ENTRY  ?  4 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_MDS_ENTRY  ?  8 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_IBPB_EXIT  ? 16 : 0);
    PFNHMVMXSTARTVM const pfnStartVm = s_aHmR0VmxStartVmFunctions[idx].pfn;
    if (pVCpu->hmr0.s.vmx.pfnStartVm != pfnStartVm)
        pVCpu->hmr0.s.vmx.pfnStartVm = pfnStartVm;
}


/**
 * Pushes a 2-byte value onto the real-mode (in virtual-8086 mode) guest's
 * stack.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @retval  VINF_EM_RESET if pushing a value to the stack caused a triple-fault.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   uValue  The value to push to the guest stack.
 */
static VBOXSTRICTRC hmR0VmxRealModeGuestStackPush(PVMCPUCC pVCpu, uint16_t uValue)
{
    /*
     * The stack limit is 0xffff in real-on-virtual 8086 mode. Real-mode with weird stack limits cannot be run in
     * virtual 8086 mode in VT-x. See Intel spec. 26.3.1.2 "Checks on Guest Segment Registers".
     * See Intel Instruction reference for PUSH and Intel spec. 22.33.1 "Segment Wraparound".
     */
    PCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
    if (pCtx->sp == 1)
        return VINF_EM_RESET;
    pCtx->sp -= sizeof(uint16_t);       /* May wrap around which is expected behaviour. */
    int rc = PGMPhysSimpleWriteGCPhys(pVCpu->CTX_SUFF(pVM), pCtx->ss.u64Base + pCtx->sp, &uValue, sizeof(uint16_t));
    AssertRC(rc);
    return rc;
}


/**
 * Wrapper around VMXWriteVmcs16 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxWriteVmcs16(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint16_t u16Val)
{
    RT_NOREF(pVCpu);
    return VMXWriteVmcs16(uFieldEnc, u16Val);
}


/**
 * Wrapper around VMXWriteVmcs32 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxWriteVmcs32(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint32_t u32Val)
{
    RT_NOREF(pVCpu);
    return VMXWriteVmcs32(uFieldEnc, u32Val);
}


/**
 * Wrapper around VMXWriteVmcs64 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxWriteVmcs64(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint64_t u64Val)
{
    RT_NOREF(pVCpu);
    return VMXWriteVmcs64(uFieldEnc, u64Val);
}


/**
 * Wrapper around VMXReadVmcs16 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxReadVmcs16(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint16_t *pu16Val)
{
    RT_NOREF(pVCpu);
    return VMXReadVmcs16(uFieldEnc, pu16Val);
}


/**
 * Wrapper around VMXReadVmcs32 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxReadVmcs32(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint32_t *pu32Val)
{
    RT_NOREF(pVCpu);
    return VMXReadVmcs32(uFieldEnc, pu32Val);
}


/**
 * Wrapper around VMXReadVmcs64 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxReadVmcs64(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint64_t *pu64Val)
{
    RT_NOREF(pVCpu);
    return VMXReadVmcs64(uFieldEnc, pu64Val);
}


/*
 * Instantiate the code we share with the NEM darwin backend.
 */
#define VCPU_2_VMXSTATE(a_pVCpu)            (a_pVCpu)->hm.s
#define VCPU_2_VMXSTATS(a_pVCpu)            (a_pVCpu)->hm.s

#define VM_IS_VMX_UNRESTRICTED_GUEST(a_pVM) (a_pVM)->hmr0.s.vmx.fUnrestrictedGuest
#define VM_IS_VMX_NESTED_PAGING(a_pVM)      (a_pVM)->hmr0.s.fNestedPaging
#define VM_IS_VMX_PREEMPT_TIMER_USED(a_pVM) (a_pVM)->hmr0.s.vmx.fUsePreemptTimer
#define VM_IS_VMX_LBR(a_pVM)                (a_pVM)->hmr0.s.vmx.fLbr

#define VMX_VMCS_WRITE_16(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs16((a_pVCpu), (a_FieldEnc), (a_Val))
#define VMX_VMCS_WRITE_32(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs32((a_pVCpu), (a_FieldEnc), (a_Val))
#define VMX_VMCS_WRITE_64(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs64((a_pVCpu), (a_FieldEnc), (a_Val))
#define VMX_VMCS_WRITE_NW(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs64((a_pVCpu), (a_FieldEnc), (a_Val))

#define VMX_VMCS_READ_16(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs16((a_pVCpu), (a_FieldEnc), (a_pVal))
#define VMX_VMCS_READ_32(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs32((a_pVCpu), (a_FieldEnc), (a_pVal))
#define VMX_VMCS_READ_64(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs64((a_pVCpu), (a_FieldEnc), (a_pVal))
#define VMX_VMCS_READ_NW(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs64((a_pVCpu), (a_FieldEnc), (a_pVal))

#include "../VMMAll/VMXAllTemplate.cpp.h"

#undef VMX_VMCS_WRITE_16
#undef VMX_VMCS_WRITE_32
#undef VMX_VMCS_WRITE_64
#undef VMX_VMCS_WRITE_NW

#undef VMX_VMCS_READ_16
#undef VMX_VMCS_READ_32
#undef VMX_VMCS_READ_64
#undef VMX_VMCS_READ_NW

#undef VM_IS_VMX_PREEMPT_TIMER_USED
#undef VM_IS_VMX_NESTED_PAGING
#undef VM_IS_VMX_UNRESTRICTED_GUEST
#undef VCPU_2_VMXSTATS
#undef VCPU_2_VMXSTATE


/**
 * Updates the VM's last error record.
 *
 * If there was a VMX instruction error, reads the error data from the VMCS and
 * updates VCPU's last error record as well.
 *
 * @param   pVCpu   The cross context virtual CPU structure of the calling EMT.
 *                  Can be NULL if @a rc is not VERR_VMX_UNABLE_TO_START_VM or
 *                  VERR_VMX_INVALID_VMCS_FIELD.
 * @param   rc      The error code.
 */
static void hmR0VmxUpdateErrorRecord(PVMCPUCC pVCpu, int rc)
{
    if (   rc == VERR_VMX_INVALID_VMCS_FIELD
        || rc == VERR_VMX_UNABLE_TO_START_VM)
    {
        AssertPtrReturnVoid(pVCpu);
        VMXReadVmcs32(VMX_VMCS32_RO_VM_INSTR_ERROR, &pVCpu->hm.s.vmx.LastError.u32InstrError);
    }
    pVCpu->CTX_SUFF(pVM)->hm.s.ForR3.rcInit = rc;
}


/**
 * Enters VMX root mode operation on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 * @param   pVM             The cross context VM structure. Can be
 *                          NULL, after a resume.
 * @param   HCPhysCpuPage   Physical address of the VMXON region.
 * @param   pvCpuPage       Pointer to the VMXON region.
 */
static int hmR0VmxEnterRootMode(PHMPHYSCPU pHostCpu, PVMCC pVM, RTHCPHYS HCPhysCpuPage, void *pvCpuPage)
{
    Assert(pHostCpu);
    Assert(HCPhysCpuPage && HCPhysCpuPage != NIL_RTHCPHYS);
    Assert(RT_ALIGN_T(HCPhysCpuPage, _4K, RTHCPHYS) == HCPhysCpuPage);
    Assert(pvCpuPage);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    if (pVM)
    {
        /* Write the VMCS revision identifier to the VMXON region. */
        *(uint32_t *)pvCpuPage = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_ID);
    }

    /* Paranoid: Disable interrupts as, in theory, interrupt handlers might mess with CR4. */
    RTCCUINTREG const fEFlags = ASMIntDisableFlags();

    /* Enable the VMX bit in CR4 if necessary. */
    RTCCUINTREG const uOldCr4 = SUPR0ChangeCR4(X86_CR4_VMXE, RTCCUINTREG_MAX);

    /* Record whether VMXE was already prior to us enabling it above. */
    pHostCpu->fVmxeAlreadyEnabled = RT_BOOL(uOldCr4 & X86_CR4_VMXE);

    /* Enter VMX root mode. */
    int rc = VMXEnable(HCPhysCpuPage);
    if (RT_FAILURE(rc))
    {
        /* Restore CR4.VMXE if it was not set prior to our attempt to set it above. */
        if (!pHostCpu->fVmxeAlreadyEnabled)
            SUPR0ChangeCR4(0 /* fOrMask */, ~(uint64_t)X86_CR4_VMXE);

        if (pVM)
            pVM->hm.s.ForR3.vmx.HCPhysVmxEnableError = HCPhysCpuPage;
    }

    /* Restore interrupts. */
    ASMSetFlags(fEFlags);
    return rc;
}


/**
 * Exits VMX root mode operation on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 */
static int hmR0VmxLeaveRootMode(PHMPHYSCPU pHostCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Paranoid: Disable interrupts as, in theory, interrupts handlers might mess with CR4. */
    RTCCUINTREG const fEFlags = ASMIntDisableFlags();

    /* If we're for some reason not in VMX root mode, then don't leave it. */
    RTCCUINTREG const uHostCr4 = ASMGetCR4();

    int rc;
    if (uHostCr4 & X86_CR4_VMXE)
    {
        /* Exit VMX root mode and clear the VMX bit in CR4. */
        VMXDisable();

        /* Clear CR4.VMXE only if it was clear prior to use setting it. */
        if (!pHostCpu->fVmxeAlreadyEnabled)
            SUPR0ChangeCR4(0 /* fOrMask */, ~(uint64_t)X86_CR4_VMXE);

        rc = VINF_SUCCESS;
    }
    else
        rc = VERR_VMX_NOT_IN_VMX_ROOT_MODE;

    /* Restore interrupts. */
    ASMSetFlags(fEFlags);
    return rc;
}


/**
 * Allocates pages specified as specified by an array of VMX page allocation info
 * objects.
 *
 * The pages contents are zero'd after allocation.
 *
 * @returns VBox status code.
 * @param   phMemObj        Where to return the handle to the allocation.
 * @param   paAllocInfo     The pointer to the first element of the VMX
 *                          page-allocation info object array.
 * @param   cEntries        The number of elements in the @a paAllocInfo array.
 */
static int hmR0VmxPagesAllocZ(PRTR0MEMOBJ phMemObj, PVMXPAGEALLOCINFO paAllocInfo, uint32_t cEntries)
{
    *phMemObj = NIL_RTR0MEMOBJ;

    /* Figure out how many pages to allocate. */
    uint32_t cPages = 0;
    for (uint32_t iPage = 0; iPage < cEntries; iPage++)
        cPages += !!paAllocInfo[iPage].fValid;

    /* Allocate the pages. */
    if (cPages)
    {
        size_t const cbPages = cPages << HOST_PAGE_SHIFT;
        int rc = RTR0MemObjAllocPage(phMemObj, cbPages, false /* fExecutable */);
        if (RT_FAILURE(rc))
            return rc;

        /* Zero the contents and assign each page to the corresponding VMX page-allocation entry. */
        void *pvFirstPage = RTR0MemObjAddress(*phMemObj);
        RT_BZERO(pvFirstPage, cbPages);

        uint32_t iPage = 0;
        for (uint32_t i = 0; i < cEntries; i++)
            if (paAllocInfo[i].fValid)
            {
                RTHCPHYS const HCPhysPage = RTR0MemObjGetPagePhysAddr(*phMemObj, iPage);
                void          *pvPage     = (void *)((uintptr_t)pvFirstPage + (iPage << X86_PAGE_4K_SHIFT));
                Assert(HCPhysPage && HCPhysPage != NIL_RTHCPHYS);
                AssertPtr(pvPage);

                Assert(paAllocInfo[iPage].pHCPhys);
                Assert(paAllocInfo[iPage].ppVirt);
                *paAllocInfo[iPage].pHCPhys = HCPhysPage;
                *paAllocInfo[iPage].ppVirt  = pvPage;

                /* Move to next page. */
                ++iPage;
            }

        /* Make sure all valid (requested) pages have been assigned. */
        Assert(iPage == cPages);
    }
    return VINF_SUCCESS;
}


/**
 * Frees pages allocated using hmR0VmxPagesAllocZ.
 *
 * @param   phMemObj    Pointer to the memory object handle.  Will be set to
 *                      NIL.
 */
DECL_FORCE_INLINE(void) hmR0VmxPagesFree(PRTR0MEMOBJ phMemObj)
{
    /* We can cleanup wholesale since it's all one allocation. */
    if (*phMemObj != NIL_RTR0MEMOBJ)
    {
        RTR0MemObjFree(*phMemObj, true /* fFreeMappings */);
        *phMemObj = NIL_RTR0MEMOBJ;
    }
}


/**
 * Initializes a VMCS info. object.
 *
 * @param   pVmcsInfo           The VMCS info. object.
 * @param   pVmcsInfoShared     The VMCS info. object shared with ring-3.
 */
static void hmR0VmxVmcsInfoInit(PVMXVMCSINFO pVmcsInfo, PVMXVMCSINFOSHARED pVmcsInfoShared)
{
    RT_ZERO(*pVmcsInfo);
    RT_ZERO(*pVmcsInfoShared);

    pVmcsInfo->pShared             = pVmcsInfoShared;
    Assert(pVmcsInfo->hMemObj == NIL_RTR0MEMOBJ);
    pVmcsInfo->HCPhysVmcs          = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysShadowVmcs    = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysMsrBitmap     = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysGuestMsrLoad  = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysGuestMsrStore = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysHostMsrLoad   = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysVirtApic      = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysEPTP          = NIL_RTHCPHYS;
    pVmcsInfo->u64VmcsLinkPtr      = NIL_RTHCPHYS;
    pVmcsInfo->idHostCpuState      = NIL_RTCPUID;
    pVmcsInfo->idHostCpuExec       = NIL_RTCPUID;
}


/**
 * Frees the VT-x structures for a VMCS info. object.
 *
 * @param   pVmcsInfo           The VMCS info. object.
 * @param   pVmcsInfoShared     The VMCS info. object shared with ring-3.
 */
static void hmR0VmxVmcsInfoFree(PVMXVMCSINFO pVmcsInfo, PVMXVMCSINFOSHARED pVmcsInfoShared)
{
    hmR0VmxPagesFree(&pVmcsInfo->hMemObj);
    hmR0VmxVmcsInfoInit(pVmcsInfo, pVmcsInfoShared);
}


/**
 * Allocates the VT-x structures for a VMCS info. object.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 *
 * @remarks The caller is expected to take care of any and all allocation failures.
 *          This function will not perform any cleanup for failures half-way
 *          through.
 */
static int hmR0VmxAllocVmcsInfo(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);

    bool const fMsrBitmaps = RT_BOOL(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_MSR_BITMAPS);
    bool const fShadowVmcs = !fIsNstGstVmcs ? pVM->hmr0.s.vmx.fUseVmcsShadowing : pVM->cpum.ro.GuestFeatures.fVmxVmcsShadowing;
    Assert(!pVM->cpum.ro.GuestFeatures.fVmxVmcsShadowing);  /* VMCS shadowing is not yet exposed to the guest. */
    VMXPAGEALLOCINFO aAllocInfo[] =
    {
        { true,        0 /* Unused */, &pVmcsInfo->HCPhysVmcs,         &pVmcsInfo->pvVmcs         },
        { true,        0 /* Unused */, &pVmcsInfo->HCPhysGuestMsrLoad, &pVmcsInfo->pvGuestMsrLoad },
        { true,        0 /* Unused */, &pVmcsInfo->HCPhysHostMsrLoad,  &pVmcsInfo->pvHostMsrLoad  },
        { fMsrBitmaps, 0 /* Unused */, &pVmcsInfo->HCPhysMsrBitmap,    &pVmcsInfo->pvMsrBitmap    },
        { fShadowVmcs, 0 /* Unused */, &pVmcsInfo->HCPhysShadowVmcs,   &pVmcsInfo->pvShadowVmcs   },
    };

    int rc = hmR0VmxPagesAllocZ(&pVmcsInfo->hMemObj, &aAllocInfo[0], RT_ELEMENTS(aAllocInfo));
    if (RT_FAILURE(rc))
        return rc;

    /*
     * We use the same page for VM-entry MSR-load and VM-exit MSR store areas.
     * Because they contain a symmetric list of guest MSRs to load on VM-entry and store on VM-exit.
     */
    AssertCompile(RT_ELEMENTS(aAllocInfo) > 0);
    Assert(pVmcsInfo->HCPhysGuestMsrLoad != NIL_RTHCPHYS);
    pVmcsInfo->pvGuestMsrStore     = pVmcsInfo->pvGuestMsrLoad;
    pVmcsInfo->HCPhysGuestMsrStore = pVmcsInfo->HCPhysGuestMsrLoad;

    /*
     * Get the virtual-APIC page rather than allocating them again.
     */
    if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_TPR_SHADOW)
    {
        if (!fIsNstGstVmcs)
        {
            if (PDMHasApic(pVM))
            {
                rc = APICGetApicPageForCpu(pVCpu, &pVmcsInfo->HCPhysVirtApic, (PRTR0PTR)&pVmcsInfo->pbVirtApic, NULL /*pR3Ptr*/);
                if (RT_FAILURE(rc))
                    return rc;
                Assert(pVmcsInfo->pbVirtApic);
                Assert(pVmcsInfo->HCPhysVirtApic && pVmcsInfo->HCPhysVirtApic != NIL_RTHCPHYS);
            }
        }
        else
        {
            /* These are setup later while marging the nested-guest VMCS. */
            Assert(pVmcsInfo->pbVirtApic == NULL);
            Assert(pVmcsInfo->HCPhysVirtApic == NIL_RTHCPHYS);
        }
    }

    return VINF_SUCCESS;
}


/**
 * Free all VT-x structures for the VM.
 *
 * @returns IPRT status code.
 * @param   pVM     The cross context VM structure.
 */
static void hmR0VmxStructsFree(PVMCC pVM)
{
    hmR0VmxPagesFree(&pVM->hmr0.s.vmx.hMemObj);
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    if (pVM->hmr0.s.vmx.fUseVmcsShadowing)
    {
        RTMemFree(pVM->hmr0.s.vmx.paShadowVmcsFields);
        pVM->hmr0.s.vmx.paShadowVmcsFields = NULL;
        RTMemFree(pVM->hmr0.s.vmx.paShadowVmcsRoFields);
        pVM->hmr0.s.vmx.paShadowVmcsRoFields = NULL;
    }
#endif

    for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
    {
        PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
        hmR0VmxVmcsInfoFree(&pVCpu->hmr0.s.vmx.VmcsInfo, &pVCpu->hm.s.vmx.VmcsInfo);
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        if (pVM->cpum.ro.GuestFeatures.fVmx)
            hmR0VmxVmcsInfoFree(&pVCpu->hmr0.s.vmx.VmcsInfoNstGst, &pVCpu->hm.s.vmx.VmcsInfoNstGst);
#endif
    }
}


/**
 * Allocate all VT-x structures for the VM.
 *
 * @returns IPRT status code.
 * @param   pVM     The cross context VM structure.
 *
 * @remarks This functions will cleanup on memory allocation failures.
 */
static int hmR0VmxStructsAlloc(PVMCC pVM)
{
    /*
     * Sanity check the VMCS size reported by the CPU as we assume 4KB allocations.
     * The VMCS size cannot be more than 4096 bytes.
     *
     * See Intel spec. Appendix A.1 "Basic VMX Information".
     */
    uint32_t const cbVmcs = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_SIZE);
    if (cbVmcs <= X86_PAGE_4K_SIZE)
    { /* likely */ }
    else
    {
        VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_INVALID_VMCS_SIZE;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /*
     * Allocate per-VM VT-x structures.
     */
    bool const fVirtApicAccess   = RT_BOOL(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS);
    bool const fUseVmcsShadowing = pVM->hmr0.s.vmx.fUseVmcsShadowing;
    VMXPAGEALLOCINFO aAllocInfo[] =
    {
        { fVirtApicAccess,   0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysApicAccess,    (PRTR0PTR)&pVM->hmr0.s.vmx.pbApicAccess },
        { fUseVmcsShadowing, 0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysVmreadBitmap,  &pVM->hmr0.s.vmx.pvVmreadBitmap         },
        { fUseVmcsShadowing, 0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysVmwriteBitmap, &pVM->hmr0.s.vmx.pvVmwriteBitmap        },
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
        { true,              0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysScratch,       (PRTR0PTR)&pVM->hmr0.s.vmx.pbScratch    },
#endif
    };

    int rc = hmR0VmxPagesAllocZ(&pVM->hmr0.s.vmx.hMemObj, &aAllocInfo[0], RT_ELEMENTS(aAllocInfo));
    if (RT_SUCCESS(rc))
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        /* Allocate the shadow VMCS-fields array. */
        if (fUseVmcsShadowing)
        {
            Assert(!pVM->hmr0.s.vmx.cShadowVmcsFields);
            Assert(!pVM->hmr0.s.vmx.cShadowVmcsRoFields);
            pVM->hmr0.s.vmx.paShadowVmcsFields   = (uint32_t *)RTMemAllocZ(sizeof(g_aVmcsFields));
            pVM->hmr0.s.vmx.paShadowVmcsRoFields = (uint32_t *)RTMemAllocZ(sizeof(g_aVmcsFields));
            if (!pVM->hmr0.s.vmx.paShadowVmcsFields || !pVM->hmr0.s.vmx.paShadowVmcsRoFields)
                rc = VERR_NO_MEMORY;
        }
#endif

        /*
         * Allocate per-VCPU VT-x structures.
         */
        for (VMCPUID idCpu = 0; idCpu < pVM->cCpus && RT_SUCCESS(rc); idCpu++)
        {
            /* Allocate the guest VMCS structures. */
            PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
            rc = hmR0VmxAllocVmcsInfo(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfo, false /* fIsNstGstVmcs */);

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            /* Allocate the nested-guest VMCS structures, when the VMX feature is exposed to the guest. */
            if (pVM->cpum.ro.GuestFeatures.fVmx && RT_SUCCESS(rc))
                rc = hmR0VmxAllocVmcsInfo(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfoNstGst, true /* fIsNstGstVmcs */);
#endif
        }
        if (RT_SUCCESS(rc))
            return VINF_SUCCESS;
    }
    hmR0VmxStructsFree(pVM);
    return rc;
}


/**
 * Pre-initializes non-zero fields in VMX structures that will be allocated.
 *
 * @param   pVM     The cross context VM structure.
 */
static void hmR0VmxStructsInit(PVMCC pVM)
{
    /* Paranoia. */
    Assert(pVM->hmr0.s.vmx.pbApicAccess == NULL);
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    Assert(pVM->hmr0.s.vmx.pbScratch == NULL);
#endif

    /*
     * Initialize members up-front so we can cleanup en masse on allocation failures.
     */
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    pVM->hmr0.s.vmx.HCPhysScratch       = NIL_RTHCPHYS;
#endif
    pVM->hmr0.s.vmx.HCPhysApicAccess    = NIL_RTHCPHYS;
    pVM->hmr0.s.vmx.HCPhysVmreadBitmap  = NIL_RTHCPHYS;
    pVM->hmr0.s.vmx.HCPhysVmwriteBitmap = NIL_RTHCPHYS;
    for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
    {
        PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
        hmR0VmxVmcsInfoInit(&pVCpu->hmr0.s.vmx.VmcsInfo,       &pVCpu->hm.s.vmx.VmcsInfo);
        hmR0VmxVmcsInfoInit(&pVCpu->hmr0.s.vmx.VmcsInfoNstGst, &pVCpu->hm.s.vmx.VmcsInfoNstGst);
    }
}

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Returns whether an MSR at the given MSR-bitmap offset is intercepted or not.
 *
 * @returns @c true if the MSR is intercepted, @c false otherwise.
 * @param   pbMsrBitmap     The MSR bitmap.
 * @param   offMsr          The MSR byte offset.
 * @param   iBit            The bit offset from the byte offset.
 */
DECLINLINE(bool) hmR0VmxIsMsrBitSet(uint8_t const *pbMsrBitmap, uint16_t offMsr, int32_t iBit)
{
    Assert(offMsr + (iBit >> 3) <= X86_PAGE_4K_SIZE);
    return ASMBitTest(pbMsrBitmap, (offMsr << 3) + iBit);
}
#endif

/**
 * Sets the permission bits for the specified MSR in the given MSR bitmap.
 *
 * If the passed VMCS is a nested-guest VMCS, this function ensures that the
 * read/write intercept is cleared from the MSR bitmap used for hardware-assisted
 * VMX execution of the nested-guest, only if nested-guest is also not intercepting
 * the read/write access of this MSR.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 * @param   idMsr           The MSR value.
 * @param   fMsrpm          The MSR permissions (see VMXMSRPM_XXX). This must
 *                          include both a read -and- a write permission!
 *
 * @sa      CPUMGetVmxMsrPermission.
 * @remarks Can be called with interrupts disabled.
 */
static void hmR0VmxSetMsrPermission(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs, uint32_t idMsr, uint32_t fMsrpm)
{
    uint8_t *pbMsrBitmap = (uint8_t *)pVmcsInfo->pvMsrBitmap;
    Assert(pbMsrBitmap);
    Assert(VMXMSRPM_IS_FLAG_VALID(fMsrpm));

    /*
     * MSR-bitmap Layout:
     *   Byte index            MSR range            Interpreted as
     * 0x000 - 0x3ff    0x00000000 - 0x00001fff    Low MSR read bits.
     * 0x400 - 0x7ff    0xc0000000 - 0xc0001fff    High MSR read bits.
     * 0x800 - 0xbff    0x00000000 - 0x00001fff    Low MSR write bits.
     * 0xc00 - 0xfff    0xc0000000 - 0xc0001fff    High MSR write bits.
     *
     * A bit corresponding to an MSR within the above range causes a VM-exit
     * if the bit is 1 on executions of RDMSR/WRMSR.  If an MSR falls out of
     * the MSR range, it always cause a VM-exit.
     *
     * See Intel spec. 24.6.9 "MSR-Bitmap Address".
     */
    uint16_t const offBitmapRead  = 0;
    uint16_t const offBitmapWrite = 0x800;
    uint16_t       offMsr;
    int32_t        iBit;
    if (idMsr <= UINT32_C(0x00001fff))
    {
        offMsr = 0;
        iBit   = idMsr;
    }
    else if (idMsr - UINT32_C(0xc0000000) <= UINT32_C(0x00001fff))
    {
        offMsr = 0x400;
        iBit   = idMsr - UINT32_C(0xc0000000);
    }
    else
        AssertMsgFailedReturnVoid(("Invalid MSR %#RX32\n", idMsr));

    /*
     * Set the MSR read permission.
     */
    uint16_t const offMsrRead = offBitmapRead + offMsr;
    Assert(offMsrRead + (iBit >> 3) < offBitmapWrite);
    if (fMsrpm & VMXMSRPM_ALLOW_RD)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        bool const fClear = !fIsNstGstVmcs ? true
                          : !hmR0VmxIsMsrBitSet(pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap, offMsrRead, iBit);
#else
        RT_NOREF2(pVCpu, fIsNstGstVmcs);
        bool const fClear = true;
#endif
        if (fClear)
            ASMBitClear(pbMsrBitmap, (offMsrRead << 3) + iBit);
    }
    else
        ASMBitSet(pbMsrBitmap, (offMsrRead << 3) + iBit);

    /*
     * Set the MSR write permission.
     */
    uint16_t const offMsrWrite = offBitmapWrite + offMsr;
    Assert(offMsrWrite + (iBit >> 3) < X86_PAGE_4K_SIZE);
    if (fMsrpm & VMXMSRPM_ALLOW_WR)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        bool const fClear = !fIsNstGstVmcs ? true
                          : !hmR0VmxIsMsrBitSet(pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap, offMsrWrite, iBit);
#else
        RT_NOREF2(pVCpu, fIsNstGstVmcs);
        bool const fClear = true;
#endif
        if (fClear)
            ASMBitClear(pbMsrBitmap, (offMsrWrite << 3) + iBit);
    }
    else
        ASMBitSet(pbMsrBitmap, (offMsrWrite << 3) + iBit);
}


/**
 * Updates the VMCS with the number of effective MSRs in the auto-load/store MSR
 * area.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 * @param   cMsrs       The number of MSRs.
 */
static int hmR0VmxSetAutoLoadStoreMsrCount(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, uint32_t cMsrs)
{
    /* Shouldn't ever happen but there -is- a number. We're well within the recommended 512. */
    uint32_t const cMaxSupportedMsrs = VMX_MISC_MAX_MSRS(g_HmMsrs.u.vmx.u64Misc);
    if (RT_LIKELY(cMsrs < cMaxSupportedMsrs))
    {
        /* Commit the MSR counts to the VMCS and update the cache. */
        if (pVmcsInfo->cEntryMsrLoad != cMsrs)
        {
            int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT, cMsrs);   AssertRC(rc);
            rc     = VMXWriteVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT, cMsrs);   AssertRC(rc);
            rc     = VMXWriteVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT,  cMsrs);   AssertRC(rc);
            pVmcsInfo->cEntryMsrLoad = cMsrs;
            pVmcsInfo->cExitMsrStore = cMsrs;
            pVmcsInfo->cExitMsrLoad  = cMsrs;
        }
        return VINF_SUCCESS;
    }

    LogRel(("Auto-load/store MSR count exceeded! cMsrs=%u MaxSupported=%u\n", cMsrs, cMaxSupportedMsrs));
    pVCpu->hm.s.u32HMError = VMX_UFC_INSUFFICIENT_GUEST_MSR_STORAGE;
    return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
}


/**
 * Adds a new (or updates the value of an existing) guest/host MSR
 * pair to be swapped during the world-switch as part of the
 * auto-load/store MSR area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   idMsr           The MSR.
 * @param   uGuestMsrValue  Value of the guest MSR.
 * @param   fSetReadWrite   Whether to set the guest read/write access of this
 *                          MSR (thus not causing a VM-exit).
 * @param   fUpdateHostMsr  Whether to update the value of the host MSR if
 *                          necessary.
 */
static int hmR0VmxAddAutoLoadStoreMsr(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient, uint32_t idMsr, uint64_t uGuestMsrValue,
                                      bool fSetReadWrite, bool fUpdateHostMsr)
{
    PVMXVMCSINFO  pVmcsInfo     = pVmxTransient->pVmcsInfo;
    bool const      fIsNstGstVmcs = pVmxTransient->fIsNestedGuest;
    PVMXAUTOMSR     pGuestMsrLoad = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    uint32_t        cMsrs         = pVmcsInfo->cEntryMsrLoad;
    uint32_t        i;

    /* Paranoia. */
    Assert(pGuestMsrLoad);

#ifndef DEBUG_bird
    LogFlowFunc(("pVCpu=%p idMsr=%#RX32 uGuestMsrValue=%#RX64\n", pVCpu, idMsr, uGuestMsrValue));
#endif

    /* Check if the MSR already exists in the VM-entry MSR-load area. */
    for (i = 0; i < cMsrs; i++)
    {
        if (pGuestMsrLoad[i].u32Msr == idMsr)
            break;
    }

    bool fAdded = false;
    if (i == cMsrs)
    {
        /* The MSR does not exist, bump the MSR count to make room for the new MSR. */
        ++cMsrs;
        int rc = hmR0VmxSetAutoLoadStoreMsrCount(pVCpu, pVmcsInfo, cMsrs);
        AssertMsgRCReturn(rc, ("Insufficient space to add MSR to VM-entry MSR-load/store area %u\n", idMsr), rc);

        /* Set the guest to read/write this MSR without causing VM-exits. */
        if (   fSetReadWrite
            && (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS))
            hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, fIsNstGstVmcs, idMsr, VMXMSRPM_ALLOW_RD_WR);

        Log4Func(("Added MSR %#RX32, cMsrs=%u\n", idMsr, cMsrs));
        fAdded = true;
    }

    /* Update the MSR value for the newly added or already existing MSR. */
    pGuestMsrLoad[i].u32Msr   = idMsr;
    pGuestMsrLoad[i].u64Value = uGuestMsrValue;

    /* Create the corresponding slot in the VM-exit MSR-store area if we use a different page. */
    if (hmR0VmxIsSeparateExitMsrStoreAreaVmcs(pVmcsInfo))
    {
        PVMXAUTOMSR pGuestMsrStore = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrStore;
        pGuestMsrStore[i].u32Msr   = idMsr;
        pGuestMsrStore[i].u64Value = uGuestMsrValue;
    }

    /* Update the corresponding slot in the host MSR area. */
    PVMXAUTOMSR pHostMsr = (PVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
    Assert(pHostMsr != pVmcsInfo->pvGuestMsrLoad);
    Assert(pHostMsr != pVmcsInfo->pvGuestMsrStore);
    pHostMsr[i].u32Msr = idMsr;

    /*
     * Only if the caller requests to update the host MSR value AND we've newly added the
     * MSR to the host MSR area do we actually update the value. Otherwise, it will be
     * updated by hmR0VmxUpdateAutoLoadHostMsrs().
     *
     * We do this for performance reasons since reading MSRs may be quite expensive.
     */
    if (fAdded)
    {
        if (fUpdateHostMsr)
        {
            Assert(!VMMRZCallRing3IsEnabled(pVCpu));
            Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
            pHostMsr[i].u64Value = ASMRdMsr(idMsr);
        }
        else
        {
            /* Someone else can do the work. */
            pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = false;
        }
    }
    return VINF_SUCCESS;
}


/**
 * Removes a guest/host MSR pair to be swapped during the world-switch from the
 * auto-load/store MSR area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   idMsr           The MSR.
 */
static int hmR0VmxRemoveAutoLoadStoreMsr(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient, uint32_t idMsr)
{
    PVMXVMCSINFO  pVmcsInfo     = pVmxTransient->pVmcsInfo;
    bool const      fIsNstGstVmcs = pVmxTransient->fIsNestedGuest;
    PVMXAUTOMSR     pGuestMsrLoad = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    uint32_t        cMsrs         = pVmcsInfo->cEntryMsrLoad;

#ifndef DEBUG_bird
    LogFlowFunc(("pVCpu=%p idMsr=%#RX32\n", pVCpu, idMsr));
#endif

    for (uint32_t i = 0; i < cMsrs; i++)
    {
        /* Find the MSR. */
        if (pGuestMsrLoad[i].u32Msr == idMsr)
        {
            /*
             * If it's the last MSR, we only need to reduce the MSR count.
             * If it's -not- the last MSR, copy the last MSR in place of it and reduce the MSR count.
             */
            if (i < cMsrs - 1)
            {
                /* Remove it from the VM-entry MSR-load area. */
                pGuestMsrLoad[i].u32Msr   = pGuestMsrLoad[cMsrs - 1].u32Msr;
                pGuestMsrLoad[i].u64Value = pGuestMsrLoad[cMsrs - 1].u64Value;

