KVM: arm64: pmu: Only handle supported event counters

Let the code never use unsupported event counters. Change
kvm_pmu_handle_pmcr() to only reset supported counters and
kvm_pmu_vcpu_reset() to only stop supported counters.

Other actions are filtered on the supported counters in
kvm/sysregs.c
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200124142535.29386-5-eric.auger@redhat.com

virt/kvm/arm/pmu.c

@@ -247,10 +247,11 @@ void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu)
  */
 void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
 {
-	int i;
+	unsigned long mask = kvm_pmu_valid_counter_mask(vcpu);
 	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	int i;
 
-	for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
+	for_each_set_bit(i, &mask, 32)
 		kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
 
 	bitmap_zero(vcpu->arch.pmu.chained, ARMV8_PMU_MAX_COUNTER_PAIRS);
@@ -527,10 +528,9 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
  */
 void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
 {
-	u64 mask;
+	unsigned long mask = kvm_pmu_valid_counter_mask(vcpu);
 	int i;
 
-	mask = kvm_pmu_valid_counter_mask(vcpu);
 	if (val & ARMV8_PMU_PMCR_E) {
 		kvm_pmu_enable_counter_mask(vcpu,
 		       __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask);
@@ -542,7 +542,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
 		kvm_pmu_set_counter_value(vcpu, ARMV8_PMU_CYCLE_IDX, 0);
 
 	if (val & ARMV8_PMU_PMCR_P) {
-		for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++)
+		for_each_set_bit(i, &mask, 32)
 			kvm_pmu_set_counter_value(vcpu, i, 0);
 	}
 }