source: vbox/trunk/src/VBox/VMM/EM.cpp@ 29329

/* $Id: EM.cpp 29329 2010-05-11 10:18:30Z vboxsync $ */
/** @file
 * EM - Execution Monitor / Manager.
 */

/*
 * Copyright (C) 2006-2007 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 */

/** @page pg_em         EM - The Execution Monitor / Manager
 *
 * The Execution Monitor/Manager is responsible for running the VM, scheduling
 * the right kind of execution (Raw-mode, Hardware Assisted, Recompiled or
 * Interpreted), and keeping the CPU states in sync. The function
 * EMR3ExecuteVM() is the 'main-loop' of the VM, while each of the execution
 * modes has different inner loops (emR3RawExecute, emR3HwAccExecute, and
 * emR3RemExecute).
 *
 * The interpreted execution is only used to avoid switching between
 * raw-mode/hwaccm and the recompiler when fielding virtualization traps/faults.
 * The interpretation is thus implemented as part of EM.
 *
 * @see grp_em
 */

/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#define LOG_GROUP LOG_GROUP_EM
#include <VBox/em.h>
#include <VBox/vmm.h>
#include <VBox/patm.h>
#include <VBox/csam.h>
#include <VBox/selm.h>
#include <VBox/trpm.h>
#include <VBox/iom.h>
#include <VBox/dbgf.h>
#include <VBox/pgm.h>
#include <VBox/rem.h>
#include <VBox/tm.h>
#include <VBox/mm.h>
#include <VBox/ssm.h>
#include <VBox/pdmapi.h>
#include <VBox/pdmcritsect.h>
#include <VBox/pdmqueue.h>
#include <VBox/hwaccm.h>
#include <VBox/patm.h>
#include "EMInternal.h"
#include <VBox/vm.h>
#include <VBox/cpumdis.h>
#include <VBox/dis.h>
#include <VBox/disopcode.h>
#include <VBox/dbgf.h>

#include <iprt/asm.h>
#include <iprt/string.h>
#include <iprt/stream.h>


/*******************************************************************************
*   Defined Constants And Macros                                               *
*******************************************************************************/
#if 0 /* Disabled till after 2.1.0 when we've time to test it. */
#define EM_NOTIFY_HWACCM
#endif


/*******************************************************************************
*   Internal Functions                                                         *
*******************************************************************************/
static DECLCALLBACK(int) emR3Save(PVM pVM, PSSMHANDLE pSSM);
static DECLCALLBACK(int) emR3Load(PVM pVM, PSSMHANDLE pSSM, uint32_t uVersion, uint32_t uPass);
static const char *emR3GetStateName(EMSTATE enmState);
static int emR3Debug(PVM pVM, PVMCPU pVCpu, int rc);
static int emR3RemStep(PVM pVM, PVMCPU pVCpu);
static int emR3RemExecute(PVM pVM, PVMCPU pVCpu, bool *pfFFDone);
int emR3HighPriorityPostForcedActions(PVM pVM, PVMCPU pVCpu, int rc);


/**
 * Initializes the EM.
 *
 * @returns VBox status code.
 * @param   pVM         The VM to operate on.
 */
VMMR3DECL(int) EMR3Init(PVM pVM)
{
    LogFlow(("EMR3Init\n"));
    /*
     * Assert alignment and sizes.
     */
    AssertCompileMemberAlignment(VM, em.s, 32);
    AssertCompile(sizeof(pVM->em.s) <= sizeof(pVM->em.padding));
    AssertCompile(sizeof(pVM->aCpus[0].em.s.u.FatalLongJump) <= sizeof(pVM->aCpus[0].em.s.u.achPaddingFatalLongJump));
    AssertCompileMemberAlignment(EM, CritSectREM, sizeof(uintptr_t));

    /*
     * Init the structure.
     */
    pVM->em.s.offVM = RT_OFFSETOF(VM, em.s);
    int rc = CFGMR3QueryBool(CFGMR3GetRoot(pVM), "RawR3Enabled", &pVM->fRawR3Enabled);
    if (RT_FAILURE(rc))
        pVM->fRawR3Enabled = true;
    rc = CFGMR3QueryBool(CFGMR3GetRoot(pVM), "RawR0Enabled", &pVM->fRawR0Enabled);
    if (RT_FAILURE(rc))
        pVM->fRawR0Enabled = true;
    Log(("EMR3Init: fRawR3Enabled=%d fRawR0Enabled=%d\n", pVM->fRawR3Enabled, pVM->fRawR0Enabled));

    /*
     * Initialize the REM critical section.
     */
    rc = PDMR3CritSectInit(pVM, &pVM->em.s.CritSectREM, RT_SRC_POS, "EM-REM");
    AssertRCReturn(rc, rc);

    /*
     * Saved state.
     */
    rc = SSMR3RegisterInternal(pVM, "em", 0, EM_SAVED_STATE_VERSION, 16,
                               NULL, NULL, NULL,
                               NULL, emR3Save, NULL,
                               NULL, emR3Load, NULL);
    if (RT_FAILURE(rc))
        return rc;

    for (VMCPUID i = 0; i < pVM->cCpus; i++)
    {
        PVMCPU pVCpu = &pVM->aCpus[i];

        pVCpu->em.s.offVMCPU = RT_OFFSETOF(VMCPU, em.s);

        pVCpu->em.s.enmState     = (i == 0) ? EMSTATE_NONE : EMSTATE_WAIT_SIPI;
        pVCpu->em.s.enmPrevState = EMSTATE_NONE;
        pVCpu->em.s.fForceRAW    = false;

        pVCpu->em.s.pCtx         = CPUMQueryGuestCtxPtr(pVCpu);
        pVCpu->em.s.pPatmGCState = PATMR3QueryGCStateHC(pVM);
        AssertMsg(pVCpu->em.s.pPatmGCState, ("PATMR3QueryGCStateHC failed!\n"));

# define EM_REG_COUNTER(a, b, c) \
        rc = STAMR3RegisterF(pVM, a, STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, c, b, i); \
        AssertRC(rc);

# define EM_REG_COUNTER_USED(a, b, c) \
        rc = STAMR3RegisterF(pVM, a, STAMTYPE_COUNTER, STAMVISIBILITY_USED, STAMUNIT_OCCURENCES, c, b, i); \
        AssertRC(rc);

# define EM_REG_PROFILE(a, b, c) \
        rc = STAMR3RegisterF(pVM, a, STAMTYPE_PROFILE, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_CALL, c, b, i); \
        AssertRC(rc);

# define EM_REG_PROFILE_ADV(a, b, c) \
        rc = STAMR3RegisterF(pVM, a, STAMTYPE_PROFILE_ADV, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_CALL, c, b, i); \
        AssertRC(rc);

        /*
         * Statistics.
         */
#ifdef VBOX_WITH_STATISTICS
        PEMSTATS pStats;
        rc = MMHyperAlloc(pVM, sizeof(*pStats), 0, MM_TAG_EM, (void **)&pStats);
        if (RT_FAILURE(rc))
            return rc;

        pVCpu->em.s.pStatsR3 = pStats;
        pVCpu->em.s.pStatsR0 = MMHyperR3ToR0(pVM, pStats);
        pVCpu->em.s.pStatsRC = MMHyperR3ToRC(pVM, pStats);

        EM_REG_PROFILE(&pStats->StatRZEmulate,               "/EM/CPU%d/RZ/Interpret",                   "Profiling of EMInterpretInstruction.");
        EM_REG_PROFILE(&pStats->StatR3Emulate,               "/EM/CPU%d/R3/Interpret",                   "Profiling of EMInterpretInstruction.");

        EM_REG_PROFILE(&pStats->StatRZInterpretSucceeded,    "/EM/CPU%d/RZ/Interpret/Success",           "The number of times an instruction was successfully interpreted.");
        EM_REG_PROFILE(&pStats->StatR3InterpretSucceeded,    "/EM/CPU%d/R3/Interpret/Success",           "The number of times an instruction was successfully interpreted.");

        EM_REG_COUNTER_USED(&pStats->StatRZAnd,                  "/EM/CPU%d/RZ/Interpret/Success/And",       "The number of times AND was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3And,                  "/EM/CPU%d/R3/Interpret/Success/And",       "The number of times AND was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZAdd,                  "/EM/CPU%d/RZ/Interpret/Success/Add",       "The number of times ADD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Add,                  "/EM/CPU%d/R3/Interpret/Success/Add",       "The number of times ADD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZAdc,                  "/EM/CPU%d/RZ/Interpret/Success/Adc",       "The number of times ADC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Adc,                  "/EM/CPU%d/R3/Interpret/Success/Adc",       "The number of times ADC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZSub,                  "/EM/CPU%d/RZ/Interpret/Success/Sub",       "The number of times SUB was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Sub,                  "/EM/CPU%d/R3/Interpret/Success/Sub",       "The number of times SUB was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZCpuId,                "/EM/CPU%d/RZ/Interpret/Success/CpuId",     "The number of times CPUID was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3CpuId,                "/EM/CPU%d/R3/Interpret/Success/CpuId",     "The number of times CPUID was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZDec,                  "/EM/CPU%d/RZ/Interpret/Success/Dec",       "The number of times DEC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Dec,                  "/EM/CPU%d/R3/Interpret/Success/Dec",       "The number of times DEC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZHlt,                  "/EM/CPU%d/RZ/Interpret/Success/Hlt",       "The number of times HLT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Hlt,                  "/EM/CPU%d/R3/Interpret/Success/Hlt",       "The number of times HLT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZInc,                  "/EM/CPU%d/RZ/Interpret/Success/Inc",       "The number of times INC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Inc,                  "/EM/CPU%d/R3/Interpret/Success/Inc",       "The number of times INC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZInvlPg,               "/EM/CPU%d/RZ/Interpret/Success/Invlpg",    "The number of times INVLPG was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3InvlPg,               "/EM/CPU%d/R3/Interpret/Success/Invlpg",    "The number of times INVLPG was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZIret,                 "/EM/CPU%d/RZ/Interpret/Success/Iret",      "The number of times IRET was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Iret,                 "/EM/CPU%d/R3/Interpret/Success/Iret",      "The number of times IRET was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZLLdt,                 "/EM/CPU%d/RZ/Interpret/Success/LLdt",      "The number of times LLDT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3LLdt,                 "/EM/CPU%d/R3/Interpret/Success/LLdt",      "The number of times LLDT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZLIdt,                 "/EM/CPU%d/RZ/Interpret/Success/LIdt",      "The number of times LIDT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3LIdt,                 "/EM/CPU%d/R3/Interpret/Success/LIdt",      "The number of times LIDT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZLGdt,                 "/EM/CPU%d/RZ/Interpret/Success/LGdt",      "The number of times LGDT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3LGdt,                 "/EM/CPU%d/R3/Interpret/Success/LGdt",      "The number of times LGDT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZMov,                  "/EM/CPU%d/RZ/Interpret/Success/Mov",       "The number of times MOV was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Mov,                  "/EM/CPU%d/R3/Interpret/Success/Mov",       "The number of times MOV was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZMovCRx,               "/EM/CPU%d/RZ/Interpret/Success/MovCRx",    "The number of times MOV CRx was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3MovCRx,               "/EM/CPU%d/R3/Interpret/Success/MovCRx",    "The number of times MOV CRx was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZMovDRx,               "/EM/CPU%d/RZ/Interpret/Success/MovDRx",    "The number of times MOV DRx was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3MovDRx,               "/EM/CPU%d/R3/Interpret/Success/MovDRx",    "The number of times MOV DRx was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZOr,                   "/EM/CPU%d/RZ/Interpret/Success/Or",        "The number of times OR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Or,                   "/EM/CPU%d/R3/Interpret/Success/Or",        "The number of times OR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZPop,                  "/EM/CPU%d/RZ/Interpret/Success/Pop",       "The number of times POP was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Pop,                  "/EM/CPU%d/R3/Interpret/Success/Pop",       "The number of times POP was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZRdtsc,                "/EM/CPU%d/RZ/Interpret/Success/Rdtsc",     "The number of times RDTSC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Rdtsc,                "/EM/CPU%d/R3/Interpret/Success/Rdtsc",     "The number of times RDTSC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZRdpmc,                "/EM/CPU%d/RZ/Interpret/Success/Rdpmc",     "The number of times RDPMC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Rdpmc,                "/EM/CPU%d/R3/Interpret/Success/Rdpmc",     "The number of times RDPMC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZSti,                  "/EM/CPU%d/RZ/Interpret/Success/Sti",       "The number of times STI was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Sti,                  "/EM/CPU%d/R3/Interpret/Success/Sti",       "The number of times STI was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZXchg,                 "/EM/CPU%d/RZ/Interpret/Success/Xchg",      "The number of times XCHG was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Xchg,                 "/EM/CPU%d/R3/Interpret/Success/Xchg",      "The number of times XCHG was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZXor,                  "/EM/CPU%d/RZ/Interpret/Success/Xor",       "The number of times XOR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Xor,                  "/EM/CPU%d/R3/Interpret/Success/Xor",       "The number of times XOR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZMonitor,              "/EM/CPU%d/RZ/Interpret/Success/Monitor",   "The number of times MONITOR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Monitor,              "/EM/CPU%d/R3/Interpret/Success/Monitor",   "The number of times MONITOR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZMWait,                "/EM/CPU%d/RZ/Interpret/Success/MWait",     "The number of times MWAIT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3MWait,                "/EM/CPU%d/R3/Interpret/Success/MWait",     "The number of times MWAIT was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZBtr,                  "/EM/CPU%d/RZ/Interpret/Success/Btr",       "The number of times BTR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Btr,                  "/EM/CPU%d/R3/Interpret/Success/Btr",       "The number of times BTR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZBts,                  "/EM/CPU%d/RZ/Interpret/Success/Bts",       "The number of times BTS was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Bts,                  "/EM/CPU%d/R3/Interpret/Success/Bts",       "The number of times BTS was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZBtc,                  "/EM/CPU%d/RZ/Interpret/Success/Btc",       "The number of times BTC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Btc,                  "/EM/CPU%d/R3/Interpret/Success/Btc",       "The number of times BTC was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZCmpXchg,              "/EM/CPU%d/RZ/Interpret/Success/CmpXchg",   "The number of times CMPXCHG was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3CmpXchg,              "/EM/CPU%d/R3/Interpret/Success/CmpXchg",   "The number of times CMPXCHG was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZCmpXchg8b,            "/EM/CPU%d/RZ/Interpret/Success/CmpXchg8b",   "The number of times CMPXCHG8B was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3CmpXchg8b,            "/EM/CPU%d/R3/Interpret/Success/CmpXchg8b",   "The number of times CMPXCHG8B was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZXAdd,                 "/EM/CPU%d/RZ/Interpret/Success/XAdd",      "The number of times XADD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3XAdd,                 "/EM/CPU%d/R3/Interpret/Success/XAdd",      "The number of times XADD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Rdmsr,                "/EM/CPU%d/R3/Interpret/Success/Rdmsr",      "The number of times RDMSR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZRdmsr,                "/EM/CPU%d/RZ/Interpret/Success/Rdmsr",      "The number of times RDMSR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Wrmsr,                "/EM/CPU%d/R3/Interpret/Success/Wrmsr",      "The number of times WRMSR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZWrmsr,                "/EM/CPU%d/RZ/Interpret/Success/Wrmsr",      "The number of times WRMSR was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3StosWD,               "/EM/CPU%d/R3/Interpret/Success/Stoswd",     "The number of times STOSWD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZStosWD,               "/EM/CPU%d/RZ/Interpret/Success/Stoswd",     "The number of times STOSWD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZWbInvd,               "/EM/CPU%d/RZ/Interpret/Success/WbInvd",     "The number of times WBINVD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3WbInvd,               "/EM/CPU%d/R3/Interpret/Success/WbInvd",     "The number of times WBINVD was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZLmsw,                 "/EM/CPU%d/RZ/Interpret/Success/Lmsw",       "The number of times LMSW was successfully interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3Lmsw,                 "/EM/CPU%d/R3/Interpret/Success/Lmsw",       "The number of times LMSW was successfully interpreted.");

