Re: [RFC PATCH 23/41] KVM: x86/pmu: Implement the save/restore of PMU state for Intel CPU

[Mingwei Zhang]

> > Is there any event in the host still having PERF_EVENT_STATE_ACTIVE?
> > If so, hmm, it will reach perf_pmu_disable(event->pmu), which will
> > access the global ctrl MSR.
>
> I don't think there is any event with PERF_EVENT_STATE_ACTIVE state on
> host when guest owns the PMU HW resource.
>
> In current solution, VM would fail to create if there is any system-wide
> event without exclude_guest attribute. If VM is created successfully and
> when vm-entry happens, the helper perf_guest_enter() would put all host
> events with exclude_guest attribute into PERF_EVENT_STATE_INACTIVE state
> and block host to create system-wide events without exclude_guest attribute.
>

Yeah, that's perfect.

Thanks.
-Mingwei