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

[Paolo Bonzini]

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.

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.

Thanks,

Paolo