On Thu, May 14, 2020 at 04:30:51PM +0800, Like Xu wrote: > @@ -6698,6 +6698,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) > > if (vcpu_to_pmu(vcpu)->version) > atomic_switch_perf_msrs(vmx); > + > atomic_switch_umwait_control_msr(vmx); > > if (enable_preemption_timer) Is this where the test to see if any of the KVM events went into ERROR state should go? if (event->state == PERF_EVENT_STATE_ERROR) { pr_warn("unhappy, someone stole our counter\n"); } like..