        EM_REG_COUNTER(&pStats->StatRZInterpretFailed,           "/EM/CPU%d/RZ/Interpret/Failed",            "The number of times an instruction was not interpreted.");
        EM_REG_COUNTER(&pStats->StatR3InterpretFailed,           "/EM/CPU%d/R3/Interpret/Failed",            "The number of times an instruction was not interpreted.");

        EM_REG_COUNTER_USED(&pStats->StatRZFailedAnd,            "/EM/CPU%d/RZ/Interpret/Failed/And",        "The number of times AND was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedAnd,            "/EM/CPU%d/R3/Interpret/Failed/And",        "The number of times AND was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedCpuId,          "/EM/CPU%d/RZ/Interpret/Failed/CpuId",      "The number of times CPUID was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedCpuId,          "/EM/CPU%d/R3/Interpret/Failed/CpuId",      "The number of times CPUID was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedDec,            "/EM/CPU%d/RZ/Interpret/Failed/Dec",        "The number of times DEC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedDec,            "/EM/CPU%d/R3/Interpret/Failed/Dec",        "The number of times DEC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedHlt,            "/EM/CPU%d/RZ/Interpret/Failed/Hlt",        "The number of times HLT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedHlt,            "/EM/CPU%d/R3/Interpret/Failed/Hlt",        "The number of times HLT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedInc,            "/EM/CPU%d/RZ/Interpret/Failed/Inc",        "The number of times INC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedInc,            "/EM/CPU%d/R3/Interpret/Failed/Inc",        "The number of times INC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedInvlPg,         "/EM/CPU%d/RZ/Interpret/Failed/InvlPg",     "The number of times INVLPG was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedInvlPg,         "/EM/CPU%d/R3/Interpret/Failed/InvlPg",     "The number of times INVLPG was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedIret,           "/EM/CPU%d/RZ/Interpret/Failed/Iret",       "The number of times IRET was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedIret,           "/EM/CPU%d/R3/Interpret/Failed/Iret",       "The number of times IRET was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedLLdt,           "/EM/CPU%d/RZ/Interpret/Failed/LLdt",       "The number of times LLDT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedLLdt,           "/EM/CPU%d/R3/Interpret/Failed/LLdt",       "The number of times LLDT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedLIdt,           "/EM/CPU%d/RZ/Interpret/Failed/LIdt",       "The number of times LIDT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedLIdt,           "/EM/CPU%d/R3/Interpret/Failed/LIdt",       "The number of times LIDT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedLGdt,           "/EM/CPU%d/RZ/Interpret/Failed/LGdt",       "The number of times LGDT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedLGdt,           "/EM/CPU%d/R3/Interpret/Failed/LGdt",       "The number of times LGDT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedMov,            "/EM/CPU%d/RZ/Interpret/Failed/Mov",        "The number of times MOV was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedMov,            "/EM/CPU%d/R3/Interpret/Failed/Mov",        "The number of times MOV was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedMovCRx,         "/EM/CPU%d/RZ/Interpret/Failed/MovCRx",     "The number of times MOV CRx was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedMovCRx,         "/EM/CPU%d/R3/Interpret/Failed/MovCRx",     "The number of times MOV CRx was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedMovDRx,         "/EM/CPU%d/RZ/Interpret/Failed/MovDRx",     "The number of times MOV DRx was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedMovDRx,         "/EM/CPU%d/R3/Interpret/Failed/MovDRx",     "The number of times MOV DRx was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedOr,             "/EM/CPU%d/RZ/Interpret/Failed/Or",         "The number of times OR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedOr,             "/EM/CPU%d/R3/Interpret/Failed/Or",         "The number of times OR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedPop,            "/EM/CPU%d/RZ/Interpret/Failed/Pop",        "The number of times POP was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedPop,            "/EM/CPU%d/R3/Interpret/Failed/Pop",        "The number of times POP was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedSti,            "/EM/CPU%d/RZ/Interpret/Failed/Sti",        "The number of times STI was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedSti,            "/EM/CPU%d/R3/Interpret/Failed/Sti",        "The number of times STI was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedXchg,           "/EM/CPU%d/RZ/Interpret/Failed/Xchg",       "The number of times XCHG was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedXchg,           "/EM/CPU%d/R3/Interpret/Failed/Xchg",       "The number of times XCHG was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedXor,            "/EM/CPU%d/RZ/Interpret/Failed/Xor",        "The number of times XOR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedXor,            "/EM/CPU%d/R3/Interpret/Failed/Xor",        "The number of times XOR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedMonitor,        "/EM/CPU%d/RZ/Interpret/Failed/Monitor",    "The number of times MONITOR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedMonitor,        "/EM/CPU%d/R3/Interpret/Failed/Monitor",    "The number of times MONITOR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedMWait,          "/EM/CPU%d/RZ/Interpret/Failed/MWait",      "The number of times MWAIT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedMWait,          "/EM/CPU%d/R3/Interpret/Failed/MWait",      "The number of times MWAIT was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedRdtsc,          "/EM/CPU%d/RZ/Interpret/Failed/Rdtsc",      "The number of times RDTSC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedRdtsc,          "/EM/CPU%d/R3/Interpret/Failed/Rdtsc",      "The number of times RDTSC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedRdpmc,          "/EM/CPU%d/RZ/Interpret/Failed/Rdpmc",      "The number of times RDPMC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedRdpmc,          "/EM/CPU%d/R3/Interpret/Failed/Rdpmc",      "The number of times RDPMC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedRdmsr,          "/EM/CPU%d/RZ/Interpret/Failed/Rdmsr",      "The number of times RDMSR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedRdmsr,          "/EM/CPU%d/R3/Interpret/Failed/Rdmsr",      "The number of times RDMSR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedWrmsr,          "/EM/CPU%d/RZ/Interpret/Failed/Wrmsr",      "The number of times WRMSR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedWrmsr,          "/EM/CPU%d/R3/Interpret/Failed/Wrmsr",      "The number of times WRMSR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedLmsw,           "/EM/CPU%d/RZ/Interpret/Failed/Lmsw",       "The number of times LMSW was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedLmsw,           "/EM/CPU%d/R3/Interpret/Failed/Lmsw",       "The number of times LMSW was not interpreted.");

        EM_REG_COUNTER_USED(&pStats->StatRZFailedMisc,           "/EM/CPU%d/RZ/Interpret/Failed/Misc",       "The number of times some misc instruction was encountered.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedMisc,           "/EM/CPU%d/R3/Interpret/Failed/Misc",       "The number of times some misc instruction was encountered.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedAdd,            "/EM/CPU%d/RZ/Interpret/Failed/Add",        "The number of times ADD was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedAdd,            "/EM/CPU%d/R3/Interpret/Failed/Add",        "The number of times ADD was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedAdc,            "/EM/CPU%d/RZ/Interpret/Failed/Adc",        "The number of times ADC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedAdc,            "/EM/CPU%d/R3/Interpret/Failed/Adc",        "The number of times ADC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedBtr,            "/EM/CPU%d/RZ/Interpret/Failed/Btr",        "The number of times BTR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedBtr,            "/EM/CPU%d/R3/Interpret/Failed/Btr",        "The number of times BTR was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedBts,            "/EM/CPU%d/RZ/Interpret/Failed/Bts",        "The number of times BTS was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedBts,            "/EM/CPU%d/R3/Interpret/Failed/Bts",        "The number of times BTS was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedBtc,            "/EM/CPU%d/RZ/Interpret/Failed/Btc",        "The number of times BTC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedBtc,            "/EM/CPU%d/R3/Interpret/Failed/Btc",        "The number of times BTC was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedCli,            "/EM/CPU%d/RZ/Interpret/Failed/Cli",        "The number of times CLI was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedCli,            "/EM/CPU%d/R3/Interpret/Failed/Cli",        "The number of times CLI was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedCmpXchg,        "/EM/CPU%d/RZ/Interpret/Failed/CmpXchg",    "The number of times CMPXCHG was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedCmpXchg,        "/EM/CPU%d/R3/Interpret/Failed/CmpXchg",    "The number of times CMPXCHG was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedCmpXchg8b,      "/EM/CPU%d/RZ/Interpret/Failed/CmpXchg8b",  "The number of times CMPXCHG8B was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedCmpXchg8b,      "/EM/CPU%d/R3/Interpret/Failed/CmpXchg8b",  "The number of times CMPXCHG8B was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedXAdd,           "/EM/CPU%d/RZ/Interpret/Failed/XAdd",       "The number of times XADD was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedXAdd,           "/EM/CPU%d/R3/Interpret/Failed/XAdd",       "The number of times XADD was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedMovNTPS,        "/EM/CPU%d/RZ/Interpret/Failed/MovNTPS",    "The number of times MOVNTPS was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedMovNTPS,        "/EM/CPU%d/R3/Interpret/Failed/MovNTPS",    "The number of times MOVNTPS was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedStosWD,         "/EM/CPU%d/RZ/Interpret/Failed/StosWD",     "The number of times STOSWD was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedStosWD,         "/EM/CPU%d/R3/Interpret/Failed/StosWD",     "The number of times STOSWD was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedSub,            "/EM/CPU%d/RZ/Interpret/Failed/Sub",        "The number of times SUB was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedSub,            "/EM/CPU%d/R3/Interpret/Failed/Sub",        "The number of times SUB was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedWbInvd,         "/EM/CPU%d/RZ/Interpret/Failed/WbInvd",     "The number of times WBINVD was not interpreted.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedWbInvd,         "/EM/CPU%d/R3/Interpret/Failed/WbInvd",     "The number of times WBINVD was not interpreted.");

