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From: Oliver Upton <oliver.upton@linux.dev>
To: Reiji Watanabe <reijiw@google.com>
Cc: Marc Zyngier <maz@kernel.org>, kvmarm@lists.cs.columbia.edu,
	kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Ricardo Koller <ricarkol@google.com>,
	Jing Zhang <jingzhangos@google.com>,
	Raghavendra Rao Anata <rananta@google.com>
Subject: Re: [PATCH 2/7] KVM: arm64: PMU: Use reset_pmu_reg() for
 PMUSERENR_EL0 and PMCCFILTR_EL0
Message-ID: <Y7zDgdmURNztXseL@google.com>
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On Mon, Jan 09, 2023 at 05:17:59PM -0800, Reiji Watanabe wrote:
> On Sun, Jan 8, 2023 at 11:13 AM Oliver Upton <oliver.upton@linux.dev> wrote:
> >
> > On Thu, Dec 29, 2022 at 07:59:23PM -0800, Reiji Watanabe wrote:
> > > The default reset function for PMU registers (reset_pmu_reg())
> > > now simply clears a specified register. Use that function for
> > > PMUSERENR_EL0 and PMCCFILTR_EL0, since those registers should
> > > simply be cleared on vCPU reset.
> >
> > AFAICT, the fields in both these registers have UNKNOWN reset values. Of
> > course, 0 is an entirely valid reset value but the architectural
> > behavior should be mentioned in the commit message.
> 
> Uh, yeah, the commit message was misleading.
> The fields in both these registers have UNKNOWN reset values.
> The ones for 32bit registers (PMUSERENR and PMCCFILTR) have zero reset
> values though.

Gosh, that silly (but highly relevant) detail escaped me.

> I will update the commit message to mention those explicitly.

Thanks!

--
Best,
Oliver