Re: [RFC 1/3] KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset
From: Marc Zyngier
Date: Thu Dec 05 2019 - 04:54:31 EST
On 2019-12-04 20:44, Eric Auger wrote:
The specification says PMSWINC increments PMEVCNTR<n>_EL1 by 1
if PMEVCNTR<n>_EL0 is enabled and configured to count SW_INCR.
For PMEVCNTR<n>_EL0 to be enabled, we need both PMCNTENSET to
be set for the corresponding event counter but we also need
the PMCR.E bit to be set.
Fixes: 7a0adc7064b8 ("arm64: KVM: Add access handler for PMSWINC
register")
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
virt/kvm/arm/pmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 8731dfeced8b..c3f8b059881e 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -486,6 +486,9 @@ void kvm_pmu_software_increment(struct kvm_vcpu
*vcpu, u64 val)
if (val == 0)
return;
+ if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
+ return;
+
enable = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++) {
if (!(val & BIT(i)))
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
M.
--
Jazz is not dead. It just smells funny...