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KVM: SVM: Handle tsc in svm_get_msr/svm_set_msr correctly

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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>
This commit is contained in:
Joerg Roedel 2009-09-16 15:24:18 +02:00 committed by Avi Kivity
parent 77b1ab1732
commit 20824f30bb
1 changed files with 17 additions and 6 deletions
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23
arch/x86/kvm/svm.c
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@ -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: