/* $Id: TMAllCpu.cpp 68019 2017-07-18 12:44:53Z vboxsync $ */ /** @file * TM - Timeout Manager, CPU Time, All Contexts. */ /* * Copyright (C) 2006-2016 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_TM #include #include /* for SUPGetCpuHzFromGIP */ #include "TMInternal.h" #include #include #include #include #include #include #include #include #include /** * Gets the raw cpu tick from current virtual time. * * @param pVM The cross context VM structure. * @param fCheckTimers Whether to check timers. */ DECLINLINE(uint64_t) tmCpuTickGetRawVirtual(PVM pVM, bool fCheckTimers) { uint64_t u64; if (fCheckTimers) u64 = TMVirtualSyncGet(pVM); else u64 = TMVirtualSyncGetNoCheck(pVM); return ASMMultU64ByU32DivByU32(u64, pVM->tm.s.cTSCTicksPerSecond, TMCLOCK_FREQ_VIRTUAL); } #ifdef IN_RING3 /** * Used by tmR3CpuTickParavirtEnable and tmR3CpuTickParavirtDisable. * * @param pVM The cross context VM structure. */ uint64_t tmR3CpuTickGetRawVirtualNoCheck(PVM pVM) { return tmCpuTickGetRawVirtual(pVM, false /*fCheckTimers*/); } #endif /** * Resumes the CPU timestamp counter ticking. * * @returns VBox status code. * @param pVM The cross context VM structure. * @param pVCpu The cross context virtual CPU structure. * @internal */ int tmCpuTickResume(PVM pVM, PVMCPU pVCpu) { if (!pVCpu->tm.s.fTSCTicking) { pVCpu->tm.s.fTSCTicking = true; /** @todo Test that pausing and resuming doesn't cause lag! (I.e. that we're * unpaused before the virtual time and stopped after it. */ if (pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET) pVCpu->tm.s.offTSCRawSrc = SUPReadTsc() - pVCpu->tm.s.u64TSC; else pVCpu->tm.s.offTSCRawSrc = tmCpuTickGetRawVirtual(pVM, false /* don't check for pending timers */) - pVCpu->tm.s.u64TSC; return VINF_SUCCESS; } AssertFailed(); return VERR_TM_TSC_ALREADY_TICKING; } /** * Resumes the CPU timestamp counter ticking. * * @returns VINF_SUCCESS or VERR_TM_VIRTUAL_TICKING_IPE (asserted). * @param pVM The cross context VM structure. * @param pVCpu The cross context virtual CPU structure. */ int tmCpuTickResumeLocked(PVM pVM, PVMCPU pVCpu) { if (!pVCpu->tm.s.fTSCTicking) { /* TSC must be ticking before calling tmCpuTickGetRawVirtual()! */ pVCpu->tm.s.fTSCTicking = true; uint32_t c = ASMAtomicIncU32(&pVM->tm.s.cTSCsTicking); AssertMsgReturn(c <= pVM->cCpus, ("%u vs %u\n", c, pVM->cCpus), VERR_TM_VIRTUAL_TICKING_IPE); if (c == 1) { /* The first VCPU to resume. */ uint64_t offTSCRawSrcOld = pVCpu->tm.s.offTSCRawSrc; STAM_COUNTER_INC(&pVM->tm.s.StatTSCResume); /* When resuming, use the TSC value of the last stopped VCPU to avoid the TSC going back. */ if (pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET) pVCpu->tm.s.offTSCRawSrc = SUPReadTsc() - pVM->tm.s.u64LastPausedTSC; else pVCpu->tm.s.offTSCRawSrc = tmCpuTickGetRawVirtual(pVM, false /* don't check for pending timers */) - pVM->tm.s.u64LastPausedTSC; /* Calculate the offset for other VCPUs to use. */ pVM->tm.s.offTSCPause = pVCpu->tm.s.offTSCRawSrc - offTSCRawSrcOld; } else { /* All other VCPUs (if any). */ pVCpu->tm.s.offTSCRawSrc += pVM->tm.s.offTSCPause; } } return VINF_SUCCESS; } /** * Pauses the CPU timestamp counter ticking. * * @returns VBox