KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset

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@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200124142535.29386-2-eric.auger@redhat.com

diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 8731dfeced8b7ea4f2bb19e19d833330914be2d8..c3f8b059881e19089b0d9b5b7fcb1d2d5f1c8e4e 100644 (file)
--- 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)))