Changeset 22242 in vbox for trunk/src/VBox/VMM

Timestamp:

Aug 13, 2009 3:38:35 PM (15 years ago)

Author:

vboxsync

Message:

Made TSC underflow checking more generic.

Location:

trunk/src/VBox/VMM

Files:

• HWACCM.cpp (modified) (1 diff)
• HWACCMInternal.h (modified) (2 diffs)
• TM.cpp (modified) (1 diff)
• TMInternal.h (modified) (2 diffs)
• VMMAll/TMAllCpu.cpp (modified) (2 diffs)
• VMMR0/HWVMXR0.cpp (modified) (4 diffs)

trunk/src/VBox/VMM/HWACCM.cpp

@@ -508 +508 @@
         HWACCM_REG_COUNTER(&pVCpu->hwaccm.s.StatTSCIntercept,           "/HWACCM/CPU%d/TSC/Intercept");
         HWACCM_REG_COUNTER(&pVCpu->hwaccm.s.StatTSCInterceptOverFlow,   "/HWACCM/CPU%d/TSC/InterceptOverflow");
-        HWACCM_REG_COUNTER(&pVCpu->hwaccm.s.StatTSCOverFlow,            "/HWACCM/CPU%d/TSC/Overflow");
         
         HWACCM_REG_COUNTER(&pVCpu->hwaccm.s.StatDRxArmed,               "/HWACCM/CPU%d/Debug/Armed");

trunk/src/VBox/VMM/HWACCMInternal.h

@@ -557 +557 @@
     RTUINT                      uCurrentASID;
 
-    /* Last seen TSC by the guest when in offsetted mode. */
-    uint64_t                    u64LastTSC;
     /* Last use TSC offset value. (cached) */
     uint64_t                    u64TSCOffset;
@@ -819 +817 @@
     STAMCOUNTER             StatTSCOffset;
     STAMCOUNTER             StatTSCIntercept;
-    STAMCOUNTER             StatTSCOverFlow;
     STAMCOUNTER             StatTSCInterceptOverFlow;
 

trunk/src/VBox/VMM/TM.cpp

@@ -623 +623 @@
     STAM_REG(pVM, &pVM->tm.s.StatTSCWarp,                             STAMTYPE_COUNTER, "/TM/TSC/Intercept/Warp",              STAMUNIT_OCCURENCES, "Warpdrive is active.");
     STAM_REG(pVM, &pVM->tm.s.StatTSCSet,                              STAMTYPE_COUNTER, "/TM/TSC/Sets",                        STAMUNIT_OCCURENCES, "Calls to TMCpuTickSet.");
+    STAM_REG(pVM, &pVM->tm.s.StatTSCUnderflow,                        STAMTYPE_COUNTER, "/TM/TSC/Underflow",                   STAMUNIT_OCCURENCES, "TSC underflow; corrected with last seen value .");
 #endif /* VBOX_WITH_STATISTICS */
 

trunk/src/VBox/VMM/TMInternal.h

@@ -546 +546 @@
     STAMCOUNTER                 StatTSCCatchupOther;
     STAMCOUNTER                 StatTSCWarp;
+    STAMCOUNTER                 StatTSCUnderflow;
     STAMCOUNTER                 StatTSCSyncNotTicking;
     /** @} */
@@ -573 +574 @@
     uint64_t                    u64TSC;
 
+    /** The last seen TSC by the guest. */
+    uint64_t                    u64TSCLastSeen;
 } TMCPU;
 /** Pointer to TM VMCPU instance data. */

trunk/src/VBox/VMM/VMMAll/TMAllCpu.cpp

@@ -210 +210 @@
         else
             u64 = ASMReadTSC();
+
+        /* Never return a value lower than what the guest has already seen. */
+        if (u64 < pVCpu->tm.s.u64TSCLastSeen)
+        {
+            STAM_COUNTER_INC(&pVM->tm.s.StatTSCUnderflow);
+            pVCpu->tm.s.u64TSCLastSeen += 64;   /* @todo choose a good increment here */
+            u64 = pVCpu->tm.s.u64TSCLastSeen;
+        }
     }
     else
@@ -271 +279 @@
 }
 
+/**
+ * Sets the last seen CPU timestamp counter.
+ *
+ * @returns VBox status code.
+ * @param   pVCpu               The virtual CPU to operate on.
+ * @param   u64LastSeenTick     The last seen timestamp value.
+ *
+ * @thread  EMT which TSC is to be set.
+ */
+VMMDECL(int) TMCpuTickSetLastSeen(PVMCPU pVCpu, uint64_t u64LastSeenTick)
+{
+    VMCPU_ASSERT_EMT(pVCpu);
+
+    Assert(pVCpu->tm.s.u64TSCLastSeen < u64LastSeenTick);
+    pVCpu->tm.s.u64TSCLastSeen = u64LastSeenTick;
+    return VINF_SUCCESS;
+}
+
+/**
+ * Gets the last seen CPU timestamp counter.
+ *
+ * @returns last seen TSC
+ * @param   pVCpu               The virtual CPU to operate on.
+ *
+ * @thread  EMT which TSC is to be set.
+ */
+VMMDECL(uint64_t) TMCpuTickGetLastSeen(PVMCPU pVCpu)
+{
+    VMCPU_ASSERT_EMT(pVCpu);
+
+    return pVCpu->tm.s.u64TSCLastSeen;
+}
+
 
 /**

trunk/src/VBox/VMM/VMMR0/HWVMXR0.cpp

@@ -1803 +1803 @@
     AssertRC(rc);
 
-    /* TSC offset. */
-    uint64_t u64TSCOffset;
-
-    if (TMCpuTickCanUseRealTSC(pVCpu, &u64TSCOffset))
+    if (TMCpuTickCanUseRealTSC(pVCpu, &pVCpu->hwaccm.s.u64TSCOffset))
     {
         uint64_t u64CurTSC = ASMReadTSC();
-        pVCpu->hwaccm.s.u64TSCOffset = u64TSCOffset;
-        if (u64CurTSC + u64TSCOffset >= pVCpu->hwaccm.s.u64LastTSC)
+        if (u64CurTSC + pVCpu->hwaccm.s.u64TSCOffset >= TMCpuTickGetLastSeen(pVCpu))
         {
             /* Note: VMX_VMCS_CTRL_PROC_EXEC_CONTROLS_RDTSC_EXIT takes precedence over TSC_OFFSET */
-            rc = VMXWriteVMCS64(VMX_VMCS_CTRL_TSC_OFFSET_FULL, u64TSCOffset);
+            rc = VMXWriteVMCS64(VMX_VMCS_CTRL_TSC_OFFSET_FULL, pVCpu->hwaccm.s.u64TSCOffset);
             AssertRC(rc);
 
@@ -1824 +1820 @@
         {
             /* Fall back to rdtsc emulation as we would otherwise pass decreasing tsc values to the guest. */
-            Log(("TSC %RX64 offset %RX64 time=%RX64 last=%RX64 (diff=%RX64, virt_tsc=%RX64)\n", u64CurTSC, u64TSCOffset, u64CurTSC + u64TSCOffset, pVCpu->hwaccm.s.u64LastTSC, pVCpu->hwaccm.s.u64LastTSC - u64CurTSC - u64TSCOffset, TMCpuTickGet(pVCpu)));
+            Log(("TSC %RX64 offset %RX64 time=%RX64 last=%RX64 (diff=%RX64, virt_tsc=%RX64)\n", u64CurTSC, pVCpu->hwaccm.s.u64TSCOffset, u64CurTSC + pVCpu->hwaccm.s.u64TSCOffset, TMCpuTickGetLastSeen(pVCpu), TMCpuTickGetLastSeen(pVCpu) - u64CurTSC - pVCpu->hwaccm.s.u64TSCOffset, TMCpuTickGet(pVCpu)));
             pVCpu->hwaccm.s.vmx.proc_ctls |= VMX_VMCS_CTRL_PROC_EXEC_CONTROLS_RDTSC_EXIT;
             rc = VMXWriteVMCS(VMX_VMCS_CTRL_PROC_EXEC_CONTROLS, pVCpu->hwaccm.s.vmx.proc_ctls);
@@ -2596 +2592 @@
     /* Possibly the last TSC value seen by the guest (too high) (only when we're in tsc offset mode). */
     if (!(pVCpu->hwaccm.s.vmx.proc_ctls & VMX_VMCS_CTRL_PROC_EXEC_CONTROLS_RDTSC_EXIT))
-        pVCpu->hwaccm.s.u64LastTSC = ASMReadTSC() + pVCpu->hwaccm.s.u64TSCOffset - 0x1000 /* guestimate of world switch overhead */;
+        TMCpuTickSetLastSeen(pVCpu, ASMReadTSC() + pVCpu->hwaccm.s.u64TSCOffset - 0x1000 /* guestimate of world switch overhead in clock ticks */);
 
     TMNotifyEndOfExecution(pVCpu);
@@ -3399 +3395 @@
         if (rc == VINF_SUCCESS)
         {
-            uint64_t u64CurrentTSC = (uint64_t)pCtx->edx << 32ULL;
-            u64CurrentTSC += pCtx->eax;
-
-            if (u64CurrentTSC < pVCpu->hwaccm.s.u64LastTSC)
-            {
-                STAM_COUNTER_INC(&pVCpu->hwaccm.s.StatTSCOverFlow);
-                Log(("invalid tsc %RX64 vs %RX64 (diff %RX64)\n", u64CurrentTSC, pVCpu->hwaccm.s.u64LastTSC, pVCpu->hwaccm.s.u64LastTSC - u64CurrentTSC));
-                pVCpu->hwaccm.s.u64LastTSC += 64;
-                pCtx->edx = (pVCpu->hwaccm.s.u64LastTSC >> 32ULL);
-                pCtx->eax = (pVCpu->hwaccm.s.u64LastTSC & 0xffffffff);
-            }
-
             /* Update EIP and continue execution. */
             Assert(cbInstr == 2);