status code. * @param pVCpu The cross context virtual CPU structure. * @internal */ int tmCpuTickPause(PVMCPU pVCpu) { if (pVCpu->tm.s.fTSCTicking) { pVCpu->tm.s.u64TSC = TMCpuTickGetNoCheck(pVCpu); pVCpu->tm.s.fTSCTicking = false; return VINF_SUCCESS; } AssertFailed(); return VERR_TM_TSC_ALREADY_PAUSED; } /** * Pauses the CPU timestamp counter ticking. * * @returns VBox status code. * @param pVM The cross context VM structure. * @param pVCpu The cross context virtual CPU structure. * @internal */ int tmCpuTickPauseLocked(PVM pVM, PVMCPU pVCpu) { if (pVCpu->tm.s.fTSCTicking) { pVCpu->tm.s.u64TSC = TMCpuTickGetNoCheck(pVCpu); pVCpu->tm.s.fTSCTicking = false; uint32_t c = ASMAtomicDecU32(&pVM->tm.s.cTSCsTicking); AssertMsgReturn(c < pVM->cCpus, ("%u vs %u\n", c, pVM->cCpus), VERR_TM_VIRTUAL_TICKING_IPE); if (c == 0) { /* When the last TSC stops, remember the value. */ STAM_COUNTER_INC(&pVM->tm.s.StatTSCPause); pVM->tm.s.u64LastPausedTSC = pVCpu->tm.s.u64TSC; } return VINF_SUCCESS; } AssertFailed(); return VERR_TM_TSC_ALREADY_PAUSED; } #ifdef VBOX_WITH_STATISTICS /** * Record why we refused to use offsetted TSC. * * Used by TMCpuTickCanUseRealTSC() and TMCpuTickGetDeadlineAndTscOffset(). * * @param pVM The cross context VM structure. * @param pVCpu The cross context virtual CPU structure of the calling EMT. */ DECLINLINE(void) tmCpuTickRecordOffsettedTscRefusal(PVM pVM, PVMCPU pVCpu) { /* Sample the reason for refusing. */ if (pVM->tm.s.enmTSCMode != TMTSCMODE_DYNAMIC) STAM_COUNTER_INC(&pVM->tm.s.StatTSCNotFixed); else if (!pVCpu->tm.s.fTSCTicking) STAM_COUNTER_INC(&pVM->tm.s.StatTSCNotTicking); else if (pVM->tm.s.enmTSCMode != TMTSCMODE_REAL_TSC_OFFSET) { if (pVM->tm.s.fVirtualSyncCatchUp) { if (pVM->tm.s.u32VirtualSyncCatchUpPercentage <= 10) STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupLE010); else if (pVM->tm.s.u32VirtualSyncCatchUpPercentage <= 25) STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupLE025); else if (pVM->tm.s.u32VirtualSyncCatchUpPercentage <= 100) STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupLE100); else STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupOther); } else if (!pVM->tm.s.fVirtualSyncTicking) STAM_COUNTER_INC(&pVM->tm.s.StatTSCSyncNotTicking); else if (pVM->tm.s.fVirtualWarpDrive) STAM_COUNTER_INC(&pVM->tm.s.StatTSCWarp); } } #endif /* VBOX_WITH_STATISTICS */ /** * Checks if AMD-V / VT-x can use an offsetted hardware TSC or not. * * @returns true/false accordingly. * @param pVM The cross context VM structure. * @param pVCpu The cross context virtual CPU structure. * @param poffRealTsc The offset against the TSC of the current host CPU, * if pfOffsettedTsc is set to true. * @param pfParavirtTsc Where to return whether paravirt TSC is enabled. * * @thread EMT(pVCpu). * @see TMCpuTickGetDeadlineAndTscOffset(). */ VMM_INT_DECL(bool) TMCpuTickCanUseRealTSC(PVM pVM, PVMCPU pVCpu, uint64_t *poffRealTsc, bool *pfParavirtTsc) { Assert(pVCpu->tm.s.fTSCTicking || DBGFIsStepping(pVCpu)); *pfParavirtTsc = pVM->tm.s.fParavirtTscEnabled; /* * In real TSC mode it's easy, we just need the delta & offTscRawSrc and * the CPU will add them to RDTSC and RDTSCP