On Mon, Mar 29, 2021 at 01:41:27PM +0800, Like Xu wrote:
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 827886c12c16..3509b18478b9 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -74,11 +74,20 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
> {
> struct kvm_pmc *pmc = perf_event->overflow_handler_context;
> struct kvm_pmu *pmu = pmc_to_pmu(pmc);
> + bool skip_pmi = false;
>
> if (!test_and_set_bit(pmc->idx, pmu->reprogram_pmi)) {
> - __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
> + if (perf_event->attr.precise_ip) {
> + /* Indicate PEBS overflow PMI to guest. */
> + skip_pmi = test_and_set_bit(GLOBAL_STATUS_BUFFER_OVF_BIT,
> + (unsigned long *)&pmu->global_status);
Is there actual concurrency here, or did you forget to type __?
And in case you're using vim, use something like: set cino=(0:0
> + } else
> + __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
> kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
>
> + if (skip_pmi)
> + return;
> +
> /*
> * Inject PMI. If vcpu was in a guest mode during NMI PMI
> * can be ejected on a guest mode re-entry. Otherwise we can't
