For some reason unknown to me, KVM allows writes to PMCR_EL0.N even though the architecture specifies that field as RO. Make sure these accesses conform to additional constraints imposed when the PMU is partitioned.
Signed-off-by: Colton Lewis coltonlewis@google.com --- arch/arm64/kvm/pmu.c | 2 +- arch/arm64/kvm/sys_regs.c | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c index 30244eb7bc9b..1e5f46c1346c 100644 --- a/arch/arm64/kvm/pmu.c +++ b/arch/arm64/kvm/pmu.c @@ -883,7 +883,7 @@ 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 ad9c406734a5..e3d4ca167881 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1247,7 +1247,9 @@ 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_arm_pmu_get_max_counters(kvm) && + (!kvm_vcpu_pmu_is_partitioned(vcpu) || + new_n <= kvm_pmu_hpmn(vcpu))) kvm->arch.nr_pmu_counters = new_n;
mutex_unlock(&kvm->arch.config_lock);