Changeset 49970 in vbox

Timestamp:

Dec 17, 2013 11:44:22 PM (11 years ago)

Author:

vboxsync

Message:

VMM/HMSVMR0: Avoid MSR write when possible.

File:

• trunk/src/VBox/VMM/VMMR0/HMSVMR0.cpp (modified) (1 diff)

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

@@ -3093 +3093 @@
     if (pSvmTransient->fRestoreTscAuxMsr)
     {
-        CPUMR0SetGuestTscAux(pVCpu, ASMRdMsr(MSR_K8_TSC_AUX));
-        ASMWrMsr(MSR_K8_TSC_AUX, pVCpu->hm.s.u64HostTscAux);
+        uint64_t u64GuestTscAuxMsr = ASMRdMsr(MSR_K8_TSC_AUX);
+        CPUMR0SetGuestTscAux(pVCpu, u64GuestTscAuxMsr);
+        if (u64GuestTscAuxMsr != pVCpu->hm.s.u64HostTscAux)
+            ASMWrMsr(MSR_K8_TSC_AUX, pVCpu->hm.s.u64HostTscAux);
     }