From: Shannon Zhao <shannon.zhao@linaro.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Christoffer Dall <christoffer.dall@linaro.org>,
Shannon Zhao <zhaoshenglong@huawei.com>,
kvm-devel <kvm@vger.kernel.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Will Deacon <will.deacon@arm.com>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
arm-mail-list <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v11 06/21] KVM: ARM64: Add access handler for PMCEID0 and PMCEID1 register
Date: Sat, 20 Feb 2016 21:34:52 +0800 [thread overview]
Message-ID: <56C86B7C.9020906@linaro.org> (raw)
In-Reply-To: <CAFEAcA8=iRkAMLStMzu0wAPWfXZ9vYu_YzEKrEyVrWHP4=VS2w@mail.gmail.com>
On 2016/2/20 21:30, Peter Maydell wrote:
> On 20 February 2016 at 13:15, Shannon Zhao<shannon.zhao@linaro.org> wrote:
>> >
>> >
>> >On 2016/2/8 20:09, Christoffer Dall wrote:
>>> >>Isn't it really a BUG_ON(p->is_write) ?
>>> >>
>>> >>Presumably a guest write to these registers will raise an undefined
>>> >>exception in EL0/1 and we don't get here by any other path than the trap
>>> >>handler, do we?
>> >
>> >Yeah, for EL1, it shouldn't get here. But for EL0, to support the function
>> >of PMUSERENR, we firstly trap the access to EL2, then according to the real
>> >value of PMUSERENR to decide whether inject an UND to EL1.
> I thought the PMUSERENR check took priority over trap-to-EL2 checks
> in the architecture; so if this is an EL0 access and you get to EL2
> at all then you know that PMUSERENR is set to permit EL0 reads.
>
> Similarly, UNDEF because of write-to-always-RO register has
> priority over trap-to-EL2, so I think Christoffer is right
> and you should never be able to get here for a write.
> (This should be easy to write a test program for if you're unsure.)
Thanks, I'll check this.
--
Shannon
next prev parent reply other threads:[~2016-02-20 13:34 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-05 7:13 [PATCH v11 00/21] KVM: ARM64: Add guest PMU support Shannon Zhao
2016-02-05 7:13 ` [PATCH v11 01/21] ARM64: Move PMU register related defines to asm/pmu.h Shannon Zhao
2016-02-05 7:13 ` [PATCH v11 02/21] KVM: ARM64: Define PMU data structure for each vcpu Shannon Zhao
2016-02-05 7:13 ` [PATCH v11 03/21] KVM: ARM64: Add offset defines for PMU registers Shannon Zhao
2016-02-05 7:13 ` [PATCH v11 04/21] KVM: ARM64: Add access handler for PMCR register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 05/21] KVM: ARM64: Add access handler for PMSELR register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 06/21] KVM: ARM64: Add access handler for PMCEID0 and PMCEID1 register Shannon Zhao
2016-02-08 12:09 ` Christoffer Dall
2016-02-20 13:15 ` Shannon Zhao
2016-02-20 13:30 ` Peter Maydell
2016-02-20 13:34 ` Shannon Zhao [this message]
2016-02-05 7:14 ` [PATCH v11 07/21] KVM: ARM64: PMU: Add perf event map and introduce perf event creating function Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 08/21] KVM: ARM64: Add access handler for event type register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 09/21] KVM: ARM64: Add access handler for event counter register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 10/21] KVM: ARM64: Add access handler for PMCNTENSET and PMCNTENCLR register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 11/21] KVM: ARM64: Add access handler for PMINTENSET and PMINTENCLR register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 12/21] KVM: ARM64: Add access handler for PMOVSSET and PMOVSCLR register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 13/21] KVM: ARM64: Add access handler for PMSWINC register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 14/21] KVM: ARM64: Add helper to handle PMCR register bits Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 15/21] KVM: ARM64: Add access handler for PMUSERENR register Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 16/21] KVM: ARM64: Add PMU overflow interrupt routing Shannon Zhao
2016-02-08 12:26 ` Christoffer Dall
2016-02-20 13:32 ` Shannon Zhao
2016-02-22 7:35 ` Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 17/21] KVM: ARM64: Reset PMU state when resetting vcpu Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 18/21] KVM: ARM64: Free perf event of PMU when destroying vcpu Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 19/21] KVM: ARM64: Add a new feature bit for PMUv3 Shannon Zhao
2016-02-08 12:29 ` Christoffer Dall
2016-02-22 7:43 ` Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 20/21] KVM: ARM: Introduce per-vcpu kvm device controls Shannon Zhao
2016-02-08 12:40 ` Christoffer Dall
2016-02-20 13:38 ` Shannon Zhao
2016-02-05 7:14 ` [PATCH v11 21/21] KVM: ARM64: Add a new vcpu device control group for PMUv3 Shannon Zhao
2016-02-08 12:52 ` Christoffer Dall
2016-02-22 7:45 ` Shannon Zhao
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