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KVM: arm64: Check ID_AA64DFR0_EL1.PMUVer in pmu_visibility()

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pmu_visibility() currently checks kvm_vcpu_has_pmu(), which only tests
whether the vCPU was initialized with KVM_ARM_VCPU_PMU_V3. If userspace
initializes a vCPU with KVM_ARM_VCPU_PMU_V3 and subsequently hides
FEAT_PMUv3 via ID_AA64DFR0_EL1.PMUVer, KVM continues to expose the PMU
system registers instead of emulating guest accesses as UNDEF.

Check ID_AA64DFR0_EL1.PMUVer directly via kvm_has_feat() in
pmu_visibility() so that PMU system registers are marked REG_HIDDEN
whenever FEAT_PMUv3 is not advertised in the ID registers.

Suggested-by: Oliver Upton <oupton@kernel.org>
Assisted-by: LLM
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Link: https://patch.msgid.link/20260930211834.2773546-3-coltonlewis@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Colton Lewis 2026-09-30 21:18:34 +00:00 committed by Marc Zyngier
parent aa41a7c3be
commit 517cdec3d4
1 changed files with 1 additions and 1 deletions
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2
arch/arm64/kvm/sys_regs.c
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@ -1028,7 +1028,7 @@ static unsigned int hidden_visibility(const struct kvm_vcpu *vcpu,
static unsigned int pmu_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *r)
{
if (kvm_vcpu_has_pmu(vcpu))
if (kvm_has_feat(vcpu->kvm, ID_AA64DFR0_EL1, PMUVer, IMP))
return 0;
return REG_HIDDEN;