From: Marc Zyngier <maz@kernel.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, will@kernel.org,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI
Date: Mon, 28 Nov 2022 08:28:43 +0000 [thread overview]
Message-ID: <86pmd7mqis.wl-maz@kernel.org> (raw)
In-Reply-To: <60767243-2f3e-a7aa-06e1-674e43f18e9c@arm.com>
On Mon, 28 Nov 2022 03:06:15 +0000,
Anshuman Khandual <anshuman.khandual@arm.com> wrote:
>
>
>
> On 11/28/22 08:24, Anshuman Khandual wrote:
> > __armv8pmu_probe_pmu() returns if detected PMU is either not implemented or
> > implementation defined. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is
> > not implemented is '0' which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI
> > defined as '0b0000'.
> >
> > Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Cc: Will Deacon <will@kernel.org>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: linux-perf-users@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> > Cc: linux-arm-kernel@lists.infradead.org
> > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> > ---
> > This applies on v6.1-rc6
> >
> > arch/arm64/kernel/perf_event.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
> > index 85a3aaefc0fb..b638f584b4dd 100644
> > --- a/arch/arm64/kernel/perf_event.c
> > +++ b/arch/arm64/kernel/perf_event.c
> > @@ -1188,7 +1188,8 @@ static void __armv8pmu_probe_pmu(void *info)
> > dfr0 = read_sysreg(id_aa64dfr0_el1);
> > pmuver = cpuid_feature_extract_unsigned_field(dfr0,
> > ID_AA64DFR0_EL1_PMUVer_SHIFT);
> > - if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF || pmuver == 0)
> > + if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF ||
> > + pmuver == ID_AA64DFR0_EL1_PMUVer_NI)
> > return;
> >
> > cpu_pmu->pmuver = pmuver;
> > --
>
> + Marc Zyngier <maz@kernel.org>
>
> There are some KVM related pmuver not-implemented check as well, should they be
> replaced in this patch or rather in a separate patch ?
>
> arch/arm64/kvm/pmu-emul.c: if (pmu->pmuver == 0 || pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
> arch/arm64/kvm/pmu-emul.c: if (pmu->pmuver == 0 ||
> arch/arm64/kvm/pmu-emul.c: pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
Separate patch please, as I have a large KVM PMU rework already
queued.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2022-11-28 8:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-28 2:54 [PATCH] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI Anshuman Khandual
2022-11-28 3:06 ` Anshuman Khandual
2022-11-28 8:28 ` Marc Zyngier [this message]
2022-11-28 12:06 ` Mark Rutland
2022-11-29 19:52 ` Will Deacon
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