linux-kernel - Re: [PATCH] KVM: selftests: aarch64: Remove unused functions from vpmu test

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Date:   Mon, 27 Nov 2023 13:41:29 -0800
From:   Raghavendra Rao Ananta <rananta@...gle.com>
To:     Shaoqin Huang <shahuang@...hat.com>
Cc:     Oliver Upton <oliver.upton@...ux.dev>,
        Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Zenghui Yu <yuzenghui@...wei.com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH] KVM: selftests: aarch64: Remove unused functions from
 vpmu test

Hi Shaoqin,

On Wed, Nov 22, 2023 at 10:43 PM Shaoqin Huang <shahuang@...hat.com> wrote:
>
> Hi Raghavendra,
>
> Those functions might be useful for other pmu tests. Recently I just
> wrote a pmu_event_filter_test[1] and use the enable_counter().
>
> There may have more pmu tests which can use the helper functions, so I
> think we can keep it now. And in my series[1], I have moved them into
> the lib/ as the helper function.
>
> [1]https://lore.kernel.org/all/20231123063750.2176250-1-shahuang@redhat.com/
>
Thanks for the pointer. If you are planning to use it, then we can
abandon this patch. However, disable_counter() may need fixing. I'll
comment directly on your patch.

Thank you.
Raghavendra

> Thanks,
> Shaoqin
>
> On 11/23/23 06:15, Raghavendra Rao Ananta wrote:
> > vpmu_counter_access's disable_counter() carries a bug that disables
> > all the counters that are enabled, instead of just the requested one.
> > Fortunately, it's not an issue as there are no callers of it. Hence,
> > instead of fixing it, remove the definition entirely.
> >
> > Remove enable_counter() as it's unused as well.
> >
> > Signed-off-by: Raghavendra Rao Ananta <rananta@...gle.com>
> > ---
> >   .../selftests/kvm/aarch64/vpmu_counter_access.c  | 16 ----------------
> >   1 file changed, 16 deletions(-)
> >
> > diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
> > index 5ea78986e665f..e2f0b720cbfcf 100644
> > --- a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
> > +++ b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
> > @@ -94,22 +94,6 @@ static inline void write_sel_evtyper(int sel, unsigned long val)
> >       isb();
> >   }
> >
> > -static inline void enable_counter(int idx)
> > -{
> > -     uint64_t v = read_sysreg(pmcntenset_el0);
> > -
> > -     write_sysreg(BIT(idx) | v, pmcntenset_el0);
> > -     isb();
> > -}
> > -
> > -static inline void disable_counter(int idx)
> > -{
> > -     uint64_t v = read_sysreg(pmcntenset_el0);
> > -
> > -     write_sysreg(BIT(idx) | v, pmcntenclr_el0);
> > -     isb();
> > -}
> > -
> >   static void pmu_disable_reset(void)
> >   {
> >       uint64_t pmcr = read_sysreg(pmcr_el0);
>