RE: [PATCH 8/9] KVM: x86/pmu: Upgrade pmu version to 5 on intel processor

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> On 1/9/2023 3:28 pm, Xiong Zhang wrote:
> > Modern intel processors have supported Architectural Performance
> > Monitoring Version 5, this commit upgrade Intel vcpu's vPMU version
> > from 2 to 5.
> >
> > Go through PMU features from version 3 to 5, the following features
> > are not supported:
> > 1. AnyThread counting: it is added in v3, and deprecated in v5.
> > 2. Streamed Freeze_PerfMon_On_PMI in v4, since legacy
> > Freeze_PerMon_ON_PMI isn't supported, the new one won't be supported
> neither.
> > 3. IA32_PERF_GLOBAL_STATUS.ASCI[bit 60]: Related to SGX, and will be
> > emulated by SGX developer later.
> > 4. Domain Separation in v5. When INV flag in IA32_PERFEVTSELx is used,
> > a counter stops counting when logical processor exits the C0 ACPI C-state.
> > First guest INV flag isn't supported, second guest ACPI C-state is vague.
> >
> > When a guest enable unsupported features through WRMSR, KVM will
> > inject a #GP into the guest.
> >
> > Signed-off-by: Xiong Zhang <xiong.y.zhang@xxxxxxxxx>
> > ---
> >   arch/x86/kvm/pmu.h | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index
> > 4bab4819ea6c..8e6bc9b1a747 100644
> > --- a/arch/x86/kvm/pmu.h
> > +++ b/arch/x86/kvm/pmu.h
> > @@ -215,7 +215,10 @@ static inline void kvm_init_pmu_capability(const
> struct kvm_pmu_ops *pmu_ops)
> >   		return;
> >   	}
> >
> > -	kvm_pmu_cap.version = min(kvm_pmu_cap.version, 2);
> 
> For AMD as of now, the kvm_pmu_cap.version will not exceed 2.
> Thus there's no need to differentiate between Intel and AMD.
> 
Get it.

thanks
> > +	if (is_intel)
> > +		kvm_pmu_cap.version = min(kvm_pmu_cap.version, 5);
> > +	else
> > +		kvm_pmu_cap.version = min(kvm_pmu_cap.version, 2);
> >   	kvm_pmu_cap.num_counters_gp =
> min(kvm_pmu_cap.num_counters_gp,
> >   					  pmu_ops->MAX_NR_GP_COUNTERS);
> >   	kvm_pmu_cap.num_counters_fixed =
> > min(kvm_pmu_cap.num_counters_fixed,




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