Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 661 insertions, 0 deletions

diff --git a/src/VBox/VMM/VMMAll/TMAllCpu.cpp b/src/VBox/VMM/VMMAll/TMAllCpu.cpp
new file mode 100644
index 00000000..7b68afe1
--- /dev/null
+++ b/src/VBox/VMM/VMMAll/TMAllCpu.cpp
@@ -0,0 +1,661 @@
+/* $Id: TMAllCpu.cpp $ */
+/** @file
+ * TM - Timeout Manager, CPU Time, All Contexts.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP LOG_GROUP_TM
+#include <VBox/vmm/tm.h>
+#include <VBox/vmm/gim.h>
+#include <VBox/vmm/dbgf.h>
+#include <VBox/vmm/nem.h>
+#if   defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
+# include <iprt/asm-amd64-x86.h> /* for SUPGetCpuHzFromGIP; ASMReadTSC */
+#elif defined(RT_ARCH_ARM64) || defined(RT_ARCH_ARM32)
+# include <iprt/asm-arm.h>
+#endif
+#include "TMInternal.h"
+#include <VBox/vmm/vmcc.h>
+#include <VBox/sup.h>
+
+#include <VBox/param.h>
+#include <VBox/err.h>
+#include <iprt/asm-math.h>
+#include <iprt/assert.h>
+#include <VBox/log.h>
+
+
+
+/**
+ * Converts from virtual time to raw CPU ticks.
+ *
+ * Mainly to have the ASMMultU64ByU32DivByU32 overflow trickery in one place.
+ *
+ * @returns raw CPU ticks.
+ * @param   pVM             The cross context VM structure.
+ * @param   u64VirtualTime  The virtual time to convert.
+ */
+DECLINLINE(uint64_t) tmCpuTickCalcFromVirtual(PVMCC pVM, uint64_t u64VirtualTime)
+{
+    if (pVM->tm.s.cTSCTicksPerSecond <= UINT32_MAX)
+        return ASMMultU64ByU32DivByU32(u64VirtualTime, (uint32_t)pVM->tm.s.cTSCTicksPerSecond, TMCLOCK_FREQ_VIRTUAL);
+    Assert(pVM->tm.s.cTSCTicksPerSecond <= ((uint64_t)UINT32_MAX << 2)); /* <= 15.99 GHz */
+    return ASMMultU64ByU32DivByU32(u64VirtualTime, (uint32_t)(pVM->tm.s.cTSCTicksPerSecond >> 2), TMCLOCK_FREQ_VIRTUAL >> 2);
+}
+
+
+/**
+ * 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(PVMCC pVM, bool fCheckTimers)
+{
+    if (fCheckTimers)
+        return tmCpuTickCalcFromVirtual(pVM, TMVirtualSyncGet(pVM));
+    return tmCpuTickCalcFromVirtual(pVM, TMVirtualSyncGetNoCheck(pVM));
+}
+
+
+#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(PVMCC pVM, PVMCPUCC 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. */
+        switch (pVM->tm.s.enmTSCMode)
+        {
+            case TMTSCMODE_REAL_TSC_OFFSET:
+                pVCpu->tm.s.offTSCRawSrc = SUPReadTsc() - pVCpu->tm.s.u64TSC;
+                break;
+            case TMTSCMODE_VIRT_TSC_EMULATED:
+            case TMTSCMODE_DYNAMIC:
+                pVCpu->tm.s.offTSCRawSrc = tmCpuTickGetRawVirtual(pVM, false /* don't check for pending timers */)
+                                         - pVCpu->tm.s.u64TSC;
+                break;
+            case TMTSCMODE_NATIVE_API:
+                pVCpu->tm.s.offTSCRawSrc = 0; /** @todo ?? */
+                /* Looks like this is only used by weird modes and MSR TSC writes.  We cannot support either on NEM/win. */
+                break;
+            default:
+                AssertFailedReturn(VERR_IPE_NOT_REACHED_DEFAULT_CASE);
+        }
+        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(PVMCC pVM, PVMCPUCC 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. */
+            switch (pVM->tm.s.enmTSCMode)
+            {
+                case TMTSCMODE_REAL_TSC_OFFSET:
