Re: [RESEND PATCH] KVM: x86/pmu: Support full width counting

[Xu, Like]

Hi Paolo,

Thanks for your comments!

On 2020/5/5 0:57, Paolo Bonzini wrote:
> On 27/04/20 09:19, Like Xu wrote:
> > +	if (vmx_supported_perf_capabilities())
> > +		kvm_cpu_cap_check_and_set(X86_FEATURE_PDCM);
> I think we can always set it, worst case it will be zero.
Sure, we could set it for x86.
> However, blocking intel_pmu_set_msr altogether is incorrect.  Instead,
> you need to:
>
> - list the MSR in msr_based_features_all so that it appears in
> KVM_GET_MSR_FEATURE_INDEX_LIST
>
> - return the supported bits in vmx_get_msr_feature
>
> - allow host-initiated writes (as long as they only set supported bits)
> of the MSR in intel_pmu_set_msr.
Please review the v2 patch for this feature,
https://lore.kernel.org/kvm/20200507021452.174646-1-like.xu@xxxxxxxxxxxxxxx/

Thanks,
Like Xu
> Thanks,
>
> Paolo