On Tue, Dec 09, 2025 at 08:51:13PM +0000, Colton Lewis wrote: > Make sure reads and writes to PMCR_EL0 conform to additional > constraints imposed when the PMU is partitioned. > > Signed-off-by: Colton Lewis <[email protected]> > --- > 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);
Why can't the value of vcpu->kvm->arch.nr_pmu_counters be trusted? > @@ -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; This is the legacy UAPI for setting the number of PMU counters by writing to PMCR_EL0.N. The 'partitioned' implementation should take a dependency on the SET_NR_COUNTERS attribute and reject attempts to change the value of PMCR_EL0.N. Just like nested. Thanks, Oliver
