[PATCH 5.5 088/120] KVM: arm64: pmu: Dont increment SW_INCR if PMCR.E is unset

[Greg Kroah-Hartman]

From: Eric Auger <eric.auger@xxxxxxxxxx>

commit 3837407c1aa1101ed5e214c7d6041e7a23335c6e upstream.

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>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Andrew Murray <andrew.murray@xxxxxxx>
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200124142535.29386-2-eric.auger@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 virt/kvm/arm/pmu.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -486,6 +486,9 @@ void kvm_pmu_software_increment(struct k
 	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)))