at runtime. * * In tmCpuTickGetInternal we do: * SUPReadTsc() - pVCpu->tm.s.offTSCRawSrc; * Where SUPReadTsc() does: * ASMReadTSC() - pGipCpu->i64TscDelta; * Which means tmCpuTickGetInternal actually does: * ASMReadTSC() - pGipCpu->i64TscDelta - pVCpu->tm.s.offTSCRawSrc; * So, the offset to be ADDED to RDTSC[P] is: * offRealTsc = -(pGipCpu->i64TscDelta + pVCpu->tm.s.offTSCRawSrc) */ if (pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET) { /** @todo We should negate both deltas! It's soo weird that we do the * exact opposite of what the hardware implements. */ #ifdef IN_RING3 *poffRealTsc = 0 - pVCpu->tm.s.offTSCRawSrc - SUPGetTscDelta(); #else *poffRealTsc = 0 - pVCpu->tm.s.offTSCRawSrc - SUPGetTscDeltaByCpuSetIndex(pVCpu->iHostCpuSet); #endif return true; } /* * We require: * 1. A fixed TSC, this is checked at init time. * 2. That the TSC is ticking (we shouldn't be here if it isn't) * 3. Either that we're using the real TSC as time source or * a) we don't have any lag to catch up, and * b) the virtual sync clock hasn't been halted by an expired timer, and * c) we're not using warp drive (accelerated virtual guest time). */ if ( pVM->tm.s.enmTSCMode == TMTSCMODE_DYNAMIC && !pVM->tm.s.fVirtualSyncCatchUp && RT_LIKELY(pVM->tm.s.fVirtualSyncTicking) && !pVM->tm.s.fVirtualWarpDrive) { /* The source is the timer synchronous virtual clock. */ uint64_t u64Now = tmCpuTickGetRawVirtual(pVM, false /* don't check for pending timers */) - pVCpu->tm.s.offTSCRawSrc; /** @todo When we start collecting statistics on how much time we spend executing * guest code before exiting, we should check this against the next virtual sync * timer timeout. If it's lower than the avg. length, we should trap rdtsc to increase * the chance that we'll get interrupted right after the timer expired. */ if (u64Now >= pVCpu->tm.s.u64TSCLastSeen) { *poffRealTsc = u64Now - ASMReadTSC(); return true; /** @todo count this? */ } } #ifdef VBOX_WITH_STATISTICS tmCpuTickRecordOffsettedTscRefusal(pVM, pVCpu); #endif return false; } /** * Calculates the number of host CPU ticks till the next virtual sync deadline. * * @note To save work, this function will not bother calculating the accurate * tick count for deadlines that are more than a second ahead. * * @returns The number of host cpu ticks to the next deadline. Max one second. * @param pVCpu The cross context virtual CPU structure of the calling EMT. * @param cNsToDeadline The number of nano seconds to the next virtual * sync deadline. */ DECLINLINE(uint64_t) tmCpuCalcTicksToDeadline(PVMCPU pVCpu, uint64_t cNsToDeadline) { AssertCompile(TMCLOCK_FREQ_VIRTUAL <= _4G); #ifdef IN_RING3 RT_NOREF_PV(pVCpu); uint64_t uCpuHz = SUPGetCpuHzFromGip(g_pSUPGlobalInfoPage); #else uint64_t uCpuHz = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, pVCpu->iHostCpuSet); #endif if (RT_UNLIKELY(cNsToDeadline >= TMCLOCK_FREQ_VIRTUAL)) return uCpuHz; uint64_t cTicks = ASMMultU64ByU32DivByU32(uCpuHz, cNsToDeadline, TMCLOCK_FREQ_VIRTUAL); if (cTicks > 4000) cTicks -= 4000; /* fudge to account for overhead */ else cTicks >>= 1; return cTicks; } /** * Gets the next deadline in host CPU clock ticks and the TSC offset if we can * use the raw TSC. * * @returns The number of host CPU clock ticks to the next timer deadline. * @param pVM The cross context VM structure. * @param pVCpu The cross context virtual CPU structure of the calling EMT. * @param poffRealTsc The offset against the TSC of the current host CPU, * if pfOffsettedTsc is set to true. * @param pfOffsettedTsc Where to return whether TSC offsetting can be used. * @param pfParavirtTsc Where to return whether paravirt TSC is enabled. * * @thread EMT(pVCpu). * @see TMCpuTickCanUseRealTSC(). */ VMM_INT_DECL(uint64_t) TMCpuTickGetDeadlineAndTscOffset(PVM pVM, PVMCPU pVCpu, uint64_t *poffRealTsc, bool *pfOffsettedTsc, bool *pfParavirtTsc) { Assert(pVCpu->tm.s.fTSCTicking || DBGFIsStepping(pVCpu)); *pfParavirtTsc = pVM->tm.s.fParavirtTscEnabled; /* * Same logic as in TMCpuTickCanUseRealTSC. */ if (pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET) { /** @todo We should negate both deltas! It's soo weird that we do the * exact opposite of what the hardware implements. */ #ifdef IN_RING3 *poffRealTsc = 0 - pVCpu->tm.s.offTSCRawSrc - SUPGetTscDelta(); #else *poffRealTsc = 0 - pVCpu->tm.s.offTSCRawSrc - SUPGetTscDeltaByCpuSetIndex(pVCpu->iHostCpuSet); #endif *pfOffsettedTsc = true; return tmCpuCalcTicksToDeadline(pVCpu, TMVirtualSyncGetNsToDeadline(pVM)); } /* * Same logic as in TMCpuTickCanUseRealTSC. */ if ( pVM->tm.s.enmTSCMode == TMTSCMODE_DYNAMIC && !pVM->tm.s.fVirtualSyncCatchUp && RT_LIKELY(pVM->tm.s.fVirtualSyncTicking) && !pVM->tm.s.fVirtualWarpDrive) { /* The source is the timer synchronous virtual clock. */ uint64_t cNsToDeadline; uint64_t u64NowVirtSync = TMVirtualSyncGetWithDeadlineNoCheck(pVM, &cNsToDeadline); uint64_t u64Now = ASMMultU64ByU32DivByU32(u64NowVirtSync, pVM->tm.s.cTSCTicksPerSecond, TMCLOCK_FREQ_VIRTUAL) u64Now -= pVCpu->tm.s.offTSCRawSrc; *poffRealTsc = u64Now - ASMReadTSC(); *pfOffsettedTsc = u64Now >= pVCpu->tm.s.u64TSCLastSeen; return tmCpuCalcTicksToDeadline(pVCpu, cNsToDeadline); } #ifdef VBOX_WITH_STATISTICS tmCpuTickRecordOffsettedTscRefusal(pVM, pVCpu); #endif *pfOffsettedTsc = false; *poffRealTsc = 0; return tmCpuCalcTicksToDeadline(pVCpu, TMVirtualSyncGetNsToDeadline(pVM)); } /** * Read the current CPU timestamp counter. * * @returns Gets the CPU tsc. * @param pVCpu The cross context virtual CPU structure. * @param fCheckTimers Whether to check timers. */ DECLINLINE(uint64_t) tmCpuTickGetInternal(PVMCPU pVCpu, bool fCheckTimers) { uint64_t u64; if (RT_LIKELY(pVCpu->tm.s.fTSCTicking)) { PVM pVM = pVCpu->CTX_SUFF(pVM); if (pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET) u64 = SUPReadTsc(); else u64 = tmCpuTickGetRawVirtual(pVM, fCheckTimers); u64 -= pVCpu->tm.s.offTSCRawSrc; /* Always return a value higher than what the guest has already seen. */ if (RT_LIKELY(u64 > pVCpu->tm.s.u64TSCLastSeen)) pVCpu->tm.s.u64TSCLastSeen = u64; else { STAM_COUNTER_INC(&pVM->tm.s.StatTSCUnderflow); pVCpu->tm.s.u64TSCLastSeen += 64; /** @todo choose a good increment here */ u64 = pVCpu->tm.s.u64TSCLastSeen; } } else u64 = pVCpu->tm.s.u64TSC; /** @todo @bugref{7243}: SVM TSC offset. */ return u64; } /** * Read the current CPU timestamp