Messages in this thread | | | Date | Fri, 27 Aug 2021 09:30:36 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 07/15] KVM: Use dedicated flag to track if KVM is handling an NMI from guest |
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On Thu, Aug 26, 2021 at 05:57:10PM -0700, Sean Christopherson wrote: > diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h > index 5cedc0e8a5d5..4c5ba4128b38 100644 > --- a/arch/x86/kvm/x86.h > +++ b/arch/x86/kvm/x86.h > @@ -395,9 +395,10 @@ static inline void kvm_unregister_perf_callbacks(void) > > DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu); > > -static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu) > +static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu, bool is_nmi) > { > __this_cpu_write(current_vcpu, vcpu); > + WRITE_ONCE(vcpu->arch.handling_nmi_from_guest, is_nmi); > > kvm_register_perf_callbacks(); > } > @@ -406,6 +407,7 @@ static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) > { > kvm_unregister_perf_callbacks(); > > + WRITE_ONCE(vcpu->arch.handling_nmi_from_guest, false); > __this_cpu_write(current_vcpu, NULL); > }
Does this rely on kvm_{,un}register_perf_callback() being a function call and thus implying a sequence point to order the stores?
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