Commit 725ce669 authored by Marc Zyngier's avatar Marc Zyngier

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: 80f393a2 ("KVM: arm/arm64: Support chained PMU counters")
Reviewed-by: default avatarAndrew Murray <andrew.murray@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 6f163714
......@@ -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))
......
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