Re: [PATCH v5 2/3] KVM: selftests: aarch64: Introduce pmu_event_filter_test

From: Eric Auger
Date: Tue Mar 19 2024 - 16:59:03 EST


Hi Shaoqin,

On 2/29/24 07:56, Shaoqin Huang wrote:
> Introduce pmu_event_filter_test for arm64 platforms. The test configures
> PMUv3 for a vCPU, and sets different pmu event filters for the vCPU, and
> check if the guest can see those events which user allow and can't use
> those events which use deny.
>
> This test refactor the create_vpmu_vm() and make it a wrapper for
> __create_vpmu_vm(), which allows some extra init code before
> KVM_ARM_VCPU_PMU_V3_INIT.
>
> And this test use the KVM_ARM_VCPU_PMU_V3_FILTER attribute to set the
> pmu event filter in KVM. And choose to filter two common event
> branches_retired and instructions_retired, and let the guest to check if
> it see the right pmceid register.
>
> Signed-off-by: Shaoqin Huang <shahuang@xxxxxxxxxx>
> ---
> tools/testing/selftests/kvm/Makefile | 1 +
> .../kvm/aarch64/pmu_event_filter_test.c | 287 ++++++++++++++++++
> 2 files changed, 288 insertions(+)
> create mode 100644 tools/testing/selftests/kvm/aarch64/pmu_event_filter_test.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 492e937fab00..732ca5f8bfc0 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -147,6 +147,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/arch_timer
> TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
> TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
> TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
> +TEST_GEN_PROGS_aarch64 += aarch64/pmu_event_filter_test
> TEST_GEN_PROGS_aarch64 += aarch64/psci_test
> TEST_GEN_PROGS_aarch64 += aarch64/set_id_regs
> TEST_GEN_PROGS_aarch64 += aarch64/smccc_filter
> diff --git a/tools/testing/selftests/kvm/aarch64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/aarch64/pmu_event_filter_test.c
> new file mode 100644
> index 000000000000..2dd8ea418f47
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/aarch64/pmu_event_filter_test.c
> @@ -0,0 +1,287 @@
> +
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * pmu_event_filter_test - Test user limit pmu event for guest.
> + *
> + * Copyright (c) 2023 Red Hat, Inc.
> + *
> + * This test checks if the guest only see the limited pmu event that userspace
> + * sets, if the guest can use those events which user allow, and if the guest
> + * can't use those events which user deny.
> + * This test runs only when KVM_CAP_ARM_PMU_V3, KVM_ARM_VCPU_PMU_V3_FILTER
> + * is supported on the host.
> + */
> +#include <kvm_util.h>
> +#include <processor.h>
> +#include <vgic.h>
> +#include <vpmu.h>
> +#include <test_util.h>
> +#include <perf/arm_pmuv3.h>
> +
> +struct pmu_common_event_ids {
> + uint64_t pmceid0;
> + uint64_t pmceid1;
> +} max_pmce, expected_pmce;
> +
> +struct vpmu_vm {
> + struct kvm_vm *vm;
> + struct kvm_vcpu *vcpu;
> + int gic_fd;
> +};
> +
> +static struct vpmu_vm vpmu_vm;
> +
> +#define FILTER_NR 10
> +
> +struct test_desc {
> + const char *name;
> + struct kvm_pmu_event_filter filter[FILTER_NR];
> +};
> +
> +#define __DEFINE_FILTER(base, num, act) \
> + ((struct kvm_pmu_event_filter) { \
> + .base_event = base, \
> + .nevents = num, \
> + .action = act, \
> + })
> +
> +#define DEFINE_FILTER(base, act) __DEFINE_FILTER(base, 1, act)
> +
> +static void guest_code(void)
> +{
> + uint64_t pmceid0 = read_sysreg(pmceid0_el0);
> + uint64_t pmceid1 = read_sysreg(pmceid1_el0);
> +
> + GUEST_ASSERT_EQ(expected_pmce.pmceid0, pmceid0);
> + GUEST_ASSERT_EQ(expected_pmce.pmceid1, pmceid1);
> +
> + GUEST_DONE();
> +}
> +
> +static void guest_get_pmceid(void)
> +{
> + max_pmce.pmceid0 = read_sysreg(pmceid0_el0);
> + max_pmce.pmceid1 = read_sysreg(pmceid1_el0);
> +
> + GUEST_DONE();
> +}
> +
> +static void run_vcpu(struct kvm_vcpu *vcpu)
> +{
> + struct ucall uc;
> +
> + while (1) {
> + vcpu_run(vcpu);
> + switch (get_ucall(vcpu, &uc)) {
> + case UCALL_DONE:
> + return;
> + case UCALL_ABORT:
> + REPORT_GUEST_ASSERT(uc);
> + break;
> + default:
> + TEST_FAIL("Unknown ucall %lu", uc.cmd);
> + }
> + }
> +}
> +
> +static void set_pmce(struct pmu_common_event_ids *pmce, int action, int event)
> +{
> + int base = 0;
> + uint64_t *pmceid = NULL;
> +
> + if (event >= 0x4000) {
> + event -= 0x4000;
> + base = 32;
> + }
> +
> + if (event >= 0 && event <= 0x1F) {
> + pmceid = &pmce->pmceid0;
> + } else if (event >= 0x20 && event <= 0x3F) {
> + event -= 0x20;
> + pmceid = &pmce->pmceid1;
> + } else {
> + return;
> + }
> +
> + event += base;
> + if (action == KVM_PMU_EVENT_ALLOW)
> + *pmceid |= BIT(event);
> + else
> + *pmceid &= ~BIT(event);
> +}
> +
> +static void prepare_expected_pmce(struct kvm_pmu_event_filter *filter)
