Re: [Patch 1/2] KVM: x86/pmu: Add Intel CPUID-hinted TopDown slots event

[Jim Mattson]

On Tue, Oct 31, 2023 at 1:58 AM Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx> wrote:
>
> This patch adds support for the architectural topdown slots event which
> is hinted by CPUID.0AH.EBX.

Can't a guest already program an event selector to count event select
0xa4, unit mask 1, unless the event is prohibited by
KVM_SET_PMU_EVENT_FILTER?

AFAICT, this change just enables event filtering based on
CPUID.0AH:EBX[bit 7] (though it's not clear to me why two independent
mechanisms are necessary for event filtering).