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

[Eric Auger <eauger@redhat.com>]

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?"

> +
> +/* 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?

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


in v4 Oliver suggested to use sysfs instead of spawning a scratch VM.
> +}
> +
> +int main(void)
> +{
> +	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
> +	TEST_REQUIRE(kvm_pmu_support_events());
> +
> +	run_tests();
> +}
Eric