[patch 19/26] KVM: SVM: Fix tsc offset adjustment when running nested

Greg KH
2009-10-09T23:17:46Z

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2.6.31-stable review patch. If anyone has any objections, please let us know.

------------------
From: Joerg Roedel <joerg.roedel@amd.com>

commit 77b1ab1732feb5e3dcbaf31d2f7547c5229f5f3a upstream.

When svm_vcpu_load is called while the vcpu is running in
guest mode the tsc adjustment made there is lost on the next
emulated #vmexit. This causes the tsc running backwards in
the guest. This patch fixes the issue by also adjusting the
tsc_offset in the emulated hsave area so that it will not
get lost.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/kvm/svm.c | 2 ++
1 file changed, 2 insertions(+)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -709,6 +709,8 @@ static void svm_vcpu_load(struct kvm_vcp
rdtscll(tsc_this);
delta = vcpu->arch.host_tsc - tsc_this;
svm->vmcb->control.tsc_offset += delta;
+ if (is_nested(svm))
+ svm->nested.hsave->control.tsc_offset += delta;
vcpu->cpu = cpu;
kvm_migrate_timers(vcpu);
svm->asid_generation = 0;