counter. * * @returns Gets the CPU tsc. * @param pVCpu The cross context virtual CPU structure. */ VMMDECL(uint64_t) TMCpuTickGet(PVMCPU pVCpu) { return tmCpuTickGetInternal(pVCpu, true /* fCheckTimers */); } /** * Read the current CPU timestamp counter, don't check for expired timers. * * @returns Gets the CPU tsc. * @param pVCpu The cross context virtual CPU structure. */ VMM_INT_DECL(uint64_t) TMCpuTickGetNoCheck(PVMCPU pVCpu) { return tmCpuTickGetInternal(pVCpu, false /* fCheckTimers */); } /** * Sets the current CPU timestamp counter. * * @returns VBox status code. * @param pVM The cross context VM structure. * @param pVCpu The cross context virtual CPU structure. * @param u64Tick The new timestamp value. * * @thread EMT which TSC is to be set. */ VMM_INT_DECL(int) TMCpuTickSet(PVM pVM, PVMCPU pVCpu, uint64_t u64Tick) { VMCPU_ASSERT_EMT(pVCpu); STAM_COUNTER_INC(&pVM->tm.s.StatTSCSet); /* * This is easier to do when the TSC is paused since resume will * do all the calculations for us. Actually, we don't need to * call tmCpuTickPause here since we overwrite u64TSC anyway. */ bool fTSCTicking = pVCpu->tm.s.fTSCTicking; pVCpu->tm.s.fTSCTicking = false; pVCpu->tm.s.u64TSC = u64Tick; pVCpu->tm.s.u64TSCLastSeen = u64Tick; if (fTSCTicking) tmCpuTickResume(pVM, pVCpu); /** @todo Try help synchronizing it better among the virtual CPUs? */ return VINF_SUCCESS; } /** * Sets the last seen CPU timestamp counter. * * @returns VBox status code. * @param pVCpu The cross context virtual CPU structure. * @param u64LastSeenTick The last seen timestamp value. * * @thread EMT which TSC is to be set. */ VMM_INT_DECL(int) TMCpuTickSetLastSeen(PVMCPU pVCpu, uint64_t u64LastSeenTick) { VMCPU_ASSERT_EMT(pVCpu); LogFlow(("TMCpuTickSetLastSeen %RX64\n", u64LastSeenTick)); if (pVCpu->tm.s.u64TSCLastSeen < u64LastSeenTick) pVCpu->tm.s.u64TSCLastSeen = u64LastSeenTick; return VINF_SUCCESS; } /** * Gets the last seen CPU timestamp counter of the guest. * * @returns the last seen TSC. * @param pVCpu The cross context virtual CPU structure. * * @thread EMT(pVCpu). */ VMM_INT_DECL(uint64_t) TMCpuTickGetLastSeen(PVMCPU pVCpu) { VMCPU_ASSERT_EMT(pVCpu); return pVCpu->tm.s.u64TSCLastSeen; } /** * Get the timestamp frequency. * * @returns Number of ticks per second. * @param pVM The cross context VM structure. */ VMMDECL(uint64_t) TMCpuTicksPerSecond(PVM pVM) { if ( pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET && g_pSUPGlobalInfoPage->u32Mode != SUPGIPMODE_INVARIANT_TSC) { #ifdef IN_RING3 uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGip(g_pSUPGlobalInfoPage); #elif defined(IN_RING0) uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, RTMpCpuIdToSetIndex(RTMpCpuId())); #else uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, VMMGetCpu(pVM)->iHostCpuSet); #endif if (RT_LIKELY(cTSCTicksPerSecond != ~(uint64_t)0)) return cTSCTicksPerSecond; } return pVM->tm.s.cTSCTicksPerSecond; } /** * Whether the TSC is ticking for the VCPU. * * @returns true if ticking, false otherwise. * @param pVCpu The cross context virtual CPU structure. */ VMM_INT_DECL(bool) TMCpuTickIsTicking(PVMCPU pVCpu) { return pVCpu->tm.s.fTSCTicking; }