linux-kernel - Re: [PATCH v3 2/5] KVM: selftests: Track unavailable

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Message-ID: <aM1uGrlftd589vLd@google.com>
Date: Fri, 19 Sep 2025 07:52:10 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Dapeng Mi <dapeng1.mi@...ux.intel.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Yi Lai <yi1.lai@...el.com>, dongsheng <dongsheng.x.zhang@...el.com>
Subject: Re: [PATCH v3 2/5] KVM: selftests: Track unavailable_mask for PMU
 events as 32-bit value

On Fri, Sep 19, 2025, Dapeng Mi wrote:
> On 9/19/2025 8:45 AM, Sean Christopherson wrote:
> > diff --git a/tools/testing/selftests/kvm/x86/pmu_counters_test.c b/tools/testing/selftests/kvm/x86/pmu_counters_test.c
> > index 8aaaf25b6111..cfeed0103341 100644
> > --- a/tools/testing/selftests/kvm/x86/pmu_counters_test.c
> > +++ b/tools/testing/selftests/kvm/x86/pmu_counters_test.c
> > @@ -311,7 +311,7 @@ static void guest_test_arch_events(void)
> >  }
> >  
> >  static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities,
> > -			     uint8_t length, uint8_t unavailable_mask)
> > +			     uint8_t length, uint32_t unavailable_mask)
> >  {
> >  	struct kvm_vcpu *vcpu;
> >  	struct kvm_vm *vm;
> > @@ -320,6 +320,9 @@ static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities,
> >  	if (!pmu_version)
> >  		return;
> >  
> > +	unavailable_mask = GENMASK(X86_PROPERTY_PMU_EVENTS_MASK.hi_bit,
> > +				   X86_PROPERTY_PMU_EVENTS_MASK.lo_bit);
> 
> Should be "unavailable_mask &="? Otherwise the incoming argument
> "unavailable_mask" would be overwritten unconditionally. 

/facepalm

Yes, definitely supposed to be &=.