KVM: SVM: Fix tsc offset adjustment when running nested

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.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 944cc9c04b3c..bf5799dc4f9f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -767,6 +767,8 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
                 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;