From: Joerg Roedel <joerg.roedel@amd.com>
Date: Wed, 16 Sep 2009 13:24:18 +0000 (+0200)
Subject: KVM: SVM: Handle tsc in svm_get_msr/svm_set_msr correctly
X-Git-Tag: v2.6.32-rc4~55^2~7
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=20824f30bb0b8ae0a4099895fd4509f54cf2e1e2;p=~shefty%2Frdma-dev.git

KVM: SVM: Handle tsc in svm_get_msr/svm_set_msr correctly

When running nested we need to touch the l1 guests
tsc_offset. Otherwise changes will be lost or a wrong value
be read.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index bf5799dc4f9..c17404add91 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2059,10 +2059,14 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
 
 	switch (ecx) {
 	case MSR_IA32_TSC: {
-		u64 tsc;
+		u64 tsc_offset;
 
-		rdtscll(tsc);
-		*data = svm->vmcb->control.tsc_offset + tsc;
+		if (is_nested(svm))
+			tsc_offset = svm->nested.hsave->control.tsc_offset;
+		else
+			tsc_offset = svm->vmcb->control.tsc_offset;
+
+		*data = tsc_offset + native_read_tsc();
 		break;
 	}
 	case MSR_K6_STAR:
@@ -2148,10 +2152,17 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 
 	switch (ecx) {
 	case MSR_IA32_TSC: {
-		u64 tsc;
+		u64 tsc_offset = data - native_read_tsc();
+		u64 g_tsc_offset = 0;
+
+		if (is_nested(svm)) {
+			g_tsc_offset = svm->vmcb->control.tsc_offset -
+				       svm->nested.hsave->control.tsc_offset;
+			svm->nested.hsave->control.tsc_offset = tsc_offset;
+		}
+
+		svm->vmcb->control.tsc_offset = tsc_offset + g_tsc_offset;
 
-		rdtscll(tsc);
-		svm->vmcb->control.tsc_offset = data - tsc;
 		break;
 	}
 	case MSR_K6_STAR: