linux-kernel - [PATCH v4 07/23] KVM: arm64: Account for partitioning in kvm_pmu_get_max

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Message-ID: <20250714225917.1396543-8-coltonlewis@google.com>
Date: Mon, 14 Jul 2025 22:59:01 +0000
From: Colton Lewis <coltonlewis@...gle.com>
To: kvm@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>, Jonathan Corbet <corbet@....net>, 
	Russell King <linux@...linux.org.uk>, Catalin Marinas <catalin.marinas@....com>, 
	Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	Mingwei Zhang <mizhang@...gle.com>, Joey Gouly <joey.gouly@....com>, 
	Suzuki K Poulose <suzuki.poulose@....com>, Zenghui Yu <yuzenghui@...wei.com>, 
	Mark Rutland <mark.rutland@....com>, Shuah Khan <shuah@...nel.org>, linux-doc@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, linux-perf-users@...r.kernel.org, 
	linux-kselftest@...r.kernel.org, Colton Lewis <coltonlewis@...gle.com>
Subject: [PATCH v4 07/23] KVM: arm64: Account for partitioning in kvm_pmu_get_max_counters()

Since cntr_mask is modified when the PMU is partitioned to remove some
bits and kvm_pmu_get_max_counters() uses that bitmask to determine how
many counters are on the system, make sure that function also counts
the counters that are no longer in the bitmask.

Signed-off-by: Colton Lewis <coltonlewis@...gle.com>
---
 arch/arm64/kvm/pmu.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index 79b7ea037153..8a21ddc42f67 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -533,6 +533,7 @@ 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 +546,12 @@ 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