        EM_REG_COUNTER_USED(&pStats->StatRZFailedUserMode,       "/EM/CPU%d/RZ/Interpret/Failed/UserMode",   "The number of rejections because of CPL.");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedUserMode,       "/EM/CPU%d/R3/Interpret/Failed/UserMode",   "The number of rejections because of CPL.");
        EM_REG_COUNTER_USED(&pStats->StatRZFailedPrefix,         "/EM/CPU%d/RZ/Interpret/Failed/Prefix",     "The number of rejections because of prefix .");
        EM_REG_COUNTER_USED(&pStats->StatR3FailedPrefix,         "/EM/CPU%d/R3/Interpret/Failed/Prefix",     "The number of rejections because of prefix .");

        EM_REG_COUNTER_USED(&pStats->StatCli,                    "/EM/CPU%d/R3/PrivInst/Cli",                "Number of cli instructions.");
        EM_REG_COUNTER_USED(&pStats->StatSti,                    "/EM/CPU%d/R3/PrivInst/Sti",                "Number of sli instructions.");
        EM_REG_COUNTER_USED(&pStats->StatIn,                     "/EM/CPU%d/R3/PrivInst/In",                 "Number of in instructions.");
        EM_REG_COUNTER_USED(&pStats->StatOut,                    "/EM/CPU%d/R3/PrivInst/Out",                "Number of out instructions.");
        EM_REG_COUNTER_USED(&pStats->StatIoRestarted,            "/EM/CPU%d/R3/PrivInst/IoRestarted",        "Number of restarted i/o instructions.");
        EM_REG_COUNTER_USED(&pStats->StatHlt,                    "/EM/CPU%d/R3/PrivInst/Hlt",                "Number of hlt instructions not handled in GC because of PATM.");
        EM_REG_COUNTER_USED(&pStats->StatInvlpg,                 "/EM/CPU%d/R3/PrivInst/Invlpg",             "Number of invlpg instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMisc,                   "/EM/CPU%d/R3/PrivInst/Misc",               "Number of misc. instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovWriteCR[0],          "/EM/CPU%d/R3/PrivInst/Mov CR0, X",         "Number of mov CR0 read instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovWriteCR[1],          "/EM/CPU%d/R3/PrivInst/Mov CR1, X",         "Number of mov CR1 read instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovWriteCR[2],          "/EM/CPU%d/R3/PrivInst/Mov CR2, X",         "Number of mov CR2 read instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovWriteCR[3],          "/EM/CPU%d/R3/PrivInst/Mov CR3, X",         "Number of mov CR3 read instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovWriteCR[4],          "/EM/CPU%d/R3/PrivInst/Mov CR4, X",         "Number of mov CR4 read instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovReadCR[0],           "/EM/CPU%d/R3/PrivInst/Mov X, CR0",         "Number of mov CR0 write instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovReadCR[1],           "/EM/CPU%d/R3/PrivInst/Mov X, CR1",         "Number of mov CR1 write instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovReadCR[2],           "/EM/CPU%d/R3/PrivInst/Mov X, CR2",         "Number of mov CR2 write instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovReadCR[3],           "/EM/CPU%d/R3/PrivInst/Mov X, CR3",         "Number of mov CR3 write instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovReadCR[4],           "/EM/CPU%d/R3/PrivInst/Mov X, CR4",         "Number of mov CR4 write instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovDRx,                 "/EM/CPU%d/R3/PrivInst/MovDRx",             "Number of mov DRx instructions.");
        EM_REG_COUNTER_USED(&pStats->StatIret,                   "/EM/CPU%d/R3/PrivInst/Iret",               "Number of iret instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovLgdt,                "/EM/CPU%d/R3/PrivInst/Lgdt",               "Number of lgdt instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovLidt,                "/EM/CPU%d/R3/PrivInst/Lidt",               "Number of lidt instructions.");
        EM_REG_COUNTER_USED(&pStats->StatMovLldt,                "/EM/CPU%d/R3/PrivInst/Lldt",               "Number of lldt instructions.");
        EM_REG_COUNTER_USED(&pStats->StatSysEnter,               "/EM/CPU%d/R3/PrivInst/Sysenter",           "Number of sysenter instructions.");
        EM_REG_COUNTER_USED(&pStats->StatSysExit,                "/EM/CPU%d/R3/PrivInst/Sysexit",            "Number of sysexit instructions.");
        EM_REG_COUNTER_USED(&pStats->StatSysCall,                "/EM/CPU%d/R3/PrivInst/Syscall",            "Number of syscall instructions.");
        EM_REG_COUNTER_USED(&pStats->StatSysRet,                 "/EM/CPU%d/R3/PrivInst/Sysret",             "Number of sysret instructions.");

        EM_REG_COUNTER(&pVCpu->em.s.StatTotalClis,               "/EM/CPU%d/Cli/Total",                      "Total number of cli instructions executed.");
        pVCpu->em.s.pCliStatTree = 0;

        /* these should be considered for release statistics. */
        EM_REG_COUNTER(&pVCpu->em.s.StatIOEmu,                 "/PROF/CPU%d/EM/Emulation/IO",      "Profiling of emR3RawExecuteIOInstruction.");
        EM_REG_COUNTER(&pVCpu->em.s.StatPrivEmu,               "/PROF/CPU%d/EM/Emulation/Priv",    "Profiling of emR3RawPrivileged.");
        EM_REG_PROFILE(&pVCpu->em.s.StatHwAccEntry,           "/PROF/CPU%d/EM/HwAccEnter",        "Profiling Hardware Accelerated Mode entry overhead.");
        EM_REG_PROFILE(&pVCpu->em.s.StatHwAccExec,            "/PROF/CPU%d/EM/HwAccExec",         "Profiling Hardware Accelerated Mode execution.");
        EM_REG_PROFILE(&pVCpu->em.s.StatREMEmu,               "/PROF/CPU%d/EM/REMEmuSingle",      "Profiling single instruction REM execution.");
        EM_REG_PROFILE(&pVCpu->em.s.StatREMExec,              "/PROF/CPU%d/EM/REMExec",           "Profiling REM execution.");
        EM_REG_PROFILE(&pVCpu->em.s.StatREMSync,              "/PROF/CPU%d/EM/REMSync",           "Profiling REM context syncing.");
        EM_REG_PROFILE(&pVCpu->em.s.StatRAWEntry,             "/PROF/CPU%d/EM/RAWEnter",          "Profiling Raw Mode entry overhead.");
        EM_REG_PROFILE(&pVCpu->em.s.StatRAWExec,              "/PROF/CPU%d/EM/RAWExec",           "Profiling Raw Mode execution.");
        EM_REG_PROFILE(&pVCpu->em.s.StatRAWTail,              "/PROF/CPU%d/EM/RAWTail",           "Profiling Raw Mode tail overhead.");

#endif /* VBOX_WITH_STATISTICS */

        EM_REG_COUNTER(&pVCpu->em.s.StatForcedActions,     "/PROF/CPU%d/EM/ForcedActions",     "Profiling forced action execution.");
        EM_REG_COUNTER(&pVCpu->em.s.StatHalted,            "/PROF/CPU%d/EM/Halted",            "Profiling halted state (VMR3WaitHalted).");
        EM_REG_COUNTER(&pVCpu->em.s.StatREMTotal,          "/PROF/CPU%d/EM/REMTotal",          "Profiling emR3RemExecute (excluding FFs).");
        EM_REG_COUNTER(&pVCpu->em.s.StatRAWTotal,          "/PROF/CPU%d/EM/RAWTotal",          "Profiling emR3RawExecute (excluding FFs).");

        EM_REG_PROFILE_ADV(&pVCpu->em.s.StatTotal,         "/PROF/CPU%d/EM/Total",             "Profiling EMR3ExecuteVM.");
    }

    return VINF_SUCCESS;
}


/**
 * Initializes the per-VCPU EM.
 *
 * @returns VBox status code.
 * @param   pVM         The VM to operate on.
 */
VMMR3DECL(int) EMR3InitCPU(PVM pVM)
{
    LogFlow(("EMR3InitCPU\n"));
    return VINF_SUCCESS;
}


/**
 * Applies relocations to data and code managed by this
 * component. This function will be called at init and
 * whenever the VMM need to relocate it self inside the GC.
 *
 * @param   pVM     The VM.
 */
VMMR3DECL(void) EMR3Relocate(PVM pVM)
{
    LogFlow(("EMR3Relocate\n"));
    for (VMCPUID i = 0; i < pVM->cCpus; i++)
    {
        PVMCPU pVCpu = &pVM->aCpus[i];
        if (pVCpu->em.s.pStatsR3)
            pVCpu->em.s.pStatsRC = MMHyperR3ToRC(pVM, pVCpu->em.s.pStatsR3);
    }
}


/**
 * Reset the EM state for a CPU.
 *
 * Called by EMR3Reset and hot plugging.
 *
 * @param   pVCpu               The virtual CPU.
 */
VMMR3DECL(void) EMR3ResetCpu(PVMCPU pVCpu)
{
    pVCpu->em.s.fForceRAW = false;

    /* VMR3Reset may return VINF_EM_RESET or VINF_EM_SUSPEND, so transition
       out of the HALTED state here so that enmPrevState doesn't end up as
       HALTED when EMR3Execute returns. */
    if (pVCpu->em.s.enmState == EMSTATE_HALTED)
    {
        Log(("EMR3ResetCpu: Cpu#%u %s -> %s\n", pVCpu->idCpu, emR3GetStateName(pVCpu->em.s.enmState), pVCpu->idCpu == 0 ? "EMSTATE_NONE" : "EMSTATE_WAIT_SIPI"));
        pVCpu->em.s.enmState = pVCpu->idCpu == 0 ? EMSTATE_NONE : EMSTATE_WAIT_SIPI;
    }
}


/**
 * Reset notification.
 *
 * @param   pVM                 The VM handle.
 */
VMMR3DECL(void) EMR3Reset(PVM pVM)
{
    Log(("EMR3Reset: \n"));
    for (VMCPUID i = 0; i < pVM->cCpus; i++)
        EMR3ResetCpu(&pVM->aCpus[i]);
}


/**
 * Terminates the EM.
 *
 * Termination means cleaning up and freeing all resources,
 * the VM it self is at this point powered off or suspended.
 *
 * @returns VBox status code.
 * @param   pVM         The VM to operate on.
 */
VMMR3DECL(int) EMR3Term(PVM pVM)
{
    AssertMsg(pVM->em.s.offVM, ("bad init order!\n"));

    PDMR3CritSectDelete(&pVM->em.s.CritSectREM);
    return VINF_SUCCESS;
}

/**
 * Terminates the per-VCPU EM.
 *
 * Termination means cleaning up and freeing all resources,
 * the VM it self is at this point powered off or suspended.
 *
 * @returns VBox status code.
 * @param   pVM         The VM to operate on.
 */
VMMR3DECL(int) EMR3TermCPU(PVM pVM)
{
    return 0;
}

/**
 * Execute state save operation.
 *
 * @returns VBox status code.
 * @param   pVM             VM Handle.
 * @param   pSSM            SSM operation handle.
 */
static DECLCALLBACK(int) emR3Save(PVM pVM, PSSMHANDLE pSSM)
{
    for (VMCPUID i = 0; i < pVM->cCpus; i++)
    {
        PVMCPU pVCpu = &pVM->aCpus[i];

        int rc = SSMR3PutBool(pSSM, pVCpu->em.s.fForceRAW);
        AssertRCReturn(rc, rc);

        Assert(pVCpu->em.s.enmState     == EMSTATE_SUSPENDED);
        Assert(pVCpu->em.s.enmPrevState != EMSTATE_SUSPENDED);
        rc = SSMR3PutU32(pSSM, pVCpu->em.s.enmPrevState);
        AssertRCReturn(rc, rc);

        /* Save mwait state. */
        rc = SSMR3PutU32(pSSM, pVCpu->em.s.mwait.fWait);
        AssertRCReturn(rc, rc);
        rc = SSMR3PutGCPtr(pSSM, pVCpu->em.s.mwait.uMWaitEAX);
        AssertRCReturn(rc, rc);
        rc = SSMR3PutGCPtr(pSSM, pVCpu->em.s.mwait.uMWaitECX);
        AssertRCReturn(rc, rc);
        rc = SSMR3PutGCPtr(pSSM, pVCpu->em.s.mwait.uMonitorEAX);
        AssertRCReturn(rc, rc);
        rc = SSMR3PutGCPtr(pSSM, pVCpu->em.s.mwait.uMonitorECX);
        AssertRCReturn(rc, rc);
        rc = SSMR3PutGCPtr(pSSM, pVCpu->em.s.mwait.uMonitorEDX);
        AssertRCReturn(rc, rc);
    }
    return VINF_SUCCESS;
}