                /* Remove it from the VM-exit MSR-store area if it's in a different page. */
                if (hmR0VmxIsSeparateExitMsrStoreAreaVmcs(pVmcsInfo))
                {
                    PVMXAUTOMSR pGuestMsrStore = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrStore;
                    Assert(pGuestMsrStore[i].u32Msr == idMsr);
                    pGuestMsrStore[i].u32Msr   = pGuestMsrStore[cMsrs - 1].u32Msr;
                    pGuestMsrStore[i].u64Value = pGuestMsrStore[cMsrs - 1].u64Value;
                }

                /* Remove it from the VM-exit MSR-load area. */
                PVMXAUTOMSR pHostMsr = (PVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
                Assert(pHostMsr[i].u32Msr == idMsr);
                pHostMsr[i].u32Msr   = pHostMsr[cMsrs - 1].u32Msr;
                pHostMsr[i].u64Value = pHostMsr[cMsrs - 1].u64Value;
            }

            /* Reduce the count to reflect the removed MSR and bail. */
            --cMsrs;
            break;
        }
    }

    /* Update the VMCS if the count changed (meaning the MSR was found and removed). */
    if (cMsrs != pVmcsInfo->cEntryMsrLoad)
    {
        int rc = hmR0VmxSetAutoLoadStoreMsrCount(pVCpu, pVmcsInfo, cMsrs);
        AssertRCReturn(rc, rc);

        /* We're no longer swapping MSRs during the world-switch, intercept guest read/writes to them. */
        if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
            hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, fIsNstGstVmcs, idMsr, VMXMSRPM_EXIT_RD | VMXMSRPM_EXIT_WR);

        Log4Func(("Removed MSR %#RX32, cMsrs=%u\n", idMsr, cMsrs));
        return VINF_SUCCESS;
    }

    return VERR_NOT_FOUND;
}


/**
 * Updates the value of all host MSRs in the VM-exit MSR-load area.
 *
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxUpdateAutoLoadHostMsrs(PCVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
    RT_NOREF(pVCpu);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    PVMXAUTOMSR pHostMsrLoad = (PVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
    uint32_t const cMsrs     = pVmcsInfo->cExitMsrLoad;
    Assert(pHostMsrLoad);
    Assert(sizeof(*pHostMsrLoad) * cMsrs <= X86_PAGE_4K_SIZE);
    LogFlowFunc(("pVCpu=%p cMsrs=%u\n", pVCpu, cMsrs));
    for (uint32_t i = 0; i < cMsrs; i++)
    {
        /*
         * Performance hack for the host EFER MSR. We use the cached value rather than re-read it.
         * Strict builds will catch mismatches in hmR0VmxCheckAutoLoadStoreMsrs(). See @bugref{7368}.
         */
        if (pHostMsrLoad[i].u32Msr == MSR_K6_EFER)
            pHostMsrLoad[i].u64Value = g_uHmVmxHostMsrEfer;
        else
            pHostMsrLoad[i].u64Value = ASMRdMsr(pHostMsrLoad[i].u32Msr);
    }
}


/**
 * Saves a set of host MSRs to allow read/write passthru access to the guest and
 * perform lazy restoration of the host MSRs while leaving VT-x.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxLazySaveHostMsrs(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /*
     * Note: If you're adding MSRs here, make sure to update the MSR-bitmap accesses in hmR0VmxSetupVmcsProcCtls().
     */
    if (!(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_SAVED_HOST))
    {
        Assert(!(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST));  /* Guest MSRs better not be loaded now. */
        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
        {
            pVCpu->hmr0.s.vmx.u64HostMsrLStar        = ASMRdMsr(MSR_K8_LSTAR);
            pVCpu->hmr0.s.vmx.u64HostMsrStar         = ASMRdMsr(MSR_K6_STAR);
            pVCpu->hmr0.s.vmx.u64HostMsrSfMask       = ASMRdMsr(MSR_K8_SF_MASK);
            pVCpu->hmr0.s.vmx.u64HostMsrKernelGsBase = ASMRdMsr(MSR_K8_KERNEL_GS_BASE);
        }
        pVCpu->hmr0.s.vmx.fLazyMsrs |= VMX_LAZY_MSRS_SAVED_HOST;
    }
}


#ifdef VBOX_STRICT

/**
 * Verifies that our cached host EFER MSR value has not changed since we cached it.
 *
 * @param   pVmcsInfo   The VMCS info. object.
 */
static void hmR0VmxCheckHostEferMsr(PCVMXVMCSINFO pVmcsInfo)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    if (pVmcsInfo->u32ExitCtls & VMX_EXIT_CTLS_LOAD_EFER_MSR)
    {
        uint64_t const uHostEferMsr      = ASMRdMsr(MSR_K6_EFER);
        uint64_t const uHostEferMsrCache = g_uHmVmxHostMsrEfer;
        uint64_t       uVmcsEferMsrVmcs;
        int rc = VMXReadVmcs64(VMX_VMCS64_HOST_EFER_FULL, &uVmcsEferMsrVmcs);
        AssertRC(rc);

        AssertMsgReturnVoid(uHostEferMsr == uVmcsEferMsrVmcs,
                            ("EFER Host/VMCS mismatch! host=%#RX64 vmcs=%#RX64\n", uHostEferMsr, uVmcsEferMsrVmcs));
        AssertMsgReturnVoid(uHostEferMsr == uHostEferMsrCache,
                            ("EFER Host/Cache mismatch! host=%#RX64 cache=%#RX64\n", uHostEferMsr, uHostEferMsrCache));
    }
}


/**
 * Verifies whether the guest/host MSR pairs in the auto-load/store area in the
 * VMCS are correct.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 */
static void hmR0VmxCheckAutoLoadStoreMsrs(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Read the various MSR-area counts from the VMCS. */
    uint32_t cEntryLoadMsrs;
    uint32_t cExitStoreMsrs;
    uint32_t cExitLoadMsrs;
    int rc = VMXReadVmcs32(VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT, &cEntryLoadMsrs);  AssertRC(rc);
    rc     = VMXReadVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT, &cExitStoreMsrs);  AssertRC(rc);
    rc     = VMXReadVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT,  &cExitLoadMsrs);   AssertRC(rc);

    /* Verify all the MSR counts are the same. */
    Assert(cEntryLoadMsrs == cExitStoreMsrs);
    Assert(cExitStoreMsrs == cExitLoadMsrs);
    uint32_t const cMsrs = cExitLoadMsrs;

    /* Verify the MSR counts do not exceed the maximum count supported by the hardware. */
    Assert(cMsrs < VMX_MISC_MAX_MSRS(g_HmMsrs.u.vmx.u64Misc));

    /* Verify the MSR counts are within the allocated page size. */
    Assert(sizeof(VMXAUTOMSR) * cMsrs <= X86_PAGE_4K_SIZE);

    /* Verify the relevant contents of the MSR areas match. */
    PCVMXAUTOMSR pGuestMsrLoad  = (PCVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    PCVMXAUTOMSR pGuestMsrStore = (PCVMXAUTOMSR)pVmcsInfo->pvGuestMsrStore;
    PCVMXAUTOMSR pHostMsrLoad   = (PCVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
    bool const   fSeparateExitMsrStorePage = hmR0VmxIsSeparateExitMsrStoreAreaVmcs(pVmcsInfo);
    for (uint32_t i = 0; i < cMsrs; i++)
    {
        /* Verify that the MSRs are paired properly and that the host MSR has the correct value. */
        if (fSeparateExitMsrStorePage)
        {
            AssertMsgReturnVoid(pGuestMsrLoad->u32Msr == pGuestMsrStore->u32Msr,
                                ("GuestMsrLoad=%#RX32 GuestMsrStore=%#RX32 cMsrs=%u\n",
                                 pGuestMsrLoad->u32Msr, pGuestMsrStore->u32Msr, cMsrs));
        }

        AssertMsgReturnVoid(pHostMsrLoad->u32Msr == pGuestMsrLoad->u32Msr,
                            ("HostMsrLoad=%#RX32 GuestMsrLoad=%#RX32 cMsrs=%u\n",
                             pHostMsrLoad->u32Msr, pGuestMsrLoad->u32Msr, cMsrs));

        uint64_t const u64HostMsr = ASMRdMsr(pHostMsrLoad->u32Msr);
        AssertMsgReturnVoid(pHostMsrLoad->u64Value == u64HostMsr,
                            ("u32Msr=%#RX32 VMCS Value=%#RX64 ASMRdMsr=%#RX64 cMsrs=%u\n",
                             pHostMsrLoad->u32Msr, pHostMsrLoad->u64Value, u64HostMsr, cMsrs));

        /* Verify that cached host EFER MSR matches what's loaded on the CPU. */
        bool const fIsEferMsr = RT_BOOL(pHostMsrLoad->u32Msr == MSR_K6_EFER);
        AssertMsgReturnVoid(!fIsEferMsr || u64HostMsr == g_uHmVmxHostMsrEfer,
                            ("Cached=%#RX64 ASMRdMsr=%#RX64 cMsrs=%u\n", g_uHmVmxHostMsrEfer, u64HostMsr, cMsrs));

        /* Verify that the accesses are as expected in the MSR bitmap for auto-load/store MSRs. */
        if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
        {
            uint32_t const fMsrpm = CPUMGetVmxMsrPermission(pVmcsInfo->pvMsrBitmap, pGuestMsrLoad->u32Msr);
            if (fIsEferMsr)
            {
                AssertMsgReturnVoid((fMsrpm & VMXMSRPM_EXIT_RD), ("Passthru read for EFER MSR!?\n"));
                AssertMsgReturnVoid((fMsrpm & VMXMSRPM_EXIT_WR), ("Passthru write for EFER MSR!?\n"));
            }
            else
            {
                /* Verify LBR MSRs (used only for debugging) are intercepted. We don't passthru these MSRs to the guest yet. */
                PCVMCC pVM = pVCpu->CTX_SUFF(pVM);
                if (   pVM->hmr0.s.vmx.fLbr
                    && (   hmR0VmxIsLbrBranchFromMsr(pVM, pGuestMsrLoad->u32Msr, NULL /* pidxMsr */)
                        || hmR0VmxIsLbrBranchToMsr(pVM, pGuestMsrLoad->u32Msr, NULL /* pidxMsr */)
                        || pGuestMsrLoad->u32Msr == pVM->hmr0.s.vmx.idLbrTosMsr))
                {
                    AssertMsgReturnVoid((fMsrpm & VMXMSRPM_MASK) == VMXMSRPM_EXIT_RD_WR,
                                        ("u32Msr=%#RX32 cMsrs=%u Passthru read/write for LBR MSRs!\n",
                                         pGuestMsrLoad->u32Msr, cMsrs));
                }
                else if (!fIsNstGstVmcs)
                {
                    AssertMsgReturnVoid((fMsrpm & VMXMSRPM_MASK) == VMXMSRPM_ALLOW_RD_WR,
                                        ("u32Msr=%#RX32 cMsrs=%u No passthru read/write!\n", pGuestMsrLoad->u32Msr, cMsrs));
                }
                else
                {
                    /*
                     * A nested-guest VMCS must -also- allow read/write passthrough for the MSR for us to
                     * execute a nested-guest with MSR passthrough.
                     *
                     * Check if the nested-guest MSR bitmap allows passthrough, and if so, assert that we
                     * allow passthrough too.
                     */
                    void const *pvMsrBitmapNstGst = pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap;
                    Assert(pvMsrBitmapNstGst);
                    uint32_t const fMsrpmNstGst = CPUMGetVmxMsrPermission(pvMsrBitmapNstGst, pGuestMsrLoad->u32Msr);
                    AssertMsgReturnVoid(fMsrpm == fMsrpmNstGst,
                                        ("u32Msr=%#RX32 cMsrs=%u Permission mismatch fMsrpm=%#x fMsrpmNstGst=%#x!\n",
                                         pGuestMsrLoad->u32Msr, cMsrs, fMsrpm, fMsrpmNstGst));
                }
            }
        }

        /* Move to the next MSR. */
        pHostMsrLoad++;
        pGuestMsrLoad++;
        pGuestMsrStore++;
    }
}

#endif /* VBOX_STRICT */

/**
 * Flushes the TLB using EPT.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure of the calling
 *                          EMT.  Can be NULL depending on @a enmTlbFlush.
 * @param   pVmcsInfo       The VMCS info. object. Can be NULL depending on @a
 *                          enmTlbFlush.
 * @param   enmTlbFlush     Type of flush.
 *
 * @remarks Caller is responsible for making sure this function is called only
 *          when NestedPaging is supported and providing @a enmTlbFlush that is
 *          supported by the CPU.
 * @remarks Can be called with interrupts disabled.
 */
static void hmR0VmxFlushEpt(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo, VMXTLBFLUSHEPT enmTlbFlush)
{
    uint64_t au64Descriptor[2];
    if (enmTlbFlush == VMXTLBFLUSHEPT_ALL_CONTEXTS)
        au64Descriptor[0] = 0;
    else
    {
        Assert(pVCpu);
        Assert(pVmcsInfo);
        au64Descriptor[0] = pVmcsInfo->HCPhysEPTP;
    }
    au64Descriptor[1] = 0;                       /* MBZ. Intel spec. 33.3 "VMX Instructions" */

    int rc = VMXR0InvEPT(enmTlbFlush, &au64Descriptor[0]);
    AssertMsg(rc == VINF_SUCCESS, ("VMXR0InvEPT %#x %#RHp failed. rc=%Rrc\n", enmTlbFlush, au64Descriptor[0], rc));

    if (   RT_SUCCESS(rc)
        && pVCpu)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushNestedPaging);
}


/**
 * Flushes the TLB using VPID.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure of the calling
 *                          EMT.  Can be NULL depending on @a enmTlbFlush.
 * @param   enmTlbFlush     Type of flush.
 * @param   GCPtr           Virtual address of the page to flush (can be 0 depending
 *                          on @a enmTlbFlush).
 *
 * @remarks Can be called with interrupts disabled.
 */
static void hmR0VmxFlushVpid(PVMCPUCC pVCpu, VMXTLBFLUSHVPID enmTlbFlush, RTGCPTR GCPtr)
{
    Assert(pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fVpid);

    uint64_t au64Descriptor[2];
    if (enmTlbFlush == VMXTLBFLUSHVPID_ALL_CONTEXTS)
    {
        au64Descriptor[0] = 0;
        au64Descriptor[1] = 0;
    }
    else
    {
        AssertPtr(pVCpu);
        AssertMsg(pVCpu->hmr0.s.uCurrentAsid != 0, ("VMXR0InvVPID: invalid ASID %lu\n", pVCpu->hmr0.s.uCurrentAsid));
        AssertMsg(pVCpu->hmr0.s.uCurrentAsid <= UINT16_MAX, ("VMXR0InvVPID: invalid ASID %lu\n", pVCpu->hmr0.s.uCurrentAsid));
        au64Descriptor[0] = pVCpu->hmr0.s.uCurrentAsid;
        au64Descriptor[1] = GCPtr;
    }

    int rc = VMXR0InvVPID(enmTlbFlush, &au64Descriptor[0]);
    AssertMsg(rc == VINF_SUCCESS,
              ("VMXR0InvVPID %#x %u %RGv failed with %Rrc\n", enmTlbFlush, pVCpu ? pVCpu->hmr0.s.uCurrentAsid : 0, GCPtr, rc));

    if (   RT_SUCCESS(rc)
        && pVCpu)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushAsid);
    NOREF(rc);
}


/**
 * Invalidates a guest page by guest virtual address. Only relevant for EPT/VPID,
 * otherwise there is nothing really to invalidate.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   GCVirt  Guest virtual address of the page to invalidate.
 */
VMMR0DECL(int) VMXR0InvalidatePage(PVMCPUCC pVCpu, RTGCPTR GCVirt)
{
    AssertPtr(pVCpu);
    LogFlowFunc(("pVCpu=%p GCVirt=%RGv\n", pVCpu, GCVirt));

    if (!VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_TLB_FLUSH))
    {
        /*
         * We must invalidate the guest TLB entry in either case, we cannot ignore it even for
         * the EPT case. See @bugref{6043} and @bugref{6177}.
         *
         * Set the VMCPU_FF_TLB_FLUSH force flag and flush before VM-entry in hmR0VmxFlushTLB*()
         * as this function maybe called in a loop with individual addresses.
         */
        PVMCC pVM = pVCpu->CTX_SUFF(pVM);
        if (pVM->hmr0.s.vmx.fVpid)
        {
            if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_INDIV_ADDR)
            {
                hmR0VmxFlushVpid(pVCpu, VMXTLBFLUSHVPID_INDIV_ADDR, GCVirt);
                STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbInvlpgVirt);
            }
            else
                VMCPU_FF_SET(pVCpu, VMCPU_FF_TLB_FLUSH);
        }
        else if (pVM->hmr0.s.fNestedPaging)
            VMCPU_FF_SET(pVCpu, VMCPU_FF_TLB_FLUSH);
    }

    return VINF_SUCCESS;
}


/**
 * Dummy placeholder for tagged-TLB flush handling before VM-entry. Used in the
 * case where neither EPT nor VPID is supported by the CPU.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbNone(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);

    VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH);

    Assert(pHostCpu->idCpu != NIL_RTCPUID);
    pVCpu->hmr0.s.idLastCpu     = pHostCpu->idCpu;
    pVCpu->hmr0.s.cTlbFlushes   = pHostCpu->cTlbFlushes;
    pVCpu->hmr0.s.fForceTLBFlush  = false;
    return;
}


/**
 * Flushes the tagged-TLB entries for EPT+VPID CPUs as necessary.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks  All references to "ASID" in this function pertains to "VPID" in Intel's
 *           nomenclature. The reason is, to avoid confusion in compare statements
 *           since the host-CPU copies are named "ASID".
 *
 * @remarks  Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbBoth(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
#ifdef VBOX_WITH_STATISTICS
    bool fTlbFlushed = false;
# define HMVMX_SET_TAGGED_TLB_FLUSHED()       do { fTlbFlushed = true; } while (0)
# define HMVMX_UPDATE_FLUSH_SKIPPED_STAT()    do { \
                                                if (!fTlbFlushed) \
                                                    STAM_COUNTER_INC(&pVCpu->hm.s.StatNoFlushTlbWorldSwitch); \
                                              } while (0)
#else
# define HMVMX_SET_TAGGED_TLB_FLUSHED()       do { } while (0)
# define HMVMX_UPDATE_FLUSH_SKIPPED_STAT()    do { } while (0)
#endif

    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);
    Assert(pHostCpu->idCpu != NIL_RTCPUID);

    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    AssertMsg(pVM->hmr0.s.fNestedPaging && pVM->hmr0.s.vmx.fVpid,
              ("hmR0VmxFlushTaggedTlbBoth cannot be invoked unless NestedPaging & VPID are enabled."
               "fNestedPaging=%RTbool fVpid=%RTbool", pVM->hmr0.s.fNestedPaging, pVM->hmr0.s.vmx.fVpid));

    /*
     * Force a TLB flush for the first world-switch if the current CPU differs from the one we
     * ran on last. If the TLB flush count changed, another VM (VCPU rather) has hit the ASID
     * limit while flushing the TLB or the host CPU is online after a suspend/resume, so we
     * cannot reuse the current ASID anymore.
     */
    if (   pVCpu->hmr0.s.idLastCpu   != pHostCpu->idCpu
        || pVCpu->hmr0.s.cTlbFlushes != pHostCpu->cTlbFlushes)
    {
        ++pHostCpu->uCurrentAsid;
        if (pHostCpu->uCurrentAsid >= g_uHmMaxAsid)
        {
            pHostCpu->uCurrentAsid = 1;            /* Wraparound to 1; host uses 0. */
            pHostCpu->cTlbFlushes++;               /* All VCPUs that run on this host CPU must use a new VPID. */
            pHostCpu->fFlushAsidBeforeUse = true;  /* All VCPUs that run on this host CPU must flush their new VPID before use. */
        }

        pVCpu->hmr0.s.uCurrentAsid = pHostCpu->uCurrentAsid;
        pVCpu->hmr0.s.idLastCpu    = pHostCpu->idCpu;
        pVCpu->hmr0.s.cTlbFlushes  = pHostCpu->cTlbFlushes;

        /*
         * Flush by EPT when we get rescheduled to a new host CPU to ensure EPT-only tagged mappings are also
         * invalidated. We don't need to flush-by-VPID here as flushing by EPT covers it. See @bugref{6568}.
         */
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVM->hmr0.s.vmx.enmTlbFlushEpt);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbWorldSwitch);
        HMVMX_SET_TAGGED_TLB_FLUSHED();
        VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH);
    }
    else if (VMCPU_FF_TEST_AND_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH))    /* Check for explicit TLB flushes. */
    {
        /*
         * Changes to the EPT paging structure by VMM requires flushing-by-EPT as the CPU
         * creates guest-physical (ie. only EPT-tagged) mappings while traversing the EPT
         * tables when EPT is in use. Flushing-by-VPID will only flush linear (only
         * VPID-tagged) and combined (EPT+VPID tagged) mappings but not guest-physical
         * mappings, see @bugref{6568}.
         *
         * See Intel spec. 28.3.2 "Creating and Using Cached Translation Information".
         */
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVM->hmr0.s.vmx.enmTlbFlushEpt);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlb);
        HMVMX_SET_TAGGED_TLB_FLUSHED();
    }
    else if (pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb)
    {
        /*
         * The nested-guest specifies its own guest-physical address to use as the APIC-access
         * address which requires flushing the TLB of EPT cached structures.
         *
         * See Intel spec. 28.3.3.4 "Guidelines for Use of the INVEPT Instruction".
         */
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVM->hmr0.s.vmx.enmTlbFlushEpt);
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = false;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbNstGst);
        HMVMX_SET_TAGGED_TLB_FLUSHED();
    }


    pVCpu->hmr0.s.fForceTLBFlush = false;
    HMVMX_UPDATE_FLUSH_SKIPPED_STAT();

    Assert(pVCpu->hmr0.s.idLastCpu == pHostCpu->idCpu);
    Assert(pVCpu->hmr0.s.cTlbFlushes == pHostCpu->cTlbFlushes);
    AssertMsg(pVCpu->hmr0.s.cTlbFlushes == pHostCpu->cTlbFlushes,
              ("Flush count mismatch for cpu %d (%u vs %u)\n", pHostCpu->idCpu, pVCpu->hmr0.s.cTlbFlushes, pHostCpu->cTlbFlushes));
    AssertMsg(pHostCpu->uCurrentAsid >= 1 && pHostCpu->uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] uCurrentAsid=%u cTlbFlushes=%u pVCpu->idLastCpu=%u pVCpu->cTlbFlushes=%u\n", pHostCpu->idCpu,
               pHostCpu->uCurrentAsid, pHostCpu->cTlbFlushes, pVCpu->hmr0.s.idLastCpu, pVCpu->hmr0.s.cTlbFlushes));
    AssertMsg(pVCpu->hmr0.s.uCurrentAsid >= 1 && pVCpu->hmr0.s.uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] pVCpu->uCurrentAsid=%u\n", pHostCpu->idCpu, pVCpu->hmr0.s.uCurrentAsid));

    /* Update VMCS with the VPID. */
    int rc  = VMXWriteVmcs16(VMX_VMCS16_VPID, pVCpu->hmr0.s.uCurrentAsid);
    AssertRC(rc);

#undef HMVMX_SET_TAGGED_TLB_FLUSHED
}


/**
 * Flushes the tagged-TLB entries for EPT CPUs as necessary.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbEpt(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);
    Assert(pHostCpu->idCpu != NIL_RTCPUID);
    AssertMsg(pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging, ("hmR0VmxFlushTaggedTlbEpt cannot be invoked without NestedPaging."));
    AssertMsg(!pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fVpid, ("hmR0VmxFlushTaggedTlbEpt cannot be invoked with VPID."));

    /*
     * Force a TLB flush for the first world-switch if the current CPU differs from the one we ran on last.
     * A change in the TLB flush count implies the host CPU is online after a suspend/resume.
     */
    if (   pVCpu->hmr0.s.idLastCpu   != pHostCpu->idCpu
        || pVCpu->hmr0.s.cTlbFlushes != pHostCpu->cTlbFlushes)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbWorldSwitch);
    }

    /* Check for explicit TLB flushes. */
    if (VMCPU_FF_TEST_AND_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH))
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlb);
    }

    /* Check for TLB flushes while switching to/from a nested-guest. */
    if (pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = false;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbNstGst);
    }

    pVCpu->hmr0.s.idLastCpu = pHostCpu->idCpu;
    pVCpu->hmr0.s.cTlbFlushes = pHostCpu->cTlbFlushes;

    if (pVCpu->hmr0.s.fForceTLBFlush)
    {
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.enmTlbFlushEpt);
        pVCpu->hmr0.s.fForceTLBFlush = false;
    }
}


/**
 * Flushes the tagged-TLB entries for VPID CPUs as necessary.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbVpid(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);
    Assert(pHostCpu->idCpu != NIL_RTCPUID);
    AssertMsg(pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fVpid, ("hmR0VmxFlushTlbVpid cannot be invoked without VPID."));
    AssertMsg(!pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging, ("hmR0VmxFlushTlbVpid cannot be invoked with NestedPaging"));

    /*
     * Force a TLB flush for the first world switch if the current CPU differs from the one we
     * ran on last. If the TLB flush count changed, another VM (VCPU rather) has hit the ASID
     * limit while flushing the TLB or the host CPU is online after a suspend/resume, so we
     * cannot reuse the current ASID anymore.
     */
    if (   pVCpu->hmr0.s.idLastCpu != pHostCpu->idCpu
        || pVCpu->hmr0.s.cTlbFlushes != pHostCpu->cTlbFlushes)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbWorldSwitch);
    }

    /* Check for explicit TLB flushes. */
    if (VMCPU_FF_TEST_AND_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH))
    {
        /*
         * If we ever support VPID flush combinations other than ALL or SINGLE-context (see
         * hmR0VmxSetupTaggedTlb()) we would need to explicitly flush in this case (add an
         * fExplicitFlush = true here and change the pHostCpu->fFlushAsidBeforeUse check below to
         * include fExplicitFlush's too) - an obscure corner case.
         */
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlb);
    }

    /* Check for TLB flushes while switching to/from a nested-guest. */
    if (pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = false;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbNstGst);
    }

    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    pVCpu->hmr0.s.idLastCpu = pHostCpu->idCpu;
    if (pVCpu->hmr0.s.fForceTLBFlush)
    {
        ++pHostCpu->uCurrentAsid;
        if (pHostCpu->uCurrentAsid >= g_uHmMaxAsid)
        {
            pHostCpu->uCurrentAsid        = 1;     /* Wraparound to 1; host uses 0 */
            pHostCpu->cTlbFlushes++;               /* All VCPUs that run on this host CPU must use a new VPID. */
            pHostCpu->fFlushAsidBeforeUse = true;  /* All VCPUs that run on this host CPU must flush their new VPID before use. */
        }

        pVCpu->hmr0.s.fForceTLBFlush = false;
        pVCpu->hmr0.s.cTlbFlushes    = pHostCpu->cTlbFlushes;
        pVCpu->hmr0.s.uCurrentAsid   = pHostCpu->uCurrentAsid;
        if (pHostCpu->fFlushAsidBeforeUse)
        {
            if (pVM->hmr0.s.vmx.enmTlbFlushVpid == VMXTLBFLUSHVPID_SINGLE_CONTEXT)
                hmR0VmxFlushVpid(pVCpu, VMXTLBFLUSHVPID_SINGLE_CONTEXT, 0 /* GCPtr */);
            else if (pVM->hmr0.s.vmx.enmTlbFlushVpid == VMXTLBFLUSHVPID_ALL_CONTEXTS)
            {
                hmR0VmxFlushVpid(pVCpu, VMXTLBFLUSHVPID_ALL_CONTEXTS, 0 /* GCPtr */);
                pHostCpu->fFlushAsidBeforeUse = false;
            }
            else
            {
                /* hmR0VmxSetupTaggedTlb() ensures we never get here. Paranoia. */
                AssertMsgFailed(("Unsupported VPID-flush context type.\n"));
            }
        }
    }

    AssertMsg(pVCpu->hmr0.s.cTlbFlushes == pHostCpu->cTlbFlushes,
              ("Flush count mismatch for cpu %d (%u vs %u)\n", pHostCpu->idCpu, pVCpu->hmr0.s.cTlbFlushes, pHostCpu->cTlbFlushes));
    AssertMsg(pHostCpu->uCurrentAsid >= 1 && pHostCpu->uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] uCurrentAsid=%u cTlbFlushes=%u pVCpu->idLastCpu=%u pVCpu->cTlbFlushes=%u\n", pHostCpu->idCpu,
               pHostCpu->uCurrentAsid, pHostCpu->cTlbFlushes, pVCpu->hmr0.s.idLastCpu, pVCpu->hmr0.s.cTlbFlushes));
    AssertMsg(pVCpu->hmr0.s.uCurrentAsid >= 1 && pVCpu->hmr0.s.uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] pVCpu->uCurrentAsid=%u\n", pHostCpu->idCpu, pVCpu->hmr0.s.uCurrentAsid));

    int rc  = VMXWriteVmcs16(VMX_VMCS16_VPID, pVCpu->hmr0.s.uCurrentAsid);
    AssertRC(rc);
}


/**
 * Flushes the guest TLB entry based on CPU capabilities.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlb(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
#ifdef HMVMX_ALWAYS_FLUSH_TLB
    VMCPU_FF_SET(pVCpu, VMCPU_FF_TLB_FLUSH);
#endif
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    switch (pVM->hmr0.s.vmx.enmTlbFlushType)
    {
        case VMXTLBFLUSHTYPE_EPT_VPID: hmR0VmxFlushTaggedTlbBoth(pHostCpu, pVCpu, pVmcsInfo); break;
        case VMXTLBFLUSHTYPE_EPT:      hmR0VmxFlushTaggedTlbEpt(pHostCpu, pVCpu, pVmcsInfo);  break;
        case VMXTLBFLUSHTYPE_VPID:     hmR0VmxFlushTaggedTlbVpid(pHostCpu, pVCpu);            break;
        case VMXTLBFLUSHTYPE_NONE:     hmR0VmxFlushTaggedTlbNone(pHostCpu, pVCpu);            break;
        default:
            AssertMsgFailed(("Invalid flush-tag function identifier\n"));
            break;
    }
    /* Don't assert that VMCPU_FF_TLB_FLUSH should no longer be pending. It can be set by other EMTs. */
}


/**
 * Sets up the appropriate tagged TLB-flush level and handler for flushing guest
 * TLB entries from the host TLB before VM-entry.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
static int hmR0VmxSetupTaggedTlb(PVMCC pVM)
{
    /*
     * Determine optimal flush type for nested paging.
     * We cannot ignore EPT if no suitable flush-types is supported by the CPU as we've already setup
     * unrestricted guest execution (see hmR3InitFinalizeR0()).
     */
    if (pVM->hmr0.s.fNestedPaging)
    {
        if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT)
        {
            if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT_SINGLE_CONTEXT)
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_SINGLE_CONTEXT;
            else if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT_ALL_CONTEXTS)
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_ALL_CONTEXTS;
            else
            {
                /* Shouldn't happen. EPT is supported but no suitable flush-types supported. */
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
                VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_FLUSH_TYPE_UNSUPPORTED;
                return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
            }

            /* Make sure the write-back cacheable memory type for EPT is supported. */
            if (RT_UNLIKELY(!(g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_MEMTYPE_WB)))
            {
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
                VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_MEM_TYPE_NOT_WB;
                return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
            }

            /* EPT requires a page-walk length of 4. */
            if (RT_UNLIKELY(!(g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_PAGE_WALK_LENGTH_4)))
            {
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
                VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_PAGE_WALK_LENGTH_UNSUPPORTED;
                return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
            }
        }
        else
        {
            /* Shouldn't happen. EPT is supported but INVEPT instruction is not supported. */
            pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
            VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_INVEPT_UNAVAILABLE;
            return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
        }
    }

    /*
     * Determine optimal flush type for VPID.
     */
    if (pVM->hmr0.s.vmx.fVpid)
    {
        if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID)
        {
            if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_SINGLE_CONTEXT)
                pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_SINGLE_CONTEXT;
            else if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_ALL_CONTEXTS)
                pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_ALL_CONTEXTS;
            else
            {
                /* Neither SINGLE nor ALL-context flush types for VPID is supported by the CPU. Ignore VPID capability. */
                if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_INDIV_ADDR)
                    LogRelFunc(("Only INDIV_ADDR supported. Ignoring VPID.\n"));
                if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_SINGLE_CONTEXT_RETAIN_GLOBALS)
                    LogRelFunc(("Only SINGLE_CONTEXT_RETAIN_GLOBALS supported. Ignoring VPID.\n"));
                pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_NOT_SUPPORTED;
                pVM->hmr0.s.vmx.fVpid           = false;
            }
        }
        else
        {
            /*  Shouldn't happen. VPID is supported but INVVPID is not supported by the CPU. Ignore VPID capability. */
            Log4Func(("VPID supported without INVEPT support. Ignoring VPID.\n"));
            pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_NOT_SUPPORTED;
            pVM->hmr0.s.vmx.fVpid           = false;
        }
    }

    /*
     * Setup the handler for flushing tagged-TLBs.
     */
    if (pVM->hmr0.s.fNestedPaging && pVM->hmr0.s.vmx.fVpid)
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_EPT_VPID;
    else if (pVM->hmr0.s.fNestedPaging)
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_EPT;
    else if (pVM->hmr0.s.vmx.fVpid)
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_VPID;
    else
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_NONE;


    /*
     * Copy out the result to ring-3.
     */
    pVM->hm.s.ForR3.vmx.fVpid           = pVM->hmr0.s.vmx.fVpid;
    pVM->hm.s.ForR3.vmx.enmTlbFlushType = pVM->hmr0.s.vmx.enmTlbFlushType;
    pVM->hm.s.ForR3.vmx.enmTlbFlushEpt  = pVM->hmr0.s.vmx.enmTlbFlushEpt;
    pVM->hm.s.ForR3.vmx.enmTlbFlushVpid = pVM->hmr0.s.vmx.enmTlbFlushVpid;
    return VINF_SUCCESS;
}


/**
 * Sets up the LBR MSR ranges based on the host CPU.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 *
 * @sa nemR3DarwinSetupLbrMsrRange
 */
static int hmR0VmxSetupLbrMsrRange(PVMCC pVM)
{
    Assert(pVM->hmr0.s.vmx.fLbr);
    uint32_t idLbrFromIpMsrFirst;
    uint32_t idLbrFromIpMsrLast;
    uint32_t idLbrToIpMsrFirst;
    uint32_t idLbrToIpMsrLast;
    uint32_t idLbrTosMsr;

