Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230607123700.40229-1-cloudliang@tencent.com>
 <20230607123700.40229-2-cloudliang@tencent.com> <ZJyj3QDu9eAtJ+eq@google.com>
In-Reply-To: <ZJyj3QDu9eAtJ+eq@google.com>
From:   Jinrong Liang <ljr.kernel@gmail.com>
Date:   Fri, 30 Jun 2023 10:47:40 +0800
Message-ID: <CAFg_LQVtcBaO-=dvrqe7OjMqift__x-F6FeJ8EEUh+Ei-tgyhg@mail.gmail.com>
Subject: Re: [PATCH v3 1/4] KVM: selftests: Introduce __kvm_pmu_event_filter
 to improved event filter settings
To:     Sean Christopherson <seanjc@google.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Jim Mattson <jmattson@google.com>,
        Shuah Khan <shuah@kernel.org>,
        Aaron Lewis <aaronlewis@google.com>,
        David Matlack <dmatlack@google.com>,
        Vishal Annapurve <vannapurve@google.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Like Xu <like.xu.linux@gmail.com>,
        Jinrong Liang <cloudliang@tencent.com>,
        linux-kselftest@vger.kernel.org, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Sean Christopherson <seanjc@google.com> =E4=BA=8E2023=E5=B9=B46=E6=9C=8829=
=E6=97=A5=E5=91=A8=E5=9B=9B 05:19=E5=86=99=E9=81=93=EF=BC=9A
>
> On Wed, Jun 07, 2023, Jinrong Liang wrote:
> > -static struct kvm_pmu_event_filter *remove_event(struct kvm_pmu_event_=
filter *f,
> > +static struct kvm_pmu_event_filter *remove_event(struct __kvm_pmu_even=
t_filter *__f,
> >                                                uint64_t event)
>
> Can you tack on a patch to drop the return?  None of the callers consume =
it, and
> it incorrectly implies that the incoming filter isn't modified.

Thank you very much for your suggestion! I'm more than happy to follow
your advice and modify the code accordingly.

>
> >  {
> >       bool found =3D false;
> >       int i;
> > +     struct kvm_pmu_event_filter *f =3D (void *)__f;
>
> Nit, reverse xmas tree is preferred:
>
>         struct kvm_pmu_event_filter *f =3D (void *)__f;
>         bool found =3D false;
>         int i;
>
> Hoever, I don't think this one needs to cast, the cast is only necessary =
when
> invoking a KVM ioctl(), e.g. I believe this should work:
>
> static void remove_event(struct __kvm_pmu_event_filter *f, uint64_t event=
)
> {
>         bool found =3D false;
>         int i;
>
>         for (i =3D 0; i < f->nevents; i++) {
>                 if (found)
>                         f->events[i - 1] =3D f->events[i];
>                 else
>                         found =3D f->events[i] =3D=3D event;
>         }
>         if (found)
>                 f->nevents--;
> }
> > @@ -569,19 +554,16 @@ static void run_masked_events_test(struct kvm_vcp=
u *vcpu,
> >                                  const uint64_t masked_events[],
> >                                  const int nmasked_events)
> >  {
> > -     struct kvm_pmu_event_filter *f;
> > +     struct __kvm_pmu_event_filter f =3D {
> > +         .nevents =3D nmasked_events,
> > +         .action =3D KVM_PMU_EVENT_ALLOW,
> > +         .flags =3D KVM_PMU_EVENT_FLAG_MASKED_EVENTS,
>
> Tabs, not spaces please.
>
> > +static int set_pmu_single_event_filter(struct kvm_vcpu *vcpu, uint64_t=
 event,
> > +                                    uint32_t flags, uint32_t action)
> > +{
> > +     struct __kvm_pmu_event_filter f =3D {
> > +         .nevents =3D 1,
> > +         .flags =3D flags,
> > +         .action =3D action,
> > +         .events =3D {
> > +             event,
>
> Tabs.

I will include these change in the new patch version and ensure that
any related code is adjusted accordingly.

Once again, I truly appreciate your guidance!