> +{
> + struct pmu_common_event_ids pmce_mask = { ~0, ~0 };
> + bool first_filter = true;
> +
> + while (filter && filter->nevents != 0) {
isn't filter->nevents != 0 sufficient?
> + if (first_filter) {
> + if (filter->action == KVM_PMU_EVENT_ALLOW)
> + memset(&pmce_mask, 0, sizeof(pmce_mask));
> + first_filter = false;
> + }
> +
> + set_pmce(&pmce_mask, filter->action, filter->base_event);
> + filter++;
> + }
> +
> + expected_pmce.pmceid0 = max_pmce.pmceid0 & pmce_mask.pmceid0;
> + expected_pmce.pmceid1 = max_pmce.pmceid1 & pmce_mask.pmceid1;
> +}
> +
> +static void pmu_event_filter_init(struct kvm_pmu_event_filter *filter)
> +{
> + while (filter && filter->nevents != 0) {
> + kvm_device_attr_set(vpmu_vm.vcpu->fd,
> + KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FILTER,
> + filter);
> + filter++;
> + }
> +}
> +
> +#define GICD_BASE_GPA 0x8000000ULL
> +#define GICR_BASE_GPA 0x80A0000ULL
I think Oliver suggested to move those defines to GIC headers?
> +
> +/* Create a VM that has one vCPU with PMUv3 configured. */
> +static void create_vpmu_vm_with_filter(void *guest_code,
> + struct kvm_pmu_event_filter *filter)
> +{
> + uint64_t irq = 23;
> +
> + /* The test creates the vpmu_vm multiple times. Ensure a clean state */
> + memset(&vpmu_vm, 0, sizeof(vpmu_vm));
> +
> + vpmu_vm.vm = vm_create(1);
> + vpmu_vm.vcpu = vm_vcpu_add_with_vpmu(vpmu_vm.vm, 0, guest_code);
> + vpmu_vm.gic_fd = vgic_v3_setup(vpmu_vm.vm, 1, 64,
> + GICD_BASE_GPA, GICR_BASE_GPA);
> + __TEST_REQUIRE(vpmu_vm.gic_fd >= 0,
> + "Failed to create vgic-v3, skipping");
> +
> + pmu_event_filter_init(filter);
> +
> + /* Initialize vPMU */
> + vpmu_set_irq(vpmu_vm.vcpu, irq);
> + vpmu_init(vpmu_vm.vcpu);
> +}
> +
> +static void create_vpmu_vm(void *guest_code)
> +{
> + create_vpmu_vm_with_filter(guest_code, NULL);
> +}
> +
> +static void destroy_vpmu_vm(void)
> +{
> + close(vpmu_vm.gic_fd);
> + kvm_vm_free(vpmu_vm.vm);
> +}
> +
> +static void run_test(struct test_desc *t)
> +{
> + pr_info("Test: %s\n", t->name);
> +
> + create_vpmu_vm_with_filter(guest_code, t->filter);
> + prepare_expected_pmce(t->filter);
> + sync_global_to_guest(vpmu_vm.vm, expected_pmce);
> +
> + run_vcpu(vpmu_vm.vcpu);
> +
> + destroy_vpmu_vm();
> +}
> +
> +static struct test_desc tests[] = {
> + {
> + .name = "without_filter",
> + .filter = {
> + { 0 }
> + },
> + },
> + {
> + .name = "member_allow_filter",
> + .filter = {
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_SW_INCR, 0),
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_INST_RETIRED, 0),
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_BR_RETIRED, 0),
> + { 0 },
> + },
> + },
> + {
> + .name = "member_deny_filter",
> + .filter = {
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_SW_INCR, 1),
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_INST_RETIRED, 1),
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_BR_RETIRED, 1),
> + { 0 },
> + },
> + },
> + {
> + .name = "not_member_deny_filter",
> + .filter = {
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_SW_INCR, 1),
> + { 0 },
> + },
> + },
> + {
> + .name = "not_member_allow_filter",
> + .filter = {
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_SW_INCR, 0),
> + { 0 },
> + },
> + },
> + {
> + .name = "deny_chain_filter",
> + .filter = {
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_CHAIN, 1),
> + { 0 },
> + },
> + },
> + {
> + .name = "deny_cpu_cycles_filter",
> + .filter = {
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_CPU_CYCLES, 1),
> + { 0 },
> + },
> + },
> + {
> + .name = "cancle_filter",
cancel
> + .filter = {
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_CPU_CYCLES, 0),
> + DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_CPU_CYCLES, 1),
> + },
> + },
> + { 0 }
> +};
> +
> +static void run_tests(void)
> +{
> + struct test_desc *t;
> +
> + for (t = &tests[0]; t->name; t++)
> + run_test(t);
> +}
> +
> +static bool kvm_pmu_support_events(void)
> +{
> + create_vpmu_vm(guest_get_pmceid);
> +
> + memset(&max_pmce, 0, sizeof(max_pmce));
> + sync_global_to_guest(vpmu_vm.vm, max_pmce);
> + run_vcpu(vpmu_vm.vcpu);
> + sync_global_from_guest(vpmu_vm.vm, max_pmce);
> + destroy_vpmu_vm();
> +
> + return max_pmce.pmceid0 &
> + (ARMV8_PMUV3_PERFCTR_BR_RETIRED |
> + ARMV8_PMUV3_PERFCTR_INST_RETIRED |
> + ARMV8_PMUV3_PERFCTR_CHAIN);
I understood Oliver suggested to use sysfs to know if te events were
supported and to use KVM_ARM_VCPU_PMU_V3_SET_PMU. On my end I am fine
with your method though.

Thanks

Eric
> +}
> +
> +int main(void)
> +{
> + TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
> + TEST_REQUIRE(kvm_pmu_support_events());
> +
> + run_tests();
> +}