[PATCH v3 09/22] KVM: arm64: Correct kvm_arm_pmu_get_max_counters()

Colton Lewis
2025-06-26T20:06:02Z

Since cntr_mask is modified when the PMU is partitioned to remove some
bits, make sure the missing counters are added back to get the right
total.

Signed-off-by: Colton Lewis <coltonlewis@google.com>
---
arch/arm64/kvm/pmu.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index 79b7ea037153..67216451b8ce 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -533,6 +533,8 @@ static bool pmu_irq_is_valid(struct kvm *kvm, int irq)
u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
{
struct arm_pmu *arm_pmu = kvm->arch.arm_pmu;
+ u8 counters;
+

/*
* PMUv3 requires that all event counters are capable of counting any
@@ -545,7 +547,12 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
* The arm_pmu->cntr_mask considers the fixed counter(s) as well.
* Ignore those and return only the general-purpose counters.
*/
- return bitmap_weight(arm_pmu->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS);
+ counters = bitmap_weight(arm_pmu->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS);
+
+ if (kvm_pmu_is_partitioned(arm_pmu))
+ counters += arm_pmu->hpmn_max;
+
+ return counters;
}

static void kvm_arm_set_nr_counters(struct kvm *kvm, unsigned int nr)
--
2.50.0.727.gbf7dc18ff4-goog