Re: [PATCH v7 2/3] KVM: selftests: aarch64: Introduce pmu_event_filter_test

Hi Eric,

On 5/7/24 16:45, Eric Auger wrote:

Hi Shaoqin,

On 4/9/24 05:03, 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@redhat.com

tools/testing/selftests/kvm/Makefile | 1 + .../kvm/aarch64/pmu_event_filter_test.c | 298 ++++++++++++++++++ 2 files changed, 299 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 741c7dc16afc..9745be534df3 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -151,6 +151,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/aarch32_id_regs 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..972384e81067 --- /dev/null +++ b/tools/testing/selftests/kvm/aarch64/pmu_event_filter_test.c @@ -0,0 +1,298 @@

+// 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;
• int i;
• while (filter && filter->nevents != 0) {

• if (first_filter) {
  

• 	if (filter->action == KVM_PMU_EVENT_ALLOW)
  

• 		memset(&pmce_mask, 0, sizeof(pmce_mask));
  

• 	first_filter = false;
  

• }
  

• for (i = 0; i < filter->nevents; i++)
  

• 	set_pmce(&pmce_mask, filter->action,
  

• 		 filter->base_event + i);
  

• 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

in v4 Oliver suggested "Shouldn't a standardized layout of the GIC frames go with the rest of the GIC stuff?"

Oliver replied there is another commits did that, so I will remove them when I update it.

...

+/* 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_FILTERShouldn't a standardized layout of the GIC frames go with the rest of
  

the GIC stuff?(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 = "cancel_filter",
  

• .filter = {
  

• 	DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_CPU_CYCLES, 0),
  

• 	DEFINE_FILTER(ARMV8_PMUV3_PERFCTR_CPU_CYCLES, 1),
  

• },
  

• },
• {

• .name = "multiple_filter",
  

• .filter = {
  

• 	__DEFINE_FILTER(0x0, 0x10, 0),
  

• 	__DEFINE_FILTER(0x6, 0x3, 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);
  

those are not bit masks but bit shifts. Also don't you want to test that all of them are supported?

Thanks for catching this bug. Yes I want to test all of them are supported but wrongly checking the bit masks. I will fix them.

BR_RETIRED is 0x21 so doesn't it belong to pmceid1?

Yes, it should belong to pmceid1. But my wrong checking didn't help me find it. Thanks a lot.

in v4 Oliver suggested to use sysfs instead of spawning a scratch VM.

In that version I changed to function name to kvm_pmu_support_events, which means I want to detect what the KVM supports about the PMU events rather than the host supportted PMU events. I think that would be more suitable if we test KVM.

Thanks, Shaoqin

...

+}

+int main(void) +{

• TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
• TEST_REQUIRE(kvm_pmu_support_events());
• run_tests();

+}

Eric