    /*
     * Determine the LBR MSRs supported for this host CPU family and model.
     *
     * See Intel spec. 17.4.8 "LBR Stack".
     * See Intel "Model-Specific Registers" spec.
     */
    uint32_t const uFamilyModel = (g_CpumHostFeatures.s.uFamily << 8)
                                | g_CpumHostFeatures.s.uModel;
    switch (uFamilyModel)
    {
        case 0x0f01: case 0x0f02:
            idLbrFromIpMsrFirst = MSR_P4_LASTBRANCH_0;
            idLbrFromIpMsrLast  = MSR_P4_LASTBRANCH_3;
            idLbrToIpMsrFirst   = 0x0;
            idLbrToIpMsrLast    = 0x0;
            idLbrTosMsr         = MSR_P4_LASTBRANCH_TOS;
            break;

        case 0x065c: case 0x065f: case 0x064e: case 0x065e: case 0x068e:
        case 0x069e: case 0x0655: case 0x0666: case 0x067a: case 0x0667:
        case 0x066a: case 0x066c: case 0x067d: case 0x067e:
            idLbrFromIpMsrFirst = MSR_LASTBRANCH_0_FROM_IP;
            idLbrFromIpMsrLast  = MSR_LASTBRANCH_31_FROM_IP;
            idLbrToIpMsrFirst   = MSR_LASTBRANCH_0_TO_IP;
            idLbrToIpMsrLast    = MSR_LASTBRANCH_31_TO_IP;
            idLbrTosMsr         = MSR_LASTBRANCH_TOS;
            break;

        case 0x063d: case 0x0647: case 0x064f: case 0x0656: case 0x063c:
        case 0x0645: case 0x0646: case 0x063f: case 0x062a: case 0x062d:
        case 0x063a: case 0x063e: case 0x061a: case 0x061e: case 0x061f:
        case 0x062e: case 0x0625: case 0x062c: case 0x062f:
            idLbrFromIpMsrFirst = MSR_LASTBRANCH_0_FROM_IP;
            idLbrFromIpMsrLast  = MSR_LASTBRANCH_15_FROM_IP;
            idLbrToIpMsrFirst   = MSR_LASTBRANCH_0_TO_IP;
            idLbrToIpMsrLast    = MSR_LASTBRANCH_15_TO_IP;
            idLbrTosMsr         = MSR_LASTBRANCH_TOS;
            break;

        case 0x0617: case 0x061d: case 0x060f:
            idLbrFromIpMsrFirst = MSR_CORE2_LASTBRANCH_0_FROM_IP;
            idLbrFromIpMsrLast  = MSR_CORE2_LASTBRANCH_3_FROM_IP;
            idLbrToIpMsrFirst   = MSR_CORE2_LASTBRANCH_0_TO_IP;
            idLbrToIpMsrLast    = MSR_CORE2_LASTBRANCH_3_TO_IP;
            idLbrTosMsr         = MSR_CORE2_LASTBRANCH_TOS;
            break;

        /* Atom and related microarchitectures we don't care about:
        case 0x0637: case 0x064a: case 0x064c: case 0x064d: case 0x065a:
        case 0x065d: case 0x061c: case 0x0626: case 0x0627: case 0x0635:
        case 0x0636: */
        /* All other CPUs: */
        default:
        {
            LogRelFunc(("Could not determine LBR stack size for the CPU model %#x\n", uFamilyModel));
            VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_LBR_STACK_SIZE_UNKNOWN;
            return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
        }
    }

    /*
     * Validate.
     */
    uint32_t const cLbrStack = idLbrFromIpMsrLast - idLbrFromIpMsrFirst + 1;
    PCVMCPU pVCpu0 = VMCC_GET_CPU_0(pVM);
    AssertCompile(   RT_ELEMENTS(pVCpu0->hm.s.vmx.VmcsInfo.au64LbrFromIpMsr)
                  == RT_ELEMENTS(pVCpu0->hm.s.vmx.VmcsInfo.au64LbrToIpMsr));
    if (cLbrStack > RT_ELEMENTS(pVCpu0->hm.s.vmx.VmcsInfo.au64LbrFromIpMsr))
    {
        LogRelFunc(("LBR stack size of the CPU (%u) exceeds our buffer size\n", cLbrStack));
        VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_LBR_STACK_SIZE_OVERFLOW;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }
    NOREF(pVCpu0);

    /*
     * Update the LBR info. to the VM struct. for use later.
     */
    pVM->hmr0.s.vmx.idLbrTosMsr = idLbrTosMsr;

    pVM->hm.s.ForR3.vmx.idLbrFromIpMsrFirst = pVM->hmr0.s.vmx.idLbrFromIpMsrFirst = idLbrFromIpMsrFirst;
    pVM->hm.s.ForR3.vmx.idLbrFromIpMsrLast  = pVM->hmr0.s.vmx.idLbrFromIpMsrLast  = idLbrFromIpMsrLast;

    pVM->hm.s.ForR3.vmx.idLbrToIpMsrFirst   = pVM->hmr0.s.vmx.idLbrToIpMsrFirst   = idLbrToIpMsrFirst;
    pVM->hm.s.ForR3.vmx.idLbrToIpMsrLast    = pVM->hmr0.s.vmx.idLbrToIpMsrLast    = idLbrToIpMsrLast;
    return VINF_SUCCESS;
}

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX

/**
 * Sets up the shadow VMCS fields arrays.
 *
 * This function builds arrays of VMCS fields to sync the shadow VMCS later while
 * executing the guest.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
static int hmR0VmxSetupShadowVmcsFieldsArrays(PVMCC pVM)
{
    /*
     * Paranoia. Ensure we haven't exposed the VMWRITE-All VMX feature to the guest
     * when the host does not support it.
     */
    bool const fGstVmwriteAll = pVM->cpum.ro.GuestFeatures.fVmxVmwriteAll;
    if (   !fGstVmwriteAll
        || (g_HmMsrs.u.vmx.u64Misc & VMX_MISC_VMWRITE_ALL))
    { /* likely. */ }
    else
    {
        LogRelFunc(("VMX VMWRITE-All feature exposed to the guest but host CPU does not support it!\n"));
        VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_GST_HOST_VMWRITE_ALL;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    uint32_t const cVmcsFields = RT_ELEMENTS(g_aVmcsFields);
    uint32_t       cRwFields   = 0;
    uint32_t       cRoFields   = 0;
    for (uint32_t i = 0; i < cVmcsFields; i++)
    {
        VMXVMCSFIELD VmcsField;
        VmcsField.u = g_aVmcsFields[i];

        /*
         * We will be writing "FULL" (64-bit) fields while syncing the shadow VMCS.
         * Therefore, "HIGH" (32-bit portion of 64-bit) fields must not be included
         * in the shadow VMCS fields array as they would be redundant.
         *
         * If the VMCS field depends on a CPU feature that is not exposed to the guest,
         * we must not include it in the shadow VMCS fields array. Guests attempting to
         * VMREAD/VMWRITE such VMCS fields would cause a VM-exit and we shall emulate
         * the required behavior.
         */
        if (   VmcsField.n.fAccessType == VMX_VMCSFIELD_ACCESS_FULL
            && CPUMIsGuestVmxVmcsFieldValid(pVM, VmcsField.u))
        {
            /*
             * Read-only fields are placed in a separate array so that while syncing shadow
             * VMCS fields later (which is more performance critical) we can avoid branches.
             *
             * However, if the guest can write to all fields (including read-only fields),
             * we treat it a as read/write field. Otherwise, writing to these fields would
             * cause a VMWRITE instruction error while syncing the shadow VMCS.
             */
            if (   fGstVmwriteAll
                || !VMXIsVmcsFieldReadOnly(VmcsField.u))
                pVM->hmr0.s.vmx.paShadowVmcsFields[cRwFields++] = VmcsField.u;
            else
                pVM->hmr0.s.vmx.paShadowVmcsRoFields[cRoFields++] = VmcsField.u;
        }
    }

    /* Update the counts. */
    pVM->hmr0.s.vmx.cShadowVmcsFields   = cRwFields;
    pVM->hmr0.s.vmx.cShadowVmcsRoFields = cRoFields;
    return VINF_SUCCESS;
}


/**
 * Sets up the VMREAD and VMWRITE bitmaps.
 *
 * @param   pVM     The cross context VM structure.
 */
static void hmR0VmxSetupVmreadVmwriteBitmaps(PVMCC pVM)
{
    /*
     * By default, ensure guest attempts to access any VMCS fields cause VM-exits.
     */
    uint32_t const cbBitmap        = X86_PAGE_4K_SIZE;
    uint8_t       *pbVmreadBitmap  = (uint8_t *)pVM->hmr0.s.vmx.pvVmreadBitmap;
    uint8_t       *pbVmwriteBitmap = (uint8_t *)pVM->hmr0.s.vmx.pvVmwriteBitmap;
    ASMMemFill32(pbVmreadBitmap,  cbBitmap, UINT32_C(0xffffffff));
    ASMMemFill32(pbVmwriteBitmap, cbBitmap, UINT32_C(0xffffffff));

    /*
     * Skip intercepting VMREAD/VMWRITE to guest read/write fields in the
     * VMREAD and VMWRITE bitmaps.
     */
    {
        uint32_t const *paShadowVmcsFields = pVM->hmr0.s.vmx.paShadowVmcsFields;
        uint32_t const  cShadowVmcsFields  = pVM->hmr0.s.vmx.cShadowVmcsFields;
        for (uint32_t i = 0; i < cShadowVmcsFields; i++)
        {
            uint32_t const uVmcsField = paShadowVmcsFields[i];
            Assert(!(uVmcsField & VMX_VMCSFIELD_RSVD_MASK));
            Assert(uVmcsField >> 3 < cbBitmap);
            ASMBitClear(pbVmreadBitmap,  uVmcsField & 0x7fff);
            ASMBitClear(pbVmwriteBitmap, uVmcsField & 0x7fff);
        }
    }

    /*
     * Skip intercepting VMREAD for guest read-only fields in the VMREAD bitmap
     * if the host supports VMWRITE to all supported VMCS fields.
     */
    if (g_HmMsrs.u.vmx.u64Misc & VMX_MISC_VMWRITE_ALL)
    {
        uint32_t const *paShadowVmcsRoFields = pVM->hmr0.s.vmx.paShadowVmcsRoFields;
        uint32_t const  cShadowVmcsRoFields  = pVM->hmr0.s.vmx.cShadowVmcsRoFields;
        for (uint32_t i = 0; i < cShadowVmcsRoFields; i++)
        {
            uint32_t const uVmcsField = paShadowVmcsRoFields[i];
            Assert(!(uVmcsField & VMX_VMCSFIELD_RSVD_MASK));
            Assert(uVmcsField >> 3 < cbBitmap);
            ASMBitClear(pbVmreadBitmap, uVmcsField & 0x7fff);
        }
    }
}

#endif /* VBOX_WITH_NESTED_HWVIRT_VMX */

/**
 * Sets up the virtual-APIC page address for the VMCS.
 *
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECLINLINE(void) hmR0VmxSetupVmcsVirtApicAddr(PCVMXVMCSINFO pVmcsInfo)
{
    RTHCPHYS const HCPhysVirtApic = pVmcsInfo->HCPhysVirtApic;
    Assert(HCPhysVirtApic != NIL_RTHCPHYS);
    Assert(!(HCPhysVirtApic & 0xfff));                       /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_VIRT_APIC_PAGEADDR_FULL, HCPhysVirtApic);
    AssertRC(rc);
}


/**
 * Sets up the MSR-bitmap address for the VMCS.
 *
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECLINLINE(void) hmR0VmxSetupVmcsMsrBitmapAddr(PCVMXVMCSINFO pVmcsInfo)
{
    RTHCPHYS const HCPhysMsrBitmap = pVmcsInfo->HCPhysMsrBitmap;
    Assert(HCPhysMsrBitmap != NIL_RTHCPHYS);
    Assert(!(HCPhysMsrBitmap & 0xfff));                      /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_MSR_BITMAP_FULL, HCPhysMsrBitmap);
    AssertRC(rc);
}


/**
 * Sets up the APIC-access page address for the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 */
DECLINLINE(void) hmR0VmxSetupVmcsApicAccessAddr(PVMCPUCC pVCpu)
{
    RTHCPHYS const HCPhysApicAccess = pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.HCPhysApicAccess;
    Assert(HCPhysApicAccess != NIL_RTHCPHYS);
    Assert(!(HCPhysApicAccess & 0xfff));                     /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_APIC_ACCESSADDR_FULL, HCPhysApicAccess);
    AssertRC(rc);
}

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX

/**
 * Sets up the VMREAD bitmap address for the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 */
DECLINLINE(void) hmR0VmxSetupVmcsVmreadBitmapAddr(PVMCPUCC pVCpu)
{
    RTHCPHYS const HCPhysVmreadBitmap = pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.HCPhysVmreadBitmap;
    Assert(HCPhysVmreadBitmap != NIL_RTHCPHYS);
    Assert(!(HCPhysVmreadBitmap & 0xfff));                     /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_VMREAD_BITMAP_FULL, HCPhysVmreadBitmap);
    AssertRC(rc);
}


/**
 * Sets up the VMWRITE bitmap address for the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 */
DECLINLINE(void) hmR0VmxSetupVmcsVmwriteBitmapAddr(PVMCPUCC pVCpu)
{
    RTHCPHYS const HCPhysVmwriteBitmap = pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.HCPhysVmwriteBitmap;
    Assert(HCPhysVmwriteBitmap != NIL_RTHCPHYS);
    Assert(!(HCPhysVmwriteBitmap & 0xfff));                     /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_VMWRITE_BITMAP_FULL, HCPhysVmwriteBitmap);
    AssertRC(rc);
}

#endif

/**
 * Sets up the VM-entry MSR load, VM-exit MSR-store and VM-exit MSR-load addresses
 * in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECLINLINE(int) hmR0VmxSetupVmcsAutoLoadStoreMsrAddrs(PVMXVMCSINFO pVmcsInfo)
{
    RTHCPHYS const HCPhysGuestMsrLoad = pVmcsInfo->HCPhysGuestMsrLoad;
    Assert(HCPhysGuestMsrLoad != NIL_RTHCPHYS);
    Assert(!(HCPhysGuestMsrLoad & 0xf));                     /* Bits 3:0 MBZ. */

    RTHCPHYS const HCPhysGuestMsrStore = pVmcsInfo->HCPhysGuestMsrStore;
    Assert(HCPhysGuestMsrStore != NIL_RTHCPHYS);
    Assert(!(HCPhysGuestMsrStore & 0xf));                    /* Bits 3:0 MBZ. */

    RTHCPHYS const HCPhysHostMsrLoad = pVmcsInfo->HCPhysHostMsrLoad;
    Assert(HCPhysHostMsrLoad != NIL_RTHCPHYS);
    Assert(!(HCPhysHostMsrLoad & 0xf));                      /* Bits 3:0 MBZ. */

    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_ENTRY_MSR_LOAD_FULL, HCPhysGuestMsrLoad);   AssertRC(rc);
    rc     = VMXWriteVmcs64(VMX_VMCS64_CTRL_EXIT_MSR_STORE_FULL, HCPhysGuestMsrStore);  AssertRC(rc);
    rc     = VMXWriteVmcs64(VMX_VMCS64_CTRL_EXIT_MSR_LOAD_FULL,  HCPhysHostMsrLoad);    AssertRC(rc);
    return VINF_SUCCESS;
}


/**
 * Sets up MSR permissions in the MSR bitmap of a VMCS info. object.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 */
static void hmR0VmxSetupVmcsMsrPermissions(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS);

    /*
     * By default, ensure guest attempts to access any MSR cause VM-exits.
     * This shall later be relaxed for specific MSRs as necessary.
     *
     * Note: For nested-guests, the entire bitmap will be merged prior to
     * executing the nested-guest using hardware-assisted VMX and hence there
     * is no need to perform this operation. See hmR0VmxMergeMsrBitmapNested.
     */
    Assert(pVmcsInfo->pvMsrBitmap);
    ASMMemFill32(pVmcsInfo->pvMsrBitmap, X86_PAGE_4K_SIZE, UINT32_C(0xffffffff));

    /*
     * The guest can access the following MSRs (read, write) without causing
     * VM-exits; they are loaded/stored automatically using fields in the VMCS.
     */
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SYSENTER_CS,  VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SYSENTER_ESP, VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SYSENTER_EIP, VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_GS_BASE,        VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_FS_BASE,        VMXMSRPM_ALLOW_RD_WR);

    /*
     * The IA32_PRED_CMD and IA32_FLUSH_CMD MSRs are write-only and has no state
     * associated with then. We never need to intercept access (writes need to be
     * executed without causing a VM-exit, reads will #GP fault anyway).
     *
     * The IA32_SPEC_CTRL MSR is read/write and has state. We allow the guest to
     * read/write them. We swap the guest/host MSR value using the
     * auto-load/store MSR area.
     */
    if (pVM->cpum.ro.GuestFeatures.fIbpb)
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_PRED_CMD,  VMXMSRPM_ALLOW_RD_WR);
    if (pVM->cpum.ro.GuestFeatures.fFlushCmd)
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_FLUSH_CMD, VMXMSRPM_ALLOW_RD_WR);
    if (pVM->cpum.ro.GuestFeatures.fIbrs)
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SPEC_CTRL, VMXMSRPM_ALLOW_RD_WR);

    /*
     * Allow full read/write access for the following MSRs (mandatory for VT-x)
     * required for 64-bit guests.
     */
    if (pVM->hmr0.s.fAllow64BitGuests)
    {
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_LSTAR,          VMXMSRPM_ALLOW_RD_WR);
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K6_STAR,           VMXMSRPM_ALLOW_RD_WR);
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_SF_MASK,        VMXMSRPM_ALLOW_RD_WR);
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_KERNEL_GS_BASE, VMXMSRPM_ALLOW_RD_WR);
    }

    /*
     * IA32_EFER MSR is always intercepted, see @bugref{9180#c37}.
     */
#ifdef VBOX_STRICT
    Assert(pVmcsInfo->pvMsrBitmap);
    uint32_t const fMsrpmEfer = CPUMGetVmxMsrPermission(pVmcsInfo->pvMsrBitmap, MSR_K6_EFER);
    Assert(fMsrpmEfer == VMXMSRPM_EXIT_RD_WR);
#endif
}


/**
 * Sets up pin-based VM-execution controls in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsPinCtls(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    uint32_t       fVal = g_HmMsrs.u.vmx.PinCtls.n.allowed0;      /* Bits set here must always be set. */
    uint32_t const fZap = g_HmMsrs.u.vmx.PinCtls.n.allowed1;      /* Bits cleared here must always be cleared. */

    fVal |= VMX_PIN_CTLS_EXT_INT_EXIT                        /* External interrupts cause a VM-exit. */
         |  VMX_PIN_CTLS_NMI_EXIT;                           /* Non-maskable interrupts (NMIs) cause a VM-exit. */

    if (g_HmMsrs.u.vmx.PinCtls.n.allowed1 & VMX_PIN_CTLS_VIRT_NMI)
        fVal |= VMX_PIN_CTLS_VIRT_NMI;                       /* Use virtual NMIs and virtual-NMI blocking features. */

    /* Enable the VMX-preemption timer. */
    if (pVM->hmr0.s.vmx.fUsePreemptTimer)
    {
        Assert(g_HmMsrs.u.vmx.PinCtls.n.allowed1 & VMX_PIN_CTLS_PREEMPT_TIMER);
        fVal |= VMX_PIN_CTLS_PREEMPT_TIMER;
    }

#if 0
    /* Enable posted-interrupt processing. */
    if (pVM->hm.s.fPostedIntrs)
    {
        Assert(g_HmMsrs.u.vmx.PinCtls.n.allowed1  & VMX_PIN_CTLS_POSTED_INT);
        Assert(g_HmMsrs.u.vmx.ExitCtls.n.allowed1 & VMX_EXIT_CTLS_ACK_EXT_INT);
        fVal |= VMX_PIN_CTLS_POSTED_INT;
    }
#endif

    if ((fVal & fZap) != fVal)
    {
        LogRelFunc(("Invalid pin-based VM-execution controls combo! Cpu=%#RX32 fVal=%#RX32 fZap=%#RX32\n",
                    g_HmMsrs.u.vmx.PinCtls.n.allowed0, fVal, fZap));
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PIN_EXEC;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Commit it to the VMCS and update our cache. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PIN_EXEC, fVal);
    AssertRC(rc);
    pVmcsInfo->u32PinCtls = fVal;

    return VINF_SUCCESS;
}


/**
 * Sets up secondary processor-based VM-execution controls in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsProcCtls2(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    uint32_t       fVal = g_HmMsrs.u.vmx.ProcCtls2.n.allowed0;    /* Bits set here must be set in the VMCS. */
    uint32_t const fZap = g_HmMsrs.u.vmx.ProcCtls2.n.allowed1;    /* Bits cleared here must be cleared in the VMCS. */

    /* WBINVD causes a VM-exit. */
    if (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_WBINVD_EXIT)
        fVal |= VMX_PROC_CTLS2_WBINVD_EXIT;

    /* Enable EPT (aka nested-paging). */
    if (pVM->hmr0.s.fNestedPaging)
        fVal |= VMX_PROC_CTLS2_EPT;

    /* Enable the INVPCID instruction if we expose it to the guest and is supported
       by the hardware. Without this, guest executing INVPCID would cause a #UD. */
    if (   pVM->cpum.ro.GuestFeatures.fInvpcid
        && (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_INVPCID))
        fVal |= VMX_PROC_CTLS2_INVPCID;

    /* Enable VPID. */
    if (pVM->hmr0.s.vmx.fVpid)
        fVal |= VMX_PROC_CTLS2_VPID;

    /* Enable unrestricted guest execution. */
    if (pVM->hmr0.s.vmx.fUnrestrictedGuest)
        fVal |= VMX_PROC_CTLS2_UNRESTRICTED_GUEST;

#if 0
    if (pVM->hm.s.fVirtApicRegs)
    {
        /* Enable APIC-register virtualization. */
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_APIC_REG_VIRT);
        fVal |= VMX_PROC_CTLS2_APIC_REG_VIRT;

        /* Enable virtual-interrupt delivery. */
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_INTR_DELIVERY);
        fVal |= VMX_PROC_CTLS2_VIRT_INTR_DELIVERY;
    }
#endif

    /* Virtualize-APIC accesses if supported by the CPU. The virtual-APIC page is
       where the TPR shadow resides. */
    /** @todo VIRT_X2APIC support, it's mutually exclusive with this. So must be
     *        done dynamically. */
    if (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
    {
        fVal |= VMX_PROC_CTLS2_VIRT_APIC_ACCESS;
        hmR0VmxSetupVmcsApicAccessAddr(pVCpu);
   }

    /* Enable the RDTSCP instruction if we expose it to the guest and is supported
       by the hardware. Without this, guest executing RDTSCP would cause a #UD. */
    if (   pVM->cpum.ro.GuestFeatures.fRdTscP
        && (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_RDTSCP))
        fVal |= VMX_PROC_CTLS2_RDTSCP;

    /* Enable Pause-Loop exiting. */
    if (   (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_PAUSE_LOOP_EXIT)
        && pVM->hm.s.vmx.cPleGapTicks
        && pVM->hm.s.vmx.cPleWindowTicks)
    {
        fVal |= VMX_PROC_CTLS2_PAUSE_LOOP_EXIT;

        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_GAP, pVM->hm.s.vmx.cPleGapTicks);          AssertRC(rc);
        rc     = VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_WINDOW, pVM->hm.s.vmx.cPleWindowTicks);    AssertRC(rc);
    }

    if ((fVal & fZap) != fVal)
    {
        LogRelFunc(("Invalid secondary processor-based VM-execution controls combo! cpu=%#RX32 fVal=%#RX32 fZap=%#RX32\n",
                    g_HmMsrs.u.vmx.ProcCtls2.n.allowed0, fVal, fZap));
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PROC_EXEC2;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Commit it to the VMCS and update our cache. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC2, fVal);
    AssertRC(rc);
    pVmcsInfo->u32ProcCtls2 = fVal;

    return VINF_SUCCESS;
}


/**
 * Sets up processor-based VM-execution controls in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsProcCtls(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    uint32_t       fVal = g_HmMsrs.u.vmx.ProcCtls.n.allowed0;     /* Bits set here must be set in the VMCS. */
    uint32_t const fZap = g_HmMsrs.u.vmx.ProcCtls.n.allowed1;     /* Bits cleared here must be cleared in the VMCS. */

    fVal |= VMX_PROC_CTLS_HLT_EXIT                                    /* HLT causes a VM-exit. */
         |  VMX_PROC_CTLS_USE_TSC_OFFSETTING                          /* Use TSC-offsetting. */
         |  VMX_PROC_CTLS_MOV_DR_EXIT                                 /* MOV DRx causes a VM-exit. */
         |  VMX_PROC_CTLS_UNCOND_IO_EXIT                              /* All IO instructions cause a VM-exit. */
         |  VMX_PROC_CTLS_RDPMC_EXIT                                  /* RDPMC causes a VM-exit. */
         |  VMX_PROC_CTLS_MONITOR_EXIT                                /* MONITOR causes a VM-exit. */
         |  VMX_PROC_CTLS_MWAIT_EXIT;                                 /* MWAIT causes a VM-exit. */

    /* We toggle VMX_PROC_CTLS_MOV_DR_EXIT later, check if it's not -always- needed to be set or clear. */
    if (   !(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_MOV_DR_EXIT)
        ||  (g_HmMsrs.u.vmx.ProcCtls.n.allowed0 & VMX_PROC_CTLS_MOV_DR_EXIT))
    {
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PROC_MOV_DRX_EXIT;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Without nested paging, INVLPG (also affects INVPCID) and MOV CR3 instructions should cause VM-exits. */
    if (!pVM->hmr0.s.fNestedPaging)
    {
        Assert(!pVM->hmr0.s.vmx.fUnrestrictedGuest);
        fVal |= VMX_PROC_CTLS_INVLPG_EXIT
             |  VMX_PROC_CTLS_CR3_LOAD_EXIT
             |  VMX_PROC_CTLS_CR3_STORE_EXIT;
    }

    /* Use TPR shadowing if supported by the CPU. */
    if (   PDMHasApic(pVM)
        && (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_TPR_SHADOW))
    {
        fVal |= VMX_PROC_CTLS_USE_TPR_SHADOW;                /* CR8 reads from the Virtual-APIC page. */
                                                             /* CR8 writes cause a VM-exit based on TPR threshold. */
        Assert(!(fVal & VMX_PROC_CTLS_CR8_STORE_EXIT));
        Assert(!(fVal & VMX_PROC_CTLS_CR8_LOAD_EXIT));
        hmR0VmxSetupVmcsVirtApicAddr(pVmcsInfo);
    }
    else
    {
        /* Some 32-bit CPUs do not support CR8 load/store exiting as MOV CR8 is
           invalid on 32-bit Intel CPUs. Set this control only for 64-bit guests. */
        if (pVM->hmr0.s.fAllow64BitGuests)
            fVal |= VMX_PROC_CTLS_CR8_STORE_EXIT             /* CR8 reads cause a VM-exit. */
                 |  VMX_PROC_CTLS_CR8_LOAD_EXIT;             /* CR8 writes cause a VM-exit. */
    }

    /* Use MSR-bitmaps if supported by the CPU. */
    if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_MSR_BITMAPS)
    {
        fVal |= VMX_PROC_CTLS_USE_MSR_BITMAPS;
        hmR0VmxSetupVmcsMsrBitmapAddr(pVmcsInfo);
    }

    /* Use the secondary processor-based VM-execution controls if supported by the CPU. */
    if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_SECONDARY_CTLS)
        fVal |= VMX_PROC_CTLS_USE_SECONDARY_CTLS;

    if ((fVal & fZap) != fVal)
    {
        LogRelFunc(("Invalid processor-based VM-execution controls combo! cpu=%#RX32 fVal=%#RX32 fZap=%#RX32\n",
                    g_HmMsrs.u.vmx.ProcCtls.n.allowed0, fVal, fZap));
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PROC_EXEC;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Commit it to the VMCS and update our cache. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, fVal);
    AssertRC(rc);
    pVmcsInfo->u32ProcCtls = fVal;

    /* Set up MSR permissions that don't change through the lifetime of the VM. */
    if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
        hmR0VmxSetupVmcsMsrPermissions(pVCpu, pVmcsInfo);

    /* Set up secondary processor-based VM-execution controls if the CPU supports it. */
    if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_SECONDARY_CTLS)
        return hmR0VmxSetupVmcsProcCtls2(pVCpu, pVmcsInfo);

    /* Sanity check, should not really happen. */
    if (RT_LIKELY(!pVM->hmr0.s.vmx.fUnrestrictedGuest))
    { /* likely */ }
    else
    {
        pVCpu->hm.s.u32HMError = VMX_UFC_INVALID_UX_COMBO;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Old CPUs without secondary processor-based VM-execution controls would end up here. */
    return VINF_SUCCESS;
}


/**
 * Sets up miscellaneous (everything other than Pin, Processor and secondary
 * Processor-based VM-execution) control fields in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsMiscCtls(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    if (pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fUseVmcsShadowing)
    {
        hmR0VmxSetupVmcsVmreadBitmapAddr(pVCpu);
        hmR0VmxSetupVmcsVmwriteBitmapAddr(pVCpu);
    }
#endif

    Assert(pVmcsInfo->u64VmcsLinkPtr == NIL_RTHCPHYS);
    int rc = VMXWriteVmcs64(VMX_VMCS64_GUEST_VMCS_LINK_PTR_FULL, NIL_RTHCPHYS);
    AssertRC(rc);

    rc = hmR0VmxSetupVmcsAutoLoadStoreMsrAddrs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        uint64_t const u64Cr0Mask = vmxHCGetFixedCr0Mask(pVCpu);
        uint64_t const u64Cr4Mask = vmxHCGetFixedCr4Mask(pVCpu);

        rc = VMXWriteVmcsNw(VMX_VMCS_CTRL_CR0_MASK, u64Cr0Mask);    AssertRC(rc);
        rc = VMXWriteVmcsNw(VMX_VMCS_CTRL_CR4_MASK, u64Cr4Mask);    AssertRC(rc);

        pVmcsInfo->u64Cr0Mask = u64Cr0Mask;
        pVmcsInfo->u64Cr4Mask = u64Cr4Mask;

        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fLbr)
        {
            rc = VMXWriteVmcsNw(VMX_VMCS64_GUEST_DEBUGCTL_FULL, MSR_IA32_DEBUGCTL_LBR);
            AssertRC(rc);
        }
        return VINF_SUCCESS;
    }
    else
        LogRelFunc(("Failed to initialize VMCS auto-load/store MSR addresses. rc=%Rrc\n", rc));
    return rc;
}


/**
 * Sets up the initial exception bitmap in the VMCS based on static conditions.
 *
 * We shall setup those exception intercepts that don't change during the
 * lifetime of the VM here. The rest are done dynamically while loading the
 * guest state.
 *
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static void hmR0VmxSetupVmcsXcptBitmap(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    /*
     * The following exceptions are always intercepted:
     *
     * #AC - To prevent the guest from hanging the CPU and for dealing with
     *       split-lock detecting host configs.
     * #DB - To maintain the DR6 state even when intercepting DRx reads/writes and
     *       recursive #DBs can cause a CPU hang.
     * #PF - To sync our shadow page tables when nested-paging is not used.
     */
    bool const fNestedPaging = pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging;
    uint32_t const uXcptBitmap = RT_BIT(X86_XCPT_AC)
                               | RT_BIT(X86_XCPT_DB)
                               | (fNestedPaging ? 0 : RT_BIT(X86_XCPT_PF));

    /* Commit it to the VMCS. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_EXCEPTION_BITMAP, uXcptBitmap);
    AssertRC(rc);

    /* Update our cache of the exception bitmap. */
    pVmcsInfo->u32XcptBitmap = uXcptBitmap;
}


#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Sets up the VMCS for executing a nested-guest using hardware-assisted VMX.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsCtlsNested(PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->u64VmcsLinkPtr == NIL_RTHCPHYS);
    int rc = VMXWriteVmcs64(VMX_VMCS64_GUEST_VMCS_LINK_PTR_FULL, NIL_RTHCPHYS);
    AssertRC(rc);

    rc = hmR0VmxSetupVmcsAutoLoadStoreMsrAddrs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_MSR_BITMAPS)
            hmR0VmxSetupVmcsMsrBitmapAddr(pVmcsInfo);

        /* Paranoia - We've not yet initialized these, they shall be done while merging the VMCS. */
        Assert(!pVmcsInfo->u64Cr0Mask);
        Assert(!pVmcsInfo->u64Cr4Mask);
        return VINF_SUCCESS;
    }
    LogRelFunc(("Failed to set up the VMCS link pointer in the nested-guest VMCS. rc=%Rrc\n", rc));
    return rc;
}
#endif


/**
 * Selector FNHMSVMVMRUN implementation.
 */
static DECLCALLBACK(int) hmR0VmxStartVmSelector(PVMXVMCSINFO pVmcsInfo, PVMCPUCC pVCpu, bool fResume)
{
    hmR0VmxUpdateStartVmFunction(pVCpu);
    return pVCpu->hmr0.s.vmx.pfnStartVm(pVmcsInfo, pVCpu, fResume);
}


/**
 * Sets up the VMCS for executing a guest (or nested-guest) using hardware-assisted
 * VMX.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 */
static int hmR0VmxSetupVmcs(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs)
{
    Assert(pVmcsInfo->pvVmcs);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Set the CPU specified revision identifier at the beginning of the VMCS structure. */
    *(uint32_t *)pVmcsInfo->pvVmcs = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_ID);
    const char * const pszVmcs     = fIsNstGstVmcs ? "nested-guest VMCS" : "guest VMCS";

    LogFlowFunc(("\n"));

    /*
     * Initialize the VMCS using VMCLEAR before loading the VMCS.
     * See Intel spec. 31.6 "Preparation And Launching A Virtual Machine".
     */
    int rc = hmR0VmxClearVmcs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        rc = hmR0VmxLoadVmcs(pVmcsInfo);
        if (RT_SUCCESS(rc))
        {
            /*
             * Initialize the hardware-assisted VMX execution handler for guest and nested-guest VMCS.
             * The host is always 64-bit since we no longer support 32-bit hosts.
             * Currently we have just a single handler for all guest modes as well, see @bugref{6208#c73}.
             */
            if (!fIsNstGstVmcs)
            {
                rc = hmR0VmxSetupVmcsPinCtls(pVCpu, pVmcsInfo);
                if (RT_SUCCESS(rc))
                {
                    rc = hmR0VmxSetupVmcsProcCtls(pVCpu, pVmcsInfo);
                    if (RT_SUCCESS(rc))
                    {
                        rc = hmR0VmxSetupVmcsMiscCtls(pVCpu, pVmcsInfo);
                        if (RT_SUCCESS(rc))
                        {
                            hmR0VmxSetupVmcsXcptBitmap(pVCpu, pVmcsInfo);
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
                            /*
                             * If a shadow VMCS is allocated for the VMCS info. object, initialize the
                             * VMCS revision ID and shadow VMCS indicator bit. Also, clear the VMCS
                             * making it fit for use when VMCS shadowing is later enabled.
                             */
                            if (pVmcsInfo->pvShadowVmcs)
                            {
                                VMXVMCSREVID VmcsRevId;
                                VmcsRevId.u = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_ID);
                                VmcsRevId.n.fIsShadowVmcs = 1;
                                *(uint32_t *)pVmcsInfo->pvShadowVmcs = VmcsRevId.u;
                                rc = vmxHCClearShadowVmcs(pVmcsInfo);
                                if (RT_SUCCESS(rc))
                                { /* likely */ }
                                else
                                    LogRelFunc(("Failed to initialize shadow VMCS. rc=%Rrc\n", rc));
                            }
#endif
                        }
                        else
                            LogRelFunc(("Failed to setup miscellaneous controls. rc=%Rrc\n", rc));
                    }
                    else
                        LogRelFunc(("Failed to setup processor-based VM-execution controls. rc=%Rrc\n", rc));
                }
                else
                    LogRelFunc(("Failed to setup pin-based controls. rc=%Rrc\n", rc));
            }
            else
            {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
                rc = hmR0VmxSetupVmcsCtlsNested(pVmcsInfo);
                if (RT_SUCCESS(rc))
                { /* likely */ }
                else
                    LogRelFunc(("Failed to initialize nested-guest VMCS. rc=%Rrc\n", rc));
#else
                AssertFailed();
#endif
            }
        }
        else
            LogRelFunc(("Failed to load the %s. rc=%Rrc\n", rc, pszVmcs));
    }
    else
        LogRelFunc(("Failed to clear the %s. rc=%Rrc\n", rc, pszVmcs));

    /* Sync any CPU internal VMCS data back into our VMCS in memory. */
    if (RT_SUCCESS(rc))
    {
        rc = hmR0VmxClearVmcs(pVmcsInfo);
        if (RT_SUCCESS(rc))
        { /* likely */ }
        else
            LogRelFunc(("Failed to clear the %s post setup. rc=%Rrc\n", rc, pszVmcs));
    }

    /*
     * Update the last-error record both for failures and success, so we
     * can propagate the status code back to ring-3 for diagnostics.
     */
    hmR0VmxUpdateErrorRecord(pVCpu, rc);
    NOREF(pszVmcs);
    return rc;
}


/**
 * Does global VT-x initialization (called during module initialization).
 *
 * @returns VBox status code.
 */
VMMR0DECL(int) VMXR0GlobalInit(void)
{
#ifdef HMVMX_USE_FUNCTION_TABLE
    AssertCompile(VMX_EXIT_MAX + 1 == RT_ELEMENTS(g_aVMExitHandlers));
# ifdef VBOX_STRICT
    for (unsigned i = 0; i < RT_ELEMENTS(g_aVMExitHandlers); i++)
        Assert(g_aVMExitHandlers[i].pfn);
# endif
#endif

    /*
     * For detecting whether DR6.RTM is writable or not (done in VMXR0InitVM).
     */
    RTTHREADPREEMPTSTATE Preempt = RTTHREADPREEMPTSTATE_INITIALIZER;
    RTThreadPreemptDisable(&Preempt);
    RTCCUINTXREG const fSavedDr6 = ASMGetDR6();
    ASMSetDR6(0);
    RTCCUINTXREG const fZeroDr6  = ASMGetDR6();
    ASMSetDR6(fSavedDr6);
    RTThreadPreemptRestore(&Preempt);

    g_fDr6Zeroed = fZeroDr6;

    return VINF_SUCCESS;
}


/**
 * Does global VT-x termination (called during module termination).
 */
VMMR0DECL(void) VMXR0GlobalTerm()
{
    /* Nothing to do currently. */
}


/**
 * Sets up and activates VT-x on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 * @param   pVM             The cross context VM structure.  Can be
 *                          NULL after a host resume operation.
 * @param   pvCpuPage       Pointer to the VMXON region (can be NULL if @a
 *                          fEnabledByHost is @c true).
 * @param   HCPhysCpuPage   Physical address of the VMXON region (can be 0 if
 *                          @a fEnabledByHost is @c true).
 * @param   fEnabledByHost  Set if SUPR0EnableVTx() or similar was used to
 *                          enable VT-x on the host.
 * @param   pHwvirtMsrs     Pointer to the hardware-virtualization MSRs.
 */
VMMR0DECL(int) VMXR0EnableCpu(PHMPHYSCPU pHostCpu, PVMCC pVM, void *pvCpuPage, RTHCPHYS HCPhysCpuPage, bool fEnabledByHost,
                              PCSUPHWVIRTMSRS pHwvirtMsrs)
{
    AssertPtr(pHostCpu);
    AssertPtr(pHwvirtMsrs);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Enable VT-x if it's not already enabled by the host. */
    if (!fEnabledByHost)
    {
        int rc = hmR0VmxEnterRootMode(pHostCpu, pVM, HCPhysCpuPage, pvCpuPage);
        if (RT_FAILURE(rc))
            return rc;
    }

    /*
     * Flush all EPT tagged-TLB entries (in case VirtualBox or any other hypervisor have been
     * using EPTPs) so we don't retain any stale guest-physical mappings which won't get
     * invalidated when flushing by VPID.
     */
    if (pHwvirtMsrs->u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT_ALL_CONTEXTS)
    {
        hmR0VmxFlushEpt(NULL /* pVCpu */, NULL /* pVmcsInfo */, VMXTLBFLUSHEPT_ALL_CONTEXTS);
        pHostCpu->fFlushAsidBeforeUse = false;
    }
    else
        pHostCpu->fFlushAsidBeforeUse = true;

    /* Ensure each VCPU scheduled on this CPU gets a new VPID on resume. See @bugref{6255}. */
    ++pHostCpu->cTlbFlushes;

    return VINF_SUCCESS;
}


/**
 * Deactivates VT-x on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 * @param   pvCpuPage       Pointer to the VMXON region.
 * @param   HCPhysCpuPage   Physical address of the VMXON region.
 *
 * @remarks This function should never be called when SUPR0EnableVTx() or
 *          similar was used to enable VT-x on the host.
 */
VMMR0DECL(int) VMXR0DisableCpu(PHMPHYSCPU pHostCpu, void *pvCpuPage, RTHCPHYS HCPhysCpuPage)
{
    RT_NOREF2(pvCpuPage, HCPhysCpuPage);

    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    return hmR0VmxLeaveRootMode(pHostCpu);
}


/**
 * Does per-VM VT-x initialization.
 *
 * @returns VBox status code.
 * @param   pVM             The cross context VM structure.
 */
VMMR0DECL(int) VMXR0InitVM(PVMCC pVM)
{
    AssertPtr(pVM);
    LogFlowFunc(("pVM=%p\n", pVM));

    hmR0VmxStructsInit(pVM);
    int rc = hmR0VmxStructsAlloc(pVM);
    if (RT_FAILURE(rc))
    {
        LogRelFunc(("Failed to allocated VMX structures. rc=%Rrc\n", rc));
        return rc;
    }

    /* Setup the crash dump page. */
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    strcpy((char *)pVM->hmr0.s.vmx.pbScratch, "SCRATCH Magic");
    *(uint64_t *)(pVM->hmr0.s.vmx.pbScratch + 16) = UINT64_C(0xdeadbeefdeadbeef);
#endif

    /*
     * Copy out stuff that's for ring-3 and determin default configuration.
     */
    pVM->hm.s.ForR3.vmx.u64HostDr6Zeroed = g_fDr6Zeroed;

    /* Since we do not emulate RTM, make sure DR6.RTM cannot be cleared by the
       guest and cause confusion there.  It appears that the DR6.RTM bit can be
       cleared even if TSX-NI is disabled (microcode update / system / whatever). */
#ifdef VMX_WITH_MAYBE_ALWAYS_INTERCEPT_MOV_DRX
    if (pVM->hm.s.vmx.fAlwaysInterceptMovDRxCfg == 0)
        pVM->hmr0.s.vmx.fAlwaysInterceptMovDRx = g_fDr6Zeroed != X86_DR6_RA1_MASK;
    else
#endif
        pVM->hmr0.s.vmx.fAlwaysInterceptMovDRx = pVM->hm.s.vmx.fAlwaysInterceptMovDRxCfg > 0;
    pVM->hm.s.ForR3.vmx.fAlwaysInterceptMovDRx = pVM->hmr0.s.vmx.fAlwaysInterceptMovDRx;

    return VINF_SUCCESS;
}


/**
 * Does per-VM VT-x termination.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
VMMR0DECL(int) VMXR0TermVM(PVMCC pVM)
{
    AssertPtr(pVM);
    LogFlowFunc(("pVM=%p\n", pVM));

#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    if (pVM->hmr0.s.vmx.pbScratch)
        RT_BZERO(pVM->hmr0.s.vmx.pbScratch, X86_PAGE_4K_SIZE);
#endif
    hmR0VmxStructsFree(pVM);
    return VINF_SUCCESS;
}


/**
 * Sets up the VM for execution using hardware-assisted VMX.
 * This function is only called once per-VM during initialization.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
VMMR0DECL(int) VMXR0SetupVM(PVMCC pVM)
{
    AssertPtr(pVM);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    LogFlowFunc(("pVM=%p\n", pVM));

    /*
     * At least verify if VMX is enabled, since we can't check if we're in VMX root mode or not
     * without causing a #GP.
     */
    RTCCUINTREG const uHostCr4 = ASMGetCR4();
    if (RT_LIKELY(uHostCr4 & X86_CR4_VMXE))
    { /* likely */ }
    else
        return VERR_VMX_NOT_IN_VMX_ROOT_MODE;

    /*
     * Check that nested paging is supported if enabled and copy over the flag to the
     * ring-0 only structure.
     */
    bool const fNestedPaging = pVM->hm.s.fNestedPagingCfg;
    AssertReturn(   !fNestedPaging
                 || (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_EPT), /** @todo use a ring-0 copy of ProcCtls2.n.allowed1 */
                 VERR_INCOMPATIBLE_CONFIG);
    pVM->hmr0.s.fNestedPaging = fNestedPaging;
    pVM->hmr0.s.fAllow64BitGuests = pVM->hm.s.fAllow64BitGuestsCfg;

    /*
     * Without unrestricted guest execution, pRealModeTSS and pNonPagingModeEPTPageTable *must*
     * always be allocated. We no longer support the highly unlikely case of unrestricted guest
     * without pRealModeTSS, see hmR3InitFinalizeR0Intel().
     */
    bool const fUnrestrictedGuest = pVM->hm.s.vmx.fUnrestrictedGuestCfg;
    AssertReturn(   !fUnrestrictedGuest
                || (   (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_UNRESTRICTED_GUEST)
                    && fNestedPaging),
                    VERR_INCOMPATIBLE_CONFIG);
    if (   !fUnrestrictedGuest
        &&  (   !pVM->hm.s.vmx.pNonPagingModeEPTPageTable
             || !pVM->hm.s.vmx.pRealModeTSS))
    {
        LogRelFunc(("Invalid real-on-v86 state.\n"));
        return VERR_INTERNAL_ERROR;
    }
    pVM->hmr0.s.vmx.fUnrestrictedGuest = fUnrestrictedGuest;

    /* Initialize these always, see hmR3InitFinalizeR0().*/
    pVM->hm.s.ForR3.vmx.enmTlbFlushEpt  = pVM->hmr0.s.vmx.enmTlbFlushEpt  = VMXTLBFLUSHEPT_NONE;
    pVM->hm.s.ForR3.vmx.enmTlbFlushVpid = pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_NONE;

    /* Setup the tagged-TLB flush handlers. */
    int rc = hmR0VmxSetupTaggedTlb(pVM);
    if (RT_FAILURE(rc))
    {
        LogRelFunc(("Failed to setup tagged TLB. rc=%Rrc\n", rc));
        return rc;
    }

    /* Determine LBR capabilities. */
    pVM->hmr0.s.vmx.fLbr = pVM->hm.s.vmx.fLbrCfg;
    if (pVM->hmr0.s.vmx.fLbr)
    {
        rc = hmR0VmxSetupLbrMsrRange(pVM);
        if (RT_FAILURE(rc))
        {
            LogRelFunc(("Failed to setup LBR MSR range. rc=%Rrc\n", rc));
            return rc;
        }
    }

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /* Setup the shadow VMCS fields array and VMREAD/VMWRITE bitmaps. */
    if (pVM->hmr0.s.vmx.fUseVmcsShadowing)
    {
        rc = hmR0VmxSetupShadowVmcsFieldsArrays(pVM);
        if (RT_SUCCESS(rc))
            hmR0VmxSetupVmreadVmwriteBitmaps(pVM);
        else
        {
            LogRelFunc(("Failed to setup shadow VMCS fields arrays. rc=%Rrc\n", rc));
            return rc;
        }
    }
#endif

    for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
    {
        PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
        Log4Func(("pVCpu=%p idCpu=%RU32\n", pVCpu, pVCpu->idCpu));

        pVCpu->hmr0.s.vmx.pfnStartVm = hmR0VmxStartVmSelector;

        rc = hmR0VmxSetupVmcs(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfo,  false /* fIsNstGstVmcs */);
        if (RT_SUCCESS(rc))
        {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            if (pVM->cpum.ro.GuestFeatures.fVmx)
            {
                rc = hmR0VmxSetupVmcs(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfoNstGst, true /* fIsNstGstVmcs */);
                if (RT_SUCCESS(rc))
                { /* likely */ }
                else
                {
                    LogRelFunc(("Nested-guest VMCS setup failed. rc=%Rrc\n", rc));
                    return rc;
                }
            }
#endif
        }
        else
        {
            LogRelFunc(("VMCS setup failed. rc=%Rrc\n", rc));
            return rc;
        }
    }

    return VINF_SUCCESS;
}


/**
 * Saves the host control registers (CR0, CR3, CR4) into the host-state area in
 * the VMCS.
 * @returns CR4 for passing along to hmR0VmxExportHostSegmentRegs.
 */
static uint64_t hmR0VmxExportHostControlRegs(void)
{
    int rc = VMXWriteVmcsNw(VMX_VMCS_HOST_CR0, ASMGetCR0());    AssertRC(rc);
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_CR3, ASMGetCR3());    AssertRC(rc);
    uint64_t uHostCr4 = ASMGetCR4();
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_CR4, uHostCr4);       AssertRC(rc);
    return uHostCr4;
}


/**
 * Saves the host segment registers and GDTR, IDTR, (TR, GS and FS bases) into
 * the host-state area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   uHostCr4    The host CR4 value.
 */
static int hmR0VmxExportHostSegmentRegs(PVMCPUCC pVCpu, uint64_t uHostCr4)
{
    /*
     * If we've executed guest code using hardware-assisted VMX, the host-state bits
     * will be messed up. We should -not- save the messed up state without restoring
     * the original host-state, see @bugref{7240}.
     *
     * This apparently can happen (most likely the FPU changes), deal with it rather than
     * asserting. Was observed booting Solaris 10u10 32-bit guest.
     */
    if (pVCpu->hmr0.s.vmx.fRestoreHostFlags > VMX_RESTORE_HOST_REQUIRED)
    {
        Log4Func(("Restoring Host State: fRestoreHostFlags=%#RX32 HostCpuId=%u\n", pVCpu->hmr0.s.vmx.fRestoreHostFlags,
                  pVCpu->idCpu));
        VMXRestoreHostState(pVCpu->hmr0.s.vmx.fRestoreHostFlags, &pVCpu->hmr0.s.vmx.RestoreHost);
        pVCpu->hmr0.s.vmx.fRestoreHostFlags = 0;
    }

    /*
     * Get all the host info.
     * ASSUME it is safe to use rdfsbase and friends if the CR4.FSGSBASE bit is set
     * without also checking the cpuid bit.
     */
    uint32_t fRestoreHostFlags;
#if RT_INLINE_ASM_EXTERNAL
    if (uHostCr4 & X86_CR4_FSGSBASE)
    {
        hmR0VmxExportHostSegmentRegsAsmHlp(&pVCpu->hmr0.s.vmx.RestoreHost, true /*fHaveFsGsBase*/);
        fRestoreHostFlags = VMX_RESTORE_HOST_CAN_USE_WRFSBASE_AND_WRGSBASE;
    }
    else
    {
        hmR0VmxExportHostSegmentRegsAsmHlp(&pVCpu->hmr0.s.vmx.RestoreHost, false /*fHaveFsGsBase*/);
        fRestoreHostFlags = 0;
    }
    RTSEL uSelES = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelES;
    RTSEL uSelDS = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelDS;
    RTSEL uSelFS = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelFS;
    RTSEL uSelGS = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelGS;
#else
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR = ASMGetTR();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS = ASMGetSS();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS = ASMGetCS();
    ASMGetGDTR((PRTGDTR)&pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr);
    ASMGetIDTR((PRTIDTR)&pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr);
    if (uHostCr4 & X86_CR4_FSGSBASE)
    {
        pVCpu->hmr0.s.vmx.RestoreHost.uHostFSBase = ASMGetFSBase();
        pVCpu->hmr0.s.vmx.RestoreHost.uHostGSBase = ASMGetGSBase();
        fRestoreHostFlags = VMX_RESTORE_HOST_CAN_USE_WRFSBASE_AND_WRGSBASE;
    }
    else
    {
        pVCpu->hmr0.s.vmx.RestoreHost.uHostFSBase = ASMRdMsr(MSR_K8_FS_BASE);
        pVCpu->hmr0.s.vmx.RestoreHost.uHostGSBase = ASMRdMsr(MSR_K8_GS_BASE);
        fRestoreHostFlags = 0;
    }
    RTSEL uSelES, uSelDS, uSelFS, uSelGS;
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelDS = uSelDS = ASMGetDS();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelES = uSelES = ASMGetES();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelFS = uSelFS = ASMGetFS();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelGS = uSelGS = ASMGetGS();
#endif

    /*
     * Determine if the host segment registers are suitable for VT-x. Otherwise use zero to
     * gain VM-entry and restore them before we get preempted.
     *
     * See Intel spec. 26.2.3 "Checks on Host Segment and Descriptor-Table Registers".
     */
    RTSEL const uSelAll = uSelFS | uSelGS | uSelES | uSelDS;
    if (uSelAll & (X86_SEL_RPL | X86_SEL_LDT))
    {
        if (!(uSelAll & X86_SEL_LDT))
        {
#define VMXLOCAL_ADJUST_HOST_SEG(a_Seg, a_uVmcsVar) \
                do { \
                    (a_uVmcsVar) = pVCpu->hmr0.s.vmx.RestoreHost.uHostSel##a_Seg; \
                    if ((a_uVmcsVar) & X86_SEL_RPL) \
                    { \
                        fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_##a_Seg; \
                        (a_uVmcsVar) = 0; \
                    } \
                } while (0)
            VMXLOCAL_ADJUST_HOST_SEG(DS, uSelDS);
            VMXLOCAL_ADJUST_HOST_SEG(ES, uSelES);
            VMXLOCAL_ADJUST_HOST_SEG(FS, uSelFS);
            VMXLOCAL_ADJUST_HOST_SEG(GS, uSelGS);
#undef VMXLOCAL_ADJUST_HOST_SEG
        }
        else
        {
#define VMXLOCAL_ADJUST_HOST_SEG(a_Seg, a_uVmcsVar) \
                do { \
                    (a_uVmcsVar) = pVCpu->hmr0.s.vmx.RestoreHost.uHostSel##a_Seg; \
                    if ((a_uVmcsVar) & (X86_SEL_RPL | X86_SEL_LDT)) \
                    { \
                        if (!((a_uVmcsVar) & X86_SEL_LDT)) \
                            fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_##a_Seg; \
                        else \
                        { \
                            uint32_t const fAttr = ASMGetSegAttr(a_uVmcsVar); \
                            if ((fAttr & X86_DESC_P) && fAttr != UINT32_MAX) \
                                fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_##a_Seg; \
                        } \
                        (a_uVmcsVar) = 0; \
                    } \
                } while (0)
            VMXLOCAL_ADJUST_HOST_SEG(DS, uSelDS);
            VMXLOCAL_ADJUST_HOST_SEG(ES, uSelES);
            VMXLOCAL_ADJUST_HOST_SEG(FS, uSelFS);
            VMXLOCAL_ADJUST_HOST_SEG(GS, uSelGS);
#undef VMXLOCAL_ADJUST_HOST_SEG
        }
    }

    /* Verification based on Intel spec. 26.2.3 "Checks on Host Segment and Descriptor-Table Registers"  */
    Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR & X86_SEL_RPL)); Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR & X86_SEL_LDT)); Assert(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR);
    Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS & X86_SEL_RPL)); Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS & X86_SEL_LDT)); Assert(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS);
    Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS & X86_SEL_RPL)); Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS & X86_SEL_LDT));
    Assert(!(uSelDS & X86_SEL_RPL)); Assert(!(uSelDS & X86_SEL_LDT));
    Assert(!(uSelES & X86_SEL_RPL)); Assert(!(uSelES & X86_SEL_LDT));
    Assert(!(uSelFS & X86_SEL_RPL)); Assert(!(uSelFS & X86_SEL_LDT));
    Assert(!(uSelGS & X86_SEL_RPL)); Assert(!(uSelGS & X86_SEL_LDT));

    /*
     * Determine if we need to manually need to restore the GDTR and IDTR limits as VT-x zaps
     * them to the maximum limit (0xffff) on every VM-exit.
     */
    if (pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb != 0xffff)
        fRestoreHostFlags |= VMX_RESTORE_HOST_GDTR;

    /*
     * IDT limit is effectively capped at 0xfff. (See Intel spec. 6.14.1 "64-Bit Mode IDT" and
     * Intel spec. 6.2 "Exception and Interrupt Vectors".)  Therefore if the host has the limit
     * as 0xfff, VT-x bloating the limit to 0xffff shouldn't cause any different CPU behavior.
     * However, several hosts either insists on 0xfff being the limit (Windows Patch Guard) or
     * uses the limit for other purposes (darwin puts the CPU ID in there but botches sidt
     * alignment in at least one consumer).  So, we're only allowing the IDTR.LIMIT to be left
     * at 0xffff on hosts where we are sure it won't cause trouble.
     */
#if defined(RT_OS_LINUX) || defined(RT_OS_SOLARIS)
    if (pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr.cb <  0x0fff)
#else
    if (pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr.cb != 0xffff)
#endif
        fRestoreHostFlags |= VMX_RESTORE_HOST_IDTR;

    /*
     * Host TR base. Verify that TR selector doesn't point past the GDT. Masking off the TI
     * and RPL bits is effectively what the CPU does for "scaling by 8". TI is always 0 and
     * RPL should be too in most cases.
     */
    RTSEL const uSelTR = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR;
    AssertMsgReturn((uSelTR | X86_SEL_RPL_LDT) <= pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb,
                    ("TR selector exceeds limit. TR=%RTsel cbGdt=%#x\n", uSelTR, pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb),
                    VERR_VMX_INVALID_HOST_STATE);

    PCX86DESCHC pDesc = (PCX86DESCHC)(pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.uAddr + (uSelTR & X86_SEL_MASK));
    uintptr_t const uTRBase = X86DESC64_BASE(pDesc);

    /*
     * VT-x unconditionally restores the TR limit to 0x67 and type to 11 (32-bit busy TSS) on
     * all VM-exits. The type is the same for 64-bit busy TSS[1]. The limit needs manual
     * restoration if the host has something else. Task switching is not supported in 64-bit
     * mode[2], but the limit still matters as IOPM is supported in 64-bit mode. Restoring the
     * limit lazily while returning to ring-3 is safe because IOPM is not applicable in ring-0.
     *
     * [1] See Intel spec. 3.5 "System Descriptor Types".
     * [2] See Intel spec. 7.2.3 "TSS Descriptor in 64-bit mode".
     */
    Assert(pDesc->System.u4Type == 11);
    if (   pDesc->System.u16LimitLow != 0x67
        || pDesc->System.u4LimitHigh)
    {
        fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_TR;

        /* If the host has made GDT read-only, we would need to temporarily toggle CR0.WP before writing the GDT. */
        if (g_fHmHostKernelFeatures & SUPKERNELFEATURES_GDT_READ_ONLY)
            fRestoreHostFlags |= VMX_RESTORE_HOST_GDT_READ_ONLY;
        if (g_fHmHostKernelFeatures & SUPKERNELFEATURES_GDT_NEED_WRITABLE)
        {
            /* The GDT is read-only but the writable GDT is available. */
            fRestoreHostFlags |= VMX_RESTORE_HOST_GDT_NEED_WRITABLE;
            pVCpu->hmr0.s.vmx.RestoreHost.HostGdtrRw.cb = pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb;
            int rc = SUPR0GetCurrentGdtRw(&pVCpu->hmr0.s.vmx.RestoreHost.HostGdtrRw.uAddr);
            AssertRCReturn(rc, rc);
        }
    }

    pVCpu->hmr0.s.vmx.fRestoreHostFlags = fRestoreHostFlags;

    /*
     * Do all the VMCS updates in one block to assist nested virtualization.
     */
    int rc;
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_CS_SEL,  pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS);       AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_SS_SEL,  pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS);       AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_DS_SEL,  uSelDS);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_ES_SEL,  uSelES);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_FS_SEL,  uSelFS);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_GS_SEL,  uSelGS);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_TR_SEL,  pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR);       AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_GDTR_BASE, pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.uAddr);   AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_IDTR_BASE, pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr.uAddr);   AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_TR_BASE,   uTRBase);                                        AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_FS_BASE,   pVCpu->hmr0.s.vmx.RestoreHost.uHostFSBase);      AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_GS_BASE,   pVCpu->hmr0.s.vmx.RestoreHost.uHostGSBase);      AssertRC(rc);

    return VINF_SUCCESS;
}


/**
 * Exports certain host MSRs in the VM-exit MSR-load area and some in the
 * host-state area of the VMCS.
 *
 * These MSRs will be automatically restored on the host after every successful
 * VM-exit.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxExportHostMsrs(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);

    /*
     * Save MSRs that we restore lazily (due to preemption or transition to ring-3)
     * rather than swapping them on every VM-entry.
     */
    hmR0VmxLazySaveHostMsrs(pVCpu);

    /*
     * Host Sysenter MSRs.
     */
    int rc = VMXWriteVmcs32(VMX_VMCS32_HOST_SYSENTER_CS, ASMRdMsr_Low(MSR_IA32_SYSENTER_CS));   AssertRC(rc);
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_SYSENTER_ESP,  ASMRdMsr(MSR_IA32_SYSENTER_ESP));      AssertRC(rc);
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_SYSENTER_EIP,  ASMRdMsr(MSR_IA32_SYSENTER_EIP));      AssertRC(rc);

    /*
     * Host EFER MSR.
     *
     * If the CPU supports the newer VMCS controls for managing EFER, use it. Otherwise it's
     * done as part of auto-load/store MSR area in the VMCS, see hmR0VmxExportGuestMsrs().
     */
    if (g_fHmVmxSupportsVmcsEfer)
    {
        rc = VMXWriteVmcs64(VMX_VMCS64_HOST_EFER_FULL, g_uHmVmxHostMsrEfer);
        AssertRC(rc);
    }

    /** @todo IA32_PERF_GLOBALCTRL, IA32_PAT also see
     *        hmR0VmxExportGuestEntryExitCtls(). */
}


/**
 * Figures out if we need to swap the EFER MSR which is particularly expensive.
 *
 * We check all relevant bits. For now, that's everything besides LMA/LME, as
 * these two bits are handled by VM-entry, see hmR0VMxExportGuestEntryExitCtls().
 *
 * @returns true if we need to load guest EFER, false otherwise.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks Requires EFER, CR4.
 * @remarks No-long-jump zone!!!
 */
static bool hmR0VmxShouldSwapEferMsr(PCVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
#ifdef HMVMX_ALWAYS_SWAP_EFER
    RT_NOREF2(pVCpu, pVmxTransient);
    return true;
#else
    PCCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
    uint64_t const u64HostEfer  = g_uHmVmxHostMsrEfer;
    uint64_t const u64GuestEfer = pCtx->msrEFER;

# ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * For nested-guests, we shall honor swapping the EFER MSR when requested by
     * the nested-guest.
     */
    if (   pVmxTransient->fIsNestedGuest
        && (   CPUMIsGuestVmxEntryCtlsSet(pCtx, VMX_ENTRY_CTLS_LOAD_EFER_MSR)
            || CPUMIsGuestVmxExitCtlsSet(pCtx, VMX_EXIT_CTLS_SAVE_EFER_MSR)
            || CPUMIsGuestVmxExitCtlsSet(pCtx, VMX_EXIT_CTLS_LOAD_EFER_MSR)))
        return true;
# else
    RT_NOREF(pVmxTransient);
#endif

    /*
     * For 64-bit guests, if EFER.SCE bit differs, we need to swap the EFER MSR
     * to ensure that the guest's SYSCALL behaviour isn't broken, see @bugref{7386}.
     */
    if (   CPUMIsGuestInLongModeEx(pCtx)
        && (u64GuestEfer & MSR_K6_EFER_SCE) != (u64HostEfer & MSR_K6_EFER_SCE))
        return true;

    /*
     * If the guest uses PAE and EFER.NXE bit differs, we need to swap the EFER MSR
     * as it affects guest paging. 64-bit paging implies CR4.PAE as well.
     *
     * See Intel spec. 4.5 "IA-32e Paging".
     * See Intel spec. 4.1.1 "Three Paging Modes".
     *
     * Verify that we always intercept CR4.PAE and CR0.PG bits, so we don't need to
     * import CR4 and CR0 from the VMCS here as those bits are always up to date.
     */
    Assert(vmxHCGetFixedCr4Mask(pVCpu) & X86_CR4_PAE);
    Assert(vmxHCGetFixedCr0Mask(pVCpu) & X86_CR0_PG);
    if (   (pCtx->cr4 & X86_CR4_PAE)
        && (pCtx->cr0 & X86_CR0_PG))
    {
        /*
         * If nested paging is not used, verify that the guest paging mode matches the
         * shadow paging mode which is/will be placed in the VMCS (which is what will
         * actually be used while executing the guest and not the CR4 shadow value).
         */
        AssertMsg(   pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_PAE
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_PAE_NX
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_AMD64
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_AMD64_NX,
                  ("enmShadowMode=%u\n", pVCpu->hm.s.enmShadowMode));
        if ((u64GuestEfer & MSR_K6_EFER_NXE) != (u64HostEfer & MSR_K6_EFER_NXE))
        {
            /* Verify that the host is NX capable. */
            Assert(g_CpumHostFeatures.s.fNoExecute);
            return true;
        }
    }

    return false;
#endif
}


/**
 * Exports the guest's RSP into the guest-state area in the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxExportGuestRsp(PVMCPUCC pVCpu)
{
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_RSP)
    {
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_RSP);

        int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_RSP, pVCpu->cpum.GstCtx.rsp);
        AssertRC(rc);

        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_RSP);
        Log4Func(("rsp=%#RX64\n", pVCpu->cpum.GstCtx.rsp));
    }
}


/**
 * Exports the guest hardware-virtualization state.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportGuestHwvirtState(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_HWVIRT)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        /*
         * Check if the VMX feature is exposed to the guest and if the host CPU supports
         * VMCS shadowing.
         */
        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fUseVmcsShadowing)
        {
            /*
             * If the nested hypervisor has loaded a current VMCS and is in VMX root mode,
             * copy the nested hypervisor's current VMCS into the shadow VMCS and enable
             * VMCS shadowing to skip intercepting some or all VMREAD/VMWRITE VM-exits.
             *
             * We check for VMX root mode here in case the guest executes VMXOFF without
             * clearing the current VMCS pointer and our VMXOFF instruction emulation does
             * not clear the current VMCS pointer.
             */
            PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
            if (   CPUMIsGuestInVmxRootMode(&pVCpu->cpum.GstCtx)
                && !CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx)
                && CPUMIsGuestVmxCurrentVmcsValid(&pVCpu->cpum.GstCtx))
            {
                /* Paranoia. */
                Assert(!pVmxTransient->fIsNestedGuest);

                /*
                 * For performance reasons, also check if the nested hypervisor's current VMCS
                 * was newly loaded or modified before copying it to the shadow VMCS.
                 */
                if (!pVCpu->hm.s.vmx.fCopiedNstGstToShadowVmcs)
                {
                    int rc = vmxHCCopyNstGstToShadowVmcs(pVCpu, pVmcsInfo);
                    AssertRCReturn(rc, rc);
                    pVCpu->hm.s.vmx.fCopiedNstGstToShadowVmcs = true;
                }
                vmxHCEnableVmcsShadowing(pVCpu, pVmcsInfo);
            }
            else
                vmxHCDisableVmcsShadowing(pVCpu, pVmcsInfo);
        }
#else
        NOREF(pVmxTransient);
#endif
        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_HWVIRT);
    }
    return VINF_SUCCESS;
}


/**
 * Exports the guest debug registers into the guest-state area in the VMCS.
 * The guest debug bits are partially shared with the host (e.g. DR6, DR0-3).
 *
 * This also sets up whether \#DB and MOV DRx accesses cause VM-exits.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportSharedDebugState(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /** @todo NSTVMX: Figure out what we want to do with nested-guest instruction
     *        stepping. */
    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if (pVmxTransient->fIsNestedGuest)
    {
        int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_DR7, CPUMGetGuestDR7(pVCpu));
        AssertRC(rc);

        /*
         * We don't want to always intercept MOV DRx for nested-guests as it causes
         * problems when the nested hypervisor isn't intercepting them, see @bugref{10080}.
         * Instead, they are strictly only requested when the nested hypervisor intercepts
         * them -- handled while merging VMCS controls.
         *
         * If neither the outer nor the nested-hypervisor is intercepting MOV DRx,
         * then the nested-guest debug state should be actively loaded on the host so that
         * nested-guest reads its own debug registers without causing VM-exits.
         */
        if (   !(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_MOV_DR_EXIT)
            && !CPUMIsGuestDebugStateActive(pVCpu))
            CPUMR0LoadGuestDebugState(pVCpu, true /* include DR6 */);
        return VINF_SUCCESS;
    }

