Messages in this thread | | | Subject | Re: [PATCH v2] KVM: arm/arm64: Introduce kvm pmu vc pu init() to setup PMU counter idx | Date | Tue, 23 Jul 2019 09:26:04 +0100 | From | Marc Zyngier <> |
| |
On 2019-07-23 09:17, Julien Thierry wrote: > Hi Zenghui, > > On 18/07/2019 09:15, Zenghui Yu wrote: >> We use "pmc->idx" and the "chained" bitmap to determine if the pmc >> is >> chained, in kvm_pmu_pmc_is_chained(). But idx might be >> uninitialized >> (and random) when we doing this decision, through a >> KVM_ARM_VCPU_INIT >> ioctl -> kvm_pmu_vcpu_reset(). And the test_bit() against this >> random >> idx will potentially hit a KASAN BUG [1]. >> >> In general, idx is the static property of a PMU counter that is not >> expected to be modified across resets, as suggested by Julien. It >> looks more reasonable if we can setup the PMU counter idx for a vcpu >> in its creation time. Introduce a new function - kvm_pmu_vcpu_init() >> for this basic setup. Oh, and the KASAN BUG will get fixed this way. >> >> [1] https://www.spinics.net/lists/kvm-arm/msg36700.html >> >> Fixes: 80f393a23be6 ("KVM: arm/arm64: Support chained PMU counters") >> Suggested-by: Andrew Murray <andrew.murray@arm.com> >> Suggested-by: Julien Thierry <julien.thierry@arm.com> >> Cc: Marc Zyngier <maz@kernel.org> >> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> >> --- >> >> Changes since v1: >> - Introduce kvm_pmu_vcpu_init() in vcpu's creation time, move the >> assignment of pmc->idx into it. >> - Thus change the subject. The old one is "KVM: arm/arm64: Assign >> pmc->idx before kvm_pmu_stop_counter()". >> >> Julien, I haven't collected your Acked-by into this version. If >> you're >> still happy with the change, please Ack again. Thanks! >> > > Thanks for making the change. This looks good to me: > > Acked-by: Julien Thierry <julien.thierry@arm.com>
Applied, thanks both.
M. -- Jazz is not dead. It just smells funny...
| |