2 files changed, 4 insertions, 8 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8a34fca6c572..b23682900f41 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -422,6 +422,7 @@ struct kvm_vcpu_arch {
         u64 last_kernel_ns;
         u64 last_tsc_nsec;
         u64 last_tsc_write;
+        u64 last_host_tsc;
         bool tsc_catchup;
         bool tsc_always_catchup;
         s8 virtual_tsc_shift;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2a59f76d96f1..39a57dac884a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2253,13 +2253,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
         kvm_x86_ops->vcpu_load(vcpu, cpu);
         if (unlikely(vcpu->cpu != cpu) || check_tsc_unstable()) {
-                /* Make sure TSC doesn't go backwards */
-                s64 tsc_delta;
-                u64 tsc;
-
-                tsc = kvm_x86_ops->read_l1_tsc(vcpu);
-                tsc_delta = tsc - vcpu->arch.last_guest_tsc;
-
+                s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 :
+                                native_read_tsc() - vcpu->arch.last_host_tsc;
                 if (tsc_delta < 0)
                         mark_tsc_unstable("KVM discovered backwards TSC");
                 if (check_tsc_unstable()) {
@@ -2282,7 +2277,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
         kvm_x86_ops->vcpu_put(vcpu);
         kvm_put_guest_fpu(vcpu);
-        vcpu->arch.last_guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu);
+        vcpu->arch.last_host_tsc = native_read_tsc();
 }
 
 static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,