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

Shaoqin Huang <shahuang@xxxxxxxxxx> · Tue, 26 Mar 2024 11:06:53 +0800

Hi Eric,

Thanks for your review.

On 3/20/24 04:58, Eric Auger wrote:
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?

No. Because the filter might be NULL.

+		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?

There is another patch[1] which move those definition to the GIC 
headers, but it hasn't been merged.

[1]https://lore.kernel.org/all/20240307183907.1184775-2-coltonlewis@xxxxxxxxxx/

+
+/* 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

Thanks for catching it.

+		.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.


I think get the supported pmu events from KVM is better than get the 
host supported pmu events even they are the same currently.

Thanks,
Shaoqin

Thanks

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


--
Shaoqin








