[PATCH 5/7] KVM: selftests: aarch64: Introduce vpmu_counter_access test

[Reiji Watanabe]

Introduce vpmu_counter_access test for arm64 platforms.
The test configures PMUv3 for a vCPU, sets PMCR_EL1.N for the vCPU,
and check if the guest can consistently see the same number of the
PMU event counters (PMCR_EL1.N) that userspace sets.
This test case is done with each PMCR_EL1.N value that is equal to
or less than PMCR_EL1.N on the host.

Signed-off-by: Reiji Watanabe <reijiw at google.com>
---
 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../kvm/aarch64/vpmu_counter_access.c         | 181 ++++++++++++++++++
 3 files changed, 183 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 4a30d684e208..98816f714051 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -9,6 +9,7 @@
 /aarch64/vcpu_width_config
 /aarch64/vgic_init
 /aarch64/vgic_irq
+/aarch64/vpmu_counter_access
 /s390x/memop
 /s390x/resets
 /s390x/sync_regs_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 1d85b8e218a0..4dc5166116f1 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -158,6 +158,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/psci_test
 TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_irq
+TEST_GEN_PROGS_aarch64 += aarch64/vpmu_counter_access
 TEST_GEN_PROGS_aarch64 += access_tracking_perf_test
 TEST_GEN_PROGS_aarch64 += demand_paging_test
 TEST_GEN_PROGS_aarch64 += dirty_log_test
diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
new file mode 100644
index 000000000000..4760030eee28
--- /dev/null
+++ b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vpmu_counter_access - Test vPMU event counter access
+ *
+ * Copyright (c) 2022 Google LLC.
+ *
+ * This test checks if the guest can see the same number of the PMU event
+ * counters (PMCR_EL1.N) that userspace sets.
+ * This test runs only when KVM_CAP_ARM_PMU_V3 is supported on the host.
+ */
+#include <kvm_util.h>
+#include <processor.h>
+#include <test_util.h>
+#include <vgic.h>
+#include <asm/perf_event.h>
+#include <linux/bitfield.h>
+
+/* The max number of the PMU event counters (excluding the cycle counter) */
+#define ARMV8_PMU_MAX_GENERAL_COUNTERS	(ARMV8_PMU_MAX_COUNTERS - 1)
+
+static uint64_t pmcr_extract_n(uint64_t pmcr_val)
+{
+	return (pmcr_val >> ARMV8_PMU_PMCR_N_SHIFT) & ARMV8_PMU_PMCR_N_MASK;
+}
+
+/*
+ * The guest is configured with PMUv3 with @expected_pmcr_n number of
+ * event counters.
+ * Check if @expected_pmcr_n is consistent with PMCR_EL0.N.
+ */
+static void guest_code(uint64_t expected_pmcr_n)
+{
+	uint64_t pmcr, pmcr_n;
+
+	GUEST_ASSERT(expected_pmcr_n <= ARMV8_PMU_MAX_GENERAL_COUNTERS);
+
+	pmcr = read_sysreg(pmcr_el0);
+	pmcr_n = pmcr_extract_n(pmcr);
+
+	/* Make sure that PMCR_EL0.N indicates the value userspace set */
+	GUEST_ASSERT_2(pmcr_n == expected_pmcr_n, pmcr_n, expected_pmcr_n);
+
+	GUEST_DONE();
+}
+
+#define GICD_BASE_GPA	0x8000000ULL
+#define GICR_BASE_GPA	0x80A0000ULL
+
+/* Create a VM that has one vCPU with PMUv3 configured. */
+static struct kvm_vm *create_vpmu_vm(void *guest_code, struct kvm_vcpu **vcpup,
+				     int *gic_fd)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vcpu_init init;
+	uint8_t pmuver;
+	uint64_t dfr0, irq = 23;
+	struct kvm_device_attr irq_attr = {
+		.group = KVM_ARM_VCPU_PMU_V3_CTRL,
+		.attr = KVM_ARM_VCPU_PMU_V3_IRQ,
+		.addr = (uint64_t)&irq,
+	};
