Re: [PATCH 1/2] KVM: arm64: Add PMU event filtering infrastructure
From: Robin Murphy <robin.murphy@arm.com>
Date: 2020-02-14 22:01:19
Also in:
kvm, kvmarm
Hi Marc, On 2020-02-14 6:36 pm, Marc Zyngier wrote: [...]
quoted hunk ↗ jump to hunk
@@ -585,6 +585,14 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx) pmc->idx != ARMV8_PMU_CYCLE_IDX) return; + /* + * If we have a filter in place and that the event isn't allowed, do + * not install a perf event either. + */ + if (vcpu->kvm->arch.pmu_filter && + !test_bit(eventsel, vcpu->kvm->arch.pmu_filter)) + return;
If I'm reading the derivation of eventsel right, this will end up treating cycle counter events (aliased to SW_INCR) differently from CPU_CYCLES, which doesn't seem desirable. Also, if the user did try to blacklist SW_INCR for ridiculous reasons, we'd need to special-case kvm_pmu_software_increment() to make it (not) work as expected, right? Robin.
+ memset(&attr, 0, sizeof(struct perf_event_attr)); attr.type = PERF_TYPE_RAW; attr.size = sizeof(attr);
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