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authorZachary Amsden2010-08-19 22:07:24 -1000
committerAvi Kivity2010-10-24 10:51:23 +0200
commit48434c20e18d59001469699fcaaf9cf30b815a20 (patch)
tree8c7f91598f3ea56550e86599c18b3e0b7daf6361 /arch/x86
parente48672fa25e879f7ae21785c7efd187738139593 (diff)
KVM: x86: Fix deep C-state TSC desynchronization
When CPUs with unstable TSCs enter deep C-state, TSC may stop running. This causes us to require resynchronization. Since we can't tell when this may potentially happen, we assume the worst by forcing re-compensation for it at every point the VCPU task is descheduled. Signed-off-by: Zachary Amsden <zamsden@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/x86.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 468fafaed1ae..9396b3f2c594 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1866,7 +1866,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
}
kvm_x86_ops->vcpu_load(vcpu, cpu);
- if (unlikely(vcpu->cpu != cpu)) {
+ if (unlikely(vcpu->cpu != cpu) || check_tsc_unstable()) {
/* Make sure TSC doesn't go backwards */
s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 :
native_read_tsc() - vcpu->arch.last_host_tsc;