#ifdef VBOX_STRICT
    /* Validate. Intel spec. 26.3.1.1 "Checks on Guest Controls Registers, Debug Registers, MSRs" */
    if (pVmcsInfo->u32EntryCtls & VMX_ENTRY_CTLS_LOAD_DEBUG)
    {
        /* Validate. Intel spec. 17.2 "Debug Registers", recompiler paranoia checks. */
        Assert((pVCpu->cpum.GstCtx.dr[7] & (X86_DR7_MBZ_MASK | X86_DR7_RAZ_MASK)) == 0);
        Assert((pVCpu->cpum.GstCtx.dr[7] & X86_DR7_RA1_MASK) == X86_DR7_RA1_MASK);
    }
#endif

    bool     fSteppingDB      = false;
    uint32_t uProcCtls        = pVmcsInfo->u32ProcCtls;
    if (pVCpu->hm.s.fSingleInstruction)
    {
        /* If the CPU supports the monitor trap flag, use it for single stepping in DBGF and avoid intercepting #DB. */
        if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_MONITOR_TRAP_FLAG)
        {
            uProcCtls |= VMX_PROC_CTLS_MONITOR_TRAP_FLAG;
            Assert(fSteppingDB == false);
        }
        else
        {
            pVCpu->cpum.GstCtx.eflags.u |= X86_EFL_TF;
            pVCpu->hm.s.fCtxChanged |= HM_CHANGED_GUEST_RFLAGS;
            pVCpu->hmr0.s.fClearTrapFlag = true;
            fSteppingDB = true;
        }
    }

#ifdef VMX_WITH_MAYBE_ALWAYS_INTERCEPT_MOV_DRX
    bool     fInterceptMovDRx = pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fAlwaysInterceptMovDRx;
#else
    bool     fInterceptMovDRx = false;
#endif
    uint64_t u64GuestDr7;
    if (   fSteppingDB
        || (CPUMGetHyperDR7(pVCpu) & X86_DR7_ENABLED_MASK))
    {
        /*
         * Use the combined guest and host DRx values found in the hypervisor register set
         * because the hypervisor debugger has breakpoints active or someone is single stepping
         * on the host side without a monitor trap flag.
         *
         * Note! DBGF expects a clean DR6 state before executing guest code.
         */
        if (!CPUMIsHyperDebugStateActive(pVCpu))
        {
            CPUMR0LoadHyperDebugState(pVCpu, true /* include DR6 */);
            Assert(CPUMIsHyperDebugStateActive(pVCpu));
            Assert(!CPUMIsGuestDebugStateActive(pVCpu));
        }

        /* Update DR7 with the hypervisor value (other DRx registers are handled by CPUM one way or another). */
        u64GuestDr7 = CPUMGetHyperDR7(pVCpu);
        pVCpu->hmr0.s.fUsingHyperDR7 = true;
        fInterceptMovDRx = true;
    }
    else
    {
        /*
         * If the guest has enabled debug registers, we need to load them prior to
         * executing guest code so they'll trigger at the right time.
         */
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_DR7);
        if (pVCpu->cpum.GstCtx.dr[7] & (X86_DR7_ENABLED_MASK | X86_DR7_GD))
        {
            if (!CPUMIsGuestDebugStateActive(pVCpu))
            {
                CPUMR0LoadGuestDebugState(pVCpu, true /* include DR6 */);
                Assert(CPUMIsGuestDebugStateActive(pVCpu));
                Assert(!CPUMIsHyperDebugStateActive(pVCpu));
                STAM_COUNTER_INC(&pVCpu->hm.s.StatDRxArmed);
            }
#ifndef VMX_WITH_MAYBE_ALWAYS_INTERCEPT_MOV_DRX
            Assert(!fInterceptMovDRx);
#endif
        }
        else if (!CPUMIsGuestDebugStateActive(pVCpu))
        {
            /*
             * If no debugging enabled, we'll lazy load DR0-3.  Unlike on AMD-V, we
             * must intercept #DB in order to maintain a correct DR6 guest value, and
             * because we need to intercept it to prevent nested #DBs from hanging the
             * CPU, we end up always having to intercept it. See hmR0VmxSetupVmcsXcptBitmap().
             */
            fInterceptMovDRx = true;
        }

        /* Update DR7 with the actual guest value. */
        u64GuestDr7 = pVCpu->cpum.GstCtx.dr[7];
        pVCpu->hmr0.s.fUsingHyperDR7 = false;
    }

    if (fInterceptMovDRx)
        uProcCtls |= VMX_PROC_CTLS_MOV_DR_EXIT;
    else
        uProcCtls &= ~VMX_PROC_CTLS_MOV_DR_EXIT;

    /*
     * Update the processor-based VM-execution controls with the MOV-DRx intercepts and the
     * monitor-trap flag and update our cache.
     */
    if (uProcCtls != pVmcsInfo->u32ProcCtls)
    {
        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, uProcCtls);
        AssertRC(rc);
        pVmcsInfo->u32ProcCtls = uProcCtls;
    }

    /*
     * Update guest DR7.
     */
    int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_DR7, u64GuestDr7);
    AssertRC(rc);

    /*
     * If we have forced EFLAGS.TF to be set because we're single-stepping in the hypervisor debugger,
     * we need to clear interrupt inhibition if any as otherwise it causes a VM-entry failure.
     *
     * See Intel spec. 26.3.1.5 "Checks on Guest Non-Register State".
     */
    if (fSteppingDB)
    {
        Assert(pVCpu->hm.s.fSingleInstruction);
        Assert(pVCpu->cpum.GstCtx.eflags.Bits.u1TF);

        uint32_t fIntrState = 0;
        rc = VMXReadVmcs32(VMX_VMCS32_GUEST_INT_STATE, &fIntrState);
        AssertRC(rc);

        if (fIntrState & (VMX_VMCS_GUEST_INT_STATE_BLOCK_STI | VMX_VMCS_GUEST_INT_STATE_BLOCK_MOVSS))
        {
            fIntrState &= ~(VMX_VMCS_GUEST_INT_STATE_BLOCK_STI | VMX_VMCS_GUEST_INT_STATE_BLOCK_MOVSS);
            rc = VMXWriteVmcs32(VMX_VMCS32_GUEST_INT_STATE, fIntrState);
            AssertRC(rc);
        }
    }

    return VINF_SUCCESS;
}


/**
 * Exports certain guest MSRs into the VM-entry MSR-load and VM-exit MSR-store
 * areas.
 *
 * These MSRs will automatically be loaded to the host CPU on every successful
 * VM-entry and stored from the host CPU on every successful VM-exit.
 *
 * We creates/updates MSR slots for the host MSRs in the VM-exit MSR-load area. The
 * actual host MSR values are not- updated here for performance reasons. See
 * hmR0VmxExportHostMsrs().
 *
 * We also exports the guest sysenter MSRs into the guest-state area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportGuestMsrs(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
    AssertPtr(pVCpu);
    AssertPtr(pVmxTransient);

    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    PCCPUMCTX pCtx = &pVCpu->cpum.GstCtx;

    /*
     * MSRs that we use the auto-load/store MSR area in the VMCS.
     * For 64-bit hosts, we load/restore them lazily, see hmR0VmxLazyLoadGuestMsrs(),
     * nothing to do here. The host MSR values are updated when it's safe in
     * hmR0VmxLazySaveHostMsrs().
     *
     * For nested-guests, the guests MSRs from the VM-entry MSR-load area are already
     * loaded (into the guest-CPU context) by the VMLAUNCH/VMRESUME instruction
     * emulation. The merged MSR permission bitmap will ensure that we get VM-exits
     * for any MSR that are not part of the lazy MSRs so we do not need to place
     * those MSRs into the auto-load/store MSR area. Nothing to do here.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_VMX_GUEST_AUTO_MSRS)
    {
        /* No auto-load/store MSRs currently. */
        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_VMX_GUEST_AUTO_MSRS);
    }

    /*
     * Guest Sysenter MSRs.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_MSR_MASK)
    {
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_SYSENTER_MSRS);

        if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_CS_MSR)
        {
            int rc = VMXWriteVmcs32(VMX_VMCS32_GUEST_SYSENTER_CS, pCtx->SysEnter.cs);
            AssertRC(rc);
            ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_SYSENTER_CS_MSR);
        }

        if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_EIP_MSR)
        {
            int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_SYSENTER_EIP, pCtx->SysEnter.eip);
            AssertRC(rc);
            ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_SYSENTER_EIP_MSR);
        }

        if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_ESP_MSR)
        {
            int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_SYSENTER_ESP, pCtx->SysEnter.esp);
            AssertRC(rc);
            ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_SYSENTER_ESP_MSR);
        }
    }

    /*
     * Guest/host EFER MSR.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_EFER_MSR)
    {
        /* Whether we are using the VMCS to swap the EFER MSR must have been
           determined earlier while exporting VM-entry/VM-exit controls. */
        Assert(!(ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_VMX_ENTRY_EXIT_CTLS));
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_EFER);

        if (hmR0VmxShouldSwapEferMsr(pVCpu, pVmxTransient))
        {
            /*
             * EFER.LME is written by software, while EFER.LMA is set by the CPU to (CR0.PG & EFER.LME).
             * This means a guest can set EFER.LME=1 while CR0.PG=0 and EFER.LMA can remain 0.
             * VT-x requires that "IA-32e mode guest" VM-entry control must be identical to EFER.LMA
             * and to CR0.PG. Without unrestricted execution, CR0.PG (used for VT-x, not the shadow)
             * must always be 1. This forces us to effectively clear both EFER.LMA and EFER.LME until
             * the guest has also set CR0.PG=1. Otherwise, we would run into an invalid-guest state
             * during VM-entry.
             */
            uint64_t uGuestEferMsr = pCtx->msrEFER;
            if (!pVM->hmr0.s.vmx.fUnrestrictedGuest)
            {
                if (!(pCtx->msrEFER & MSR_K6_EFER_LMA))
                    uGuestEferMsr &= ~MSR_K6_EFER_LME;
                else
                    Assert((pCtx->msrEFER & (MSR_K6_EFER_LMA | MSR_K6_EFER_LME)) == (MSR_K6_EFER_LMA | MSR_K6_EFER_LME));
            }

            /*
             * If the CPU supports VMCS controls for swapping EFER, use it. Otherwise, we have no option
             * but to use the auto-load store MSR area in the VMCS for swapping EFER. See @bugref{7368}.
             */
            if (g_fHmVmxSupportsVmcsEfer)
            {
                int rc = VMXWriteVmcs64(VMX_VMCS64_GUEST_EFER_FULL, uGuestEferMsr);
                AssertRC(rc);
            }
            else
            {
                /*
                 * We shall use the auto-load/store MSR area only for loading the EFER MSR but we must
                 * continue to intercept guest read and write accesses to it, see @bugref{7386#c16}.
                 */
                int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K6_EFER, uGuestEferMsr,
                                                    false /* fSetReadWrite */, false /* fUpdateHostMsr */);
                AssertRCReturn(rc, rc);
            }

            Log4Func(("efer=%#RX64 shadow=%#RX64\n", uGuestEferMsr, pCtx->msrEFER));
        }
        else if (!g_fHmVmxSupportsVmcsEfer)
            hmR0VmxRemoveAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K6_EFER);

        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_EFER_MSR);
    }

    /*
     * Other MSRs.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_OTHER_MSRS)
    {
        /* Speculation Control (R/W). */
        HMVMX_CPUMCTX_ASSERT(pVCpu, HM_CHANGED_GUEST_OTHER_MSRS);
        if (pVM->cpum.ro.GuestFeatures.fIbrs)
        {
            int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_IA32_SPEC_CTRL, CPUMGetGuestSpecCtrl(pVCpu),
                                                false /* fSetReadWrite */, false /* fUpdateHostMsr */);
            AssertRCReturn(rc, rc);
        }

        /* Last Branch Record. */
        if (pVM->hmr0.s.vmx.fLbr)
        {
            PVMXVMCSINFOSHARED const pVmcsInfoShared = pVmxTransient->pVmcsInfo->pShared;
            uint32_t const idFromIpMsrStart = pVM->hmr0.s.vmx.idLbrFromIpMsrFirst;
            uint32_t const idToIpMsrStart   = pVM->hmr0.s.vmx.idLbrToIpMsrFirst;
            uint32_t const cLbrStack        = pVM->hmr0.s.vmx.idLbrFromIpMsrLast - pVM->hmr0.s.vmx.idLbrFromIpMsrFirst + 1;
            Assert(cLbrStack <= 32);
            for (uint32_t i = 0; i < cLbrStack; i++)
            {
                int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, idFromIpMsrStart + i,
                                                    pVmcsInfoShared->au64LbrFromIpMsr[i],
                                                    false /* fSetReadWrite */, false /* fUpdateHostMsr */);
                AssertRCReturn(rc, rc);

                /* Some CPUs don't have a Branch-To-IP MSR (P4 and related Xeons). */
                if (idToIpMsrStart != 0)
                {
                    rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, idToIpMsrStart + i,
                                                    pVmcsInfoShared->au64LbrToIpMsr[i],
                                                    false /* fSetReadWrite */, false /* fUpdateHostMsr */);
                    AssertRCReturn(rc, rc);
                }
            }

            /* Add LBR top-of-stack MSR (which contains the index to the most recent record). */
            int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, pVM->hmr0.s.vmx.idLbrTosMsr,
                                                pVmcsInfoShared->u64LbrTosMsr, false /* fSetReadWrite */,
                                                false /* fUpdateHostMsr */);
            AssertRCReturn(rc, rc);
        }

        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_OTHER_MSRS);
    }

    return VINF_SUCCESS;
}


/**
 * Wrapper for running the guest code in VT-x.
 *
 * @returns VBox status code, no informational status codes.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
DECLINLINE(int) hmR0VmxRunGuest(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
    /* Mark that HM is the keeper of all guest-CPU registers now that we're going to execute guest code. */
    pVCpu->cpum.GstCtx.fExtrn |= HMVMX_CPUMCTX_EXTRN_ALL | CPUMCTX_EXTRN_KEEPER_HM;

    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    bool const   fResumeVM = RT_BOOL(pVmcsInfo->fVmcsState & VMX_V_VMCS_LAUNCH_STATE_LAUNCHED);
#ifdef VBOX_WITH_STATISTICS
    if (fResumeVM)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxVmResume);
    else
        STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxVmLaunch);
#endif
    int rc = pVCpu->hmr0.s.vmx.pfnStartVm(pVmcsInfo, pVCpu, fResumeVM);
    AssertMsg(rc <= VINF_SUCCESS, ("%Rrc\n", rc));
    return rc;
}


/**
 * Reports world-switch error and dumps some useful debug info.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   rcVMRun         The return code from VMLAUNCH/VMRESUME.
 * @param   pVmxTransient   The VMX-transient structure (only
 *                          exitReason updated).
 */
static void hmR0VmxReportWorldSwitchError(PVMCPUCC pVCpu, int rcVMRun, PVMXTRANSIENT pVmxTransient)
{
    Assert(pVCpu);
    Assert(pVmxTransient);
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);

    Log4Func(("VM-entry failure: %Rrc\n", rcVMRun));
    switch (rcVMRun)
    {
        case VERR_VMX_INVALID_VMXON_PTR:
            AssertFailed();
            break;
        case VINF_SUCCESS:                  /* VMLAUNCH/VMRESUME succeeded but VM-entry failed... yeah, true story. */
        case VERR_VMX_UNABLE_TO_START_VM:   /* VMLAUNCH/VMRESUME itself failed. */
        {
            int rc = VMXReadVmcs32(VMX_VMCS32_RO_EXIT_REASON, &pVCpu->hm.s.vmx.LastError.u32ExitReason);
            rc    |= VMXReadVmcs32(VMX_VMCS32_RO_VM_INSTR_ERROR, &pVCpu->hm.s.vmx.LastError.u32InstrError);
            AssertRC(rc);
            vmxHCReadToTransientSlow<HMVMX_READ_EXIT_QUALIFICATION>(pVCpu, pVmxTransient);

            pVCpu->hm.s.vmx.LastError.idEnteredCpu = pVCpu->hmr0.s.idEnteredCpu;
            /* LastError.idCurrentCpu was already updated in hmR0VmxPreRunGuestCommitted().
               Cannot do it here as we may have been long preempted. */

#ifdef VBOX_STRICT
                PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
                Log4(("uExitReason        %#RX32 (VmxTransient %#RX16)\n", pVCpu->hm.s.vmx.LastError.u32ExitReason,
                     pVmxTransient->uExitReason));
                Log4(("Exit Qualification %#RX64\n", pVmxTransient->uExitQual));
                Log4(("InstrError         %#RX32\n", pVCpu->hm.s.vmx.LastError.u32InstrError));
                if (pVCpu->hm.s.vmx.LastError.u32InstrError <= HMVMX_INSTR_ERROR_MAX)
                    Log4(("InstrError Desc.  \"%s\"\n", g_apszVmxInstrErrors[pVCpu->hm.s.vmx.LastError.u32InstrError]));
                else
                    Log4(("InstrError Desc.    Range exceeded %u\n", HMVMX_INSTR_ERROR_MAX));
                Log4(("Entered host CPU   %u\n", pVCpu->hm.s.vmx.LastError.idEnteredCpu));
                Log4(("Current host CPU   %u\n", pVCpu->hm.s.vmx.LastError.idCurrentCpu));

                static struct
                {
                    /** Name of the field to log. */
                    const char     *pszName;
                    /** The VMCS field. */
                    uint32_t        uVmcsField;
                    /** Whether host support of this field needs to be checked. */
                    bool            fCheckSupport;
                } const s_aVmcsFields[] =
                {
                    { "VMX_VMCS32_CTRL_PIN_EXEC",                 VMX_VMCS32_CTRL_PIN_EXEC,                   false  },
                    { "VMX_VMCS32_CTRL_PROC_EXEC",                VMX_VMCS32_CTRL_PROC_EXEC,                  false  },
                    { "VMX_VMCS32_CTRL_PROC_EXEC2",               VMX_VMCS32_CTRL_PROC_EXEC2,                 true   },
                    { "VMX_VMCS32_CTRL_ENTRY",                    VMX_VMCS32_CTRL_ENTRY,                      false  },
                    { "VMX_VMCS32_CTRL_EXIT",                     VMX_VMCS32_CTRL_EXIT,                       false  },
                    { "VMX_VMCS32_CTRL_CR3_TARGET_COUNT",         VMX_VMCS32_CTRL_CR3_TARGET_COUNT,           false  },
                    { "VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO",  VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO,    false  },
                    { "VMX_VMCS32_CTRL_ENTRY_EXCEPTION_ERRCODE",  VMX_VMCS32_CTRL_ENTRY_EXCEPTION_ERRCODE,    false  },
                    { "VMX_VMCS32_CTRL_ENTRY_INSTR_LENGTH",       VMX_VMCS32_CTRL_ENTRY_INSTR_LENGTH,         false  },
                    { "VMX_VMCS32_CTRL_TPR_THRESHOLD",            VMX_VMCS32_CTRL_TPR_THRESHOLD,              false  },
                    { "VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT",     VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT,       false  },
                    { "VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT",      VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT,        false  },
                    { "VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT",     VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT,       false  },
                    { "VMX_VMCS32_CTRL_EXCEPTION_BITMAP",         VMX_VMCS32_CTRL_EXCEPTION_BITMAP,           false  },
                    { "VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MASK",     VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MASK,       false  },
                    { "VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MATCH",    VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MATCH,      false  },
                    { "VMX_VMCS_CTRL_CR0_MASK",                   VMX_VMCS_CTRL_CR0_MASK,                     false  },
                    { "VMX_VMCS_CTRL_CR0_READ_SHADOW",            VMX_VMCS_CTRL_CR0_READ_SHADOW,              false  },
                    { "VMX_VMCS_CTRL_CR4_MASK",                   VMX_VMCS_CTRL_CR4_MASK,                     false  },
                    { "VMX_VMCS_CTRL_CR4_READ_SHADOW",            VMX_VMCS_CTRL_CR4_READ_SHADOW,              false  },
                    { "VMX_VMCS64_CTRL_EPTP_FULL",                VMX_VMCS64_CTRL_EPTP_FULL,                  true   },
                    { "VMX_VMCS_GUEST_RIP",                       VMX_VMCS_GUEST_RIP,                         false  },
                    { "VMX_VMCS_GUEST_RSP",                       VMX_VMCS_GUEST_RSP,                         false  },
                    { "VMX_VMCS_GUEST_RFLAGS",                    VMX_VMCS_GUEST_RFLAGS,                      false  },
                    { "VMX_VMCS16_VPID",                          VMX_VMCS16_VPID,                            true,  },
                    { "VMX_VMCS_HOST_CR0",                        VMX_VMCS_HOST_CR0,                          false  },
                    { "VMX_VMCS_HOST_CR3",                        VMX_VMCS_HOST_CR3,                          false  },
                    { "VMX_VMCS_HOST_CR4",                        VMX_VMCS_HOST_CR4,                          false  },
                    /* The order of selector fields below are fixed! */
                    { "VMX_VMCS16_HOST_ES_SEL",                   VMX_VMCS16_HOST_ES_SEL,                     false  },
                    { "VMX_VMCS16_HOST_CS_SEL",                   VMX_VMCS16_HOST_CS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_SS_SEL",                   VMX_VMCS16_HOST_SS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_DS_SEL",                   VMX_VMCS16_HOST_DS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_FS_SEL",                   VMX_VMCS16_HOST_FS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_GS_SEL",                   VMX_VMCS16_HOST_GS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_TR_SEL",                   VMX_VMCS16_HOST_TR_SEL,                     false  },
                    /* End of ordered selector fields. */
                    { "VMX_VMCS_HOST_TR_BASE",                    VMX_VMCS_HOST_TR_BASE,                      false  },
                    { "VMX_VMCS_HOST_GDTR_BASE",                  VMX_VMCS_HOST_GDTR_BASE,                    false  },
                    { "VMX_VMCS_HOST_IDTR_BASE",                  VMX_VMCS_HOST_IDTR_BASE,                    false  },
                    { "VMX_VMCS32_HOST_SYSENTER_CS",              VMX_VMCS32_HOST_SYSENTER_CS,                false  },
                    { "VMX_VMCS_HOST_SYSENTER_EIP",               VMX_VMCS_HOST_SYSENTER_EIP,                 false  },
                    { "VMX_VMCS_HOST_SYSENTER_ESP",               VMX_VMCS_HOST_SYSENTER_ESP,                 false  },
                    { "VMX_VMCS_HOST_RSP",                        VMX_VMCS_HOST_RSP,                          false  },
                    { "VMX_VMCS_HOST_RIP",                        VMX_VMCS_HOST_RIP,                          false  }
                };

                RTGDTR      HostGdtr;
                ASMGetGDTR(&HostGdtr);

                uint32_t const cVmcsFields = RT_ELEMENTS(s_aVmcsFields);
                for (uint32_t i = 0; i < cVmcsFields; i++)
                {
                    uint32_t const uVmcsField = s_aVmcsFields[i].uVmcsField;

                    bool fSupported;
                    if (!s_aVmcsFields[i].fCheckSupport)
                        fSupported = true;
                    else
                    {
                        PVMCC pVM = pVCpu->CTX_SUFF(pVM);
                        switch (uVmcsField)
                        {
                            case VMX_VMCS64_CTRL_EPTP_FULL:  fSupported = pVM->hmr0.s.fNestedPaging;    break;
                            case VMX_VMCS16_VPID:            fSupported = pVM->hmr0.s.vmx.fVpid;          break;
                            case VMX_VMCS32_CTRL_PROC_EXEC2:
                                fSupported = RT_BOOL(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_SECONDARY_CTLS);
                                break;
                            default:
                                AssertMsgFailedReturnVoid(("Failed to provide VMCS field support for %#RX32\n", uVmcsField));
                        }
                    }

                    if (fSupported)
                    {
                        uint8_t const uWidth = RT_BF_GET(uVmcsField, VMX_BF_VMCSFIELD_WIDTH);
                        switch (uWidth)
                        {
                            case VMX_VMCSFIELD_WIDTH_16BIT:
                            {
                                uint16_t u16Val;
                                rc = VMXReadVmcs16(uVmcsField, &u16Val);
                                AssertRC(rc);
                                Log4(("%-40s = %#RX16\n", s_aVmcsFields[i].pszName, u16Val));

                                if (   uVmcsField >= VMX_VMCS16_HOST_ES_SEL
                                    && uVmcsField <= VMX_VMCS16_HOST_TR_SEL)
                                {
                                    if (u16Val < HostGdtr.cbGdt)
                                    {
                                        /* Order of selectors in s_apszSel is fixed and matches the order in s_aVmcsFields. */
                                        static const char * const s_apszSel[] = { "Host ES", "Host CS", "Host SS", "Host DS",
                                                                                  "Host FS", "Host GS", "Host TR" };
                                        uint8_t const idxSel = RT_BF_GET(uVmcsField, VMX_BF_VMCSFIELD_INDEX);
                                        Assert(idxSel < RT_ELEMENTS(s_apszSel));
                                        PCX86DESCHC pDesc = (PCX86DESCHC)(HostGdtr.pGdt + (u16Val & X86_SEL_MASK));
                                        hmR0DumpDescriptor(pDesc, u16Val, s_apszSel[idxSel]);
                                    }
                                    else
                                        Log4(("  Selector value exceeds GDT limit!\n"));
                                }
                                break;
                            }

                            case VMX_VMCSFIELD_WIDTH_32BIT:
                            {
                                uint32_t u32Val;
                                rc = VMXReadVmcs32(uVmcsField, &u32Val);
                                AssertRC(rc);
                                Log4(("%-40s = %#RX32\n", s_aVmcsFields[i].pszName, u32Val));
                                break;
                            }

                            case VMX_VMCSFIELD_WIDTH_64BIT:
                            case VMX_VMCSFIELD_WIDTH_NATURAL:
                            {
                                uint64_t u64Val;
                                rc = VMXReadVmcs64(uVmcsField, &u64Val);
                                AssertRC(rc);
                                Log4(("%-40s = %#RX64\n", s_aVmcsFields[i].pszName, u64Val));
                                break;
                            }
                        }
                    }
                }

                Log4(("MSR_K6_EFER            = %#RX64\n", ASMRdMsr(MSR_K6_EFER)));
                Log4(("MSR_K8_CSTAR           = %#RX64\n", ASMRdMsr(MSR_K8_CSTAR)));
                Log4(("MSR_K8_LSTAR           = %#RX64\n", ASMRdMsr(MSR_K8_LSTAR)));
                Log4(("MSR_K6_STAR            = %#RX64\n", ASMRdMsr(MSR_K6_STAR)));
                Log4(("MSR_K8_SF_MASK         = %#RX64\n", ASMRdMsr(MSR_K8_SF_MASK)));
                Log4(("MSR_K8_KERNEL_GS_BASE  = %#RX64\n", ASMRdMsr(MSR_K8_KERNEL_GS_BASE)));
#endif /* VBOX_STRICT */
            break;
        }

        default:
            /* Impossible */
            AssertMsgFailed(("hmR0VmxReportWorldSwitchError %Rrc (%#x)\n", rcVMRun, rcVMRun));
            break;
    }
}


/**
 * Sets up the usage of TSC-offsetting and updates the VMCS.
 *
 * If offsetting is not possible, cause VM-exits on RDTSC(P)s. Also sets up the
 * VMX-preemption timer.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   idCurrentCpu    The current CPU number.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxUpdateTscOffsettingAndPreemptTimer(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, RTCPUID idCurrentCpu)
{
    bool         fOffsettedTsc;
    bool         fParavirtTsc;
    uint64_t     uTscOffset;
    PVMCC        pVM       = pVCpu->CTX_SUFF(pVM);
    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);

    if (pVM->hmr0.s.vmx.fUsePreemptTimer)
    {
        /* The TMCpuTickGetDeadlineAndTscOffset function is expensive (calling it on
           every entry slowed down the bs2-test1 CPUID testcase by ~33% (on an 10980xe). */
        uint64_t cTicksToDeadline;
        if (   idCurrentCpu == pVCpu->hmr0.s.idLastCpu
            && TMVirtualSyncIsCurrentDeadlineVersion(pVM, pVCpu->hmr0.s.vmx.uTscDeadlineVersion))
        {
            STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionReusingDeadline);
            fOffsettedTsc = TMCpuTickCanUseRealTSC(pVM, pVCpu, &uTscOffset, &fParavirtTsc);
            cTicksToDeadline = pVCpu->hmr0.s.vmx.uTscDeadline - SUPReadTsc();
            if ((int64_t)cTicksToDeadline > 0)
            { /* hopefully */ }
            else
            {
                STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionReusingDeadlineExpired);
                cTicksToDeadline = 0;
            }
        }
        else
        {
            STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionRecalcingDeadline);
            cTicksToDeadline = TMCpuTickGetDeadlineAndTscOffset(pVM, pVCpu, &uTscOffset, &fOffsettedTsc, &fParavirtTsc,
                                                                &pVCpu->hmr0.s.vmx.uTscDeadline,
                                                                &pVCpu->hmr0.s.vmx.uTscDeadlineVersion);
            pVCpu->hmr0.s.vmx.uTscDeadline += cTicksToDeadline;
            if (cTicksToDeadline >= 128)
            { /* hopefully */ }
            else
                STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionRecalcingDeadlineExpired);
        }

        /* Make sure the returned values have sane upper and lower boundaries. */
        uint64_t const u64CpuHz = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, pVCpu->iHostCpuSet);
        cTicksToDeadline   = RT_MIN(cTicksToDeadline, u64CpuHz / 64);      /* 1/64th of a second,  15.625ms. */ /** @todo r=bird: Once real+virtual timers move to separate thread, we can raise the upper limit (16ms isn't much). ASSUMES working poke cpu function. */
        cTicksToDeadline   = RT_MAX(cTicksToDeadline, u64CpuHz / 32678);   /* 1/32768th of a second,  ~30us. */
        cTicksToDeadline >>= pVM->hm.s.vmx.cPreemptTimerShift;

        /** @todo r=ramshankar: We need to find a way to integrate nested-guest
         *        preemption timers here. We probably need to clamp the preemption timer,
         *        after converting the timer value to the host. */
        uint32_t const cPreemptionTickCount = (uint32_t)RT_MIN(cTicksToDeadline, UINT32_MAX - 16);
        int rc = VMXWriteVmcs32(VMX_VMCS32_PREEMPT_TIMER_VALUE, cPreemptionTickCount);
        AssertRC(rc);
    }
    else
        fOffsettedTsc = TMCpuTickCanUseRealTSC(pVM, pVCpu, &uTscOffset, &fParavirtTsc);

    if (fParavirtTsc)
    {
        /* Currently neither Hyper-V nor KVM need to update their paravirt. TSC
           information before every VM-entry, hence disable it for performance sake. */
#if 0
        int rc = GIMR0UpdateParavirtTsc(pVM, 0 /* u64Offset */);
        AssertRC(rc);
#endif
        STAM_COUNTER_INC(&pVCpu->hm.s.StatTscParavirt);
    }

    if (   fOffsettedTsc
        && RT_LIKELY(!pVCpu->hmr0.s.fDebugWantRdTscExit))
    {
        if (pVmxTransient->fIsNestedGuest)
            uTscOffset = CPUMApplyNestedGuestTscOffset(pVCpu, uTscOffset);
        hmR0VmxSetTscOffsetVmcs(pVmcsInfo, uTscOffset);
        hmR0VmxRemoveProcCtlsVmcs(pVCpu, pVmxTransient, VMX_PROC_CTLS_RDTSC_EXIT);
    }
    else
    {
        /* We can't use TSC-offsetting (non-fixed TSC, warp drive active etc.), VM-exit on RDTSC(P). */
        hmR0VmxSetProcCtlsVmcs(pVmxTransient, VMX_PROC_CTLS_RDTSC_EXIT);
    }
}


/**
 * Saves the guest state from the VMCS into the guest-CPU context.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   fWhat   What to import, CPUMCTX_EXTRN_XXX.
 */
VMMR0DECL(int) VMXR0ImportStateOnDemand(PVMCPUCC pVCpu, uint64_t fWhat)
{
    AssertPtr(pVCpu);
    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    return vmxHCImportGuestStateEx(pVCpu, pVmcsInfo, fWhat);
}


/**
 * Gets VMX VM-exit auxiliary information.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxExitAux     Where to store the VM-exit auxiliary info.
 * @param   fWhat           What to fetch, HMVMX_READ_XXX.
 */
VMMR0DECL(int) VMXR0GetExitAuxInfo(PVMCPUCC pVCpu, PVMXEXITAUX pVmxExitAux, uint32_t fWhat)
{
    PVMXTRANSIENT pVmxTransient = pVCpu->hmr0.s.vmx.pVmxTransient;
    if (RT_LIKELY(pVmxTransient))
    {
        AssertCompile(sizeof(fWhat) == sizeof(pVmxTransient->fVmcsFieldsRead));

        /* The exit reason is always available. */
        pVmxExitAux->uReason = pVmxTransient->uExitReason;


        if (fWhat & HMVMX_READ_EXIT_QUALIFICATION)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_EXIT_QUALIFICATION>(pVCpu, pVmxTransient);
            pVmxExitAux->u64Qual = pVmxTransient->uExitQual;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_EXIT_QUALIFICATION;
#endif
        }

        if (fWhat & HMVMX_READ_IDT_VECTORING_INFO)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_IDT_VECTORING_INFO>(pVCpu, pVmxTransient);
            pVmxExitAux->uIdtVectoringInfo = pVmxTransient->uIdtVectoringInfo;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_IDT_VECTORING_INFO;
#endif
        }

        if (fWhat & HMVMX_READ_IDT_VECTORING_ERROR_CODE)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_IDT_VECTORING_ERROR_CODE>(pVCpu, pVmxTransient);
            pVmxExitAux->uIdtVectoringErrCode = pVmxTransient->uIdtVectoringErrorCode;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_IDT_VECTORING_ERROR_CODE;
#endif
        }

        if (fWhat & HMVMX_READ_EXIT_INSTR_LEN)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_EXIT_INSTR_LEN>(pVCpu, pVmxTransient);
            pVmxExitAux->cbInstr = pVmxTransient->cbExitInstr;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_EXIT_INSTR_LEN;
#endif
        }

        if (fWhat & HMVMX_READ_EXIT_INTERRUPTION_INFO)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_EXIT_INTERRUPTION_INFO>(pVCpu, pVmxTransient);
            pVmxExitAux->uExitIntInfo = pVmxTransient->uExitIntInfo;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_EXIT_INTERRUPTION_INFO;
#endif
        }

        if (fWhat & HMVMX_READ_EXIT_INTERRUPTION_ERROR_CODE)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_EXIT_INTERRUPTION_ERROR_CODE>(pVCpu, pVmxTransient);
            pVmxExitAux->uExitIntErrCode = pVmxTransient->uExitIntErrorCode;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_EXIT_INTERRUPTION_ERROR_CODE;
#endif
        }

        if (fWhat & HMVMX_READ_EXIT_INSTR_INFO)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_EXIT_INSTR_INFO>(pVCpu, pVmxTransient);
            pVmxExitAux->InstrInfo.u = pVmxTransient->ExitInstrInfo.u;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_EXIT_INSTR_INFO;
#endif
        }

        if (fWhat & HMVMX_READ_GUEST_LINEAR_ADDR)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_GUEST_LINEAR_ADDR>(pVCpu, pVmxTransient);
            pVmxExitAux->u64GuestLinearAddr = pVmxTransient->uGuestLinearAddr;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_GUEST_LINEAR_ADDR;
#endif
        }

        if (fWhat & HMVMX_READ_GUEST_PHYSICAL_ADDR)
        {
            vmxHCReadToTransientSlow<HMVMX_READ_GUEST_PHYSICAL_ADDR>(pVCpu, pVmxTransient);
            pVmxExitAux->u64GuestPhysAddr = pVmxTransient->uGuestPhysicalAddr;
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_GUEST_PHYSICAL_ADDR;
#endif
        }

        if (fWhat & HMVMX_READ_GUEST_PENDING_DBG_XCPTS)
        {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            vmxHCReadToTransientSlow<HMVMX_READ_GUEST_PENDING_DBG_XCPTS>(pVCpu, pVmxTransient);
            pVmxExitAux->u64GuestPendingDbgXcpts = pVmxTransient->uGuestPendingDbgXcpts;
#else
            pVmxExitAux->u64GuestPendingDbgXcpts = 0;
#endif
#ifdef VBOX_STRICT
            fWhat &= ~HMVMX_READ_GUEST_PENDING_DBG_XCPTS;
#endif
        }