/**
 * Execute state load operation.
 *
 * @returns VBox status code.
 * @param   pVM             VM Handle.
 * @param   pSSM            SSM operation handle.
 * @param   uVersion        Data layout version.
 * @param   uPass           The data pass.
 */
static DECLCALLBACK(int) emR3Load(PVM pVM, PSSMHANDLE pSSM, uint32_t uVersion, uint32_t uPass)
{
    /*
     * Validate version.
     */
    if (    uVersion != EM_SAVED_STATE_VERSION
        &&  uVersion != EM_SAVED_STATE_VERSION_PRE_MWAIT
        &&  uVersion != EM_SAVED_STATE_VERSION_PRE_SMP)
    {
        AssertMsgFailed(("emR3Load: Invalid version uVersion=%d (current %d)!\n", uVersion, EM_SAVED_STATE_VERSION));
        return VERR_SSM_UNSUPPORTED_DATA_UNIT_VERSION;
    }
    Assert(uPass == SSM_PASS_FINAL); NOREF(uPass);

    /*
     * Load the saved state.
     */
    for (VMCPUID i = 0; i < pVM->cCpus; i++)
    {
        PVMCPU pVCpu = &pVM->aCpus[i];

        int rc = SSMR3GetBool(pSSM, &pVCpu->em.s.fForceRAW);
        if (RT_FAILURE(rc))
            pVCpu->em.s.fForceRAW = false;
        AssertRCReturn(rc, rc);

        if (uVersion > EM_SAVED_STATE_VERSION_PRE_SMP)
        {
            AssertCompile(sizeof(pVCpu->em.s.enmPrevState) == sizeof(uint32_t));
            rc = SSMR3GetU32(pSSM, (uint32_t *)&pVCpu->em.s.enmPrevState);
            AssertRCReturn(rc, rc);
            Assert(pVCpu->em.s.enmPrevState != EMSTATE_SUSPENDED);

            pVCpu->em.s.enmState = EMSTATE_SUSPENDED;
        }
        if (uVersion > EM_SAVED_STATE_VERSION_PRE_MWAIT)
        {
            /* Load mwait state. */
            rc = SSMR3GetU32(pSSM, &pVCpu->em.s.mwait.fWait);
            AssertRCReturn(rc, rc);
            rc = SSMR3GetGCPtr(pSSM, &pVCpu->em.s.mwait.uMWaitEAX);
            AssertRCReturn(rc, rc);
            rc = SSMR3GetGCPtr(pSSM, &pVCpu->em.s.mwait.uMWaitECX);
            AssertRCReturn(rc, rc);
            rc = SSMR3GetGCPtr(pSSM, &pVCpu->em.s.mwait.uMonitorEAX);
            AssertRCReturn(rc, rc);
            rc = SSMR3GetGCPtr(pSSM, &pVCpu->em.s.mwait.uMonitorECX);
            AssertRCReturn(rc, rc);
            rc = SSMR3GetGCPtr(pSSM, &pVCpu->em.s.mwait.uMonitorEDX);
            AssertRCReturn(rc, rc);
        }

        Assert(!pVCpu->em.s.pCliStatTree);
    }
    return VINF_SUCCESS;
}


/**
 * Raise a fatal error.
 *
 * Safely terminate the VM with full state report and stuff. This function
 * will naturally never return.
 *
 * @param   pVCpu       VMCPU handle.
 * @param   rc          VBox status code.
 */
VMMR3DECL(void) EMR3FatalError(PVMCPU pVCpu, int rc)
{
    pVCpu->em.s.enmState = EMSTATE_GURU_MEDITATION;
    longjmp(pVCpu->em.s.u.FatalLongJump, rc);
    AssertReleaseMsgFailed(("longjmp returned!\n"));
}


/**
 * Gets the EM state name.
 *
 * @returns pointer to read only state name,
 * @param   enmState    The state.
 */
static const char *emR3GetStateName(EMSTATE enmState)
{
    switch (enmState)
    {
        case EMSTATE_NONE:              return "EMSTATE_NONE";
        case EMSTATE_RAW:               return "EMSTATE_RAW";
        case EMSTATE_HWACC:             return "EMSTATE_HWACC";
        case EMSTATE_REM:               return "EMSTATE_REM";
        case EMSTATE_PARAV:             return "EMSTATE_PARAV";
        case EMSTATE_HALTED:            return "EMSTATE_HALTED";
        case EMSTATE_WAIT_SIPI:         return "EMSTATE_WAIT_SIPI";
        case EMSTATE_SUSPENDED:         return "EMSTATE_SUSPENDED";
        case EMSTATE_TERMINATING:       return "EMSTATE_TERMINATING";
        case EMSTATE_DEBUG_GUEST_RAW:   return "EMSTATE_DEBUG_GUEST_RAW";
        case EMSTATE_DEBUG_GUEST_REM:   return "EMSTATE_DEBUG_GUEST_REM";
        case EMSTATE_DEBUG_HYPER:       return "EMSTATE_DEBUG_HYPER";
        case EMSTATE_GURU_MEDITATION:   return "EMSTATE_GURU_MEDITATION";
        default:                        return "Unknown!";
    }
}


/**
 * Debug loop.
 *
 * @returns VBox status code for EM.
 * @param   pVM     VM handle.
 * @param   pVCpu   VMCPU handle.
 * @param   rc      Current EM VBox status code..
 */
static int emR3Debug(PVM pVM, PVMCPU pVCpu, int rc)
{
    for (;;)
    {
        Log(("emR3Debug: rc=%Rrc\n", rc));
        const int rcLast = rc;

        /*
         * Debug related RC.
         */
        switch (rc)
        {
            /*
             * Single step an instruction.
             */
            case VINF_EM_DBG_STEP:
                if (    pVCpu->em.s.enmState == EMSTATE_DEBUG_GUEST_RAW
                    ||  pVCpu->em.s.enmState == EMSTATE_DEBUG_HYPER
                    ||  pVCpu->em.s.fForceRAW /* paranoia */)
                    rc = emR3RawStep(pVM, pVCpu);
                else
                {
                    Assert(pVCpu->em.s.enmState == EMSTATE_DEBUG_GUEST_REM);
                    rc = emR3RemStep(pVM, pVCpu);
                }
                break;

            /*
             * Simple events: stepped, breakpoint, stop/assertion.
             */
            case VINF_EM_DBG_STEPPED:
                rc = DBGFR3Event(pVM, DBGFEVENT_STEPPED);
                break;

            case VINF_EM_DBG_BREAKPOINT:
                rc = DBGFR3EventBreakpoint(pVM, DBGFEVENT_BREAKPOINT);
                break;

            case VINF_EM_DBG_STOP:
                rc = DBGFR3EventSrc(pVM, DBGFEVENT_DEV_STOP, NULL, 0, NULL, NULL);
                break;

            case VINF_EM_DBG_HYPER_STEPPED:
                rc = DBGFR3Event(pVM, DBGFEVENT_STEPPED_HYPER);
                break;

            case VINF_EM_DBG_HYPER_BREAKPOINT:
                rc = DBGFR3EventBreakpoint(pVM, DBGFEVENT_BREAKPOINT_HYPER);
                break;

            case VINF_EM_DBG_HYPER_ASSERTION:
                RTPrintf("\nVINF_EM_DBG_HYPER_ASSERTION:\n%s%s\n", VMMR3GetRZAssertMsg1(pVM), VMMR3GetRZAssertMsg2(pVM));
                rc = DBGFR3EventAssertion(pVM, DBGFEVENT_ASSERTION_HYPER, VMMR3GetRZAssertMsg1(pVM), VMMR3GetRZAssertMsg2(pVM));
                break;

            /*
             * Guru meditation.
             */
            case VERR_VMM_RING0_ASSERTION: /** @todo Make a guru meditation event! */
                rc = DBGFR3EventSrc(pVM, DBGFEVENT_FATAL_ERROR, "VERR_VMM_RING0_ASSERTION", 0, NULL, NULL);
                break;
            case VERR_REM_TOO_MANY_TRAPS: /** @todo Make a guru meditation event! */
                rc = DBGFR3EventSrc(pVM, DBGFEVENT_DEV_STOP, "VERR_REM_TOO_MANY_TRAPS", 0, NULL, NULL);
                break;

            default: /** @todo don't use default for guru, but make special errors code! */
                rc = DBGFR3Event(pVM, DBGFEVENT_FATAL_ERROR);
                break;
        }

        /*
         * Process the result.
         */
        do
        {
            switch (rc)
            {
                /*
                 * Continue the debugging loop.
                 */
                case VINF_EM_DBG_STEP:
                case VINF_EM_DBG_STOP:
                case VINF_EM_DBG_STEPPED:
                case VINF_EM_DBG_BREAKPOINT:
                case VINF_EM_DBG_HYPER_STEPPED:
                case VINF_EM_DBG_HYPER_BREAKPOINT:
                case VINF_EM_DBG_HYPER_ASSERTION:
                    break;

                /*
                 * Resuming execution (in some form) has to be done here if we got
                 * a hypervisor debug event.
                 */
                case VINF_SUCCESS:
                case VINF_EM_RESUME:
                case VINF_EM_SUSPEND:
                case VINF_EM_RESCHEDULE:
                case VINF_EM_RESCHEDULE_RAW:
                case VINF_EM_RESCHEDULE_REM:
                case VINF_EM_HALT:
                    if (pVCpu->em.s.enmState == EMSTATE_DEBUG_HYPER)
                    {
                        rc = emR3RawResumeHyper(pVM, pVCpu);
                        if (rc != VINF_SUCCESS && RT_SUCCESS(rc))
                            continue;
                    }
                    if (rc == VINF_SUCCESS)
                        rc = VINF_EM_RESCHEDULE;
                    return rc;

                /*
                 * The debugger isn't attached.
                 * We'll simply turn the thing off since that's the easiest thing to do.
                 */
                case VERR_DBGF_NOT_ATTACHED:
                    switch (rcLast)
                    {
                        case VINF_EM_DBG_HYPER_STEPPED:
                        case VINF_EM_DBG_HYPER_BREAKPOINT:
                        case VINF_EM_DBG_HYPER_ASSERTION:
                        case VERR_TRPM_PANIC:
                        case VERR_TRPM_DONT_PANIC:
                        case VERR_VMM_RING0_ASSERTION:
                        case VERR_VMM_HYPER_CR3_MISMATCH:
                        case VERR_VMM_RING3_CALL_DISABLED:
                            return rcLast;
                    }
                    return VINF_EM_OFF;

                /*
                 * Status codes terminating the VM in one or another sense.
                 */
                case VINF_EM_TERMINATE:
                case VINF_EM_OFF:
                case VINF_EM_RESET:
                case VINF_EM_NO_MEMORY:
                case VINF_EM_RAW_STALE_SELECTOR:
                case VINF_EM_RAW_IRET_TRAP:
                case VERR_TRPM_PANIC:
                case VERR_TRPM_DONT_PANIC:
                case VERR_VMM_RING0_ASSERTION:
                case VERR_VMM_HYPER_CR3_MISMATCH:
                case VERR_VMM_RING3_CALL_DISABLED:
                case VERR_INTERNAL_ERROR:
                case VERR_INTERNAL_ERROR_2:
                case VERR_INTERNAL_ERROR_3:
                case VERR_INTERNAL_ERROR_4:
                case VERR_INTERNAL_ERROR_5:
                case VERR_IPE_UNEXPECTED_STATUS:
                case VERR_IPE_UNEXPECTED_INFO_STATUS:
                case VERR_IPE_UNEXPECTED_ERROR_STATUS:
                    return rc;

                /*
                 * The rest is unexpected, and will keep us here.
                 */
                default:
                    AssertMsgFailed(("Unxpected rc %Rrc!\n", rc));
                    break;
            }
        } while (false);
    } /* debug for ever */
}

/**
 * Steps recompiled code.
 *
 * @returns VBox status code. The most important ones are: VINF_EM_STEP_EVENT,
 *          VINF_EM_RESCHEDULE, VINF_EM_SUSPEND, VINF_EM_RESET and VINF_EM_TERMINATE.
 *
 * @param   pVM         VM handle.
 * @param   pVCpu       VMCPU handle.
 */
static int emR3RemStep(PVM pVM, PVMCPU pVCpu)
{
    LogFlow(("emR3RemStep: cs:eip=%04x:%08x\n", CPUMGetGuestCS(pVCpu),  CPUMGetGuestEIP(pVCpu)));

