linux-kernel - [PATCH v5 16/24] KVM: arm64: Account for partitioning in PMCR

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Message-ID: <20251209205121.1871534-17-coltonlewis@google.com>
Date: Tue,  9 Dec 2025 20:51:13 +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>, 
	Ganapatrao Kulkarni <gankulkarni@...amperecomputing.com>, 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 v5 16/24] KVM: arm64: Account for partitioning in PMCR_EL0 access

Make sure reads and writes to PMCR_EL0 conform to additional
constraints imposed when the PMU is partitioned.

Signed-off-by: Colton Lewis <coltonlewis@...gle.com>
---
 arch/arm64/kvm/pmu.c      | 2 +-
 arch/arm64/kvm/sys_regs.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index 1fd012f8ff4a9..48b39f096fa12 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -877,7 +877,7 @@ u64 kvm_pmu_accessible_counter_mask(struct kvm_vcpu *vcpu)
 u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu)
 {
 	u64 pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0);
-	u64 n = vcpu->kvm->arch.nr_pmu_counters;
+	u64 n = kvm_pmu_guest_num_counters(vcpu);
 
 	if (vcpu_has_nv(vcpu) && !vcpu_is_el2(vcpu))
 		n = FIELD_GET(MDCR_EL2_HPMN, __vcpu_sys_reg(vcpu, MDCR_EL2));
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 70104087b6c7b..f2ae761625a66 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1360,7 +1360,7 @@ static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	 */
 	if (!kvm_vm_has_ran_once(kvm) &&
 	    !vcpu_has_nv(vcpu)	      &&
-	    new_n <= kvm_arm_pmu_get_max_counters(kvm))
+	    new_n <= kvm_pmu_hpmn(vcpu))
 		kvm->arch.nr_pmu_counters = new_n;
 
 	mutex_unlock(&kvm->arch.config_lock);
-- 
2.52.0.239.gd5f0c6e74e-goog