From 725ce66979fb6da5c1aec5b064d0871bedc23bf7 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 8 Oct 2019 15:09:55 +0100 Subject: KVM: arm64: pmu: Set the CHAINED attribute before creating the in-kernel event The current convention for KVM to request a chained event from the host PMU is to set bit[0] in attr.config1 (PERF_ATTR_CFG1_KVM_PMU_CHAINED). But as it turns out, this bit gets set *after* we create the kernel event that backs our virtual counter, meaning that we never get a 64bit counter. Moving the setting to an earlier point solves the problem. Fixes: 80f393a23be6 ("KVM: arm/arm64: Support chained PMU counters") Reviewed-by: Andrew Murray Signed-off-by: Marc Zyngier --- virt/kvm/arm/pmu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c index c30c3a74fc7f..f291d4ac3519 100644 --- a/virt/kvm/arm/pmu.c +++ b/virt/kvm/arm/pmu.c @@ -569,12 +569,12 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx) * high counter. */ attr.sample_period = (-counter) & GENMASK(63, 0); + if (kvm_pmu_counter_is_enabled(vcpu, pmc->idx + 1)) + attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED; + event = perf_event_create_kernel_counter(&attr, -1, current, kvm_pmu_perf_overflow, pmc + 1); - - if (kvm_pmu_counter_is_enabled(vcpu, pmc->idx + 1)) - attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED; } else { /* The initial sample period (overflow count) of an event. */ if (kvm_pmu_idx_is_64bit(vcpu, pmc->idx)) -- cgit v1.2.3