commit 54bbee190d42166209185d89070c58a343bf514b upstream.
DDI0487K.a D13.3.1 describes the PMU overflow condition, which evaluates
to true if any counter's global enable (PMCR_EL0.E), overflow flag
(PMOVSSET_EL0[n]), and interrupt enable (PMINTENSET_EL1[n]) are all 1.
Of note, this does not require a counter to be enabled
(i.e. PMCNTENSET_EL0[n] = 1) to generate an overflow.
Align kvm_pmu_overflow_status() with the reality of the architecture
and stop using PMCNTENSET_EL0 as part of the overflow condition. The
bug was discovered while running an SBSA PMU test [*], which only sets
PMCR.E, PMOVSSET<0>, PMINTENSET<0>, and expects an overflow interrupt.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 76d883c4e640 ("arm64: KVM: Add access handler for PMOVSSET and PMOVSCLR register")
Link: https://github.com/ARM-software/sbsa-acs/blob/master/test_pool/pmu/operating_system/test_pmu001.c
Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
[ oliver: massaged changelog ]
Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241120005230.2335682-2-oliver.upton@xxxxxxxxx
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
---
virt/kvm/arm/pmu.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 6d52fd50c1ff..b92b1d406374 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -195,7 +195,6 @@ static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
if ((__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E)) {
reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
- reg &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
reg &= __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
reg &= kvm_pmu_valid_counter_mask(vcpu);
}
--
2.47.0.338.g60cca15819-goog
