On Mon, 20 Jul 2026 at 06:44, Akihiko Odaki <[email protected]> wrote: > > Add a regression test that runs one vCPU and then tries to change the > VM-scoped PMU counter count through an idle sibling. Verify that > SET_NR_COUNTERS fails with EBUSY once any vCPU has run. > > Assisted-by: Codex:gpt-5.6-sol > Signed-off-by: Akihiko Odaki <[email protected]>
Reviewed-by: Fuad Tabba <[email protected]> Cheers, /fuad > --- > .../selftests/kvm/arm64/vpmu_counter_access.c | 38 > ++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c > b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c > index 22223395969e..3b5bb421f401 100644 > --- a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c > +++ b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c > @@ -461,6 +461,11 @@ static void run_vcpu(struct kvm_vcpu *vcpu, u64 pmcr_n) > } > } > > +static void guest_code_done(void) > +{ > + GUEST_DONE(); > +} > + > static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters, > bool expect_fail) > { > struct kvm_vcpu *vcpu; > @@ -622,6 +627,37 @@ static bool kvm_supports_nr_counters_attr(void) > return supported; > } > > +static void test_set_nr_counters_after_vcpu_run(void) > +{ > + struct kvm_vcpu *running_vcpu, *stopped_vcpu; > + unsigned int nr_counters = 0; > + struct kvm_vcpu_init init; > + struct kvm_vm *vm; > + int ret; > + u64 irq = 23; > + > + vm = vm_create(2); > + vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init); > + init.features[0] |= BIT(KVM_ARM_VCPU_PMU_V3); > + running_vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code_done); > + stopped_vcpu = aarch64_vcpu_add(vm, 1, &init, guest_code_done); > + kvm_arch_vm_finalize_vcpus(vm); > + > + vcpu_device_attr_set(running_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL, > + KVM_ARM_VCPU_PMU_V3_IRQ, &irq); > + vcpu_device_attr_set(running_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL, > + KVM_ARM_VCPU_PMU_V3_INIT, NULL); > + vcpu_run(running_vcpu); > + > + ret = __vcpu_device_attr_set(stopped_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL, > + KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTERS, > + &nr_counters); > + TEST_ASSERT(ret == -1 && errno == EBUSY, > + KVM_IOCTL_ERROR(KVM_SET_DEVICE_ATTR, ret)); > + > + kvm_vm_free(vm); > +} > + > int main(void) > { > u64 i, pmcr_n; > @@ -630,6 +666,8 @@ int main(void) > TEST_REQUIRE(kvm_supports_vgic_v3()); > TEST_REQUIRE(kvm_supports_nr_counters_attr()); > > + test_set_nr_counters_after_vcpu_run(); > + > pmcr_n = get_pmcr_n_limit(); > for (i = 0; i <= pmcr_n; i++) { > run_access_test(i); > > -- > 2.55.0 > >