        AssertMsg(!fWhat, ("fWhat=%#RX32 fVmcsFieldsRead=%#RX32\n", fWhat, pVmxTransient->fVmcsFieldsRead));
        return VINF_SUCCESS;
    }
    return VERR_NOT_AVAILABLE;
}


/**
 * Does the necessary state syncing before returning to ring-3 for any reason
 * (longjmp, preemption, voluntary exits to ring-3) from VT-x.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   fImportState    Whether to import the guest state from the VMCS back
 *                          to the guest-CPU context.
 *
 * @remarks No-long-jmp zone!!!
 */
static int hmR0VmxLeave(PVMCPUCC pVCpu, bool fImportState)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    RTCPUID const idCpu = RTMpCpuId();
    Log4Func(("HostCpuId=%u\n", idCpu));

    /*
     * !!! IMPORTANT !!!
     * If you modify code here, check whether VMXR0CallRing3Callback() needs to be updated too.
     */

    /* Save the guest state if necessary. */
    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    if (fImportState)
    {
        int rc = vmxHCImportGuestStateEx(pVCpu, pVmcsInfo, HMVMX_CPUMCTX_EXTRN_ALL);
        AssertRCReturn(rc, rc);
    }

    /* Restore host FPU state if necessary. We will resync on next R0 reentry. */
    CPUMR0FpuStateMaybeSaveGuestAndRestoreHost(pVCpu);
    Assert(!CPUMIsGuestFPUStateActive(pVCpu));

    /* Restore host debug registers if necessary. We will resync on next R0 reentry. */
#ifdef VMX_WITH_MAYBE_ALWAYS_INTERCEPT_MOV_DRX
    Assert(   (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_MOV_DR_EXIT)
           || (!CPUMIsHyperDebugStateActive(pVCpu) && !pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fAlwaysInterceptMovDRx));
#else
    Assert((pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_MOV_DR_EXIT) || !CPUMIsHyperDebugStateActive(pVCpu));
#endif
    CPUMR0DebugStateMaybeSaveGuestAndRestoreHost(pVCpu, true /* save DR6 */);
    Assert(!CPUMIsGuestDebugStateActive(pVCpu));
    Assert(!CPUMIsHyperDebugStateActive(pVCpu));

    /* Restore host-state bits that VT-x only restores partially. */
    if (pVCpu->hmr0.s.vmx.fRestoreHostFlags > VMX_RESTORE_HOST_REQUIRED)
    {
        Log4Func(("Restoring Host State: fRestoreHostFlags=%#RX32 HostCpuId=%u\n", pVCpu->hmr0.s.vmx.fRestoreHostFlags, idCpu));
        VMXRestoreHostState(pVCpu->hmr0.s.vmx.fRestoreHostFlags, &pVCpu->hmr0.s.vmx.RestoreHost);
    }
    pVCpu->hmr0.s.vmx.fRestoreHostFlags = 0;

    /* Restore the lazy host MSRs as we're leaving VT-x context. */
    if (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
    {
        /* We shouldn't restore the host MSRs without saving the guest MSRs first. */
        if (!fImportState)
        {
            int rc = vmxHCImportGuestStateEx(pVCpu, pVmcsInfo, CPUMCTX_EXTRN_KERNEL_GS_BASE | CPUMCTX_EXTRN_SYSCALL_MSRS);
            AssertRCReturn(rc, rc);
        }
        hmR0VmxLazyRestoreHostMsrs(pVCpu);
        Assert(!pVCpu->hmr0.s.vmx.fLazyMsrs);
    }
    else
        pVCpu->hmr0.s.vmx.fLazyMsrs = 0;

    /* Update auto-load/store host MSRs values when we re-enter VT-x (as we could be on a different CPU). */
    pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = false;

    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatEntry);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatImportGuestState);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExportGuestState);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatPreExit);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitHandling);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitIO);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitMovCRx);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitXcptNmi);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitVmentry);
    STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchLongJmpToR3);

    VMCPU_CMPXCHG_STATE(pVCpu, VMCPUSTATE_STARTED_HM, VMCPUSTATE_STARTED_EXEC);

    /** @todo This partially defeats the purpose of having preemption hooks.
     *  The problem is, deregistering the hooks should be moved to a place that
     *  lasts until the EMT is about to be destroyed not everytime while leaving HM
     *  context.
     */
    int rc = hmR0VmxClearVmcs(pVmcsInfo);
    AssertRCReturn(rc, rc);

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * A valid shadow VMCS is made active as part of VM-entry. It is necessary to
     * clear a shadow VMCS before allowing that VMCS to become active on another
     * logical processor. We may or may not be importing guest state which clears
     * it, so cover for it here.
     *
     * See Intel spec. 24.11.1 "Software Use of Virtual-Machine Control Structures".
     */
    if (   pVmcsInfo->pvShadowVmcs
        && pVmcsInfo->fShadowVmcsState != VMX_V_VMCS_LAUNCH_STATE_CLEAR)
    {
        rc = vmxHCClearShadowVmcs(pVmcsInfo);
        AssertRCReturn(rc, rc);
    }

    /*
     * Flag that we need to re-export the host state if we switch to this VMCS before
     * executing guest or nested-guest code.
     */
    pVmcsInfo->idHostCpuState = NIL_RTCPUID;
#endif

    Log4Func(("Cleared Vmcs. HostCpuId=%u\n", idCpu));
    NOREF(idCpu);
    return VINF_SUCCESS;
}


/**
 * Leaves the VT-x session.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jmp zone!!!
 */
static int hmR0VmxLeaveSession(PVMCPUCC pVCpu)
{
    HM_DISABLE_PREEMPT(pVCpu);
    HMVMX_ASSERT_CPU_SAFE(pVCpu);
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* When thread-context hooks are used, we can avoid doing the leave again if we had been preempted before
       and done this from the VMXR0ThreadCtxCallback(). */
    if (!pVCpu->hmr0.s.fLeaveDone)
    {
        int rc2 = hmR0VmxLeave(pVCpu, true /* fImportState */);
        AssertRCReturnStmt(rc2, HM_RESTORE_PREEMPT(), rc2);
        pVCpu->hmr0.s.fLeaveDone = true;
    }
    Assert(!pVCpu->cpum.GstCtx.fExtrn);

    /*
     * !!! IMPORTANT !!!
     * If you modify code here, make sure to check whether VMXR0CallRing3Callback() needs to be updated too.
     */

    /* Deregister hook now that we've left HM context before re-enabling preemption. */
    /** @todo Deregistering here means we need to VMCLEAR always
     *        (longjmp/exit-to-r3) in VT-x which is not efficient, eliminate need
     *        for calling VMMR0ThreadCtxHookDisable here! */
    VMMR0ThreadCtxHookDisable(pVCpu);

    /* Leave HM context. This takes care of local init (term) and deregistering the longjmp-to-ring-3 callback. */
    int rc = HMR0LeaveCpu(pVCpu);
    HM_RESTORE_PREEMPT();
    return rc;
}


/**
 * Take necessary actions before going back to ring-3.
 *
 * An action requires us to go back to ring-3. This function does the necessary
 * steps before we can safely return to ring-3. This is not the same as longjmps
 * to ring-3, this is voluntary and prepares the guest so it may continue
 * executing outside HM (recompiler/IEM).
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   rcExit  The reason for exiting to ring-3. Can be
 *                  VINF_VMM_UNKNOWN_RING3_CALL.
 */
static int hmR0VmxExitToRing3(PVMCPUCC pVCpu, VBOXSTRICTRC rcExit)
{
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);

    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    if (RT_UNLIKELY(rcExit == VERR_VMX_INVALID_VMCS_PTR))
    {
        VMXGetCurrentVmcs(&pVCpu->hm.s.vmx.LastError.HCPhysCurrentVmcs);
        pVCpu->hm.s.vmx.LastError.u32VmcsRev   = *(uint32_t *)pVmcsInfo->pvVmcs;
        pVCpu->hm.s.vmx.LastError.idEnteredCpu = pVCpu->hmr0.s.idEnteredCpu;
        /* LastError.idCurrentCpu was updated in hmR0VmxPreRunGuestCommitted(). */
    }

    /* Please, no longjumps here (any logging shouldn't flush jump back to ring-3). NO LOGGING BEFORE THIS POINT! */
    VMMRZCallRing3Disable(pVCpu);
    Log4Func(("rcExit=%d\n", VBOXSTRICTRC_VAL(rcExit)));

    /*
     * Convert any pending HM events back to TRPM due to premature exits to ring-3.
     * We need to do this only on returns to ring-3 and not for longjmps to ring3.
     *
     * This is because execution may continue from ring-3 and we would need to inject
     * the event from there (hence place it back in TRPM).
     */
    if (pVCpu->hm.s.Event.fPending)
    {
        vmxHCPendingEventToTrpmTrap(pVCpu);
        Assert(!pVCpu->hm.s.Event.fPending);

        /* Clear the events from the VMCS. */
        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO, 0);    AssertRC(rc);
        rc     = VMXWriteVmcs32(VMX_VMCS_GUEST_PENDING_DEBUG_XCPTS, 0);         AssertRC(rc);
    }
#ifdef VBOX_STRICT
    /*
     * We check for rcExit here since for errors like VERR_VMX_UNABLE_TO_START_VM (which are
     * fatal), we don't care about verifying duplicate injection of events. Errors like
     * VERR_EM_INTERPRET are converted to their VINF_* counterparts -prior- to  calling this
     * function so those should and will be checked below.
     */
    else if (RT_SUCCESS(rcExit))
    {
        /*
         * Ensure we don't accidentally clear a pending HM event without clearing the VMCS.
         * This can be pretty hard to debug otherwise, interrupts might get injected twice
         * occasionally, see @bugref{9180#c42}.
         *
         * However, if the VM-entry failed, any VM entry-interruption info. field would
         * be left unmodified as the event would not have been injected to the guest. In
         * such cases, don't assert, we're not going to continue guest execution anyway.
         */
        uint32_t uExitReason;
        uint32_t uEntryIntInfo;
        int rc = VMXReadVmcs32(VMX_VMCS32_RO_EXIT_REASON, &uExitReason);
        rc    |= VMXReadVmcs32(VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO, &uEntryIntInfo);
        AssertRC(rc);
        AssertMsg(VMX_EXIT_REASON_HAS_ENTRY_FAILED(uExitReason) || !VMX_ENTRY_INT_INFO_IS_VALID(uEntryIntInfo),
                  ("uExitReason=%#RX32 uEntryIntInfo=%#RX32 rcExit=%d\n", uExitReason, uEntryIntInfo, VBOXSTRICTRC_VAL(rcExit)));
    }
#endif

    /*
     * Clear the interrupt-window and NMI-window VMCS controls as we could have got
     * a VM-exit with higher priority than interrupt-window or NMI-window VM-exits
     * (e.g. TPR below threshold).
     */
    if (!CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
    {
        vmxHCClearIntWindowExitVmcs(pVCpu, pVmcsInfo);
        vmxHCClearNmiWindowExitVmcs(pVCpu, pVmcsInfo);
    }

    /* If we're emulating an instruction, we shouldn't have any TRPM traps pending
       and if we're injecting an event we should have a TRPM trap pending. */
    AssertMsg(rcExit != VINF_EM_RAW_INJECT_TRPM_EVENT || TRPMHasTrap(pVCpu), ("%Rrc\n", VBOXSTRICTRC_VAL(rcExit)));
#ifndef DEBUG_bird /* Triggered after firing an NMI against NT4SP1, possibly a triple fault in progress. */
    AssertMsg(rcExit != VINF_EM_RAW_EMULATE_INSTR || !TRPMHasTrap(pVCpu), ("%Rrc\n", VBOXSTRICTRC_VAL(rcExit)));
#endif

    /* Save guest state and restore host state bits. */
    int rc = hmR0VmxLeaveSession(pVCpu);
    AssertRCReturn(rc, rc);
    STAM_COUNTER_DEC(&pVCpu->hm.s.StatSwitchLongJmpToR3);

    /* Thread-context hooks are unregistered at this point!!! */
    /* Ring-3 callback notifications are unregistered at this point!!! */

    /* Sync recompiler state. */
    VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_TO_R3);
    CPUMSetChangedFlags(pVCpu, CPUM_CHANGED_SYSENTER_MSR
                             | CPUM_CHANGED_LDTR
                             | CPUM_CHANGED_GDTR
                             | CPUM_CHANGED_IDTR
                             | CPUM_CHANGED_TR
                             | CPUM_CHANGED_HIDDEN_SEL_REGS);
    if (   pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging
        && CPUMIsGuestPagingEnabledEx(&pVCpu->cpum.GstCtx))
        CPUMSetChangedFlags(pVCpu, CPUM_CHANGED_GLOBAL_TLB_FLUSH);

    Assert(!pVCpu->hmr0.s.fClearTrapFlag);

    /* Update the exit-to-ring 3 reason. */
    pVCpu->hm.s.rcLastExitToR3 = VBOXSTRICTRC_VAL(rcExit);

    /* On our way back from ring-3 reload the guest state if there is a possibility of it being changed. */
    if (   rcExit != VINF_EM_RAW_INTERRUPT
        || CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
    {
        Assert(!(pVCpu->cpum.GstCtx.fExtrn & HMVMX_CPUMCTX_EXTRN_ALL));
        ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_ALL_GUEST);
    }

    STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchExitToR3);
    VMMRZCallRing3Enable(pVCpu);
    return rc;
}


/**
 * VMMRZCallRing3() callback wrapper which saves the guest state before we
 * longjump due to a ring-0 assertion.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 */
VMMR0DECL(int) VMXR0AssertionCallback(PVMCPUCC pVCpu)
{
    /*
     * !!! IMPORTANT !!!
     * If you modify code here, check whether hmR0VmxLeave() and hmR0VmxLeaveSession() needs to be updated too.
     * This is a stripped down version which gets out ASAP, trying to not trigger any further assertions.
     */
    VMMR0AssertionRemoveNotification(pVCpu);
    VMMRZCallRing3Disable(pVCpu);
    HM_DISABLE_PREEMPT(pVCpu);

    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    vmxHCImportGuestStateEx(pVCpu, pVmcsInfo, HMVMX_CPUMCTX_EXTRN_ALL);
    CPUMR0FpuStateMaybeSaveGuestAndRestoreHost(pVCpu);
    CPUMR0DebugStateMaybeSaveGuestAndRestoreHost(pVCpu, true /* save DR6 */);

    /* Restore host-state bits that VT-x only restores partially. */
    if (pVCpu->hmr0.s.vmx.fRestoreHostFlags > VMX_RESTORE_HOST_REQUIRED)
        VMXRestoreHostState(pVCpu->hmr0.s.vmx.fRestoreHostFlags, &pVCpu->hmr0.s.vmx.RestoreHost);
    pVCpu->hmr0.s.vmx.fRestoreHostFlags = 0;

    /* Restore the lazy host MSRs as we're leaving VT-x context. */
    if (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
        hmR0VmxLazyRestoreHostMsrs(pVCpu);

    /* Update auto-load/store host MSRs values when we re-enter VT-x (as we could be on a different CPU). */
    pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = false;
    VMCPU_CMPXCHG_STATE(pVCpu, VMCPUSTATE_STARTED_HM, VMCPUSTATE_STARTED_EXEC);

    /* Clear the current VMCS data back to memory (shadow VMCS if any would have been
       cleared as part of importing the guest state above. */
    hmR0VmxClearVmcs(pVmcsInfo);

    /** @todo eliminate the need for calling VMMR0ThreadCtxHookDisable here!  */
    VMMR0ThreadCtxHookDisable(pVCpu);

    /* Leave HM context. This takes care of local init (term). */
    HMR0LeaveCpu(pVCpu);
    HM_RESTORE_PREEMPT();
    return VINF_SUCCESS;
}


/**
 * Enters the VT-x session.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 */
VMMR0DECL(int) VMXR0Enter(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    Assert(pVCpu->CTX_SUFF(pVM)->hm.s.vmx.fSupported);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    LogFlowFunc(("pVCpu=%p\n", pVCpu));
    Assert((pVCpu->hm.s.fCtxChanged &  (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE))
                                    == (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE));

#ifdef VBOX_STRICT
    /* At least verify VMX is enabled, since we can't check if we're in VMX root mode without #GP'ing. */
    RTCCUINTREG uHostCr4 = ASMGetCR4();
    if (!(uHostCr4 & X86_CR4_VMXE))
    {
        LogRelFunc(("X86_CR4_VMXE bit in CR4 is not set!\n"));
        return VERR_VMX_X86_CR4_VMXE_CLEARED;
    }
#endif

    /*
     * Do the EMT scheduled L1D and MDS flush here if needed.
     */
    if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_L1D_SCHED)
        ASMWrMsr(MSR_IA32_FLUSH_CMD, MSR_IA32_FLUSH_CMD_F_L1D);
    else if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_MDS_SCHED)
        hmR0MdsClear();

    /*
     * Load the appropriate VMCS as the current and active one.
     */
    PVMXVMCSINFO pVmcsInfo;
    bool const fInNestedGuestMode = CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx);
    if (!fInNestedGuestMode)
        pVmcsInfo = &pVCpu->hmr0.s.vmx.VmcsInfo;
    else
        pVmcsInfo = &pVCpu->hmr0.s.vmx.VmcsInfoNstGst;
    int rc = hmR0VmxLoadVmcs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs           = fInNestedGuestMode;
        pVCpu->hm.s.vmx.fSwitchedToNstGstVmcsCopyForRing3 = fInNestedGuestMode;
        pVCpu->hmr0.s.fLeaveDone = false;
        Log4Func(("Loaded Vmcs. HostCpuId=%u\n", RTMpCpuId()));
    }
    return rc;
}


/**
 * The thread-context callback.
 *
 * This is used together with RTThreadCtxHookCreate() on platforms which
 * supports it, and directly from VMMR0EmtPrepareForBlocking() and
 * VMMR0EmtResumeAfterBlocking() on platforms which don't.
 *
 * @param   enmEvent        The thread-context event.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   fGlobalInit     Whether global VT-x/AMD-V init. was used.
 * @thread  EMT(pVCpu)
 */
VMMR0DECL(void) VMXR0ThreadCtxCallback(RTTHREADCTXEVENT enmEvent, PVMCPUCC pVCpu, bool fGlobalInit)
{
    AssertPtr(pVCpu);
    RT_NOREF1(fGlobalInit);

    switch (enmEvent)
    {
        case RTTHREADCTXEVENT_OUT:
        {
            Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
            VMCPU_ASSERT_EMT(pVCpu);

            /* No longjmps (logger flushes, locks) in this fragile context. */
            VMMRZCallRing3Disable(pVCpu);
            Log4Func(("Preempting: HostCpuId=%u\n", RTMpCpuId()));

            /* Restore host-state (FPU, debug etc.) */
            if (!pVCpu->hmr0.s.fLeaveDone)
            {
                /*
                 * Do -not- import the guest-state here as we might already be in the middle of importing
                 * it, esp. bad if we're holding the PGM lock, see comment in hmR0VmxImportGuestState().
                 */
                hmR0VmxLeave(pVCpu, false /* fImportState */);
                pVCpu->hmr0.s.fLeaveDone = true;
            }

            /* Leave HM context, takes care of local init (term). */
            int rc = HMR0LeaveCpu(pVCpu);
            AssertRC(rc);

            /* Restore longjmp state. */
            VMMRZCallRing3Enable(pVCpu);
            STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatSwitchPreempt);
            break;
        }

        case RTTHREADCTXEVENT_IN:
        {
            Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
            VMCPU_ASSERT_EMT(pVCpu);

            /* Do the EMT scheduled L1D and MDS flush here if needed. */
            if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_L1D_SCHED)
                ASMWrMsr(MSR_IA32_FLUSH_CMD, MSR_IA32_FLUSH_CMD_F_L1D);
            else if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_MDS_SCHED)
                hmR0MdsClear();

            /* No longjmps here, as we don't want to trigger preemption (& its hook) while resuming. */
            VMMRZCallRing3Disable(pVCpu);
            Log4Func(("Resumed: HostCpuId=%u\n", RTMpCpuId()));

            /* Initialize the bare minimum state required for HM. This takes care of
               initializing VT-x if necessary (onlined CPUs, local init etc.) */
            int rc = hmR0EnterCpu(pVCpu);
            AssertRC(rc);
            Assert(   (pVCpu->hm.s.fCtxChanged & (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE))
                                              == (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE));

            /* Load the active VMCS as the current one. */
            PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
            rc = hmR0VmxLoadVmcs(pVmcsInfo);
            AssertRC(rc);
            Log4Func(("Resumed: Loaded Vmcs. HostCpuId=%u\n", RTMpCpuId()));
            pVCpu->hmr0.s.fLeaveDone = false;

            /* Restore longjmp state. */
            VMMRZCallRing3Enable(pVCpu);
            break;
        }

        default:
            break;
    }
}


/**
 * Exports the host state into the VMCS host-state area.
 * Sets up the VM-exit MSR-load area.
 *
 * The CPU state will be loaded from these fields on every successful VM-exit.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportHostState(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    int rc = VINF_SUCCESS;
    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_HOST_CONTEXT)
    {
        uint64_t uHostCr4 = hmR0VmxExportHostControlRegs();

        rc = hmR0VmxExportHostSegmentRegs(pVCpu, uHostCr4);
        AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

        hmR0VmxExportHostMsrs(pVCpu);

        pVCpu->hm.s.fCtxChanged &= ~HM_CHANGED_HOST_CONTEXT;
    }
    return rc;
}


/**
 * Saves the host state in the VMCS host-state.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
VMMR0DECL(int) VMXR0ExportHostState(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /*
     * Export the host state here while entering HM context.
     * When thread-context hooks are used, we might get preempted and have to re-save the host
     * state but most of the time we won't be, so do it here before we disable interrupts.
     */
    return hmR0VmxExportHostState(pVCpu);
}


/**
 * Exports the guest state into the VMCS guest-state area.
 *
 * The will typically be done before VM-entry when the guest-CPU state and the
 * VMCS state may potentially be out of sync.
 *
 * Sets up the VM-entry MSR-load and VM-exit MSR-store areas. Sets up the
 * VM-entry controls.
 * Sets up the appropriate VMX non-root function to execute guest code based on
 * the guest CPU mode.
 *
 * @returns VBox strict status code.
 * @retval  VINF_EM_RESCHEDULE_REM if we try to emulate non-paged guest code
 *          without unrestricted guest execution and the VMMDev is not presently
 *          mapped (e.g. EFI32).
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static VBOXSTRICTRC hmR0VmxExportGuestState(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    AssertPtr(pVCpu);
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);
    LogFlowFunc(("pVCpu=%p\n", pVCpu));

    STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatExportGuestState, x);

    /*
     * Determine real-on-v86 mode.
     * Used when the guest is in real-mode and unrestricted guest execution is not used.
     */
    PVMXVMCSINFOSHARED pVmcsInfoShared = pVmxTransient->pVmcsInfo->pShared;
    if (    pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fUnrestrictedGuest
        || !CPUMIsGuestInRealModeEx(&pVCpu->cpum.GstCtx))
        pVmcsInfoShared->RealMode.fRealOnV86Active = false;
    else
    {
        Assert(!pVmxTransient->fIsNestedGuest);
        pVmcsInfoShared->RealMode.fRealOnV86Active = true;
    }

    /*
     * Any ordering dependency among the sub-functions below must be explicitly stated using comments.
     * Ideally, assert that the cross-dependent bits are up-to-date at the point of using it.
     */
    int rc = vmxHCExportGuestEntryExitCtls(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    rc = vmxHCExportGuestCR0(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    VBOXSTRICTRC rcStrict = vmxHCExportGuestCR3AndCR4(pVCpu, pVmxTransient);
    if (rcStrict == VINF_SUCCESS)
    { /* likely */ }
    else
    {
        Assert(rcStrict == VINF_EM_RESCHEDULE_REM || RT_FAILURE_NP(rcStrict));
        return rcStrict;
    }

    rc = vmxHCExportGuestSegRegsXdtr(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    rc = hmR0VmxExportGuestMsrs(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    vmxHCExportGuestApicTpr(pVCpu, pVmxTransient);
    vmxHCExportGuestXcptIntercepts(pVCpu, pVmxTransient);
    vmxHCExportGuestRip(pVCpu);
    hmR0VmxExportGuestRsp(pVCpu);
    vmxHCExportGuestRflags(pVCpu, pVmxTransient);

    rc = hmR0VmxExportGuestHwvirtState(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    /* Clear any bits that may be set but exported unconditionally or unused/reserved bits. */
    ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~(  (HM_CHANGED_GUEST_GPRS_MASK & ~HM_CHANGED_GUEST_RSP)
                                                  |  HM_CHANGED_GUEST_CR2
                                                  | (HM_CHANGED_GUEST_DR_MASK & ~HM_CHANGED_GUEST_DR7)
                                                  |  HM_CHANGED_GUEST_X87
                                                  |  HM_CHANGED_GUEST_SSE_AVX
                                                  |  HM_CHANGED_GUEST_OTHER_XSAVE
                                                  |  HM_CHANGED_GUEST_XCRx
                                                  |  HM_CHANGED_GUEST_KERNEL_GS_BASE /* Part of lazy or auto load-store MSRs. */
                                                  |  HM_CHANGED_GUEST_SYSCALL_MSRS   /* Part of lazy or auto load-store MSRs. */
                                                  |  HM_CHANGED_GUEST_TSC_AUX
                                                  |  HM_CHANGED_GUEST_OTHER_MSRS
                                                  | (HM_CHANGED_KEEPER_STATE_MASK & ~HM_CHANGED_VMX_MASK)));

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExportGuestState, x);
    return rc;
}


/**
 * Exports the state shared between the host and guest into the VMCS.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxExportSharedState(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_GUEST_DR_MASK)
    {
        int rc = hmR0VmxExportSharedDebugState(pVCpu, pVmxTransient);
        AssertRC(rc);
        pVCpu->hm.s.fCtxChanged &= ~HM_CHANGED_GUEST_DR_MASK;

        /* Loading shared debug bits might have changed eflags.TF bit for debugging purposes. */
        if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_GUEST_RFLAGS)
            vmxHCExportGuestRflags(pVCpu, pVmxTransient);
    }

    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_VMX_GUEST_LAZY_MSRS)
    {
        hmR0VmxLazyLoadGuestMsrs(pVCpu);
        pVCpu->hm.s.fCtxChanged &= ~HM_CHANGED_VMX_GUEST_LAZY_MSRS;
    }

    AssertMsg(!(pVCpu->hm.s.fCtxChanged & HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE),
              ("fCtxChanged=%#RX64\n", pVCpu->hm.s.fCtxChanged));
}


/**
 * Worker for loading the guest-state bits in the inner VT-x execution loop.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @retval  VINF_EM_RESCHEDULE_REM if we try to emulate non-paged guest code
 *          without unrestricted guest execution and the VMMDev is not presently
 *          mapped (e.g. EFI32).
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static VBOXSTRICTRC hmR0VmxExportGuestStateOptimal(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

#ifdef HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE
    ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_ALL_GUEST);
#endif

    /*
     * For many VM-exits only RIP/RSP/RFLAGS (and HWVIRT state when executing a nested-guest)
     * changes. First try to export only these without going through all other changed-flag checks.
     */
    VBOXSTRICTRC   rcStrict;
    uint64_t const fCtxMask     = HM_CHANGED_ALL_GUEST & ~HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE;
    uint64_t const fMinimalMask = HM_CHANGED_GUEST_RIP | HM_CHANGED_GUEST_RSP | HM_CHANGED_GUEST_RFLAGS | HM_CHANGED_GUEST_HWVIRT;
    uint64_t const fCtxChanged  = ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged);

    /* If only RIP/RSP/RFLAGS/HWVIRT changed, export only those (quicker, happens more often).*/
    if (    (fCtxChanged & fMinimalMask)
        && !(fCtxChanged & (fCtxMask & ~fMinimalMask)))
    {
        vmxHCExportGuestRip(pVCpu);
        hmR0VmxExportGuestRsp(pVCpu);
        vmxHCExportGuestRflags(pVCpu, pVmxTransient);
        rcStrict = hmR0VmxExportGuestHwvirtState(pVCpu, pVmxTransient);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExportMinimal);
    }
    /* If anything else also changed, go through the full export routine and export as required. */
    else if (fCtxChanged & fCtxMask)
    {
        rcStrict = hmR0VmxExportGuestState(pVCpu, pVmxTransient);
        if (RT_LIKELY(rcStrict == VINF_SUCCESS))
        { /* likely */}
        else
        {
            AssertMsg(rcStrict == VINF_EM_RESCHEDULE_REM, ("Failed to export guest state! rc=%Rrc\n",
                                                           VBOXSTRICTRC_VAL(rcStrict)));
            Assert(!VMMRZCallRing3IsEnabled(pVCpu));
            return rcStrict;
        }
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExportFull);
    }
    /* Nothing changed, nothing to load here. */
    else
        rcStrict = VINF_SUCCESS;

#ifdef VBOX_STRICT
    /* All the guest state bits should be loaded except maybe the host context and/or the shared host/guest bits. */
    uint64_t const fCtxChangedCur = ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged);
    AssertMsg(!(fCtxChangedCur & fCtxMask), ("fCtxChangedCur=%#RX64\n", fCtxChangedCur));
#endif
    return rcStrict;
}


/**
 * Map the APIC-access page for virtualizing APIC accesses.
 *
 * This can cause a longjumps to R3 due to the acquisition of the PGM lock. Hence,
 * this not done as part of exporting guest state, see @bugref{8721}.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   GCPhysApicBase  The guest-physical address of the APIC access page.
 */
static int hmR0VmxMapHCApicAccessPage(PVMCPUCC pVCpu, RTGCPHYS GCPhysApicBase)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    Assert(GCPhysApicBase);

    LogFunc(("Mapping HC APIC-access page at %#RGp\n", GCPhysApicBase));

    /* Unalias the existing mapping. */
    int rc = PGMHandlerPhysicalReset(pVM, GCPhysApicBase);
    AssertRCReturn(rc, rc);

    /* Map the HC APIC-access page in place of the MMIO page, also updates the shadow page tables if necessary. */
    Assert(pVM->hmr0.s.vmx.HCPhysApicAccess != NIL_RTHCPHYS);
    rc = IOMR0MmioMapMmioHCPage(pVM, pVCpu, GCPhysApicBase, pVM->hmr0.s.vmx.HCPhysApicAccess, X86_PTE_RW | X86_PTE_P);
    AssertRCReturn(rc, rc);

    return VINF_SUCCESS;
}


/**
 * Worker function passed to RTMpOnSpecific() that is to be called on the target
 * CPU.
 *
 * @param   idCpu       The ID for the CPU the function is called on.
 * @param   pvUser1     Null, not used.
 * @param   pvUser2     Null, not used.
 */
static DECLCALLBACK(void) hmR0DispatchHostNmi(RTCPUID idCpu, void *pvUser1, void *pvUser2)
{
    RT_NOREF3(idCpu, pvUser1, pvUser2);
    VMXDispatchHostNmi();
}


/**
 * Dispatching an NMI on the host CPU that received it.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object corresponding to the VMCS that was
 *                      executing when receiving the host NMI in VMX non-root
 *                      operation.
 */
static int hmR0VmxExitHostNmi(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
    RTCPUID const idCpu = pVmcsInfo->idHostCpuExec;
    Assert(idCpu != NIL_RTCPUID);

    /*
     * We don't want to delay dispatching the NMI any more than we have to. However,
     * we have already chosen -not- to dispatch NMIs when interrupts were still disabled
     * after executing guest or nested-guest code for the following reasons:
     *
     *   - We would need to perform VMREADs with interrupts disabled and is orders of
     *     magnitude worse when we run as a nested hypervisor without VMCS shadowing
     *     supported by the host hypervisor.
     *
     *   - It affects the common VM-exit scenario and keeps interrupts disabled for a
     *     longer period of time just for handling an edge case like host NMIs which do
     *     not occur nearly as frequently as other VM-exits.
     *
     * Let's cover the most likely scenario first. Check if we are on the target CPU
     * and dispatch the NMI right away. This should be much faster than calling into
     * RTMpOnSpecific() machinery.
     */
    bool fDispatched = false;
    RTCCUINTREG const fEFlags = ASMIntDisableFlags();
    if (idCpu == RTMpCpuId())
    {
        VMXDispatchHostNmi();
        fDispatched = true;
    }
    ASMSetFlags(fEFlags);
    if (fDispatched)
    {
        STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatExitHostNmiInGC);
        return VINF_SUCCESS;
    }

    /*
     * RTMpOnSpecific() waits until the worker function has run on the target CPU. So
     * there should be no race or recursion even if we are unlucky enough to be preempted
     * (to the target CPU) without dispatching the host NMI above.
     */
    STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatExitHostNmiInGCIpi);
    return RTMpOnSpecific(idCpu, &hmR0DispatchHostNmi, NULL /* pvUser1 */,  NULL /* pvUser2 */);
}


#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Merges the guest with the nested-guest MSR bitmap in preparation of executing the
 * nested-guest using hardware-assisted VMX.
 *
 * @param   pVCpu               The cross context virtual CPU structure.
 * @param   pVmcsInfoNstGst     The nested-guest VMCS info. object.
 * @param   pVmcsInfoGst        The guest VMCS info. object.
 */
static void hmR0VmxMergeMsrBitmapNested(PCVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfoNstGst, PCVMXVMCSINFO pVmcsInfoGst)
{
    uint32_t const cbMsrBitmap    = X86_PAGE_4K_SIZE;
    uint64_t       *pu64MsrBitmap = (uint64_t *)pVmcsInfoNstGst->pvMsrBitmap;
    Assert(pu64MsrBitmap);