    EMRemLock(pVM);

    /*
     * Switch to REM, step instruction, switch back.
     */
    int rc = REMR3State(pVM, pVCpu);
    if (RT_SUCCESS(rc))
    {
        rc = REMR3Step(pVM, pVCpu);
        REMR3StateBack(pVM, pVCpu);
    }
    EMRemUnlock(pVM);

    LogFlow(("emR3RemStep: returns %Rrc cs:eip=%04x:%08x\n", rc, CPUMGetGuestCS(pVCpu),  CPUMGetGuestEIP(pVCpu)));
    return rc;
}


/**
 * emR3RemExecute helper that syncs the state back from REM and leave the REM
 * critical section.
 *
 * @returns false - new fInREMState value.
 * @param   pVM         The VM handle.
 * @param   pVCpu       The virtual CPU handle.
 */
DECLINLINE(bool) emR3RemExecuteSyncBack(PVM pVM, PVMCPU pVCpu)
{
    STAM_PROFILE_START(&pVCpu->em.s.StatREMSync, a);
    REMR3StateBack(pVM, pVCpu);
    STAM_PROFILE_STOP(&pVCpu->em.s.StatREMSync, a);

    EMRemUnlock(pVM);
    return false;
}


/**
 * Executes recompiled code.
 *
 * This function contains the recompiler version of the inner
 * execution loop (the outer loop being in EMR3ExecuteVM()).
 *
 * @returns VBox status code. The most important ones are: VINF_EM_RESCHEDULE,
 *          VINF_EM_SUSPEND, VINF_EM_RESET and VINF_EM_TERMINATE.
 *
 * @param   pVM         VM handle.
 * @param   pVCpu       VMCPU handle.
 * @param   pfFFDone    Where to store an indicator telling wheter or not
 *                      FFs were done before returning.
 *
 */
static int emR3RemExecute(PVM pVM, PVMCPU pVCpu, bool *pfFFDone)
{
#ifdef LOG_ENABLED
    PCPUMCTX pCtx = pVCpu->em.s.pCtx;
    uint32_t cpl = CPUMGetGuestCPL(pVCpu, CPUMCTX2CORE(pCtx));

    if (pCtx->eflags.Bits.u1VM)
        Log(("EMV86: %04X:%08X IF=%d\n", pCtx->cs, pCtx->eip, pCtx->eflags.Bits.u1IF));
    else
        Log(("EMR%d: %04X:%08X ESP=%08X IF=%d CR0=%x\n", cpl, pCtx->cs, pCtx->eip, pCtx->esp, pCtx->eflags.Bits.u1IF, (uint32_t)pCtx->cr0));
#endif
    STAM_REL_PROFILE_ADV_START(&pVCpu->em.s.StatREMTotal, a);

#if defined(VBOX_STRICT) && defined(DEBUG_bird)
    AssertMsg(   VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_PGM_SYNC_CR3 | VMCPU_FF_PGM_SYNC_CR3_NON_GLOBAL)
              || !MMHyperIsInsideArea(pVM, CPUMGetGuestEIP(pVCpu)),  /** @todo #1419 - get flat address. */
              ("cs:eip=%RX16:%RX32\n", CPUMGetGuestCS(pVCpu), CPUMGetGuestEIP(pVCpu)));
#endif

    /*
     * Spin till we get a forced action which returns anything but VINF_SUCCESS
     * or the REM suggests raw-mode execution.
     */
    *pfFFDone = false;
    bool    fInREMState = false;
    int     rc          = VINF_SUCCESS;
    for (;;)
    {
        /*
         * Lock REM and update the state if not already in sync.
         *
         * Note! Big lock, but you are not supposed to own any lock when
         *       coming in here.
         */
        if (!fInREMState)
        {
            EMRemLock(pVM);
            STAM_PROFILE_START(&pVCpu->em.s.StatREMSync, b);

            /* Flush the recompiler translation blocks if the VCPU has changed,
               also force a full CPU state resync. */
            if (pVM->em.s.idLastRemCpu != pVCpu->idCpu)
            {
                REMFlushTBs(pVM);
                CPUMSetChangedFlags(pVCpu, CPUM_CHANGED_ALL);
            }
            pVM->em.s.idLastRemCpu = pVCpu->idCpu;

            rc = REMR3State(pVM, pVCpu);

            STAM_PROFILE_STOP(&pVCpu->em.s.StatREMSync, b);
            if (RT_FAILURE(rc))
                break;
            fInREMState = true;

            /*
             * We might have missed the raising of VMREQ, TIMER and some other
             * imporant FFs while we were busy switching the state. So, check again.
             */
            if (    VM_FF_ISPENDING(pVM, VM_FF_REQUEST | VM_FF_PDM_QUEUES | VM_FF_DBGF | VM_FF_TERMINATE | VM_FF_RESET)
                ||  VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_TIMER | VMCPU_FF_REQUEST))
            {
                LogFlow(("emR3RemExecute: Skipping run, because FF is set. %#x\n", pVM->fGlobalForcedActions));
                goto l_REMDoForcedActions;
            }
        }


        /*
         * Execute REM.
         */
        STAM_PROFILE_START(&pVCpu->em.s.StatREMExec, c);
        rc = REMR3Run(pVM, pVCpu);
        STAM_PROFILE_STOP(&pVCpu->em.s.StatREMExec, c);


        /*
         * Deal with high priority post execution FFs before doing anything
         * else.  Sync back the state and leave the lock to be on the safe side.
         */
        if (    VM_FF_ISPENDING(pVM, VM_FF_HIGH_PRIORITY_POST_MASK)
            ||  VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_HIGH_PRIORITY_POST_MASK))
        {
            fInREMState = emR3RemExecuteSyncBack(pVM, pVCpu);
            rc = emR3HighPriorityPostForcedActions(pVM, pVCpu, rc);
        }

        /*
         * Process the returned status code.
         */
        if (rc != VINF_SUCCESS)
        {
            if (rc >= VINF_EM_FIRST && rc <= VINF_EM_LAST)
                break;
            if (rc != VINF_REM_INTERRUPED_FF)
            {
                /*
                 * Anything which is not known to us means an internal error
                 * and the termination of the VM!
                 */
                AssertMsg(rc == VERR_REM_TOO_MANY_TRAPS, ("Unknown GC return code: %Rra\n", rc));
                break;
            }
        }


        /*
         * Check and execute forced actions.
         *
         * Sync back the VM state and leave the lock  before calling any of
         * these, you never know what's going to happen here.
         */
#ifdef VBOX_HIGH_RES_TIMERS_HACK
        TMTimerPollVoid(pVM, pVCpu);
#endif
        AssertCompile((VMCPU_FF_ALL_BUT_RAW_MASK & ~(VMCPU_FF_CSAM_PENDING_ACTION | VMCPU_FF_CSAM_SCAN_PAGE)) & VMCPU_FF_TIMER);
        if (    VM_FF_ISPENDING(pVM, VM_FF_ALL_BUT_RAW_MASK)
            ||  VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_ALL_BUT_RAW_MASK & ~(VMCPU_FF_CSAM_PENDING_ACTION | VMCPU_FF_CSAM_SCAN_PAGE)))
        {
l_REMDoForcedActions:
            if (fInREMState)
                fInREMState = emR3RemExecuteSyncBack(pVM, pVCpu);
            STAM_REL_PROFILE_ADV_SUSPEND(&pVCpu->em.s.StatREMTotal, a);
            rc = emR3ForcedActions(pVM, pVCpu, rc);
            STAM_REL_PROFILE_ADV_RESUME(&pVCpu->em.s.StatREMTotal, a);
            if (    rc != VINF_SUCCESS
                &&  rc != VINF_EM_RESCHEDULE_REM)
            {
                *pfFFDone = true;
                break;
            }
        }

    } /* The Inner Loop, recompiled execution mode version. */


    /*
     * Returning. Sync back the VM state if required.
     */
    if (fInREMState)
        fInREMState = emR3RemExecuteSyncBack(pVM, pVCpu);

    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatREMTotal, a);
    return rc;
}


#ifdef DEBUG

int emR3SingleStepExecRem(PVM pVM, PVMCPU pVCpu, uint32_t cIterations)
{
    EMSTATE  enmOldState = pVCpu->em.s.enmState;

    pVCpu->em.s.enmState = EMSTATE_DEBUG_GUEST_REM;

    Log(("Single step BEGIN:\n"));
    for (uint32_t i = 0; i < cIterations; i++)
    {
        DBGFR3PrgStep(pVCpu);
        DBGFR3DisasInstrCurrentLog(pVCpu, "RSS: ");
        emR3RemStep(pVM, pVCpu);
        if (emR3Reschedule(pVM, pVCpu, pVCpu->em.s.pCtx) != EMSTATE_REM)
            break;
    }
    Log(("Single step END:\n"));
    CPUMSetGuestEFlags(pVCpu, CPUMGetGuestEFlags(pVCpu) & ~X86_EFL_TF);
    pVCpu->em.s.enmState = enmOldState;
    return VINF_EM_RESCHEDULE;
}

#endif /* DEBUG */


/**
 * Decides whether to execute RAW, HWACC or REM.
 *
 * @returns new EM state
 * @param   pVM     The VM.
 * @param   pVCpu   The VMCPU handle.
 * @param   pCtx    The CPU context.
 */
EMSTATE emR3Reschedule(PVM pVM, PVMCPU pVCpu, PCPUMCTX pCtx)
{
    /*
     * When forcing raw-mode execution, things are simple.
     */
    if (pVCpu->em.s.fForceRAW)
        return EMSTATE_RAW;

    /*
     * We stay in the wait for SIPI state unless explicitly told otherwise.
     */
    if (pVCpu->em.s.enmState == EMSTATE_WAIT_SIPI)
        return EMSTATE_WAIT_SIPI;

    /* !!! THIS MUST BE IN SYNC WITH remR3CanExecuteRaw !!! */
    /* !!! THIS MUST BE IN SYNC WITH remR3CanExecuteRaw !!! */
    /* !!! THIS MUST BE IN SYNC WITH remR3CanExecuteRaw !!! */

    X86EFLAGS EFlags = pCtx->eflags;
    if (HWACCMIsEnabled(pVM))
    {
        /* Hardware accelerated raw-mode:
         *
         * Typically only 32-bits protected mode, with paging enabled, code is allowed here.
         */
        if (HWACCMR3CanExecuteGuest(pVM, pCtx) == true)
            return EMSTATE_HWACC;

        /* Note: Raw mode and hw accelerated mode are incompatible. The latter turns
         * off monitoring features essential for raw mode! */
        return EMSTATE_REM;
    }

    /*
     * Standard raw-mode:
     *
     * Here we only support 16 & 32 bits protected mode ring 3 code that has no IO privileges
     * or 32 bits protected mode ring 0 code
     *
     * The tests are ordered by the likelyhood of being true during normal execution.
     */
    if (EFlags.u32 & (X86_EFL_TF /* | HF_INHIBIT_IRQ_MASK*/))
    {
        Log2(("raw mode refused: EFlags=%#x\n", EFlags.u32));
        return EMSTATE_REM;
    }

#ifndef VBOX_RAW_V86
    if (EFlags.u32 & X86_EFL_VM) {
        Log2(("raw mode refused: VM_MASK\n"));
        return EMSTATE_REM;
    }
#endif

    /** @todo check up the X86_CR0_AM flag in respect to raw mode!!! We're probably not emulating it right! */
    uint32_t u32CR0 = pCtx->cr0;
    if ((u32CR0 & (X86_CR0_PG | X86_CR0_PE)) != (X86_CR0_PG | X86_CR0_PE))
    {
        //Log2(("raw mode refused: %s%s%s\n", (u32CR0 & X86_CR0_PG) ? "" : " !PG", (u32CR0 & X86_CR0_PE) ? "" : " !PE", (u32CR0 & X86_CR0_AM) ? "" : " !AM"));
        return EMSTATE_REM;
    }

    if (pCtx->cr4 & X86_CR4_PAE)
    {
        uint32_t u32Dummy, u32Features;

        CPUMGetGuestCpuId(pVCpu, 1, &u32Dummy, &u32Dummy, &u32Dummy, &u32Features);
        if (!(u32Features & X86_CPUID_FEATURE_EDX_PAE))
            return EMSTATE_REM;
    }

    unsigned uSS = pCtx->ss;
    if (    pCtx->eflags.Bits.u1VM
        ||  (uSS & X86_SEL_RPL) == 3)
    {
        if (!EMIsRawRing3Enabled(pVM))
            return EMSTATE_REM;

        if (!(EFlags.u32 & X86_EFL_IF))
        {
            Log2(("raw mode refused: IF (RawR3)\n"));
            return EMSTATE_REM;
        }

        if (!(u32CR0 & X86_CR0_WP) && EMIsRawRing0Enabled(pVM))
        {
            Log2(("raw mode refused: CR0.WP + RawR0\n"));
            return EMSTATE_REM;
        }
    }
    else
    {
        if (!EMIsRawRing0Enabled(pVM))
            return EMSTATE_REM;

