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

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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: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Oliver Upton 2025-09-17 14:20:40 -07:00 committed by Marc Zyngier
parent 0910778e49
commit 7ae44d1cda
1 changed files with 28 additions and 31 deletions
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59
tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
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@ -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++) {