Changeset 62186 in vbox

Timestamp:

Jul 12, 2016 11:17:25 AM (8 years ago)

Author:

vboxsync

Message:

SVM: Read the TSC before writing MSRs (serializing, slow).

File:

• trunk/src/VBox/VMM/VMMR0/HMSVMR0.cpp (modified) (2 diffs)

trunk/src/VBox/VMM/VMMR0/HMSVMR0.cpp

@@ -3259 +3259 @@
     pVmcb->ctrl.u64VmcbCleanBits = HMSVM_VMCB_CLEAN_ALL;        /* Mark the VMCB-state cache as unmodified by VMM. */
 
+    /* TSC read must be done early for maximum accuracy. */
+    if (!(pVmcb->ctrl.u32InterceptCtrl1 & SVM_CTRL1_INTERCEPT_RDTSC))
+        TMCpuTickSetLastSeen(pVCpu, ASMReadTSC() + pVmcb->ctrl.u64TSCOffset);
+
+
     if (pSvmTransient->fRestoreTscAuxMsr)
     {
@@ -3266 +3271 @@
             ASMWrMsr(MSR_K8_TSC_AUX, pVCpu->hm.s.u64HostTscAux);
     }
-
-    if (!(pVmcb->ctrl.u32InterceptCtrl1 & SVM_CTRL1_INTERCEPT_RDTSC))
-        TMCpuTickSetLastSeen(pVCpu, ASMReadTSC() + pVmcb->ctrl.u64TSCOffset);
 
     STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatInGC, &pVCpu->hm.s.StatExit1, x);