From: James Morse <james.morse@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH 3/5] kvm: arm64: Limit PMU version to ARMv8.1
Date: Tue, 18 Feb 2020 17:43:51 +0000 [thread overview]
Message-ID: <eb0294ef-5ad2-9940-2d59-b92220948ffc@arm.com> (raw)
In-Reply-To: <20200216185324.32596-4-maz@kernel.org>
Hi Marc,
On 16/02/2020 18:53, Marc Zyngier wrote:
> Our PMU code is only implementing the ARMv8.1 features, so let's
> stick to this when reporting the feature set to the guest.
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 682fedd7700f..06b2d0dc6c73 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1093,6 +1093,11 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
> FEATURE(ID_AA64ISAR1_GPA) |
> FEATURE(ID_AA64ISAR1_GPI));
> break;
> + case SYS_ID_AA64DFR0_EL1:
> + /* Limit PMU to ARMv8.1 */
Not just limit, but upgrade too! (force?)
This looks safe because ARMV8_PMU_EVTYPE_EVENT always includes the extra bits this added,
and the register is always trapped.
The PMU version is also readable via ID_DFR0_EL1.PerfMon, should that be sanitised to be
the same?
(I don't think we've hidden an aarch64 feature that also existed in aarch32 before).
Regardless:
Reviewed-by: James Morse <james.morse@arm.com>
Thanks,
James
> + val &= ~FEATURE(ID_AA64DFR0_PMUVER);
> + val |= FIELD_PREP(FEATURE(ID_AA64DFR0_PMUVER), 4);
> + break;
> }
>
> return val;
>
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next prev parent reply other threads:[~2020-02-18 17:43 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-16 18:53 [PATCH 0/5] Random debug/PMU fixes for 5.6 Marc Zyngier
2020-02-16 18:53 ` [PATCH 1/5] KVM: arm64: Fix missing RES1 in emulation of DBGBIDR Marc Zyngier
2020-02-18 17:43 ` James Morse
2020-02-18 18:01 ` Robin Murphy
2020-02-18 18:15 ` James Morse
2020-02-16 18:53 ` [PATCH 2/5] KVM: arm64: Refactor filtering of ID registers Marc Zyngier
2020-02-20 14:12 ` Andre Przywara
2020-02-16 18:53 ` [PATCH 3/5] kvm: arm64: Limit PMU version to ARMv8.1 Marc Zyngier
2020-02-18 17:43 ` James Morse [this message]
2020-02-19 9:46 ` Marc Zyngier
2020-02-19 10:18 ` James Morse
2020-02-19 11:14 ` Marc Zyngier
2020-02-16 18:53 ` [PATCH 4/5] KVM: arm64: Limit the debug architecture to ARMv8.0 Marc Zyngier
2020-02-18 17:45 ` James Morse
2020-02-16 18:53 ` [PATCH 5/5] KVM: arm64: Upgrade PMU support to ARMv8.4 Marc Zyngier
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