+	struct kvm_device_attr init_attr = {
+		.group = KVM_ARM_VCPU_PMU_V3_CTRL,
+		.attr = KVM_ARM_VCPU_PMU_V3_INIT,
+	};
+
+	vm = vm_create(1);
+	ucall_init(vm, NULL);
+
+	/* Create vCPU with PMUv3 */
+	vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
+	init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
+	vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
+	*gic_fd = vgic_v3_setup(vm, 1, 64, GICD_BASE_GPA, GICR_BASE_GPA);
+
+	/* Make sure that PMUv3 support is indicated in the ID register */
+	vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64DFR0_EL1), &dfr0);
+	pmuver = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_PMUVER), dfr0);
+	TEST_ASSERT(pmuver != ID_AA64DFR0_PMUVER_IMP_DEF &&
+		    pmuver >= ID_AA64DFR0_PMUVER_8_0,
+		    "Unexpected PMUVER (0x%x) on the vCPU with PMUv3", pmuver);
+
+	/* Initialize vPMU */
+	vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &irq_attr);
+	vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &init_attr);
+
+	*vcpup = vcpu;
+	return vm;
+}
+
+static void run_vcpu(struct kvm_vcpu *vcpu, uint64_t pmcr_n)
+{
+	struct ucall uc;
+
+	vcpu_args_set(vcpu, 1, pmcr_n);
+	vcpu_run(vcpu);
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT_2(uc, "values:%#lx %#lx");
+		break;
+	case UCALL_DONE:
+		break;
+	default:
+		TEST_FAIL("Unknown ucall %lu", uc.cmd);
+		break;
+	}
+}
+
+/*
+ * Create a guest with one vCPU, set the PMCR_EL1.N for the vCPU to @pmcr_n,
+ * and run the test.
+ */
+static void run_test(uint64_t pmcr_n)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	int gic_fd;
+	uint64_t sp, pmcr, pmcr_orig;
+	struct kvm_vcpu_init init;
+
+	pr_debug("Test with pmcr_n %lu\n", pmcr_n);
+	vm = create_vpmu_vm(guest_code, &vcpu, &gic_fd);
+
+	/* Save the initial sp to restore them later to run the guest again */
+	vcpu_get_reg(vcpu, ARM64_CORE_REG(sp_el1), &sp);
+
+	/* Update the PMCR_EL1.N with @pmcr_n */
+	vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), &pmcr_orig);
+	pmcr = pmcr_orig & ~(ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
+	pmcr |= (pmcr_n & ARMV8_PMU_PMCR_N_MASK) << ARMV8_PMU_PMCR_N_SHIFT;
+	vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), pmcr);
+
+	run_vcpu(vcpu, pmcr_n);
+
+	/*
+	 * Reset and re-initialize the vCPU, and run the guest code again to
+	 * check if PMCR_EL1.N is preserved.
+	 */
+	vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
+	init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
+	aarch64_vcpu_setup(vcpu, &init);
+	vcpu_set_reg(vcpu, ARM64_CORE_REG(sp_el1), sp);
+	vcpu_set_reg(vcpu, ARM64_CORE_REG(regs.pc), (uint64_t)guest_code);
+
+	run_vcpu(vcpu, pmcr_n);
+
+	close(gic_fd);
+	kvm_vm_free(vm);
+}
+
+/*
+ * Return the default number of implemented PMU event counters excluding
+ * the cycle counter (i.e. PMCR_EL1.N value) for the guest.
+ */
+static uint64_t get_pmcr_n_limit(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	int gic_fd;
+	uint64_t pmcr;
+
+	vm = create_vpmu_vm(guest_code, &vcpu, &gic_fd);
+	vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), &pmcr);
+	close(gic_fd);
+	kvm_vm_free(vm);
+	return pmcr_extract_n(pmcr);
+}
+
+int main(void)
+{
+	uint64_t i, pmcr_n;
+
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
+
+	pmcr_n = get_pmcr_n_limit();
+	for (i = 0; i <= pmcr_n; i++)
+		run_test(i);
+
+	return 0;
+}
-- 
2.39.0.314.g84b9a713c41-goog