Commit 7ae44d1c authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
Browse files

KVM: arm64: selftests: Use the vCPU attr for setting nr of PMU counters 



Configuring the number of implemented counters via PMCR_EL0.N was a bad
idea in retrospect as it interacts poorly with nested. Migrate the
selftest to use the vCPU attribute instead of the KVM_SET_ONE_REG
mechanism.

Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 0910778e

tools/testing/selftests/kvm/arm64/vpmu_counter_access.c

+28 −31
Original line number Diff line number Diff line
@@ -44,11 +44,6 @@ static uint64_t get_pmcr_n(uint64_t pmcr) 
	return FIELD_GET(ARMV8_PMU_PMCR_N, pmcr);

}



static void set_pmcr_n(uint64_t *pmcr, uint64_t pmcr_n)

{

	u64p_replace_bits((__u64 *) pmcr, pmcr_n, ARMV8_PMU_PMCR_N);

}



static uint64_t get_counters_mask(uint64_t n)

{

	uint64_t mask = BIT(ARMV8_PMU_CYCLE_IDX);
@@ -414,10 +409,6 @@ static void create_vpmu_vm(void *guest_code) 
		.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,

	};



	/* The test creates the vpmu_vm multiple times. Ensure a clean state */

	memset(&vpmu_vm, 0, sizeof(vpmu_vm));
@@ -444,9 +435,7 @@ static void create_vpmu_vm(void *guest_code) 
		    pmuver >= ID_AA64DFR0_EL1_PMUVer_IMP,

		    "Unexpected PMUVER (0x%x) on the vCPU with PMUv3", pmuver);



	/* Initialize vPMU */

	vcpu_ioctl(vpmu_vm.vcpu, KVM_SET_DEVICE_ATTR, &irq_attr);

	vcpu_ioctl(vpmu_vm.vcpu, KVM_SET_DEVICE_ATTR, &init_attr);

}



static void destroy_vpmu_vm(void)
@@ -472,33 +461,28 @@ static void run_vcpu(struct kvm_vcpu *vcpu, uint64_t pmcr_n) 
	}

}



static void test_create_vpmu_vm_with_pmcr_n(uint64_t pmcr_n, bool expect_fail)

static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters, bool expect_fail)

{

	struct kvm_vcpu *vcpu;

	uint64_t pmcr, pmcr_orig;

	unsigned int prev;

	int ret;



	create_vpmu_vm(guest_code);

	vcpu = vpmu_vm.vcpu;



	pmcr_orig = vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0));

	pmcr = pmcr_orig;

	prev = get_pmcr_n(vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0)));



	/*

	 * Setting a larger value of PMCR.N should not modify the field, and

	 * return a success.

	 */

	set_pmcr_n(&pmcr, pmcr_n);

	vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), pmcr);

	pmcr = vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0));

	ret = __vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,

				     KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTERS, &nr_counters);



	if (expect_fail)

		TEST_ASSERT(pmcr_orig == pmcr,

			    "PMCR.N modified by KVM to a larger value (PMCR: 0x%lx) for pmcr_n: 0x%lx",

			    pmcr, pmcr_n);

		TEST_ASSERT(ret && errno == EINVAL,

			    "Setting more PMU counters (%u) than available (%u) unexpectedly succeeded",

			    nr_counters, prev);

	else

		TEST_ASSERT(pmcr_n == get_pmcr_n(pmcr),

			    "Failed to update PMCR.N to %lu (received: %lu)",

			    pmcr_n, get_pmcr_n(pmcr));

		TEST_ASSERT(!ret, KVM_IOCTL_ERROR(KVM_SET_DEVICE_ATTR, ret));



	vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL, KVM_ARM_VCPU_PMU_V3_INIT, NULL);

}



/*
@@ -513,7 +497,7 @@ static void run_access_test(uint64_t pmcr_n) 


	pr_debug("Test with pmcr_n %lu\n", pmcr_n);



	test_create_vpmu_vm_with_pmcr_n(pmcr_n, false);

	test_create_vpmu_vm_with_nr_counters(pmcr_n, false);

	vcpu = vpmu_vm.vcpu;



	/* Save the initial sp to restore them later to run the guest again */
@@ -554,7 +538,7 @@ static void run_pmregs_validity_test(uint64_t pmcr_n) 
	uint64_t set_reg_id, clr_reg_id, reg_val;

	uint64_t valid_counters_mask, max_counters_mask;



	test_create_vpmu_vm_with_pmcr_n(pmcr_n, false);

	test_create_vpmu_vm_with_nr_counters(pmcr_n, false);

	vcpu = vpmu_vm.vcpu;



	valid_counters_mask = get_counters_mask(pmcr_n);
@@ -608,7 +592,7 @@ static void run_error_test(uint64_t pmcr_n) 
{

	pr_debug("Error test with pmcr_n %lu (larger than the host)\n", pmcr_n);



	test_create_vpmu_vm_with_pmcr_n(pmcr_n, true);

	test_create_vpmu_vm_with_nr_counters(pmcr_n, true);

	destroy_vpmu_vm();

}
@@ -626,12 +610,25 @@ static uint64_t get_pmcr_n_limit(void) 
	return get_pmcr_n(pmcr);

}



static bool kvm_supports_nr_counters_attr(void)

{

	bool supported;



	create_vpmu_vm(NULL);

	supported = !__vcpu_has_device_attr(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,

					    KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTERS);

	destroy_vpmu_vm();



	return supported;

}



int main(void)

{

	uint64_t i, pmcr_n;



	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));

	TEST_REQUIRE(kvm_supports_vgic_v3());

	TEST_REQUIRE(kvm_supports_nr_counters_attr());



	pmcr_n = get_pmcr_n_limit();

	for (i = 0; i <= pmcr_n; i++) {