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,