    /*
     * We merge the guest MSR bitmap with the nested-guest MSR bitmap such that any
     * MSR that is intercepted by the guest is also intercepted while executing the
     * nested-guest using hardware-assisted VMX.
     *
     * Note! If the nested-guest is not using an MSR bitmap, every MSR must cause a
     *       nested-guest VM-exit even if the outer guest is not intercepting some
     *       MSRs. We cannot assume the caller has initialized the nested-guest
     *       MSR bitmap in this case.
     *
     *       The nested hypervisor may also switch whether it uses MSR bitmaps for
     *       each of its VM-entry, hence initializing it once per-VM while setting
     *       up the nested-guest VMCS is not sufficient.
     */
    PCVMXVVMCS const pVmcsNstGst  = &pVCpu->cpum.GstCtx.hwvirt.vmx.Vmcs;
    if (pVmcsNstGst->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
    {
        uint64_t const *pu64MsrBitmapNstGst = (uint64_t const *)&pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap[0];
        uint64_t const *pu64MsrBitmapGst    = (uint64_t const *)pVmcsInfoGst->pvMsrBitmap;
        Assert(pu64MsrBitmapNstGst);
        Assert(pu64MsrBitmapGst);

        /** @todo Detect and use EVEX.POR? */
        uint32_t const cFrags = cbMsrBitmap / sizeof(uint64_t);
        for (uint32_t i = 0; i < cFrags; i++)
            pu64MsrBitmap[i] = pu64MsrBitmapNstGst[i] | pu64MsrBitmapGst[i];
    }
    else
        ASMMemFill32(pu64MsrBitmap, cbMsrBitmap, UINT32_C(0xffffffff));
}


/**
 * Merges the guest VMCS in to the nested-guest VMCS controls in preparation of
 * hardware-assisted VMX execution of the nested-guest.
 *
 * For a guest, we don't modify these controls once we set up the VMCS and hence
 * this function is never called.
 *
 * For nested-guests since the nested hypervisor provides these controls on every
 * nested-guest VM-entry and could potentially change them everytime we need to
 * merge them before every nested-guest VM-entry.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 */
static int hmR0VmxMergeVmcsNested(PVMCPUCC pVCpu)
{
    PVMCC const         pVM          = pVCpu->CTX_SUFF(pVM);
    PCVMXVMCSINFO const pVmcsInfoGst = &pVCpu->hmr0.s.vmx.VmcsInfo;
    PCVMXVVMCS const    pVmcsNstGst  = &pVCpu->cpum.GstCtx.hwvirt.vmx.Vmcs;

    /*
     * Merge the controls with the requirements of the guest VMCS.
     *
     * We do not need to validate the nested-guest VMX features specified in the nested-guest
     * VMCS with the features supported by the physical CPU as it's already done by the
     * VMLAUNCH/VMRESUME instruction emulation.
     *
     * This is because the VMX features exposed by CPUM (through CPUID/MSRs) to the guest are
     * derived from the VMX features supported by the physical CPU.
     */

    /* Pin-based VM-execution controls. */
    uint32_t const u32PinCtls = pVmcsNstGst->u32PinCtls | pVmcsInfoGst->u32PinCtls;

    /* Processor-based VM-execution controls. */
    uint32_t       u32ProcCtls = (pVmcsNstGst->u32ProcCtls  & ~VMX_PROC_CTLS_USE_IO_BITMAPS)
                               | (pVmcsInfoGst->u32ProcCtls & ~(  VMX_PROC_CTLS_INT_WINDOW_EXIT
                                                                | VMX_PROC_CTLS_NMI_WINDOW_EXIT
                                                                | VMX_PROC_CTLS_MOV_DR_EXIT /* hmR0VmxExportSharedDebugState makes
                                                                                               sure guest DRx regs are loaded. */
                                                                | VMX_PROC_CTLS_USE_TPR_SHADOW
                                                                | VMX_PROC_CTLS_MONITOR_TRAP_FLAG));

    /* Secondary processor-based VM-execution controls. */
    uint32_t const u32ProcCtls2 = (pVmcsNstGst->u32ProcCtls2  & ~VMX_PROC_CTLS2_VPID)
                                | (pVmcsInfoGst->u32ProcCtls2 & ~(  VMX_PROC_CTLS2_VIRT_APIC_ACCESS
                                                                  | VMX_PROC_CTLS2_INVPCID
                                                                  | VMX_PROC_CTLS2_VMCS_SHADOWING
                                                                  | VMX_PROC_CTLS2_RDTSCP
                                                                  | VMX_PROC_CTLS2_XSAVES_XRSTORS
                                                                  | VMX_PROC_CTLS2_APIC_REG_VIRT
                                                                  | VMX_PROC_CTLS2_VIRT_INT_DELIVERY
                                                                  | VMX_PROC_CTLS2_VMFUNC));

    /*
     * VM-entry controls:
     * These controls contains state that depends on the nested-guest state (primarily
     * EFER MSR) and is thus not constant between VMLAUNCH/VMRESUME and the nested-guest
     * VM-exit. Although the nested hypervisor cannot change it, we need to in order to
     * properly continue executing the nested-guest if the EFER MSR changes but does not
     * cause a nested-guest VM-exits.
     *
     * VM-exit controls:
     * These controls specify the host state on return. We cannot use the controls from
     * the nested hypervisor state as is as it would contain the guest state rather than
     * the host state. Since the host state is subject to change (e.g. preemption, trips
     * to ring-3, longjmp and rescheduling to a different host CPU) they are not constant
     * through VMLAUNCH/VMRESUME and the nested-guest VM-exit.
     *
     * VM-entry MSR-load:
     * The guest MSRs from the VM-entry MSR-load area are already loaded into the guest-CPU
     * context by the VMLAUNCH/VMRESUME instruction emulation.
     *
     * VM-exit MSR-store:
     * The VM-exit emulation will take care of populating the MSRs from the guest-CPU context
     * back into the VM-exit MSR-store area.
     *
     * VM-exit MSR-load areas:
     * This must contain the real host MSRs with hardware-assisted VMX execution. Hence, we
     * can entirely ignore what the nested hypervisor wants to load here.
     */

    /*
     * Exception bitmap.
     *
     * We could remove #UD from the guest bitmap and merge it with the nested-guest bitmap
     * here (and avoid doing anything while exporting nested-guest state), but to keep the
     * code more flexible if intercepting exceptions become more dynamic in the future we do
     * it as part of exporting the nested-guest state.
     */
    uint32_t const u32XcptBitmap = pVmcsNstGst->u32XcptBitmap | pVmcsInfoGst->u32XcptBitmap;

    /*
     * CR0/CR4 guest/host mask.
     *
     * Modifications by the nested-guest to CR0/CR4 bits owned by the host and the guest must
     * cause VM-exits, so we need to merge them here.
     */
    uint64_t const u64Cr0Mask = pVmcsNstGst->u64Cr0Mask.u | pVmcsInfoGst->u64Cr0Mask;
    uint64_t const u64Cr4Mask = pVmcsNstGst->u64Cr4Mask.u | pVmcsInfoGst->u64Cr4Mask;

    /*
     * Page-fault error-code mask and match.
     *
     * Although we require unrestricted guest execution (and thereby nested-paging) for
     * hardware-assisted VMX execution of nested-guests and thus the outer guest doesn't
     * normally intercept #PFs, it might intercept them for debugging purposes.
     *
     * If the outer guest is not intercepting #PFs, we can use the nested-guest #PF filters.
     * If the outer guest is intercepting #PFs, we must intercept all #PFs.
     */
    uint32_t u32XcptPFMask;
    uint32_t u32XcptPFMatch;
    if (!(pVmcsInfoGst->u32XcptBitmap & RT_BIT(X86_XCPT_PF)))
    {
        u32XcptPFMask  = pVmcsNstGst->u32XcptPFMask;
        u32XcptPFMatch = pVmcsNstGst->u32XcptPFMatch;
    }
    else
    {
        u32XcptPFMask  = 0;
        u32XcptPFMatch = 0;
    }

    /*
     * Pause-Loop exiting.
     */
    /** @todo r=bird: given that both pVM->hm.s.vmx.cPleGapTicks and
     *        pVM->hm.s.vmx.cPleWindowTicks defaults to zero, I cannot see how
     *        this will work... */
    uint32_t const cPleGapTicks    = RT_MIN(pVM->hm.s.vmx.cPleGapTicks,    pVmcsNstGst->u32PleGap);
    uint32_t const cPleWindowTicks = RT_MIN(pVM->hm.s.vmx.cPleWindowTicks, pVmcsNstGst->u32PleWindow);

    /*
     * Pending debug exceptions.
     * Currently just copy whatever the nested-guest provides us.
     */
    uint64_t const uPendingDbgXcpts = pVmcsNstGst->u64GuestPendingDbgXcpts.u;

    /*
     * I/O Bitmap.
     *
     * We do not use the I/O bitmap that may be provided by the nested hypervisor as we always
     * intercept all I/O port accesses.
     */
    Assert(u32ProcCtls & VMX_PROC_CTLS_UNCOND_IO_EXIT);
    Assert(!(u32ProcCtls & VMX_PROC_CTLS_USE_IO_BITMAPS));

    /*
     * VMCS shadowing.
     *
     * We do not yet expose VMCS shadowing to the guest and thus VMCS shadowing should not be
     * enabled while executing the nested-guest.
     */
    Assert(!(u32ProcCtls2 & VMX_PROC_CTLS2_VMCS_SHADOWING));

    /*
     * APIC-access page.
     */
    RTHCPHYS HCPhysApicAccess;
    if (u32ProcCtls2 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
    {
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS);
        RTGCPHYS const GCPhysApicAccess = pVmcsNstGst->u64AddrApicAccess.u;

        void          *pvPage;
        PGMPAGEMAPLOCK PgLockApicAccess;
        int rc = PGMPhysGCPhys2CCPtr(pVM, GCPhysApicAccess, &pvPage, &PgLockApicAccess);
        if (RT_SUCCESS(rc))
        {
            rc = PGMPhysGCPhys2HCPhys(pVM, GCPhysApicAccess, &HCPhysApicAccess);
            AssertMsgRCReturn(rc, ("Failed to get host-physical address for APIC-access page at %#RGp\n", GCPhysApicAccess), rc);

            /** @todo Handle proper releasing of page-mapping lock later. */
            PGMPhysReleasePageMappingLock(pVCpu->CTX_SUFF(pVM), &PgLockApicAccess);
        }
        else
            return rc;
    }
    else
        HCPhysApicAccess = 0;

    /*
     * Virtual-APIC page and TPR threshold.
     */
    RTHCPHYS HCPhysVirtApic;
    uint32_t u32TprThreshold;
    if (u32ProcCtls & VMX_PROC_CTLS_USE_TPR_SHADOW)
    {
        Assert(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_TPR_SHADOW);
        RTGCPHYS const GCPhysVirtApic = pVmcsNstGst->u64AddrVirtApic.u;

        void          *pvPage;
        PGMPAGEMAPLOCK PgLockVirtApic;
        int rc = PGMPhysGCPhys2CCPtr(pVM, GCPhysVirtApic, &pvPage, &PgLockVirtApic);
        if (RT_SUCCESS(rc))
        {
            rc = PGMPhysGCPhys2HCPhys(pVM, GCPhysVirtApic, &HCPhysVirtApic);
            AssertMsgRCReturn(rc, ("Failed to get host-physical address for virtual-APIC page at %#RGp\n", GCPhysVirtApic), rc);

            /** @todo Handle proper releasing of page-mapping lock later. */
            PGMPhysReleasePageMappingLock(pVCpu->CTX_SUFF(pVM), &PgLockVirtApic);
        }
        else
            return rc;

        u32TprThreshold = pVmcsNstGst->u32TprThreshold;
    }
    else
    {
        HCPhysVirtApic  = 0;
        u32TprThreshold = 0;

        /*
         * We must make sure CR8 reads/write must cause VM-exits when TPR shadowing is not
         * used by the nested hypervisor. Preventing MMIO accesses to the physical APIC will
         * be taken care of by EPT/shadow paging.
         */
        if (pVM->hmr0.s.fAllow64BitGuests)
            u32ProcCtls |= VMX_PROC_CTLS_CR8_STORE_EXIT
                        |  VMX_PROC_CTLS_CR8_LOAD_EXIT;
    }

    /*
     * Validate basic assumptions.
     */
    PVMXVMCSINFO pVmcsInfoNstGst = &pVCpu->hmr0.s.vmx.VmcsInfoNstGst;
    Assert(pVM->hmr0.s.vmx.fUnrestrictedGuest);
    Assert(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_SECONDARY_CTLS);
    Assert(hmGetVmxActiveVmcsInfo(pVCpu) == pVmcsInfoNstGst);

    /*
     * Commit it to the nested-guest VMCS.
     */
    int rc = VINF_SUCCESS;
    if (pVmcsInfoNstGst->u32PinCtls != u32PinCtls)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PIN_EXEC, u32PinCtls);
    if (pVmcsInfoNstGst->u32ProcCtls != u32ProcCtls)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, u32ProcCtls);
    if (pVmcsInfoNstGst->u32ProcCtls2 != u32ProcCtls2)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC2, u32ProcCtls2);
    if (pVmcsInfoNstGst->u32XcptBitmap != u32XcptBitmap)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_EXCEPTION_BITMAP, u32XcptBitmap);
    if (pVmcsInfoNstGst->u64Cr0Mask != u64Cr0Mask)
        rc |= VMXWriteVmcsNw(VMX_VMCS_CTRL_CR0_MASK, u64Cr0Mask);
    if (pVmcsInfoNstGst->u64Cr4Mask != u64Cr4Mask)
        rc |= VMXWriteVmcsNw(VMX_VMCS_CTRL_CR4_MASK, u64Cr4Mask);
    if (pVmcsInfoNstGst->u32XcptPFMask != u32XcptPFMask)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MASK, u32XcptPFMask);
    if (pVmcsInfoNstGst->u32XcptPFMatch != u32XcptPFMatch)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MATCH, u32XcptPFMatch);
    if (   !(u32ProcCtls  & VMX_PROC_CTLS_PAUSE_EXIT)
        &&  (u32ProcCtls2 & VMX_PROC_CTLS2_PAUSE_LOOP_EXIT))
    {
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_PAUSE_LOOP_EXIT);
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_GAP, cPleGapTicks);
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_WINDOW, cPleWindowTicks);
    }
    if (pVmcsInfoNstGst->HCPhysVirtApic != HCPhysVirtApic)
        rc |= VMXWriteVmcs64(VMX_VMCS64_CTRL_VIRT_APIC_PAGEADDR_FULL, HCPhysVirtApic);
    rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_TPR_THRESHOLD, u32TprThreshold);
    if (u32ProcCtls2 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
        rc |= VMXWriteVmcs64(VMX_VMCS64_CTRL_APIC_ACCESSADDR_FULL, HCPhysApicAccess);
    rc |= VMXWriteVmcsNw(VMX_VMCS_GUEST_PENDING_DEBUG_XCPTS, uPendingDbgXcpts);
    AssertRC(rc);

    /*
     * Update the nested-guest VMCS cache.
     */
    pVmcsInfoNstGst->u32PinCtls     = u32PinCtls;
    pVmcsInfoNstGst->u32ProcCtls    = u32ProcCtls;
    pVmcsInfoNstGst->u32ProcCtls2   = u32ProcCtls2;
    pVmcsInfoNstGst->u32XcptBitmap  = u32XcptBitmap;
    pVmcsInfoNstGst->u64Cr0Mask     = u64Cr0Mask;
    pVmcsInfoNstGst->u64Cr4Mask     = u64Cr4Mask;
    pVmcsInfoNstGst->u32XcptPFMask  = u32XcptPFMask;
    pVmcsInfoNstGst->u32XcptPFMatch = u32XcptPFMatch;
    pVmcsInfoNstGst->HCPhysVirtApic = HCPhysVirtApic;

    /*
     * We need to flush the TLB if we are switching the APIC-access page address.
     * See Intel spec. 28.3.3.4 "Guidelines for Use of the INVEPT Instruction".
     */
    if (u32ProcCtls2 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = true;

    /*
     * MSR bitmap.
     *
     * The MSR bitmap address has already been initialized while setting up the nested-guest
     * VMCS, here we need to merge the MSR bitmaps.
     */
    if (u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
        hmR0VmxMergeMsrBitmapNested(pVCpu, pVmcsInfoNstGst, pVmcsInfoGst);

    return VINF_SUCCESS;
}
#endif /* VBOX_WITH_NESTED_HWVIRT_VMX */


/**
 * Does the preparations before executing guest code in VT-x.
 *
 * This may cause longjmps to ring-3 and may even result in rescheduling to the
 * recompiler/IEM. We must be cautious what we do here regarding committing
 * guest-state information into the VMCS assuming we assuredly execute the
 * guest in VT-x mode.
 *
 * If we fall back to the recompiler/IEM after updating the VMCS and clearing
 * the common-state (TRPM/forceflags), we must undo those changes so that the
 * recompiler/IEM can (and should) use them when it resumes guest execution.
 * Otherwise such operations must be done when we can no longer exit to ring-3.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @retval  VINF_SUCCESS if we can proceed with running the guest, interrupts
 *          have been disabled.
 * @retval  VINF_VMX_VMEXIT if a nested-guest VM-exit occurs (e.g., while evaluating
 *          pending events).
 * @retval  VINF_EM_RESET if a triple-fault occurs while injecting a
 *          double-fault into the guest.
 * @retval  VINF_EM_DBG_STEPPED if @a fStepping is true and an event was
 *          dispatched directly.
 * @retval  VINF_* scheduling changes, we have to go back to ring-3.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   fStepping       Whether we are single-stepping the guest in the
 *                          hypervisor debugger. Makes us ignore some of the reasons
 *                          for returning to ring-3, and return VINF_EM_DBG_STEPPED
 *                          if event dispatching took place.
 */
static VBOXSTRICTRC hmR0VmxPreRunGuest(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, bool fStepping)
{
    Assert(VMMRZCallRing3IsEnabled(pVCpu));

    Log4Func(("fIsNested=%RTbool fStepping=%RTbool\n", pVmxTransient->fIsNestedGuest, fStepping));

#ifdef VBOX_WITH_NESTED_HWVIRT_ONLY_IN_IEM
    if (pVmxTransient->fIsNestedGuest)
    {
        RT_NOREF2(pVCpu, fStepping);
        Log2Func(("Rescheduling to IEM due to nested-hwvirt or forced IEM exec -> VINF_EM_RESCHEDULE_REM\n"));
        return VINF_EM_RESCHEDULE_REM;
    }
#endif

    /*
     * Check and process force flag actions, some of which might require us to go back to ring-3.
     */
    VBOXSTRICTRC rcStrict = vmxHCCheckForceFlags(pVCpu, pVmxTransient->fIsNestedGuest, fStepping);
    if (rcStrict == VINF_SUCCESS)
    {
        /* FFs don't get set all the time. */
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        if (   pVmxTransient->fIsNestedGuest
            && !CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
        {
            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
            return VINF_VMX_VMEXIT;
        }
#endif
    }
    else
        return rcStrict;

    /*
     * Virtualize memory-mapped accesses to the physical APIC (may take locks).
     */
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    if (   !pVCpu->hm.s.vmx.u64GstMsrApicBase
        && (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
        && PDMHasApic(pVM))
    {
        /* Get the APIC base MSR from the virtual APIC device. */
        uint64_t const uApicBaseMsr = APICGetBaseMsrNoCheck(pVCpu);

        /* Map the APIC access page. */
        int rc = hmR0VmxMapHCApicAccessPage(pVCpu, uApicBaseMsr & ~(RTGCPHYS)GUEST_PAGE_OFFSET_MASK);
        AssertRCReturn(rc, rc);

        /* Update the per-VCPU cache of the APIC base MSR corresponding to the mapped APIC access page. */
        pVCpu->hm.s.vmx.u64GstMsrApicBase = uApicBaseMsr;
    }

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * Merge guest VMCS controls with the nested-guest VMCS controls.
     *
     * Even if we have not executed the guest prior to this (e.g. when resuming from a
     * saved state), we should be okay with merging controls as we initialize the
     * guest VMCS controls as part of VM setup phase.
     */
    if (   pVmxTransient->fIsNestedGuest
        && !pVCpu->hm.s.vmx.fMergedNstGstCtls)
    {
        int rc = hmR0VmxMergeVmcsNested(pVCpu);
        AssertRCReturn(rc, rc);
        pVCpu->hm.s.vmx.fMergedNstGstCtls = true;
    }
#endif

    /*
     * Evaluate events to be injected into the guest.
     *
     * Events in TRPM can be injected without inspecting the guest state.
     * If any new events (interrupts/NMI) are pending currently, we try to set up the
     * guest to cause a VM-exit the next time they are ready to receive the event.
     */
    if (TRPMHasTrap(pVCpu))
        vmxHCTrpmTrapToPendingEvent(pVCpu);

    uint32_t fIntrState;
    rcStrict = vmxHCEvaluatePendingEvent(pVCpu, pVmxTransient->pVmcsInfo, pVmxTransient->fIsNestedGuest,
                                         &fIntrState);

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * While evaluating pending events if something failed (unlikely) or if we were
     * preparing to run a nested-guest but performed a nested-guest VM-exit, we should bail.
     */
    if (rcStrict != VINF_SUCCESS)
        return rcStrict;
    if (   pVmxTransient->fIsNestedGuest
        && !CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
    {
        STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
        return VINF_VMX_VMEXIT;
    }
#else
    Assert(rcStrict == VINF_SUCCESS);
#endif

    /*
     * Event injection may take locks (currently the PGM lock for real-on-v86 case) and thus
     * needs to be done with longjmps or interrupts + preemption enabled. Event injection might
     * also result in triple-faulting the VM.
     *
     * With nested-guests, the above does not apply since unrestricted guest execution is a
     * requirement. Regardless, we do this here to avoid duplicating code elsewhere.
     */
    rcStrict = vmxHCInjectPendingEvent(pVCpu, pVmxTransient->pVmcsInfo, pVmxTransient->fIsNestedGuest,
                                       fIntrState, fStepping);
    if (RT_LIKELY(rcStrict == VINF_SUCCESS))
    { /* likely */ }
    else
    {
        AssertMsg(rcStrict == VINF_EM_RESET || (rcStrict == VINF_EM_DBG_STEPPED && fStepping),
                  ("%Rrc\n", VBOXSTRICTRC_VAL(rcStrict)));
        return rcStrict;
    }

    /*
     * A longjump might result in importing CR3 even for VM-exits that don't necessarily
     * import CR3 themselves. We will need to update them here, as even as late as the above
     * hmR0VmxInjectPendingEvent() call may lazily import guest-CPU state on demand causing
     * the below force flags to be set.
     */
    if (VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3))
    {
        Assert(!(ASMAtomicUoReadU64(&pVCpu->cpum.GstCtx.fExtrn) & CPUMCTX_EXTRN_CR3));
        int rc2 = PGMUpdateCR3(pVCpu, CPUMGetGuestCR3(pVCpu));
        AssertMsgReturn(rc2 == VINF_SUCCESS || rc2 == VINF_PGM_SYNC_CR3,
                        ("%Rrc\n", rc2), RT_FAILURE_NP(rc2) ? rc2 : VERR_IPE_UNEXPECTED_INFO_STATUS);
        Assert(!VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3));
    }

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /* Paranoia. */
    Assert(!pVmxTransient->fIsNestedGuest || CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx));
#endif

    /*
     * No longjmps to ring-3 from this point on!!!
     * Asserts() will still longjmp to ring-3 (but won't return), which is intentional, better than a kernel panic.
     * This also disables flushing of the R0-logger instance (if any).
     */
    VMMRZCallRing3Disable(pVCpu);

    /*
     * Export the guest state bits.
     *
     * We cannot perform longjmps while loading the guest state because we do not preserve the
     * host/guest state (although the VMCS will be preserved) across longjmps which can cause
     * CPU migration.
     *
     * If we are injecting events to a real-on-v86 mode guest, we would have updated RIP and some segment
     * registers. Hence, exporting of the guest state needs to be done -after- injection of events.
     */
    rcStrict = hmR0VmxExportGuestStateOptimal(pVCpu, pVmxTransient);
    if (RT_LIKELY(rcStrict == VINF_SUCCESS))
    { /* likely */ }
    else
    {
        VMMRZCallRing3Enable(pVCpu);
        return rcStrict;
    }

    /*
     * We disable interrupts so that we don't miss any interrupts that would flag preemption
     * (IPI/timers etc.) when thread-context hooks aren't used and we've been running with
     * preemption disabled for a while.  Since this is purely to aid the
     * RTThreadPreemptIsPending() code, it doesn't matter that it may temporarily reenable and
     * disable interrupt on NT.
     *
     * We need to check for force-flags that could've possible been altered since we last
     * checked them (e.g. by PDMGetInterrupt() leaving the PDM critical section,
     * see @bugref{6398}).
     *
     * We also check a couple of other force-flags as a last opportunity to get the EMT back
     * to ring-3 before executing guest code.
     */
    pVmxTransient->fEFlags = ASMIntDisableFlags();

    if (   (   !VM_FF_IS_ANY_SET(pVM, VM_FF_EMT_RENDEZVOUS | VM_FF_TM_VIRTUAL_SYNC)
            && !VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HM_TO_R3_MASK))
        || (   fStepping /* Optimized for the non-stepping case, so a bit of unnecessary work when stepping. */
            && !VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HM_TO_R3_MASK & ~(VMCPU_FF_TIMER | VMCPU_FF_PDM_CRITSECT))) )
    {
        if (!RTThreadPreemptIsPending(NIL_RTTHREAD))
        {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            /*
             * If we are executing a nested-guest make sure that we should intercept subsequent
             * events. The one we are injecting might be part of VM-entry. This is mainly to keep
             * the VM-exit instruction emulation happy.
             */
            if (pVmxTransient->fIsNestedGuest)
                CPUMSetGuestVmxInterceptEvents(&pVCpu->cpum.GstCtx, true);
#endif

            /*
             * We've injected any pending events. This is really the point of no return (to ring-3).
             *
             * Note! The caller expects to continue with interrupts & longjmps disabled on successful
             *       returns from this function, so do -not- enable them here.
             */
            pVCpu->hm.s.Event.fPending = false;
            return VINF_SUCCESS;
        }

        STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchPendingHostIrq);
        rcStrict = VINF_EM_RAW_INTERRUPT;
    }
    else
    {
        STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchHmToR3FF);
        rcStrict = VINF_EM_RAW_TO_R3;
    }

    ASMSetFlags(pVmxTransient->fEFlags);
    VMMRZCallRing3Enable(pVCpu);

    return rcStrict;
}


/**
 * Final preparations before executing guest code using hardware-assisted VMX.
 *
 * We can no longer get preempted to a different host CPU and there are no returns
 * to ring-3. We ignore any errors that may happen from this point (e.g. VMWRITE
 * failures), this function is not intended to fail sans unrecoverable hardware
 * errors.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks Called with preemption disabled.
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxPreRunGuestCommitted(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!pVCpu->hm.s.Event.fPending);

    /*
     * Indicate start of guest execution and where poking EMT out of guest-context is recognized.
     */
    VMCPU_ASSERT_STATE(pVCpu, VMCPUSTATE_STARTED_HM);
    VMCPU_SET_STATE(pVCpu, VMCPUSTATE_STARTED_EXEC);

    PVMCC         pVM          = pVCpu->CTX_SUFF(pVM);
    PVMXVMCSINFO  pVmcsInfo    = pVmxTransient->pVmcsInfo;
    PHMPHYSCPU    pHostCpu     = hmR0GetCurrentCpu();
    RTCPUID const idCurrentCpu = pHostCpu->idCpu;

    if (!CPUMIsGuestFPUStateActive(pVCpu))
    {
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatLoadGuestFpuState, x);
        if (CPUMR0LoadGuestFPU(pVM, pVCpu) == VINF_CPUM_HOST_CR0_MODIFIED)
            pVCpu->hm.s.fCtxChanged |= HM_CHANGED_HOST_CONTEXT;
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatLoadGuestFpuState, x);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatLoadGuestFpu);
    }

    /*
     * Re-export the host state bits as we may've been preempted (only happens when
     * thread-context hooks are used or when the VM start function changes) or if
     * the host CR0 is modified while loading the guest FPU state above.
     *
     * The 64-on-32 switcher saves the (64-bit) host state into the VMCS and if we
     * changed the switcher back to 32-bit, we *must* save the 32-bit host state here,
     * see @bugref{8432}.
     *
     * This may also happen when switching to/from a nested-guest VMCS without leaving
     * ring-0.
     */
    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_HOST_CONTEXT)
    {
        hmR0VmxExportHostState(pVCpu);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExportHostState);
    }
    Assert(!(pVCpu->hm.s.fCtxChanged & HM_CHANGED_HOST_CONTEXT));

    /*
     * Export the state shared between host and guest (FPU, debug, lazy MSRs).
     */
    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE)
        hmR0VmxExportSharedState(pVCpu, pVmxTransient);
    AssertMsg(!pVCpu->hm.s.fCtxChanged, ("fCtxChanged=%#RX64\n", pVCpu->hm.s.fCtxChanged));

    /*
     * Store status of the shared guest/host debug state at the time of VM-entry.
     */
    pVmxTransient->fWasGuestDebugStateActive = CPUMIsGuestDebugStateActive(pVCpu);
    pVmxTransient->fWasHyperDebugStateActive = CPUMIsHyperDebugStateActive(pVCpu);

    /*
     * Always cache the TPR-shadow if the virtual-APIC page exists, thereby skipping
     * more than one conditional check. The post-run side of our code shall determine
     * if it needs to sync. the virtual APIC TPR with the TPR-shadow.
     */
    if (pVmcsInfo->pbVirtApic)
        pVmxTransient->u8GuestTpr = pVmcsInfo->pbVirtApic[XAPIC_OFF_TPR];

    /*
     * Update the host MSRs values in the VM-exit MSR-load area.
     */
    if (!pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs)
    {
        if (pVmcsInfo->cExitMsrLoad > 0)
            hmR0VmxUpdateAutoLoadHostMsrs(pVCpu, pVmcsInfo);
        pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = true;
    }

    /*
     * Evaluate if we need to intercept guest RDTSC/P accesses. Set up the
     * VMX-preemption timer based on the next virtual sync clock deadline.
     */
    if (   !pVmxTransient->fUpdatedTscOffsettingAndPreemptTimer
        || idCurrentCpu != pVCpu->hmr0.s.idLastCpu)
    {
        hmR0VmxUpdateTscOffsettingAndPreemptTimer(pVCpu, pVmxTransient, idCurrentCpu);
        pVmxTransient->fUpdatedTscOffsettingAndPreemptTimer = true;
    }

    /* Record statistics of how often we use TSC offsetting as opposed to intercepting RDTSC/P. */
    bool const fIsRdtscIntercepted = RT_BOOL(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_RDTSC_EXIT);
    if (!fIsRdtscIntercepted)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatTscOffset);
    else
        STAM_COUNTER_INC(&pVCpu->hm.s.StatTscIntercept);

    ASMAtomicUoWriteBool(&pVCpu->hm.s.fCheckedTLBFlush, true);  /* Used for TLB flushing, set this across the world switch. */
    hmR0VmxFlushTaggedTlb(pHostCpu, pVCpu, pVmcsInfo);          /* Invalidate the appropriate guest entries from the TLB. */
    Assert(idCurrentCpu == pVCpu->hmr0.s.idLastCpu);
    pVCpu->hm.s.vmx.LastError.idCurrentCpu = idCurrentCpu;      /* Record the error reporting info. with the current host CPU. */
    pVmcsInfo->idHostCpuState = idCurrentCpu;                   /* Record the CPU for which the host-state has been exported. */
    pVmcsInfo->idHostCpuExec  = idCurrentCpu;                   /* Record the CPU on which we shall execute. */

    STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatEntry, &pVCpu->hm.s.StatInGC, x);

    TMNotifyStartOfExecution(pVM, pVCpu);                       /* Notify TM to resume its clocks when TSC is tied to execution,
                                                                   as we're about to start executing the guest. */

    /*
     * Load the guest TSC_AUX MSR when we are not intercepting RDTSCP.
     *
     * This is done this late as updating the TSC offsetting/preemption timer above
     * figures out if we can skip intercepting RDTSCP by calculating the number of
     * host CPU ticks till the next virtual sync deadline (for the dynamic case).
     */
    if (   (pVmcsInfo->u32ProcCtls2 & VMX_PROC_CTLS2_RDTSCP)
        && !fIsRdtscIntercepted)
    {
        vmxHCImportGuestStateEx(pVCpu, pVmcsInfo, CPUMCTX_EXTRN_TSC_AUX);

        /* NB: Because we call hmR0VmxAddAutoLoadStoreMsr with fUpdateHostMsr=true,
           it's safe even after hmR0VmxUpdateAutoLoadHostMsrs has already been done. */
        int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K8_TSC_AUX, CPUMGetGuestTscAux(pVCpu),
                                            true /* fSetReadWrite */, true /* fUpdateHostMsr */);
        AssertRC(rc);
        Assert(!pVmxTransient->fRemoveTscAuxMsr);
        pVmxTransient->fRemoveTscAuxMsr = true;
    }

#ifdef VBOX_STRICT
    Assert(pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs);
    hmR0VmxCheckAutoLoadStoreMsrs(pVCpu, pVmcsInfo, pVmxTransient->fIsNestedGuest);
    hmR0VmxCheckHostEferMsr(pVmcsInfo);
    AssertRC(vmxHCCheckCachedVmcsCtls(pVCpu, pVmcsInfo, pVmxTransient->fIsNestedGuest));
#endif

#ifdef HMVMX_ALWAYS_CHECK_GUEST_STATE
    /** @todo r=ramshankar: We can now probably use iemVmxVmentryCheckGuestState here.
     *        Add a PVMXMSRS parameter to it, so that IEM can look at the host MSRs,
     *        see @bugref{9180#c54}. */
    uint32_t const uInvalidReason = hmR0VmxCheckGuestState(pVCpu, pVmcsInfo);
    if (uInvalidReason != VMX_IGS_REASON_NOT_FOUND)
        Log4(("hmR0VmxCheckGuestState returned %#x\n", uInvalidReason));
#endif
}


/**
 * First C routine invoked after running guest code using hardware-assisted VMX.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   rcVMRun         Return code of VMLAUNCH/VMRESUME.
 *
 * @remarks Called with interrupts disabled, and returns with interrupts enabled!
 *
 * @remarks No-long-jump zone!!! This function will however re-enable longjmps
 *          unconditionally when it is safe to do so.
 */
static void hmR0VmxPostRunGuest(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, int rcVMRun)
{
    ASMAtomicUoWriteBool(&pVCpu->hm.s.fCheckedTLBFlush, false); /* See HMInvalidatePageOnAllVCpus(): used for TLB flushing. */
    ASMAtomicIncU32(&pVCpu->hmr0.s.cWorldSwitchExits);          /* Initialized in vmR3CreateUVM(): used for EMT poking. */
    pVCpu->hm.s.fCtxChanged            = 0;                     /* Exits/longjmps to ring-3 requires saving the guest state. */
    pVmxTransient->fVmcsFieldsRead     = 0;                     /* Transient fields need to be read from the VMCS. */
    pVmxTransient->fVectoringPF        = false;                 /* Vectoring page-fault needs to be determined later. */
    pVmxTransient->fVectoringDoublePF  = false;                 /* Vectoring double page-fault needs to be determined later. */

