/* $Id: TRPMRC.cpp 44528 2013-02-04 14:27:54Z vboxsync $ */ /** @file * TRPM - The Trap Monitor, Guest Context */ /* * Copyright (C) 2006-2012 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. */ /******************************************************************************* * Header Files * *******************************************************************************/ #define LOG_GROUP LOG_GROUP_TRPM #include #include #include #include #include "TRPMInternal.h" #include #include #include #include #include #include #include /** * Arms a temporary trap handler for traps in Hypervisor code. * * The operation is similar to a System V signal handler. I.e. when the handler * is called it is first set to default action. So, if you need to handler more * than one trap, you must reinstall the handler. * * To uninstall the temporary handler, call this function with pfnHandler set to NULL. * * @returns VBox status. * @param pVM Pointer to the VM. * @param iTrap Trap number to install handler [0..255]. * @param pfnHandler Pointer to the handler. Use NULL for uninstalling the handler. */ VMMRCDECL(int) TRPMGCSetTempHandler(PVM pVM, unsigned iTrap, PFNTRPMGCTRAPHANDLER pfnHandler) { /* * Validate input. */ if (iTrap >= RT_ELEMENTS(pVM->trpm.s.aTmpTrapHandlers)) { AssertMsgFailed(("Trap handler iTrap=%u is out of range!\n", iTrap)); return VERR_INVALID_PARAMETER; } /* * Install handler. */ pVM->trpm.s.aTmpTrapHandlers[iTrap] = (RTRCPTR)(uintptr_t)pfnHandler; return VINF_SUCCESS; } /** * Return to host context from a hypervisor trap handler. * * This function will *never* return. * It will also reset any traps that are pending. * * @param pVM Pointer to the VM. * @param rc The return code for host context. */ VMMRCDECL(void) TRPMGCHyperReturnToHost(PVM pVM, int rc) { PVMCPU pVCpu = VMMGetCpu0(pVM); LogFlow(("TRPMGCHyperReturnToHost: rc=%Rrc\n", rc)); TRPMResetTrap(pVCpu); VMMGCGuestToHost(pVM, rc); AssertReleaseFailed(); } /** * \#PF Virtual Handler callback for Guest write access to the Guest's own current IDT. * * @returns VBox status code (appropriate for trap handling and GC return). * @param pVM Pointer to the VM. * @param uErrorCode CPU Error code. * @param pRegFrame Trap register frame. * @param pvFault The fault address (cr2). * @param pvRange The base address of the handled virtual range. * @param offRange The offset of the access into this range. * (If it's a EIP range this is the EIP, if not it's pvFault.) */ VMMRCDECL(int) trpmRCGuestIDTWriteHandler(PVM pVM, RTGCUINT uErrorCode, PCPUMCTXCORE pRegFrame, RTGCPTR pvFault, RTGCPTR pvRange, uintptr_t offRange) { PVMCPU pVCpu = VMMGetCpu0(pVM); uint16_t cbIDT; RTGCPTR GCPtrIDT = (RTGCPTR)CPUMGetGuestIDTR(pVCpu, &cbIDT); #ifdef VBOX_STRICT RTGCPTR GCPtrIDTEnd = (RTGCPTR)((RTGCUINTPTR)GCPtrIDT + cbIDT + 1); #endif uint32_t iGate = ((RTGCUINTPTR)pvFault - (RTGCUINTPTR)GCPtrIDT)/sizeof(VBOXIDTE); AssertMsg(offRange < (uint32_t)cbIDT+1, ("pvFault=%RGv GCPtrIDT=%RGv-%RGv pvRange=%RGv\n", pvFault, GCPtrIDT, GCPtrIDTEnd, pvRange)); Assert((RTGCPTR)(RTRCUINTPTR)pvRange == GCPtrIDT); NOREF(uErrorCode); #if 0 /* Note! this causes problems in Windows XP as instructions following the update can be dangerous (str eax has been seen) */ /* Note! not going back to ring 3 could make the code scanner miss them. */ /* Check if we can handle the write here. */ if ( iGate != 3 /* Gate 3 is handled differently; could do it here as well, but let ring 3 handle this case for now. */ && !ASMBitTest(&pVM->trpm.s.au32IdtPatched[0], iGate)) /* Passthru gates need special attention too. */ { uint32_t cb; int rc = EMInterpretInstructionEx(pVM, pVCpu, pRegFrame, pvFault, &cb); if (RT_SUCCESS(rc) && cb) { uint32_t iGate1 = (offRange + cb - 1)/sizeof(VBOXIDTE); Log(("trpmRCGuestIDTWriteHandler: write to gate %x (%x) offset %x cb=%d\n", iGate, iGate1, offRange, cb)); trpmClearGuestTrapHandler(pVM, iGate); if (iGate != iGate1) trpmClearGuestTrapHandler(pVM, iGate1); STAM_COUNTER_INC(&pVM->trpm.s.StatRCWriteGuestIDTHandled); return VINF_SUCCESS; } } #else NOREF(iGate); #endif Log(("trpmRCGuestIDTWriteHandler: eip=%RGv write to gate %x offset %x\n", pRegFrame->eip, iGate, offRange)); /** @todo Check which IDT entry and keep the update cost low in TRPMR3SyncIDT() and CSAMCheckGates(). */ VMCPU_FF_SET(pVCpu, VMCPU_FF_TRPM_SYNC_IDT); STAM_COUNTER_INC(&pVM->trpm.s.StatRCWriteGuestIDTFault); return VINF_EM_RAW_EMULATE_INSTR_IDT_FAULT; } /** * \#PF Virtual Handler callback for Guest write access to the VBox shadow IDT. * * @returns VBox status code (appropriate for trap handling and GC return). * @param pVM Pointer to the VM. * @param uErrorCode CPU Error code. * @param pRegFrame Trap register frame. * @param pvFault The fault address (cr2). * @param pvRange The base address of the handled virtual range. * @param offRange The offset of the access into this range. * (If it's a EIP range this is the EIP, if not it's pvFault.) */ VMMRCDECL(int) trpmRCShadowIDTWriteHandler(PVM pVM, RTGCUINT uErrorCode, PCPUMCTXCORE pRegFrame, RTGCPTR pvFault, RTGCPTR pvRange, uintptr_t offRange) { PVMCPU pVCpu = VMMGetCpu0(pVM); LogRel(("FATAL ERROR: trpmRCShadowIDTWriteHandler: eip=%08X pvFault=%RGv pvRange=%08RGv\r\n", pRegFrame->eip, pvFault, pvRange)); NOREF(uErrorCode); NOREF(offRange); /* * If we ever get here, then the guest has *probably* executed an SIDT * instruction that we failed to patch. In theory this could be very bad, * but there are nasty applications out there that install device drivers * that mess with the guest's IDT. In those cases, it's quite ok to simply * ignore the writes and pretend success. * * Another posibility is that the guest is touching some page memory and * it having nothing to do with our IDT or anything like that, just a * potential conflict that we didn't discover in time. */ DISSTATE Dis; int rc = EMInterpretDisasCurrent(pVM, pVCpu, &Dis, NULL); if (rc == VINF_SUCCESS) { /* Just ignore the write. */ pRegFrame->eip += Dis.cbInstr; return VINF_SUCCESS; } return VERR_TRPM_SHADOW_IDT_WRITE; }