From: Marc Zyngier <maz@kernel.org>
To: James Morse <james.morse@arm.com>
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: Wed, 19 Feb 2020 09:46:11 +0000 [thread overview]
Message-ID: <c0a848e3ababff4ee9ecaa4b246d5875@kernel.org> (raw)
In-Reply-To: <eb0294ef-5ad2-9940-2d59-b92220948ffc@arm.com>
On 2020-02-18 17:43, James Morse wrote:
> 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.
That's definitely not what I intended! Let me fix that one.
> 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).
Indeed, yet another oversight. I'll fix that too.
> Regardless:
> Reviewed-by: James Morse <james.morse@arm.com>
You're way too kind! ;-)
M.
--
Jazz is not dead. It just smells funny...
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next prev parent reply other threads:[~2020-02-19 9:46 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
2020-02-19 9:46 ` Marc Zyngier [this message]
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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