        /* Only ring 0 supervisor code. */
        if ((uSS & X86_SEL_RPL) != 0)
        {
            Log2(("raw r0 mode refused: CPL %d\n", uSS & X86_SEL_RPL));
            return EMSTATE_REM;
        }

        // Let's start with pure 32 bits ring 0 code first
        /** @todo What's pure 32-bit mode? flat? */
        if (    !(pCtx->ssHid.Attr.n.u1DefBig)
            ||  !(pCtx->csHid.Attr.n.u1DefBig))
        {
            Log2(("raw r0 mode refused: SS/CS not 32bit\n"));
            return EMSTATE_REM;
        }

        /* Write protection must be turned on, or else the guest can overwrite our hypervisor code and data. */
        if (!(u32CR0 & X86_CR0_WP))
        {
            Log2(("raw r0 mode refused: CR0.WP=0!\n"));
            return EMSTATE_REM;
        }

        if (PATMShouldUseRawMode(pVM, (RTGCPTR)pCtx->eip))
        {
            Log2(("raw r0 mode forced: patch code\n"));
            return EMSTATE_RAW;
        }

#if !defined(VBOX_ALLOW_IF0) && !defined(VBOX_RUN_INTERRUPT_GATE_HANDLERS)
        if (!(EFlags.u32 & X86_EFL_IF))
        {
            ////Log2(("R0: IF=0 VIF=%d %08X\n", eip, pVMeflags));
            //Log2(("RR0: Interrupts turned off; fall back to emulation\n"));
            return EMSTATE_REM;
        }
#endif

        /** @todo still necessary??? */
        if (EFlags.Bits.u2IOPL != 0)
        {
            Log2(("raw r0 mode refused: IOPL %d\n", EFlags.Bits.u2IOPL));
            return EMSTATE_REM;
        }
    }

    Assert(PGMPhysIsA20Enabled(pVCpu));
    return EMSTATE_RAW;
}


/**
 * Executes all high priority post execution force actions.
 *
 * @returns rc or a fatal status code.
 *
 * @param   pVM         VM handle.
 * @param   pVCpu       VMCPU handle.
 * @param   rc          The current rc.
 */
int emR3HighPriorityPostForcedActions(PVM pVM, PVMCPU pVCpu, int rc)
{
    if (VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_PDM_CRITSECT))
        PDMCritSectFF(pVCpu);

    if (VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_CSAM_PENDING_ACTION))
        CSAMR3DoPendingAction(pVM, pVCpu);

    if (VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY))
    {
        if (    rc > VINF_EM_NO_MEMORY
            &&  rc <= VINF_EM_LAST)
            rc = VINF_EM_NO_MEMORY;
    }

    return rc;
}


/**
 * Executes all pending forced actions.
 *
 * Forced actions can cause execution delays and execution
 * rescheduling. The first we deal with using action priority, so
 * that for instance pending timers aren't scheduled and ran until
 * right before execution. The rescheduling we deal with using
 * return codes. The same goes for VM termination, only in that case
 * we exit everything.
 *
 * @returns VBox status code of equal or greater importance/severity than rc.
 *          The most important ones are: VINF_EM_RESCHEDULE,
 *          VINF_EM_SUSPEND, VINF_EM_RESET and VINF_EM_TERMINATE.
 *
 * @param   pVM         VM handle.
 * @param   pVCpu       VMCPU handle.
 * @param   rc          The current rc.
 *
 */
int emR3ForcedActions(PVM pVM, PVMCPU pVCpu, int rc)
{
    STAM_REL_PROFILE_START(&pVCpu->em.s.StatForcedActions, a);
#ifdef VBOX_STRICT
    int rcIrq = VINF_SUCCESS;
#endif
    int rc2;
#define UPDATE_RC() \
        do { \
            AssertMsg(rc2 <= 0 || (rc2 >= VINF_EM_FIRST && rc2 <= VINF_EM_LAST), ("Invalid FF return code: %Rra\n", rc2)); \
            if (rc2 == VINF_SUCCESS || rc < VINF_SUCCESS) \
                break; \
            if (!rc || rc2 < rc) \
                rc = rc2; \
        } while (0)

    /*
     * Post execution chunk first.
     */
    if (    VM_FF_ISPENDING(pVM, VM_FF_NORMAL_PRIORITY_POST_MASK)
        ||  VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_NORMAL_PRIORITY_POST_MASK))
    {
        /*
         * EMT Rendezvous (must be serviced before termination).
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_EMT_RENDEZVOUS))
        {
            rc2 = VMMR3EmtRendezvousFF(pVM, pVCpu);
            UPDATE_RC();
            /** @todo HACK ALERT! The following test is to make sure EM+TM things the VM is
             * stopped/reset before the next VM state change is made. We need a better
             * solution for this, or at least make it possible to do: (rc >= VINF_EM_FIRST
             * && rc >= VINF_EM_SUSPEND). */
            if (RT_UNLIKELY(rc == VINF_EM_SUSPEND || rc == VINF_EM_RESET || rc == VINF_EM_OFF))
            {
                Log2(("emR3ForcedActions: returns %Rrc\n", rc));
                STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
                return rc;
            }
        }

        /*
         * Termination request.
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_TERMINATE))
        {
            Log2(("emR3ForcedActions: returns VINF_EM_TERMINATE\n"));
            STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
            return VINF_EM_TERMINATE;
        }

        /*
         * Debugger Facility polling.
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_DBGF))
        {
            rc2 = DBGFR3VMMForcedAction(pVM);
            UPDATE_RC();
        }

        /*
         * Postponed reset request.
         */
        if (VM_FF_TESTANDCLEAR(pVM, VM_FF_RESET))
        {
            rc2 = VMR3Reset(pVM);
            UPDATE_RC();
        }

        /*
         * CSAM page scanning.
         */
        if (    !VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY)
            &&  VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_CSAM_SCAN_PAGE))
        {
            PCPUMCTX pCtx = pVCpu->em.s.pCtx;

            /** @todo: check for 16 or 32 bits code! (D bit in the code selector) */
            Log(("Forced action VMCPU_FF_CSAM_SCAN_PAGE\n"));

            CSAMR3CheckCodeEx(pVM, CPUMCTX2CORE(pCtx), pCtx->eip);
            VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_CSAM_SCAN_PAGE);
        }

        /*
         * Out of memory? Putting this after CSAM as it may in theory cause us to run out of memory.
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY))
        {
            rc2 = PGMR3PhysAllocateHandyPages(pVM);
            UPDATE_RC();
            if (rc == VINF_EM_NO_MEMORY)
                return rc;
        }

        /* check that we got them all  */
        AssertCompile(VM_FF_NORMAL_PRIORITY_POST_MASK == (VM_FF_TERMINATE | VM_FF_DBGF | VM_FF_RESET | VM_FF_PGM_NO_MEMORY | VM_FF_EMT_RENDEZVOUS));
        AssertCompile(VMCPU_FF_NORMAL_PRIORITY_POST_MASK == VMCPU_FF_CSAM_SCAN_PAGE);
    }

    /*
     * Normal priority then.
     * (Executed in no particular order.)
     */
    if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_NORMAL_PRIORITY_MASK, VM_FF_PGM_NO_MEMORY))
    {
        /*
         * PDM Queues are pending.
         */
        if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_PDM_QUEUES, VM_FF_PGM_NO_MEMORY))
            PDMR3QueueFlushAll(pVM);

        /*
         * PDM DMA transfers are pending.
         */
        if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_PDM_DMA, VM_FF_PGM_NO_MEMORY))
            PDMR3DmaRun(pVM);

        /*
         * EMT Rendezvous (make sure they are handled before the requests).
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_EMT_RENDEZVOUS))
        {
            rc2 = VMMR3EmtRendezvousFF(pVM, pVCpu);
            UPDATE_RC();
            /** @todo HACK ALERT! The following test is to make sure EM+TM things the VM is
             * stopped/reset before the next VM state change is made. We need a better
             * solution for this, or at least make it possible to do: (rc >= VINF_EM_FIRST
             * && rc >= VINF_EM_SUSPEND). */
            if (RT_UNLIKELY(rc == VINF_EM_SUSPEND || rc == VINF_EM_RESET || rc == VINF_EM_OFF))
            {
                Log2(("emR3ForcedActions: returns %Rrc\n", rc));
                STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
                return rc;
            }
        }

        /*
         * Requests from other threads.
         */
        if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_REQUEST, VM_FF_PGM_NO_MEMORY))
        {
            rc2 = VMR3ReqProcessU(pVM->pUVM, VMCPUID_ANY);
            if (rc2 == VINF_EM_OFF || rc2 == VINF_EM_TERMINATE) /** @todo this shouldn't be necessary */
            {
                Log2(("emR3ForcedActions: returns %Rrc\n", rc2));
                STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
                return rc2;
            }
            UPDATE_RC();
            /** @todo HACK ALERT! The following test is to make sure EM+TM things the VM is
             * stopped/reset before the next VM state change is made. We need a better
             * solution for this, or at least make it possible to do: (rc >= VINF_EM_FIRST
             * && rc >= VINF_EM_SUSPEND). */
            if (RT_UNLIKELY(rc == VINF_EM_SUSPEND || rc == VINF_EM_RESET || rc == VINF_EM_OFF))
            {
                Log2(("emR3ForcedActions: returns %Rrc\n", rc));
                STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
                return rc;
            }
        }

        /* Replay the handler notification changes. */
        if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_REM_HANDLER_NOTIFY, VM_FF_PGM_NO_MEMORY))
        {
            /* Try not to cause deadlocks. */
            if (    pVM->cCpus == 1
                ||  (   !PGMIsLockOwner(pVM)
                     && !IOMIsLockOwner(pVM))
               )
            {
                EMRemLock(pVM);
                REMR3ReplayHandlerNotifications(pVM);
                EMRemUnlock(pVM);
            }
        }

        /* check that we got them all  */
        AssertCompile(VM_FF_NORMAL_PRIORITY_MASK == (VM_FF_REQUEST | VM_FF_PDM_QUEUES | VM_FF_PDM_DMA | VM_FF_REM_HANDLER_NOTIFY | VM_FF_EMT_RENDEZVOUS));
    }

    /*
     * Normal priority then. (per-VCPU)
     * (Executed in no particular order.)
     */
    if (    !VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY)
        &&  VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_NORMAL_PRIORITY_MASK))
    {
        /*
         * Requests from other threads.
         */
        if (VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_REQUEST))
        {
            rc2 = VMR3ReqProcessU(pVM->pUVM, pVCpu->idCpu);
            if (rc2 == VINF_EM_OFF || rc2 == VINF_EM_TERMINATE || rc2 == VINF_EM_RESET)
            {
                Log2(("emR3ForcedActions: returns %Rrc\n", rc2));
                STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
                return rc2;
            }
            UPDATE_RC();
            /** @todo HACK ALERT! The following test is to make sure EM+TM things the VM is
             * stopped/reset before the next VM state change is made. We need a better
             * solution for this, or at least make it possible to do: (rc >= VINF_EM_FIRST
             * && rc >= VINF_EM_SUSPEND). */
            if (RT_UNLIKELY(rc == VINF_EM_SUSPEND || rc == VINF_EM_RESET || rc == VINF_EM_OFF))
            {
                Log2(("emR3ForcedActions: returns %Rrc\n", rc));
                STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
                return rc;
            }
        }

        /* check that we got them all  */
        Assert(!(VMCPU_FF_NORMAL_PRIORITY_MASK & ~(VMCPU_FF_REQUEST)));
    }

    /*
     * High priority pre execution chunk last.
     * (Executed in ascending priority order.)
     */
    if (    VM_FF_ISPENDING(pVM, VM_FF_HIGH_PRIORITY_PRE_MASK)
        ||  VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_HIGH_PRIORITY_PRE_MASK))
    {
        /*
         * Timers before interrupts.
         */
        if (    VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_TIMER)
            &&  !VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY))
            TMR3TimerQueuesDo(pVM);