+                    pVCpu->tm.s.offTSCRawSrc = SUPReadTsc() - pVM->tm.s.u64LastPausedTSC;
+                    break;
+                case TMTSCMODE_VIRT_TSC_EMULATED:
+                case TMTSCMODE_DYNAMIC:
+                    pVCpu->tm.s.offTSCRawSrc = tmCpuTickGetRawVirtual(pVM, false /* don't check for pending timers */)
+                                             - pVM->tm.s.u64LastPausedTSC;
+                    break;
+                case TMTSCMODE_NATIVE_API:
+                {
+                    int rc = NEMHCResumeCpuTickOnAll(pVM, pVCpu, pVM->tm.s.u64LastPausedTSC);
+                    AssertRCReturn(rc, rc);
+                    pVCpu->tm.s.offTSCRawSrc = offTSCRawSrcOld = 0;
+                    break;
+                }
+                default:
+                    AssertFailedReturn(VERR_IPE_NOT_REACHED_DEFAULT_CASE);
+            }
+
+            /* Calculate the offset addendum 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(PVMCPUCC 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(PVMCC pVM, PVMCPUCC 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 IN_RING0 /* Only used in ring-0 at present (AMD-V and VT-x). */
+
+# 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(PVMCC pVM, PVMCPUCC 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 = (uint64_t)0 - pVCpu->tm.s.offTSCRawSrc - (uint64_t)SUPGetTscDelta(g_pSUPGlobalInfoPage);
+# else
+        *poffRealTsc = (uint64_t)0 - pVCpu->tm.s.offTSCRawSrc - (uint64_t)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 uTscNow;
+        uint64_t u64Now = tmCpuTickCalcFromVirtual(pVM, TMVirtualSyncGetNoCheckWithTsc(pVM, &uTscNow))
+                        - 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)
+        {
+# ifdef IN_RING3
+            *poffRealTsc = u64Now - (uTscNow + (uint64_t)SUPGetTscDelta(g_pSUPGlobalInfoPage);
+# else
+            *poffRealTsc = u64Now - (uTscNow + (uint64_t)SUPGetTscDeltaByCpuSetIndex(pVCpu->iHostCpuSet));
+# endif
+            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(PVMCPUCC pVCpu, uint64_t cNsToDeadline)
+{
+    AssertCompile(TMCLOCK_FREQ_VIRTUAL <= _4G);
+# ifdef IN_RING3
+    RT_NOREF_PV(pVCpu);
+    PSUPGIP const pGip = g_pSUPGlobalInfoPage;
+    uint64_t uCpuHz = pGip ? SUPGetCpuHzFromGip(pGip) : pVCpu->pVMR3->tm.s.cTSCTicksPerSecondHost;
+# else
+    uint64_t uCpuHz = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, pVCpu->iHostCpuSet);
+# endif
+    if (RT_UNLIKELY(cNsToDeadline >= TMCLOCK_FREQ_VIRTUAL))
+        return uCpuHz;
+    AssertCompile(TMCLOCK_FREQ_VIRTUAL <= UINT32_MAX);
+    uint64_t cTicks = ASMMultU64ByU32DivByU32(uCpuHz, (uint32_t)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.
+ * @param   puTscNow            Where to return the TSC value that the return
+ *                              value is relative to.   This is delta adjusted.
+ * @param   puDeadlineVersion   Where to return the deadline "version" number.
+ *                              Use with TMVirtualSyncIsCurrentDeadlineVersion()
+ *                              to check if the absolute deadline is still up to
+ *                              date and the caller can skip calling this
+ *                              function.
+ *
+ * @thread  EMT(pVCpu).
+ * @see     TMCpuTickCanUseRealTSC().
