Re: [PATCH v6 3/6] KVM: selftests: Introduce __kvm_pmu_event_filter to improved event filter settings

[Jinrong Liang]

Isaku Yamahata <isaku.yamahata@xxxxxxxxx> 于2023年8月15日周二 07:49写道：
>
> On Thu, Aug 10, 2023 at 05:09:42PM +0800,
> Jinrong Liang <ljr.kernel@xxxxxxxxx> wrote:
>
> > From: Jinrong Liang <cloudliang@xxxxxxxxxxx>
> >
> > Add custom "__kvm_pmu_event_filter" structure to improve pmu event
> > filter settings. Simplifies event filter setup by organizing event
> > filter parameters in a cleaner, more organized way.
> >
> > Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> > Signed-off-by: Jinrong Liang <cloudliang@xxxxxxxxxxx>
> > ---
> >  .../kvm/x86_64/pmu_event_filter_test.c        | 182 +++++++++---------
> >  1 file changed, 90 insertions(+), 92 deletions(-)
> >
> > diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> > index 5ac05e64bec9..94f5a89aac40 100644
> > --- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> > +++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> > @@ -28,6 +28,10 @@
> >
> >  #define NUM_BRANCHES 42
> >
> > +/* Matches KVM_PMU_EVENT_FILTER_MAX_EVENTS in pmu.c */
> > +#define MAX_FILTER_EVENTS            300
>
> Can we simply use KVM_PMU_EVENT_FILTER_MAX_EVENTS and remove MAX_FILTER_EVENTS?

I didn't find the definition of KVM_PMU_EVENT_FILTER_MAX_EVENTS in
selftests. KVM_PMU_EVENT_FILTER_MAX_EVENTS is defined in pmu.c. To use
it, we need to define it in selftests.

>
>
> > +#define MAX_TEST_EVENTS              10
> > +
> >  /*
> >   * This is how the event selector and unit mask are stored in an AMD
> >   * core performance event-select register. Intel's format is similar,
> > @@ -69,21 +73,33 @@
> >
> >  #define INST_RETIRED EVENT(0xc0, 0)
> >
> > +struct __kvm_pmu_event_filter {
> > +     __u32 action;
> > +     __u32 nevents;
> > +     __u32 fixed_counter_bitmap;
> > +     __u32 flags;
> > +     __u32 pad[4];
> > +     __u64 events[MAX_FILTER_EVENTS];
> > +};
> > +
>
> Is this same to struct kvm_pmu_event_filter?

In tools/arch/x86/include/uapi/asm/kvm.h

/* for KVM_CAP_PMU_EVENT_FILTER */
struct kvm_pmu_event_filter {
__u32 action;
__u32 nevents;
__u32 fixed_counter_bitmap;
__u32 flags;
__u32 pad[4];
__u64 events[];
};

>
> Except two trivial issue, looks good to me.
> --
> Isaku Yamahata <isaku.yamahata@xxxxxxxxx>