        /*
         * The instruction following an emulated STI should *always* be executed!
         */
        if (    VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_INHIBIT_INTERRUPTS)
            &&  !VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY))
        {
            Log(("VM_FF_EMULATED_STI at %RGv successor %RGv\n", (RTGCPTR)CPUMGetGuestRIP(pVCpu), EMGetInhibitInterruptsPC(pVCpu)));
            if (CPUMGetGuestEIP(pVCpu) != EMGetInhibitInterruptsPC(pVCpu))
            {
                /* Note: we intentionally don't clear VM_FF_INHIBIT_INTERRUPTS here if the eip is the same as the inhibited instr address.
                 *  Before we are able to execute this instruction in raw mode (iret to guest code) an external interrupt might
                 *  force a world switch again. Possibly allowing a guest interrupt to be dispatched in the process. This could
                 *  break the guest. Sounds very unlikely, but such timing sensitive problem are not as rare as you might think.
                 */
                VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_INHIBIT_INTERRUPTS);
            }
            if (HWACCMR3IsActive(pVCpu))
                rc2 = VINF_EM_RESCHEDULE_HWACC;
            else
                rc2 = PATMAreInterruptsEnabled(pVM) ? VINF_EM_RESCHEDULE_RAW : VINF_EM_RESCHEDULE_REM;

            UPDATE_RC();
        }

        /*
         * Interrupts.
         */
        if (    !VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY)
            &&  !VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_INHIBIT_INTERRUPTS)
            &&  (!rc || rc >= VINF_EM_RESCHEDULE_HWACC)
            &&  !TRPMHasTrap(pVCpu) /* an interrupt could already be scheduled for dispatching in the recompiler. */
            &&  PATMAreInterruptsEnabled(pVM)
            &&  !HWACCMR3IsEventPending(pVCpu))
        {
            Assert(pVCpu->em.s.enmState != EMSTATE_WAIT_SIPI);
            if (VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_INTERRUPT_APIC | VMCPU_FF_INTERRUPT_PIC))
            {
                /* Note: it's important to make sure the return code from TRPMR3InjectEvent isn't ignored! */
                /** @todo this really isn't nice, should properly handle this */
                rc2 = TRPMR3InjectEvent(pVM, pVCpu, TRPM_HARDWARE_INT);
#ifdef VBOX_STRICT
                rcIrq = rc2;
#endif
                UPDATE_RC();
            }
            /** @todo really ugly; if we entered the hlt state when exiting the recompiler and an interrupt was pending, we previously got stuck in the halted state. */
            else if (REMR3QueryPendingInterrupt(pVM, pVCpu) != REM_NO_PENDING_IRQ)
            {
                rc2 = VINF_EM_RESCHEDULE_REM;
                UPDATE_RC();
            }
        }

        /*
         * Allocate handy pages.
         */
        if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_PGM_NEED_HANDY_PAGES, VM_FF_PGM_NO_MEMORY))
        {
            rc2 = PGMR3PhysAllocateHandyPages(pVM);
            UPDATE_RC();
        }

        /*
         * Debugger Facility request.
         */
        if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_DBGF, VM_FF_PGM_NO_MEMORY))
        {
            rc2 = DBGFR3VMMForcedAction(pVM);
            UPDATE_RC();
        }

        /*
         * EMT Rendezvous (must be serviced before termination).
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_EMT_RENDEZVOUS))
        {
            rc2 = VMMR3EmtRendezvousFF(pVM, pVCpu);
            UPDATE_RC();
            /** @todo HACK ALERT! The following test is to make sure EM+TM things the VM is
             * stopped/reset before the next VM state change is made. We need a better
             * solution for this, or at least make it possible to do: (rc >= VINF_EM_FIRST
             * && rc >= VINF_EM_SUSPEND). */
            if (RT_UNLIKELY(rc == VINF_EM_SUSPEND || rc == VINF_EM_RESET || rc == VINF_EM_OFF))
            {
                Log2(("emR3ForcedActions: returns %Rrc\n", rc));
                STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
                return rc;
            }
        }

        /*
         * Termination request.
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_TERMINATE))
        {
            Log2(("emR3ForcedActions: returns VINF_EM_TERMINATE\n"));
            STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
            return VINF_EM_TERMINATE;
        }

        /*
         * Out of memory? Since most of our fellow high priority actions may cause us
         * to run out of memory, we're employing VM_FF_IS_PENDING_EXCEPT and putting this
         * at the end rather than the start. Also, VM_FF_TERMINATE has higher priority
         * than us since we can terminate without allocating more memory.
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_PGM_NO_MEMORY))
        {
            rc2 = PGMR3PhysAllocateHandyPages(pVM);
            UPDATE_RC();
            if (rc == VINF_EM_NO_MEMORY)
                return rc;
        }

        /*
         * If the virtual sync clock is still stopped, make TM restart it.
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_TM_VIRTUAL_SYNC))
            TMR3VirtualSyncFF(pVM, pVCpu);

#ifdef DEBUG
        /*
         * Debug, pause the VM.
         */
        if (VM_FF_ISPENDING(pVM, VM_FF_DEBUG_SUSPEND))
        {
            VM_FF_CLEAR(pVM, VM_FF_DEBUG_SUSPEND);
            Log(("emR3ForcedActions: returns VINF_EM_SUSPEND\n"));
            return VINF_EM_SUSPEND;
        }
#endif

        /* check that we got them all  */
        AssertCompile(VM_FF_HIGH_PRIORITY_PRE_MASK == (VM_FF_TM_VIRTUAL_SYNC | VM_FF_DBGF | VM_FF_TERMINATE | VM_FF_DEBUG_SUSPEND | VM_FF_PGM_NEED_HANDY_PAGES | VM_FF_PGM_NO_MEMORY | VM_FF_EMT_RENDEZVOUS));
        AssertCompile(VMCPU_FF_HIGH_PRIORITY_PRE_MASK == (VMCPU_FF_TIMER | VMCPU_FF_INTERRUPT_APIC | VMCPU_FF_INTERRUPT_PIC | VMCPU_FF_PGM_SYNC_CR3 | VMCPU_FF_PGM_SYNC_CR3_NON_GLOBAL | VMCPU_FF_SELM_SYNC_TSS | VMCPU_FF_TRPM_SYNC_IDT | VMCPU_FF_SELM_SYNC_GDT | VMCPU_FF_SELM_SYNC_LDT | VMCPU_FF_INHIBIT_INTERRUPTS));
    }

#undef UPDATE_RC
    Log2(("emR3ForcedActions: returns %Rrc\n", rc));
    STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatForcedActions, a);
    Assert(rcIrq == VINF_SUCCESS || rcIrq == rc);
    return rc;
}

/**
 * Release the IOM lock if owned by the current VCPU
 *
 * @param   pVM         The VM to operate on.
 */
VMMR3DECL(void) EMR3ReleaseOwnedLocks(PVM pVM)
{
    while (PDMCritSectIsOwner(&pVM->em.s.CritSectREM))
        PDMCritSectLeave(&pVM->em.s.CritSectREM);
}


/**
 * Execute VM.
 *
 * This function is the main loop of the VM. The emulation thread
 * calls this function when the VM has been successfully constructed
 * and we're ready for executing the VM.
 *
 * Returning from this function means that the VM is turned off or
 * suspended (state already saved) and deconstruction in next in line.
 *
 * All interaction from other thread are done using forced actions
 * and signaling of the wait object.
 *
 * @returns VBox status code, informational status codes may indicate failure.
 * @param   pVM         The VM to operate on.
 * @param   pVCpu       The VMCPU to operate on.
 */
VMMR3DECL(int) EMR3ExecuteVM(PVM pVM, PVMCPU pVCpu)
{
    Log(("EMR3ExecuteVM: pVM=%p enmVMState=%d (%s)  enmState=%d (%s) enmPrevState=%d (%s) fForceRAW=%RTbool\n",
         pVM,
         pVM->enmVMState,          VMR3GetStateName(pVM->enmVMState),
         pVCpu->em.s.enmState,     emR3GetStateName(pVCpu->em.s.enmState),
         pVCpu->em.s.enmPrevState, emR3GetStateName(pVCpu->em.s.enmPrevState),
         pVCpu->em.s.fForceRAW));
    VM_ASSERT_EMT(pVM);
    AssertMsg(   pVCpu->em.s.enmState == EMSTATE_NONE
              || pVCpu->em.s.enmState == EMSTATE_WAIT_SIPI
              || pVCpu->em.s.enmState == EMSTATE_SUSPENDED,
              ("%s\n", emR3GetStateName(pVCpu->em.s.enmState)));

    int rc = setjmp(pVCpu->em.s.u.FatalLongJump);
    if (rc == 0)
    {
        /*
         * Start the virtual time.
         */
        TMR3NotifyResume(pVM, pVCpu);

        /*
         * The Outer Main Loop.
         */
        bool fFFDone = false;

        /* Reschedule right away to start in the right state. */
        rc = VINF_SUCCESS;

        /* If resuming after a pause or a state load, restore the previous
           state or else we'll start executing code. Else, just reschedule. */
        if (    pVCpu->em.s.enmState == EMSTATE_SUSPENDED
            &&  (   pVCpu->em.s.enmPrevState == EMSTATE_WAIT_SIPI
                 || pVCpu->em.s.enmPrevState == EMSTATE_HALTED))
            pVCpu->em.s.enmState = pVCpu->em.s.enmPrevState;
        else
            pVCpu->em.s.enmState = emR3Reschedule(pVM, pVCpu, pVCpu->em.s.pCtx);

        STAM_REL_PROFILE_ADV_START(&pVCpu->em.s.StatTotal, x);
        for (;;)
        {
            /*
             * Before we can schedule anything (we're here because
             * scheduling is required) we must service any pending
             * forced actions to avoid any pending action causing
             * immediate rescheduling upon entering an inner loop
             *
             * Do forced actions.
             */
            if (   !fFFDone
                && rc != VINF_EM_TERMINATE
                && rc != VINF_EM_OFF
                && (   VM_FF_ISPENDING(pVM, VM_FF_ALL_BUT_RAW_MASK)
                    || VMCPU_FF_ISPENDING(pVCpu, VMCPU_FF_ALL_BUT_RAW_MASK)))
            {
                rc = emR3ForcedActions(pVM, pVCpu, rc);
                if (    (   rc == VINF_EM_RESCHEDULE_REM
                         || rc == VINF_EM_RESCHEDULE_HWACC)
                    &&  pVCpu->em.s.fForceRAW)
                    rc = VINF_EM_RESCHEDULE_RAW;
            }
            else if (fFFDone)
                fFFDone = false;

            /*
             * Now what to do?
             */
            Log2(("EMR3ExecuteVM: rc=%Rrc\n", rc));
            switch (rc)
            {
                /*
                 * Keep doing what we're currently doing.
                 */
                case VINF_SUCCESS:
                    break;

                /*
                 * Reschedule - to raw-mode execution.
                 */
                case VINF_EM_RESCHEDULE_RAW:
                    Log2(("EMR3ExecuteVM: VINF_EM_RESCHEDULE_RAW: %d -> %d (EMSTATE_RAW)\n", pVCpu->em.s.enmState, EMSTATE_RAW));
                    pVCpu->em.s.enmState = EMSTATE_RAW;
                    break;

                /*
                 * Reschedule - to hardware accelerated raw-mode execution.
                 */
                case VINF_EM_RESCHEDULE_HWACC:
                    Log2(("EMR3ExecuteVM: VINF_EM_RESCHEDULE_HWACC: %d -> %d (EMSTATE_HWACC)\n", pVCpu->em.s.enmState, EMSTATE_HWACC));
                    Assert(!pVCpu->em.s.fForceRAW);
                    pVCpu->em.s.enmState = EMSTATE_HWACC;
                    break;

                /*
                 * Reschedule - to recompiled execution.
                 */
                case VINF_EM_RESCHEDULE_REM:
                    Log2(("EMR3ExecuteVM: VINF_EM_RESCHEDULE_REM: %d -> %d (EMSTATE_REM)\n", pVCpu->em.s.enmState, EMSTATE_REM));
                    pVCpu->em.s.enmState = EMSTATE_REM;
                    break;

                /*
                 * Resume.
                 */
                case VINF_EM_RESUME:
                    Log2(("EMR3ExecuteVM: VINF_EM_RESUME: %d -> VINF_EM_RESCHEDULE\n", pVCpu->em.s.enmState));
                    /* Don't reschedule in the halted or wait for SIPI case. */
                    if (    pVCpu->em.s.enmPrevState == EMSTATE_WAIT_SIPI
                        ||  pVCpu->em.s.enmPrevState == EMSTATE_HALTED)
                        break;
                    /* fall through and get scheduled. */

                /*
                 * Reschedule.
                 */
                case VINF_EM_RESCHEDULE:
                {
                    EMSTATE enmState = emR3Reschedule(pVM, pVCpu, pVCpu->em.s.pCtx);
                    Log2(("EMR3ExecuteVM: VINF_EM_RESCHEDULE: %d -> %d (%s)\n", pVCpu->em.s.enmState, enmState, emR3GetStateName(enmState)));
                    pVCpu->em.s.enmState = enmState;
                    break;
                }

