Messages in this thread Patch in this message | | | From | Like Xu <> | Subject | Re: [PATCH] KVM: x86/pt: Do not inject TraceToPAPMI when guest PT isn't supported | Date | Mon, 21 Jun 2021 12:03:36 +0800 |
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On 27/5/2021 1:38 am, Sean Christopherson wrote: > On Fri, May 14, 2021, Like Xu wrote: >> When a PT perf user is running in system-wide mode on the host, >> the guest (w/ pt_mode=0) will warn about anonymous NMIs from >> kvm_handle_intel_pt_intr(): >> >> [ 18.126444] Uhhuh. NMI received for unknown reason 10 on CPU 0. >> [ 18.126447] Do you have a strange power saving mode enabled? >> [ 18.126448] Dazed and confused, but trying to continue >> >> In this case, these PMIs should be handled by the host PT handler(). >> When PT is used in guest-only mode, it's harmless to call host handler. >> >> Fix: 8479e04e7d("KVM: x86: Inject PMI for KVM guest") > > s/Fix/Fixes > >> Signed-off-by: Like Xu <like.xu@linux.intel.com> >> --- >> arch/x86/events/intel/core.c | 3 +-- >> arch/x86/kvm/x86.c | 3 +++ >> 2 files changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c >> index 2521d03de5e0..2f09eb0853de 100644 >> --- a/arch/x86/events/intel/core.c >> +++ b/arch/x86/events/intel/core.c >> @@ -2853,8 +2853,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) >> if (unlikely(perf_guest_cbs && perf_guest_cbs->is_in_guest() && >> perf_guest_cbs->handle_intel_pt_intr)) >> perf_guest_cbs->handle_intel_pt_intr(); >> - else >> - intel_pt_interrupt(); >> + intel_pt_interrupt(); > > Would it make sense to instead do something like: > > bool host_pmi = true; > > ... > > if (unlikely(perf_guest_cbs && perf_guest_cbs->is_in_guest() && > perf_guest_cbs->handle_intel_pt_intr) > host_pmi = !perf_guest_cbs->handle_intel_pt_intr();
struct perf_guest_info_callbacks { ... void (*handle_intel_pt_intr)(void); };
This fix is deferred until the following proposal is finalized.
https://lore.kernel.org/lkml/YKImQ2%2FDilGIkrfe@hirez.programming.kicks-ass.net/
> > if (likely(host_pmi)) > intel_pt_interrupt(); >> } >> >> /* >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index 6529e2023147..6660f3948cea 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -8087,6 +8087,9 @@ static void kvm_handle_intel_pt_intr(void) >> { >> struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); >> >> + if (!guest_cpuid_has(vcpu, X86_FEATURE_INTEL_PT)) >> + return; >> + >> kvm_make_request(KVM_REQ_PMI, vcpu); >> __set_bit(MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI_BIT, >> (unsigned long *)&vcpu->arch.pmu.global_status); >> -- >> 2.31.1 >> >
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