[PATCH 17/17] KVM: arm64: selftests: Add test case for partitioned PMU

[Colton Lewis <coltonlewis@google.com>]

Run separate test cases for a partitioned PMU in
vpmu_counter_access. Notably, partitioning the PMU untraps PMCR_EL0.N,
so that is no longer settable by KVM.

Add a boolean argument to run_access_test() that will partition the
PMU by reserving one host counter if true then run the test for the
PMCR_EL0.N value that implies, one less than the number of counters on
the host system.

Signed-off-by: Colton Lewis <coltonlewis@google.com>
---
 tools/include/uapi/linux/kvm.h                |  2 +
 .../selftests/kvm/arm64/vpmu_counter_access.c | 40 ++++++++++++++++---
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h
index b6ae8ad8934b..cb72b57b9b6c 100644
--- a/tools/include/uapi/linux/kvm.h
+++ b/tools/include/uapi/linux/kvm.h
@@ -930,6 +930,7 @@ struct kvm_enable_cap {
 #define KVM_CAP_X86_APIC_BUS_CYCLES_NS 237
 #define KVM_CAP_X86_GUEST_MODE 238
 #define KVM_CAP_ARM_WRITABLE_IMP_ID_REGS 239
+#define KVM_CAP_ARM_PARTITION_PMU 242
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
@@ -1356,6 +1357,7 @@ struct kvm_vfio_spapr_tce {
 #define KVM_S390_SET_CMMA_BITS      _IOW(KVMIO, 0xb9, struct kvm_s390_cmma_log)
 /* Memory Encryption Commands */
 #define KVM_MEMORY_ENCRYPT_OP      _IOWR(KVMIO, 0xba, unsigned long)
+#define KVM_ARM_PARTITION_PMU	_IOWR(KVMIO, 0xce, u8)
 
 struct kvm_enc_region {
 	__u64 addr;
diff --git a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
index f16b3b27e32e..e06448c1fbb5 100644
--- a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
+++ b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
@@ -369,6 +369,7 @@ static void guest_code(uint64_t expected_pmcr_n)
 	pmcr = read_sysreg(pmcr_el0);
 	pmcr_n = get_pmcr_n(pmcr);
 
+	/* __GUEST_ASSERT(0, "Expect PMCR: %lx", pmcr); */
 	/* Make sure that PMCR_EL0.N indicates the value userspace set */
 	__GUEST_ASSERT(pmcr_n == expected_pmcr_n,
 			"Expected PMCR.N: 0x%lx, PMCR.N: 0x%lx",
@@ -508,16 +509,18 @@ static void test_create_vpmu_vm_with_pmcr_n(uint64_t pmcr_n, bool expect_fail)
  * Create a guest with one vCPU, set the PMCR_EL0.N for the vCPU to @pmcr_n,
  * and run the test.
  */
-static void run_access_test(uint64_t pmcr_n)
+static void run_access_test(uint64_t pmcr_n, bool partition)
 {
 	uint64_t sp;
 	struct kvm_vcpu *vcpu;
 	struct kvm_vcpu_init init;
+	uint8_t host_counters = (uint8_t)partition;
 
 	pr_debug("Test with pmcr_n %lu\n", pmcr_n);
 
 	test_create_vpmu_vm_with_pmcr_n(pmcr_n, false);
 	vcpu = vpmu_vm.vcpu;
+	vcpu_ioctl(vcpu, KVM_ARM_PARTITION_PMU, &host_counters);
 
 	/* Save the initial sp to restore them later to run the guest again */
 	sp = vcpu_get_reg(vcpu, ARM64_CORE_REG(sp_el1));
@@ -529,6 +532,8 @@ static void run_access_test(uint64_t pmcr_n)
 	 * check if PMCR_EL0.N is preserved.
 	 */
 	vm_ioctl(vpmu_vm.vm, KVM_ARM_PREFERRED_TARGET, &init);
+	vcpu_ioctl(vcpu, KVM_ARM_PARTITION_PMU, &host_counters);
+
 	init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
 	aarch64_vcpu_setup(vcpu, &init);
 	vcpu_init_descriptor_tables(vcpu);
@@ -609,7 +614,7 @@ static void run_pmregs_validity_test(uint64_t pmcr_n)
  */
 static void run_error_test(uint64_t pmcr_n)
 {
-	pr_debug("Error test with pmcr_n %lu (larger than the host)\n", pmcr_n);
+	pr_debug("Error test with pmcr_n %lu (larger than the host allows)\n", pmcr_n);
 
 	test_create_vpmu_vm_with_pmcr_n(pmcr_n, true);
 	destroy_vpmu_vm();
@@ -629,20 +634,45 @@ static uint64_t get_pmcr_n_limit(void)
 	return get_pmcr_n(pmcr);
 }
 
-int main(void)
+void test_emulated_pmu(void)
 {
 	uint64_t i, pmcr_n;
 
-	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
+	pr_info("Testing Emulated PMU\n");
 
 	pmcr_n = get_pmcr_n_limit();
 	for (i = 0; i <= pmcr_n; i++) {
-		run_access_test(i);
+		run_access_test(i, false);
 		run_pmregs_validity_test(i);
 	}
 
 	for (i = pmcr_n + 1; i < ARMV8_PMU_MAX_COUNTERS; i++)
 		run_error_test(i);
+}
+
+void test_partitioned_pmu(void)
+{
+	uint64_t i, pmcr_n;
+
+	pr_info("Testing Partitioned PMU\n");
+
+	pmcr_n = get_pmcr_n_limit();
+	run_access_test(pmcr_n - 1, true);
+
+	/* Partitioning implies only one PMCR.N allowed */
+	for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
+		if (i != pmcr_n)
+			run_error_test(i);
+}
+
+int main(void)
+{
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
+
+	test_emulated_pmu();
+
+	if (kvm_has_cap(KVM_CAP_ARM_PARTITION_PMU))
+		test_partitioned_pmu();
 
 	return 0;
 }
-- 
2.49.0.1204.g71687c7c1d-goog