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authorMarc Zyngier <maz@kernel.org>2019-10-08 17:09:55 +0300
committerMarc Zyngier <maz@kernel.org>2019-10-20 12:47:07 +0300
commit725ce66979fb6da5c1aec5b064d0871bedc23bf7 (patch)
tree160b07ae49fd048279fc3a8684fafc17de14bbd4
parent6f16371453476fd094760ea3d6f00144e9ae3057 (diff)
downloadlinux-725ce66979fb6da5c1aec5b064d0871bedc23bf7.tar.xz
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 <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
-rw-r--r--virt/kvm/arm/pmu.c6
1 files changed, 3 insertions, 3 deletions
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))