[PATCH v2 1/2] KVM: arm64: Fix enforcement of upper bound on MDCR_EL2.HPMN

Ben Horgan ben.horgan at arm.com
Wed Jul 9 02:38:07 PDT 2025


Previously, u64_replace_bits() was used to no effect as the return value
was ignored. Convert to u64p_replace_bits() so the value is updated in
place.

Reviewed-by: Zenghui Yu <yuzenghui at huawei.com>
Signed-off-by: Ben Horgan <ben.horgan at arm.com>
Fixes: efff9dd2fee7 ("KVM: arm64: Handle out-of-bound write to MDCR_EL2.HPMN")
Cc: Marc Zyngier <maz at kernel.org>
Cc: stable at vger.kernel.org
---
 arch/arm64/kvm/sys_regs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 76c2f0da821f..c20bd6f21e60 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2624,7 +2624,7 @@ static bool access_mdcr(struct kvm_vcpu *vcpu,
 	 */
 	if (hpmn > vcpu->kvm->arch.nr_pmu_counters) {
 		hpmn = vcpu->kvm->arch.nr_pmu_counters;
-		u64_replace_bits(val, hpmn, MDCR_EL2_HPMN);
+		u64p_replace_bits(&val, hpmn, MDCR_EL2_HPMN);
 	}
 
 	__vcpu_assign_sys_reg(vcpu, MDCR_EL2, val);
-- 
2.43.0




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