From: Marc Zyngier <maz@kernel.org>
To: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Subject: Re: [PATCH 5/8] KVM: arm64: Remove PMU RAZ/WI handling
Date: Fri, 27 Nov 2020 08:50:02 +0000 [thread overview]
Message-ID: <7ae93087a57bd5f6a348f0d4d6a7db2d@kernel.org> (raw)
In-Reply-To: <cb7ebedb-5525-8493-007f-72c81b16189b@arm.com>
On 2020-11-26 15:06, Alexandru Elisei wrote:
> Hi Marc,
>
> This patch looks correct to me, I checked in the Arm ARM DDI 0487F.b
> and indeed
> all accesses to the PMU registers are UNDEFINED if the PMU is not
> present.
>
> I checked all the accessors and now all the PMU registers that KVM
> emulates will
> inject an undefined exception if the VCPU feature isn't set. There's
> one register
> that we don't emulate, PMMIR_EL1, I suppose that's because it's part of
> PMU
> ARMv8.4 and KVM advertises ARMv8.1; if the guest tries to access it, it
> will get
> an undefined exception and KVM will print a warning in
> emulate_sys_reg().
Funny that. I wrote a patch for that a long while ago, and obviously
never did anything with it [1]... Actually, the whole series was
silently
dropped. I guess I had other things to think about at the time!
Let me pick that up again.
> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Thanks!
M.
[1]
https://lore.kernel.org/kvmarm/20200216185324.32596-6-maz@kernel.org/
--
Jazz is not dead. It just smells funny...
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next prev parent reply other threads:[~2020-11-27 8:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 18:25 [PATCH 0/8] KVM: arm64: Disabled PMU handling Marc Zyngier
2020-11-13 18:25 ` [PATCH 1/8] KVM: arm64: Add kvm_vcpu_has_pmu() helper Marc Zyngier
2020-11-13 18:25 ` [PATCH 2/8] KVM: arm64: Set ID_AA64DFR0_EL1.PMUVer to 0 when no PMU support Marc Zyngier
2020-11-13 18:25 ` [PATCH 3/8] KVM: arm64: Refuse illegal KVM_ARM_VCPU_PMU_V3 at reset time Marc Zyngier
2020-11-26 14:59 ` Alexandru Elisei
2020-11-26 15:25 ` Marc Zyngier
2020-11-26 15:49 ` Alexandru Elisei
2020-11-13 18:25 ` [PATCH 4/8] KVM: arm64: Inject UNDEF on PMU access when no PMU configured Marc Zyngier
2020-11-13 18:25 ` [PATCH 5/8] KVM: arm64: Remove PMU RAZ/WI handling Marc Zyngier
2020-11-26 15:06 ` Alexandru Elisei
2020-11-27 8:50 ` Marc Zyngier [this message]
2020-11-13 18:26 ` [PATCH 6/8] KVM: arm64: Remove dead PMU sysreg decoding code Marc Zyngier
2020-11-26 15:18 ` Alexandru Elisei
2020-11-26 15:34 ` Marc Zyngier
2020-11-26 15:54 ` Alexandru Elisei
2020-11-26 15:57 ` Marc Zyngier
2020-11-13 18:26 ` [PATCH 7/8] KVM: arm64: Gate kvm_pmu_update_state() on the PMU feature Marc Zyngier
2020-11-13 18:26 ` [PATCH 8/8] KVM: arm64: Get rid of the PMU ready state Marc Zyngier
2020-11-24 17:28 ` [PATCH 0/8] KVM: arm64: Disabled PMU handling Alexandru Elisei
2020-11-25 8:39 ` Marc Zyngier
2020-11-26 16:34 ` Alexandru Elisei
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