+ */
+VMM_INT_DECL(uint64_t) TMCpuTickGetDeadlineAndTscOffset(PVMCC pVM, PVMCPUCC pVCpu, uint64_t *poffRealTsc,
+                                                        bool *pfOffsettedTsc, bool *pfParavirtTsc,
+                                                        uint64_t *puTscNow, uint64_t *puDeadlineVersion)
+{
+    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     = (uint64_t)0 - pVCpu->tm.s.offTSCRawSrc - (uint64_t)SUPGetTscDelta(g_pSUPGlobalInfoPage);
+# else
+        *poffRealTsc     = (uint64_t)0 - pVCpu->tm.s.offTSCRawSrc - (uint64_t)SUPGetTscDeltaByCpuSetIndex(pVCpu->iHostCpuSet);
+# endif
+        *pfOffsettedTsc  = true;
+        return tmCpuCalcTicksToDeadline(pVCpu, TMVirtualSyncGetNsToDeadline(pVM, puDeadlineVersion, puTscNow));
+    }
+
+    /*
+     * 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, puDeadlineVersion, puTscNow);
+        uint64_t u64Now = tmCpuTickCalcFromVirtual(pVM, u64NowVirtSync);
+        u64Now -= pVCpu->tm.s.offTSCRawSrc;
+
+# ifdef IN_RING3
+        *poffRealTsc     = u64Now - (*puTscNow + (uint64_t)SUPGetTscDelta(g_pSUPGlobalInfoPage)); /* undoing delta */
+# else
+        *poffRealTsc     = u64Now - (*puTscNow + (uint64_t)SUPGetTscDeltaByCpuSetIndex(pVCpu->iHostCpuSet)); /* undoing delta */
+# endif
+        *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, puDeadlineVersion, puTscNow));
+}
+
+#endif /* IN_RING0 - at the moment */
+
+/**
+ * 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(PVMCPUCC pVCpu, bool fCheckTimers)
+{
+    uint64_t u64;
+
+    if (RT_LIKELY(pVCpu->tm.s.fTSCTicking))
+    {
+        PVMCC pVM = pVCpu->CTX_SUFF(pVM);
+        switch (pVM->tm.s.enmTSCMode)
+        {
+            case TMTSCMODE_REAL_TSC_OFFSET:
+                u64 = SUPReadTsc();
+                break;
+            case TMTSCMODE_VIRT_TSC_EMULATED:
+            case TMTSCMODE_DYNAMIC:
+                u64 = tmCpuTickGetRawVirtual(pVM, fCheckTimers);
+                break;
+            case TMTSCMODE_NATIVE_API:
+            {
+                u64 = 0;
+                int rcNem = NEMHCQueryCpuTick(pVCpu, &u64, NULL);
+                AssertLogRelRCReturn(rcNem, SUPReadTsc());
+                break;
+            }
+            default:
+                AssertFailedBreakStmt(u64 = SUPReadTsc());
+        }
+        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;
+    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(PVMCPUCC 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(PVMCPUCC 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(PVMCC pVM, PVMCPUCC 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(PVMCPUCC pVCpu, uint64_t u64LastSeenTick)
+{
+    VMCPU_ASSERT_EMT(pVCpu);
+
+    LogFlow(("TMCpuTickSetLastSeen %RX64\n", u64LastSeenTick));
+    /** @todo deal with wraparound!   */
+    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(PVMCPUCC 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(PVMCC pVM)
+{
+    if (pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET)
+    {
+        PSUPGLOBALINFOPAGE const pGip = g_pSUPGlobalInfoPage;
+        if (pGip && pGip->u32Mode != SUPGIPMODE_INVARIANT_TSC)
+        {
+#ifdef IN_RING3
+            uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGip(pGip);
+#elif defined(IN_RING0)
+            uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGipBySetIndex(pGip, (uint32_t)RTMpCpuIdToSetIndex(RTMpCpuId()));
+#else
+            uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGipBySetIndex(pGip, 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(PVMCPUCC pVCpu)
+{
+    return pVCpu->tm.s.fTSCTicking;
+}
+