    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if (!(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_RDTSC_EXIT))
    {
        uint64_t uGstTsc;
        if (!pVmxTransient->fIsNestedGuest)
            uGstTsc = pVCpu->hmr0.s.uTscExit + pVmcsInfo->u64TscOffset;
        else
        {
            uint64_t const uNstGstTsc = pVCpu->hmr0.s.uTscExit + pVmcsInfo->u64TscOffset;
            uGstTsc = CPUMRemoveNestedGuestTscOffset(pVCpu, uNstGstTsc);
        }
        TMCpuTickSetLastSeen(pVCpu, uGstTsc);                           /* Update TM with the guest TSC. */
    }

    STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatInGC, &pVCpu->hm.s.StatPreExit, x);
    TMNotifyEndOfExecution(pVCpu->CTX_SUFF(pVM), pVCpu, pVCpu->hmr0.s.uTscExit); /* Notify TM that the guest is no longer running. */
    VMCPU_SET_STATE(pVCpu, VMCPUSTATE_STARTED_HM);

    pVCpu->hmr0.s.vmx.fRestoreHostFlags |= VMX_RESTORE_HOST_REQUIRED;   /* Some host state messed up by VMX needs restoring. */
    pVmcsInfo->fVmcsState |= VMX_V_VMCS_LAUNCH_STATE_LAUNCHED;          /* Use VMRESUME instead of VMLAUNCH in the next run. */
#ifdef VBOX_STRICT
    hmR0VmxCheckHostEferMsr(pVmcsInfo);                                 /* Verify that the host EFER MSR wasn't modified. */
#endif
    Assert(!ASMIntAreEnabled());
    ASMSetFlags(pVmxTransient->fEFlags);                                /* Enable interrupts. */
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

#ifdef HMVMX_ALWAYS_CLEAN_TRANSIENT
    /*
     * Clean all the VMCS fields in the transient structure before reading
     * anything from the VMCS.
     */
    pVmxTransient->uExitReason            = 0;
    pVmxTransient->uExitIntErrorCode      = 0;
    pVmxTransient->uExitQual              = 0;
    pVmxTransient->uGuestLinearAddr       = 0;
    pVmxTransient->uExitIntInfo           = 0;
    pVmxTransient->cbExitInstr            = 0;
    pVmxTransient->ExitInstrInfo.u        = 0;
    pVmxTransient->uEntryIntInfo          = 0;
    pVmxTransient->uEntryXcptErrorCode    = 0;
    pVmxTransient->cbEntryInstr           = 0;
    pVmxTransient->uIdtVectoringInfo      = 0;
    pVmxTransient->uIdtVectoringErrorCode = 0;
#endif

    /*
     * Save the basic VM-exit reason and check if the VM-entry failed.
     * See Intel spec. 24.9.1 "Basic VM-exit Information".
     */
    uint32_t uExitReason;
    int rc = VMXReadVmcs32(VMX_VMCS32_RO_EXIT_REASON, &uExitReason);
    AssertRC(rc);
    pVmxTransient->uExitReason    = VMX_EXIT_REASON_BASIC(uExitReason);
    pVmxTransient->fVMEntryFailed = VMX_EXIT_REASON_HAS_ENTRY_FAILED(uExitReason);

    /*
     * Log the VM-exit before logging anything else as otherwise it might be a
     * tad confusing what happens before and after the world-switch.
     */
    HMVMX_LOG_EXIT(pVCpu, uExitReason);

    /*
     * Remove the TSC_AUX MSR from the auto-load/store MSR area and reset any MSR
     * bitmap permissions, if it was added before VM-entry.
     */
    if (pVmxTransient->fRemoveTscAuxMsr)
    {
        hmR0VmxRemoveAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K8_TSC_AUX);
        pVmxTransient->fRemoveTscAuxMsr = false;
    }

    /*
     * Check if VMLAUNCH/VMRESUME succeeded.
     * If this failed, we cause a guru meditation and cease further execution.
     */
    if (RT_LIKELY(rcVMRun == VINF_SUCCESS))
    {
        /*
         * Update the VM-exit history array here even if the VM-entry failed due to:
         *   - Invalid guest state.
         *   - MSR loading.
         *   - Machine-check event.
         *
         * In any of the above cases we will still have a "valid" VM-exit reason
         * despite @a fVMEntryFailed being false.
         *
         * See Intel spec. 26.7 "VM-Entry failures during or after loading guest state".
         *
         * Note! We don't have CS or RIP at this point.  Will probably address that later
         *       by amending the history entry added here.
         */
        EMHistoryAddExit(pVCpu, EMEXIT_MAKE_FT(EMEXIT_F_KIND_VMX, pVmxTransient->uExitReason & EMEXIT_F_TYPE_MASK),
                         UINT64_MAX, pVCpu->hmr0.s.uTscExit);

        if (RT_LIKELY(!pVmxTransient->fVMEntryFailed))
        {
            VMMRZCallRing3Enable(pVCpu);
            Assert(!VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3));

#ifdef HMVMX_ALWAYS_SAVE_RO_GUEST_STATE
            vmxHCReadAllRoFieldsVmcs(pVCpu, pVmxTransient);
#endif

            /*
             * Always import the guest-interruptibility state as we need it while evaluating
             * injecting events on re-entry.  We could in *theory* postpone reading it for
             * exits that does not involve instruction emulation, but since most exits are
             * for instruction emulation (exceptions being external interrupts, shadow
             * paging building page faults and EPT violations, and interrupt window stuff)
             * this is a reasonable simplification.
             *
             * We don't import CR0 (when unrestricted guest execution is unavailable) despite
             * checking for real-mode while exporting the state because all bits that cause
             * mode changes wrt CR0 are intercepted.
             *
             * Note! This mask _must_ match the default value for the default a_fDonePostExit
             *       value for the vmxHCImportGuestState template!
             */
            /** @todo r=bird: consider dropping the INHIBIT_XXX and fetch the state
             * explicitly in the exit handlers and injection function.  That way we have
             * fewer clusters of vmread spread around the code, because the EM history
             * executor won't execute very many non-exiting instructions before stopping. */
            rc = vmxHCImportGuestState<  CPUMCTX_EXTRN_INHIBIT_INT
                                       | CPUMCTX_EXTRN_INHIBIT_NMI
#if defined(HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE) || defined(HMVMX_ALWAYS_SAVE_FULL_GUEST_STATE)
                                       | HMVMX_CPUMCTX_EXTRN_ALL
#elif defined(HMVMX_ALWAYS_SAVE_GUEST_RFLAGS)
                                       | CPUMCTX_EXTRN_RFLAGS
#endif
                                       , 0 /*a_fDoneLocal*/, 0 /*a_fDonePostExit*/>(pVCpu, pVmcsInfo, __FUNCTION__);
            AssertRC(rc);

            /*
             * Sync the TPR shadow with our APIC state.
             */
            if (   !pVmxTransient->fIsNestedGuest
                && (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_TPR_SHADOW))
            {
                Assert(pVmcsInfo->pbVirtApic);
                if (pVmxTransient->u8GuestTpr != pVmcsInfo->pbVirtApic[XAPIC_OFF_TPR])
                {
                    rc = APICSetTpr(pVCpu, pVmcsInfo->pbVirtApic[XAPIC_OFF_TPR]);
                    AssertRC(rc);
                    ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_GUEST_APIC_TPR);
                }
            }

            Assert(VMMRZCallRing3IsEnabled(pVCpu));
            Assert(   pVmxTransient->fWasGuestDebugStateActive == false
                   || pVmxTransient->fWasHyperDebugStateActive == false);
            return;
        }
    }
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    else if (pVmxTransient->fIsNestedGuest)
        AssertMsgFailed(("VMLAUNCH/VMRESUME failed but shouldn't happen when VMLAUNCH/VMRESUME was emulated in IEM!\n"));
#endif
    else
        Log4Func(("VM-entry failure: rcVMRun=%Rrc fVMEntryFailed=%RTbool\n", rcVMRun, pVmxTransient->fVMEntryFailed));

    VMMRZCallRing3Enable(pVCpu);
}


/**
 * Runs the guest code using hardware-assisted VMX the normal way.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pcLoops     Pointer to the number of executed loops.
 */
static VBOXSTRICTRC hmR0VmxRunGuestCodeNormal(PVMCPUCC pVCpu, uint32_t *pcLoops)
{
    uint32_t const cMaxResumeLoops = pVCpu->CTX_SUFF(pVM)->hmr0.s.cMaxResumeLoops;
    Assert(pcLoops);
    Assert(*pcLoops <= cMaxResumeLoops);
    Assert(!CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx));

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * Switch to the guest VMCS as we may have transitioned from executing the nested-guest
     * without leaving ring-0. Otherwise, if we came from ring-3 we would have loaded the
     * guest VMCS while entering the VMX ring-0 session.
     */
    if (pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs)
    {
        int rc = vmxHCSwitchToGstOrNstGstVmcs(pVCpu, false /* fSwitchToNstGstVmcs */);
        if (RT_SUCCESS(rc))
        { /* likely */ }
        else
        {
            LogRelFunc(("Failed to switch to the guest VMCS. rc=%Rrc\n", rc));
            return rc;
        }
    }
#endif

    VMXTRANSIENT VmxTransient;
    RT_ZERO(VmxTransient);
    VmxTransient.pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);

    /* Paranoia. */
    Assert(VmxTransient.pVmcsInfo == &pVCpu->hmr0.s.vmx.VmcsInfo);

    VBOXSTRICTRC rcStrict = VERR_INTERNAL_ERROR_5;
    for (;;)
    {
        Assert(!HMR0SuspendPending());
        HMVMX_ASSERT_CPU_SAFE(pVCpu);
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatEntry, x);

        /*
         * Preparatory work for running nested-guest code, this may force us to
         * return to ring-3.
         *
         * Warning! This bugger disables interrupts on VINF_SUCCESS!
         */
        rcStrict = hmR0VmxPreRunGuest(pVCpu, &VmxTransient, false /* fStepping */);
        if (rcStrict != VINF_SUCCESS)
            break;

        /* Interrupts are disabled at this point! */
        hmR0VmxPreRunGuestCommitted(pVCpu, &VmxTransient);
        int rcRun = hmR0VmxRunGuest(pVCpu, &VmxTransient);
        hmR0VmxPostRunGuest(pVCpu, &VmxTransient, rcRun);
        /* Interrupts are re-enabled at this point! */

        /*
         * Check for errors with running the VM (VMLAUNCH/VMRESUME).
         */
        if (RT_SUCCESS(rcRun))
        { /* very likely */ }
        else
        {
            STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatPreExit, x);
            hmR0VmxReportWorldSwitchError(pVCpu, rcRun, &VmxTransient);
            return rcRun;
        }

        /*
         * Profile the VM-exit.
         */
        AssertMsg(VmxTransient.uExitReason <= VMX_EXIT_MAX, ("%#x\n", VmxTransient.uExitReason));
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExitAll);
        STAM_COUNTER_INC(&pVCpu->hm.s.aStatExitReason[VmxTransient.uExitReason & MASK_EXITREASON_STAT]);
        STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatPreExit, &pVCpu->hm.s.StatExitHandling, x);
        HMVMX_START_EXIT_DISPATCH_PROF();

        VBOXVMM_R0_HMVMX_VMEXIT_NOCTX(pVCpu, &pVCpu->cpum.GstCtx, VmxTransient.uExitReason);

        /*
         * Handle the VM-exit.
         */
#ifdef HMVMX_USE_FUNCTION_TABLE
        rcStrict = g_aVMExitHandlers[VmxTransient.uExitReason].pfn(pVCpu, &VmxTransient);
#else
        rcStrict = hmR0VmxHandleExit(pVCpu, &VmxTransient);
#endif
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExitHandling, x);
        if (rcStrict == VINF_SUCCESS)
        {
            if (++(*pcLoops) <= cMaxResumeLoops)
                continue;
            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
            rcStrict = VINF_EM_RAW_INTERRUPT;
        }
        break;
    }

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatEntry, x);
    return rcStrict;
}


#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Runs the nested-guest code using hardware-assisted VMX.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pcLoops     Pointer to the number of executed loops.
 *
 * @sa      hmR0VmxRunGuestCodeNormal.
 */
static VBOXSTRICTRC hmR0VmxRunGuestCodeNested(PVMCPUCC pVCpu, uint32_t *pcLoops)
{
    uint32_t const cMaxResumeLoops = pVCpu->CTX_SUFF(pVM)->hmr0.s.cMaxResumeLoops;
    Assert(pcLoops);
    Assert(*pcLoops <= cMaxResumeLoops);
    Assert(CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx));

    /*
     * Switch to the nested-guest VMCS as we may have transitioned from executing the
     * guest without leaving ring-0. Otherwise, if we came from ring-3 we would have
     * loaded the nested-guest VMCS while entering the VMX ring-0 session.
     */
    if (!pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs)
    {
        int rc = vmxHCSwitchToGstOrNstGstVmcs(pVCpu, true /* fSwitchToNstGstVmcs */);
        if (RT_SUCCESS(rc))
        { /* likely */ }
        else
        {
            LogRelFunc(("Failed to switch to the nested-guest VMCS. rc=%Rrc\n", rc));
            return rc;
        }
    }

    VMXTRANSIENT VmxTransient;
    RT_ZERO(VmxTransient);
    VmxTransient.pVmcsInfo      = hmGetVmxActiveVmcsInfo(pVCpu);
    VmxTransient.fIsNestedGuest = true;

    /* Paranoia. */
    Assert(VmxTransient.pVmcsInfo == &pVCpu->hmr0.s.vmx.VmcsInfoNstGst);

    /* Setup pointer so PGM/IEM can query VM-exit auxiliary info on demand in ring-0. */
    pVCpu->hmr0.s.vmx.pVmxTransient = &VmxTransient;

    VBOXSTRICTRC rcStrict = VERR_INTERNAL_ERROR_5;
    for (;;)
    {
        Assert(!HMR0SuspendPending());
        HMVMX_ASSERT_CPU_SAFE(pVCpu);
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatEntry, x);

        /*
         * Preparatory work for running guest code, this may force us to
         * return to ring-3.
         *
         * Warning! This bugger disables interrupts on VINF_SUCCESS!
         */
        rcStrict = hmR0VmxPreRunGuest(pVCpu, &VmxTransient, false /* fStepping */);
        if (rcStrict != VINF_SUCCESS)
            break;

        /* Interrupts are disabled at this point! */
        hmR0VmxPreRunGuestCommitted(pVCpu, &VmxTransient);
        int rcRun = hmR0VmxRunGuest(pVCpu, &VmxTransient);
        hmR0VmxPostRunGuest(pVCpu, &VmxTransient, rcRun);
        /* Interrupts are re-enabled at this point! */

        /*
         * Check for errors with running the VM (VMLAUNCH/VMRESUME).
         */
        if (RT_SUCCESS(rcRun))
        { /* very likely */ }
        else
        {
            STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatPreExit, x);
            hmR0VmxReportWorldSwitchError(pVCpu, rcRun, &VmxTransient);
            rcStrict = rcRun;
            break;
        }

        /*
         * Profile the VM-exit.
         */
        AssertMsg(VmxTransient.uExitReason <= VMX_EXIT_MAX, ("%#x\n", VmxTransient.uExitReason));
        STAM_COUNTER_INC(&pVCpu->hm.s.StatNestedExitAll);
        STAM_COUNTER_INC(&pVCpu->hm.s.aStatNestedExitReason[VmxTransient.uExitReason & MASK_EXITREASON_STAT]);
        STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatPreExit, &pVCpu->hm.s.StatExitHandling, x);
        HMVMX_START_EXIT_DISPATCH_PROF();

        VBOXVMM_R0_HMVMX_VMEXIT_NOCTX(pVCpu, &pVCpu->cpum.GstCtx, VmxTransient.uExitReason);

        /*
         * Handle the VM-exit.
         */
        rcStrict = vmxHCHandleExitNested(pVCpu, &VmxTransient);
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExitHandling, x);
        if (rcStrict == VINF_SUCCESS)
        {
            if (!CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
            {
                STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
                rcStrict = VINF_VMX_VMEXIT;
            }
            else
            {
                if (++(*pcLoops) <= cMaxResumeLoops)
                    continue;
                STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
                rcStrict = VINF_EM_RAW_INTERRUPT;
            }
        }
        else
            Assert(rcStrict != VINF_VMX_VMEXIT);
        break;
    }

    /* Ensure VM-exit auxiliary info. is no longer available. */
    pVCpu->hmr0.s.vmx.pVmxTransient = NULL;

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatEntry, x);
    return rcStrict;
}
#endif /* VBOX_WITH_NESTED_HWVIRT_VMX */


/** @name Execution loop for single stepping, DBGF events and expensive Dtrace
 *  probes.
 *
 * The following few functions and associated structure contains the bloat
 * necessary for providing detailed debug events and dtrace probes as well as
 * reliable host side single stepping.  This works on the principle of
 * "subclassing" the normal execution loop and workers.  We replace the loop
 * method completely and override selected helpers to add necessary adjustments
 * to their core operation.
 *
 * The goal is to keep the "parent" code lean and mean, so as not to sacrifice
 * any performance for debug and analysis features.
 *
 * @{
 */

/**
 * Single steps guest code using hardware-assisted VMX.
 *
 * This is -not- the same as the guest single-stepping itself (say using EFLAGS.TF)
 * but single-stepping through the hypervisor debugger.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pcLoops     Pointer to the number of executed loops.
 *
 * @note    Mostly the same as hmR0VmxRunGuestCodeNormal().
 */
static VBOXSTRICTRC hmR0VmxRunGuestCodeDebug(PVMCPUCC pVCpu, uint32_t *pcLoops)
{
    uint32_t const cMaxResumeLoops = pVCpu->CTX_SUFF(pVM)->hmr0.s.cMaxResumeLoops;
    Assert(pcLoops);
    Assert(*pcLoops <= cMaxResumeLoops);

    VMXTRANSIENT VmxTransient;
    RT_ZERO(VmxTransient);
    VmxTransient.pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);

    /* Set HMCPU indicators.  */
    bool const fSavedSingleInstruction = pVCpu->hm.s.fSingleInstruction;
    pVCpu->hm.s.fSingleInstruction     = pVCpu->hm.s.fSingleInstruction || DBGFIsStepping(pVCpu);
    pVCpu->hmr0.s.fDebugWantRdTscExit    = false;
    pVCpu->hmr0.s.fUsingDebugLoop        = true;

    /* State we keep to help modify and later restore the VMCS fields we alter, and for detecting steps.  */
    VMXRUNDBGSTATE DbgState;
    vmxHCRunDebugStateInit(pVCpu, &VmxTransient, &DbgState);
    vmxHCPreRunGuestDebugStateUpdate(pVCpu, &VmxTransient, &DbgState);

    /*
     * The loop.
     */
    VBOXSTRICTRC rcStrict  = VERR_INTERNAL_ERROR_5;
    for (;;)
    {
        Assert(!HMR0SuspendPending());
        HMVMX_ASSERT_CPU_SAFE(pVCpu);
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatEntry, x);
        bool fStepping = pVCpu->hm.s.fSingleInstruction;

        /* Set up VM-execution controls the next two can respond to. */
        vmxHCPreRunGuestDebugStateApply(pVCpu, &VmxTransient, &DbgState);

        /*
         * Preparatory work for running guest code, this may force us to
         * return to ring-3.
         *
         * Warning! This bugger disables interrupts on VINF_SUCCESS!
         */
        rcStrict = hmR0VmxPreRunGuest(pVCpu, &VmxTransient, fStepping);
        if (rcStrict != VINF_SUCCESS)
            break;

        /* Interrupts are disabled at this point! */
        hmR0VmxPreRunGuestCommitted(pVCpu, &VmxTransient);

        /* Override any obnoxious code in the above two calls. */
        vmxHCPreRunGuestDebugStateApply(pVCpu, &VmxTransient, &DbgState);

        /*
         * Finally execute the guest.
         */
        int rcRun = hmR0VmxRunGuest(pVCpu, &VmxTransient);

        hmR0VmxPostRunGuest(pVCpu, &VmxTransient, rcRun);
        /* Interrupts are re-enabled at this point! */

        /* Check for errors with running the VM (VMLAUNCH/VMRESUME). */
        if (RT_SUCCESS(rcRun))
        { /* very likely */ }
        else
        {
            STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatPreExit, x);
            hmR0VmxReportWorldSwitchError(pVCpu, rcRun, &VmxTransient);
            return rcRun;
        }

        /* Profile the VM-exit. */
        AssertMsg(VmxTransient.uExitReason <= VMX_EXIT_MAX, ("%#x\n", VmxTransient.uExitReason));
        STAM_COUNTER_INC(&pVCpu->hm.s.StatDebugExitAll);
        STAM_COUNTER_INC(&pVCpu->hm.s.aStatExitReason[VmxTransient.uExitReason & MASK_EXITREASON_STAT]);
        STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatPreExit, &pVCpu->hm.s.StatExitHandling, x);
        HMVMX_START_EXIT_DISPATCH_PROF();

        VBOXVMM_R0_HMVMX_VMEXIT_NOCTX(pVCpu, &pVCpu->cpum.GstCtx, VmxTransient.uExitReason);

        /*
         * Handle the VM-exit - we quit earlier on certain VM-exits, see hmR0VmxHandleExitDebug().
         */
        rcStrict = vmxHCRunDebugHandleExit(pVCpu, &VmxTransient, &DbgState);
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExitHandling, x);
        if (rcStrict != VINF_SUCCESS)
            break;
        if (++(*pcLoops) > cMaxResumeLoops)
        {
            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
            rcStrict = VINF_EM_RAW_INTERRUPT;
            break;
        }

        /*
         * Stepping: Did the RIP change, if so, consider it a single step.
         * Otherwise, make sure one of the TFs gets set.
         */
        if (fStepping)
        {
            int rc = vmxHCImportGuestStateEx(pVCpu, VmxTransient.pVmcsInfo, CPUMCTX_EXTRN_CS | CPUMCTX_EXTRN_RIP);
            AssertRC(rc);
            if (   pVCpu->cpum.GstCtx.rip    != DbgState.uRipStart
                || pVCpu->cpum.GstCtx.cs.Sel != DbgState.uCsStart)
            {
                rcStrict = VINF_EM_DBG_STEPPED;
                break;
            }
            ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_GUEST_DR7);
        }

        /*
         * Update when dtrace settings changes (DBGF kicks us, so no need to check).
         */
        if (VBOXVMM_GET_SETTINGS_SEQ_NO() != DbgState.uDtraceSettingsSeqNo)
            vmxHCPreRunGuestDebugStateUpdate(pVCpu, &VmxTransient, &DbgState);

        /* Restore all controls applied by hmR0VmxPreRunGuestDebugStateApply above. */
        rcStrict = vmxHCRunDebugStateRevert(pVCpu, &VmxTransient, &DbgState, rcStrict);
        Assert(rcStrict == VINF_SUCCESS);
    }

    /*
     * Clear the X86_EFL_TF if necessary.
     */
    if (pVCpu->hmr0.s.fClearTrapFlag)
    {
        int rc = vmxHCImportGuestStateEx(pVCpu, VmxTransient.pVmcsInfo, CPUMCTX_EXTRN_RFLAGS);
        AssertRC(rc);
        pVCpu->hmr0.s.fClearTrapFlag = false;
        pVCpu->cpum.GstCtx.eflags.Bits.u1TF = 0;
    }
    /** @todo there seems to be issues with the resume flag when the monitor trap
     *        flag is pending without being used. Seen early in bios init when
     *        accessing APIC page in protected mode. */

/** @todo we need to do hmR0VmxRunDebugStateRevert here too, in case we broke
 *        out of the above loop. */

    /* Restore HMCPU indicators. */
    pVCpu->hmr0.s.fUsingDebugLoop     = false;
    pVCpu->hmr0.s.fDebugWantRdTscExit = false;
    pVCpu->hm.s.fSingleInstruction  = fSavedSingleInstruction;

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatEntry, x);
    return rcStrict;
}

/** @} */


/**
 * Checks if any expensive dtrace probes are enabled and we should go to the
 * debug loop.
 *
 * @returns true if we should use debug loop, false if not.
 */
static bool hmR0VmxAnyExpensiveProbesEnabled(void)
{
    /* It's probably faster to OR the raw 32-bit counter variables together.
       Since the variables are in an array and the probes are next to one
       another (more or less), we have good locality.  So, better read
       eight-nine cache lines ever time and only have one conditional, than
       128+ conditionals, right? */
    return (  VBOXVMM_R0_HMVMX_VMEXIT_ENABLED_RAW() /* expensive too due to context */
            | VBOXVMM_XCPT_DE_ENABLED_RAW()
            | VBOXVMM_XCPT_DB_ENABLED_RAW()
            | VBOXVMM_XCPT_BP_ENABLED_RAW()
            | VBOXVMM_XCPT_OF_ENABLED_RAW()
            | VBOXVMM_XCPT_BR_ENABLED_RAW()
            | VBOXVMM_XCPT_UD_ENABLED_RAW()
            | VBOXVMM_XCPT_NM_ENABLED_RAW()
            | VBOXVMM_XCPT_DF_ENABLED_RAW()
            | VBOXVMM_XCPT_TS_ENABLED_RAW()
            | VBOXVMM_XCPT_NP_ENABLED_RAW()
            | VBOXVMM_XCPT_SS_ENABLED_RAW()
            | VBOXVMM_XCPT_GP_ENABLED_RAW()
            | VBOXVMM_XCPT_PF_ENABLED_RAW()
            | VBOXVMM_XCPT_MF_ENABLED_RAW()
            | VBOXVMM_XCPT_AC_ENABLED_RAW()
            | VBOXVMM_XCPT_XF_ENABLED_RAW()
            | VBOXVMM_XCPT_VE_ENABLED_RAW()
            | VBOXVMM_XCPT_SX_ENABLED_RAW()
            | VBOXVMM_INT_SOFTWARE_ENABLED_RAW()
            | VBOXVMM_INT_HARDWARE_ENABLED_RAW()
           ) != 0
        || (  VBOXVMM_INSTR_HALT_ENABLED_RAW()
            | VBOXVMM_INSTR_MWAIT_ENABLED_RAW()
            | VBOXVMM_INSTR_MONITOR_ENABLED_RAW()
            | VBOXVMM_INSTR_CPUID_ENABLED_RAW()
            | VBOXVMM_INSTR_INVD_ENABLED_RAW()
            | VBOXVMM_INSTR_WBINVD_ENABLED_RAW()
            | VBOXVMM_INSTR_INVLPG_ENABLED_RAW()
            | VBOXVMM_INSTR_RDTSC_ENABLED_RAW()
            | VBOXVMM_INSTR_RDTSCP_ENABLED_RAW()
            | VBOXVMM_INSTR_RDPMC_ENABLED_RAW()
            | VBOXVMM_INSTR_RDMSR_ENABLED_RAW()
            | VBOXVMM_INSTR_WRMSR_ENABLED_RAW()
            | VBOXVMM_INSTR_CRX_READ_ENABLED_RAW()
            | VBOXVMM_INSTR_CRX_WRITE_ENABLED_RAW()
            | VBOXVMM_INSTR_DRX_READ_ENABLED_RAW()
            | VBOXVMM_INSTR_DRX_WRITE_ENABLED_RAW()
            | VBOXVMM_INSTR_PAUSE_ENABLED_RAW()
            | VBOXVMM_INSTR_XSETBV_ENABLED_RAW()
            | VBOXVMM_INSTR_SIDT_ENABLED_RAW()
            | VBOXVMM_INSTR_LIDT_ENABLED_RAW()
            | VBOXVMM_INSTR_SGDT_ENABLED_RAW()
            | VBOXVMM_INSTR_LGDT_ENABLED_RAW()
            | VBOXVMM_INSTR_SLDT_ENABLED_RAW()
            | VBOXVMM_INSTR_LLDT_ENABLED_RAW()
            | VBOXVMM_INSTR_STR_ENABLED_RAW()
            | VBOXVMM_INSTR_LTR_ENABLED_RAW()
            | VBOXVMM_INSTR_GETSEC_ENABLED_RAW()
            | VBOXVMM_INSTR_RSM_ENABLED_RAW()
            | VBOXVMM_INSTR_RDRAND_ENABLED_RAW()
            | VBOXVMM_INSTR_RDSEED_ENABLED_RAW()
            | VBOXVMM_INSTR_XSAVES_ENABLED_RAW()
            | VBOXVMM_INSTR_XRSTORS_ENABLED_RAW()
            | VBOXVMM_INSTR_VMM_CALL_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMCLEAR_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMLAUNCH_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMPTRLD_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMPTRST_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMREAD_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMRESUME_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMWRITE_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMXOFF_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMXON_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMFUNC_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_INVEPT_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_INVVPID_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_INVPCID_ENABLED_RAW()
           ) != 0
        || (  VBOXVMM_EXIT_TASK_SWITCH_ENABLED_RAW()
            | VBOXVMM_EXIT_HALT_ENABLED_RAW()
            | VBOXVMM_EXIT_MWAIT_ENABLED_RAW()
            | VBOXVMM_EXIT_MONITOR_ENABLED_RAW()
            | VBOXVMM_EXIT_CPUID_ENABLED_RAW()
            | VBOXVMM_EXIT_INVD_ENABLED_RAW()
            | VBOXVMM_EXIT_WBINVD_ENABLED_RAW()
            | VBOXVMM_EXIT_INVLPG_ENABLED_RAW()
            | VBOXVMM_EXIT_RDTSC_ENABLED_RAW()
            | VBOXVMM_EXIT_RDTSCP_ENABLED_RAW()
            | VBOXVMM_EXIT_RDPMC_ENABLED_RAW()
            | VBOXVMM_EXIT_RDMSR_ENABLED_RAW()
            | VBOXVMM_EXIT_WRMSR_ENABLED_RAW()
            | VBOXVMM_EXIT_CRX_READ_ENABLED_RAW()
            | VBOXVMM_EXIT_CRX_WRITE_ENABLED_RAW()
            | VBOXVMM_EXIT_DRX_READ_ENABLED_RAW()
            | VBOXVMM_EXIT_DRX_WRITE_ENABLED_RAW()
            | VBOXVMM_EXIT_PAUSE_ENABLED_RAW()
            | VBOXVMM_EXIT_XSETBV_ENABLED_RAW()
            | VBOXVMM_EXIT_SIDT_ENABLED_RAW()
            | VBOXVMM_EXIT_LIDT_ENABLED_RAW()
            | VBOXVMM_EXIT_SGDT_ENABLED_RAW()
            | VBOXVMM_EXIT_LGDT_ENABLED_RAW()
            | VBOXVMM_EXIT_SLDT_ENABLED_RAW()
            | VBOXVMM_EXIT_LLDT_ENABLED_RAW()
            | VBOXVMM_EXIT_STR_ENABLED_RAW()
            | VBOXVMM_EXIT_LTR_ENABLED_RAW()
            | VBOXVMM_EXIT_GETSEC_ENABLED_RAW()
            | VBOXVMM_EXIT_RSM_ENABLED_RAW()
            | VBOXVMM_EXIT_RDRAND_ENABLED_RAW()
            | VBOXVMM_EXIT_RDSEED_ENABLED_RAW()
            | VBOXVMM_EXIT_XSAVES_ENABLED_RAW()
            | VBOXVMM_EXIT_XRSTORS_ENABLED_RAW()
            | VBOXVMM_EXIT_VMM_CALL_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMCLEAR_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMLAUNCH_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMPTRLD_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMPTRST_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMREAD_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMRESUME_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMWRITE_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMXOFF_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMXON_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMFUNC_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_INVEPT_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_INVVPID_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_INVPCID_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_EPT_VIOLATION_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_EPT_MISCONFIG_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VAPIC_ACCESS_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VAPIC_WRITE_ENABLED_RAW()
           ) != 0;
}


/**
 * Runs the guest using hardware-assisted VMX.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @param   pVCpu   The cross context virtual CPU structure.
 */
VMMR0DECL(VBOXSTRICTRC) VMXR0RunGuestCode(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    PCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
    Assert(VMMRZCallRing3IsEnabled(pVCpu));
    Assert(!ASMAtomicUoReadU64(&pCtx->fExtrn));
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);

    VBOXSTRICTRC rcStrict;
    uint32_t     cLoops = 0;
    for (;;)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        bool const fInNestedGuestMode = CPUMIsGuestInVmxNonRootMode(pCtx);
#else
        NOREF(pCtx);
        bool const fInNestedGuestMode = false;
#endif
        if (!fInNestedGuestMode)
        {
            if (   !pVCpu->hm.s.fUseDebugLoop
                && (!VBOXVMM_ANY_PROBES_ENABLED() || !hmR0VmxAnyExpensiveProbesEnabled())
                && !DBGFIsStepping(pVCpu)
                && !pVCpu->CTX_SUFF(pVM)->dbgf.ro.cEnabledInt3Breakpoints)
                rcStrict = hmR0VmxRunGuestCodeNormal(pVCpu, &cLoops);
            else
                rcStrict = hmR0VmxRunGuestCodeDebug(pVCpu, &cLoops);
        }
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        else
            rcStrict = hmR0VmxRunGuestCodeNested(pVCpu, &cLoops);

        if (rcStrict == VINF_VMX_VMLAUNCH_VMRESUME)
        {
            Assert(CPUMIsGuestInVmxNonRootMode(pCtx));
            continue;
        }
        if (rcStrict == VINF_VMX_VMEXIT)
        {
            Assert(!CPUMIsGuestInVmxNonRootMode(pCtx));
            continue;
        }
#endif
        break;
    }

    int const rcLoop = VBOXSTRICTRC_VAL(rcStrict);
    switch (rcLoop)
    {
        case VERR_EM_INTERPRETER:   rcStrict = VINF_EM_RAW_EMULATE_INSTR;   break;
        case VINF_EM_RESET:         rcStrict = VINF_EM_TRIPLE_FAULT;        break;
    }

    int rc2 = hmR0VmxExitToRing3(pVCpu, rcStrict);
    if (RT_FAILURE(rc2))
    {
        pVCpu->hm.s.u32HMError = (uint32_t)VBOXSTRICTRC_VAL(rcStrict);
        rcStrict = rc2;
    }
    Assert(!ASMAtomicUoReadU64(&pCtx->fExtrn));
    Assert(!VMMR0AssertionIsNotificationSet(pVCpu));
    return rcStrict;
}