                /*
                 * Halted.
                 */
                case VINF_EM_HALT:
                    Log2(("EMR3ExecuteVM: VINF_EM_HALT: %d -> %d\n", pVCpu->em.s.enmState, EMSTATE_HALTED));
                    pVCpu->em.s.enmState = EMSTATE_HALTED;
                    break;

                /*
                 * Switch to the wait for SIPI state (application processor only)
                 */
                case VINF_EM_WAIT_SIPI:
                    Assert(pVCpu->idCpu != 0);
                    Log2(("EMR3ExecuteVM: VINF_EM_WAIT_SIPI: %d -> %d\n", pVCpu->em.s.enmState, EMSTATE_WAIT_SIPI));
                    pVCpu->em.s.enmState = EMSTATE_WAIT_SIPI;
                    break;


                /*
                 * Suspend.
                 */
                case VINF_EM_SUSPEND:
                    Log2(("EMR3ExecuteVM: VINF_EM_SUSPEND: %d -> %d\n", pVCpu->em.s.enmState, EMSTATE_SUSPENDED));
                    pVCpu->em.s.enmPrevState = pVCpu->em.s.enmState;
                    pVCpu->em.s.enmState     = EMSTATE_SUSPENDED;
                    break;

                /*
                 * Reset.
                 * We might end up doing a double reset for now, we'll have to clean up the mess later.
                 */
                case VINF_EM_RESET:
                {
                    if (pVCpu->idCpu == 0)
                    {
                        EMSTATE enmState = emR3Reschedule(pVM, pVCpu, pVCpu->em.s.pCtx);
                        Log2(("EMR3ExecuteVM: VINF_EM_RESET: %d -> %d (%s)\n", pVCpu->em.s.enmState, enmState, emR3GetStateName(enmState)));
                        pVCpu->em.s.enmState = enmState;
                    }
                    else
                    {
                        /* All other VCPUs go into the wait for SIPI state. */
                        pVCpu->em.s.enmState = EMSTATE_WAIT_SIPI;
                    }
                    break;
                }

                /*
                 * Power Off.
                 */
                case VINF_EM_OFF:
                    pVCpu->em.s.enmState = EMSTATE_TERMINATING;
                    Log2(("EMR3ExecuteVM: returns VINF_EM_OFF (%d -> %d)\n", pVCpu->em.s.enmState, EMSTATE_TERMINATING));
                    TMR3NotifySuspend(pVM, pVCpu);
                    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);
                    return rc;

                /*
                 * Terminate the VM.
                 */
                case VINF_EM_TERMINATE:
                    pVCpu->em.s.enmState = EMSTATE_TERMINATING;
                    Log(("EMR3ExecuteVM returns VINF_EM_TERMINATE (%d -> %d)\n", pVCpu->em.s.enmState, EMSTATE_TERMINATING));
                    if (pVM->enmVMState < VMSTATE_DESTROYING) /* ugly */
                        TMR3NotifySuspend(pVM, pVCpu);
                    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);
                    return rc;


                /*
                 * Out of memory, suspend the VM and stuff.
                 */
                case VINF_EM_NO_MEMORY:
                    Log2(("EMR3ExecuteVM: VINF_EM_NO_MEMORY: %d -> %d\n", pVCpu->em.s.enmState, EMSTATE_SUSPENDED));
                    pVCpu->em.s.enmPrevState = pVCpu->em.s.enmState;
                    pVCpu->em.s.enmState = EMSTATE_SUSPENDED;
                    TMR3NotifySuspend(pVM, pVCpu);
                    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);

                    rc = VMSetRuntimeError(pVM, VMSETRTERR_FLAGS_SUSPEND, "HostMemoryLow",
                                           N_("Unable to allocate and lock memory. The virtual machine will be paused. Please close applications to free up memory or close the VM"));
                    if (rc != VINF_EM_SUSPEND)
                    {
                        if (RT_SUCCESS_NP(rc))
                        {
                            AssertLogRelMsgFailed(("%Rrc\n", rc));
                            rc = VERR_EM_INTERNAL_ERROR;
                        }
                        pVCpu->em.s.enmState = EMSTATE_GURU_MEDITATION;
                    }
                    return rc;

                /*
                 * Guest debug events.
                 */
                case VINF_EM_DBG_STEPPED:
                    AssertMsgFailed(("VINF_EM_DBG_STEPPED cannot be here!"));
                case VINF_EM_DBG_STOP:
                case VINF_EM_DBG_BREAKPOINT:
                case VINF_EM_DBG_STEP:
                    if (pVCpu->em.s.enmState == EMSTATE_RAW)
                    {
                        Log2(("EMR3ExecuteVM: %Rrc: %d -> %d\n", rc, pVCpu->em.s.enmState, EMSTATE_DEBUG_GUEST_RAW));
                        pVCpu->em.s.enmState = EMSTATE_DEBUG_GUEST_RAW;
                    }
                    else
                    {
                        Log2(("EMR3ExecuteVM: %Rrc: %d -> %d\n", rc, pVCpu->em.s.enmState, EMSTATE_DEBUG_GUEST_REM));
                        pVCpu->em.s.enmState = EMSTATE_DEBUG_GUEST_REM;
                    }
                    break;

                /*
                 * Hypervisor debug events.
                 */
                case VINF_EM_DBG_HYPER_STEPPED:
                case VINF_EM_DBG_HYPER_BREAKPOINT:
                case VINF_EM_DBG_HYPER_ASSERTION:
                    Log2(("EMR3ExecuteVM: %Rrc: %d -> %d\n", rc, pVCpu->em.s.enmState, EMSTATE_DEBUG_HYPER));
                    pVCpu->em.s.enmState = EMSTATE_DEBUG_HYPER;
                    break;

                /*
                 * Guru mediations.
                 */
                case VERR_VMM_RING0_ASSERTION:
                    Log(("EMR3ExecuteVM: %Rrc: %d -> %d (EMSTATE_GURU_MEDITATION)\n", rc, pVCpu->em.s.enmState, EMSTATE_GURU_MEDITATION));
                    pVCpu->em.s.enmState = EMSTATE_GURU_MEDITATION;
                    break;

                /*
                 * Any error code showing up here other than the ones we
                 * know and process above are considered to be FATAL.
                 *
                 * Unknown warnings and informational status codes are also
                 * included in this.
                 */
                default:
                    if (RT_SUCCESS_NP(rc))
                    {
                        AssertMsgFailed(("Unexpected warning or informational status code %Rra!\n", rc));
                        rc = VERR_EM_INTERNAL_ERROR;
                    }
                    Log(("EMR3ExecuteVM: %Rrc: %d -> %d (EMSTATE_GURU_MEDITATION)\n", rc, pVCpu->em.s.enmState, EMSTATE_GURU_MEDITATION));
                    pVCpu->em.s.enmState = EMSTATE_GURU_MEDITATION;
                    break;
            }

            STAM_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x); /* (skip this in release) */
            STAM_PROFILE_ADV_START(&pVCpu->em.s.StatTotal, x);

            /*
             * Act on the state.
             */
            switch (pVCpu->em.s.enmState)
            {
                /*
                 * Execute raw.
                 */
                case EMSTATE_RAW:
                    rc = emR3RawExecute(pVM, pVCpu, &fFFDone);
                    break;

                /*
                 * Execute hardware accelerated raw.
                 */
                case EMSTATE_HWACC:
                    rc = emR3HwAccExecute(pVM, pVCpu, &fFFDone);
                    break;

                /*
                 * Execute recompiled.
                 */
                case EMSTATE_REM:
                    rc = emR3RemExecute(pVM, pVCpu, &fFFDone);
                    Log2(("EMR3ExecuteVM: emR3RemExecute -> %Rrc\n", rc));
                    break;

                /*
                 * Application processor execution halted until SIPI.
                 */
                case EMSTATE_WAIT_SIPI:
                    /* no break */
                /*
                 * hlt - execution halted until interrupt.
                 */
                case EMSTATE_HALTED:
                {
                    STAM_REL_PROFILE_START(&pVCpu->em.s.StatHalted, y);
                    if (pVCpu->em.s.mwait.fWait & EMMWAIT_FLAG_ACTIVE)
                    {
                        /* mwait has a special extension where it's woken up when an interrupt is pending even when IF=0. */
                        rc = VMR3WaitHalted(pVM, pVCpu, !(pVCpu->em.s.mwait.fWait & EMMWAIT_FLAG_BREAKIRQIF0) && !(CPUMGetGuestEFlags(pVCpu) & X86_EFL_IF));
                        pVCpu->em.s.mwait.fWait &= ~(EMMWAIT_FLAG_ACTIVE | EMMWAIT_FLAG_BREAKIRQIF0);
                    }
                    else
                        rc = VMR3WaitHalted(pVM, pVCpu, !(CPUMGetGuestEFlags(pVCpu) & X86_EFL_IF));

                    STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatHalted, y);
                    break;
                }

                /*
                 * Suspended - return to VM.cpp.
                 */
                case EMSTATE_SUSPENDED:
                    TMR3NotifySuspend(pVM, pVCpu);
                    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);
                    Log(("EMR3ExecuteVM: actually returns %Rrc (state %s / %s)\n", rc, emR3GetStateName(pVCpu->em.s.enmState), emR3GetStateName(pVCpu->em.s.enmPrevState)));
                    return VINF_EM_SUSPEND;

                /*
                 * Debugging in the guest.
                 */
                case EMSTATE_DEBUG_GUEST_REM:
                case EMSTATE_DEBUG_GUEST_RAW:
                    TMR3NotifySuspend(pVM, pVCpu);
                    rc = emR3Debug(pVM, pVCpu, rc);
                    TMR3NotifyResume(pVM, pVCpu);
                    Log2(("EMR3ExecuteVM: enmr3Debug -> %Rrc (state %d)\n", rc, pVCpu->em.s.enmState));
                    break;

                /*
                 * Debugging in the hypervisor.
                 */
                case EMSTATE_DEBUG_HYPER:
                {
                    TMR3NotifySuspend(pVM, pVCpu);
                    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);

                    rc = emR3Debug(pVM, pVCpu, rc);
                    Log2(("EMR3ExecuteVM: enmr3Debug -> %Rrc (state %d)\n", rc, pVCpu->em.s.enmState));
                    if (rc != VINF_SUCCESS)
                    {
                        /* switch to guru meditation mode */
                        pVCpu->em.s.enmState = EMSTATE_GURU_MEDITATION;
                        VMMR3FatalDump(pVM, pVCpu, rc);
                        Log(("EMR3ExecuteVM: actually returns %Rrc (state %s / %s)\n", rc, emR3GetStateName(pVCpu->em.s.enmState), emR3GetStateName(pVCpu->em.s.enmPrevState)));
                        return rc;
                    }

                    STAM_REL_PROFILE_ADV_START(&pVCpu->em.s.StatTotal, x);
                    TMR3NotifyResume(pVM, pVCpu);
                    break;
                }

                /*
                 * Guru meditation takes place in the debugger.
                 */
                case EMSTATE_GURU_MEDITATION:
                {
                    TMR3NotifySuspend(pVM, pVCpu);
                    VMMR3FatalDump(pVM, pVCpu, rc);
                    emR3Debug(pVM, pVCpu, rc);
                    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);
                    Log(("EMR3ExecuteVM: actually returns %Rrc (state %s / %s)\n", rc, emR3GetStateName(pVCpu->em.s.enmState), emR3GetStateName(pVCpu->em.s.enmPrevState)));
                    return rc;
                }

                /*
                 * The states we don't expect here.
                 */
                case EMSTATE_NONE:
                case EMSTATE_TERMINATING:
                default:
                    AssertMsgFailed(("EMR3ExecuteVM: Invalid state %d!\n", pVCpu->em.s.enmState));
                    pVCpu->em.s.enmState = EMSTATE_GURU_MEDITATION;
                    TMR3NotifySuspend(pVM, pVCpu);
                    STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);
                    Log(("EMR3ExecuteVM: actually returns %Rrc (state %s / %s)\n", rc, emR3GetStateName(pVCpu->em.s.enmState), emR3GetStateName(pVCpu->em.s.enmPrevState)));
                    return VERR_EM_INTERNAL_ERROR;
            }
        } /* The Outer Main Loop */
    }
    else
    {
        /*
         * Fatal error.
         */
        Log(("EMR3ExecuteVM: returns %Rrc because of longjmp / fatal error; (state %s / %s)\n", rc, emR3GetStateName(pVCpu->em.s.enmState), emR3GetStateName(pVCpu->em.s.enmPrevState)));
        TMR3NotifySuspend(pVM, pVCpu);
        VMMR3FatalDump(pVM, pVCpu, rc);
        emR3Debug(pVM, pVCpu, rc);
        STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatTotal, x);
        /** @todo change the VM state! */
        return rc;
    }

    /* (won't ever get here). */
    AssertFailed();
}