[PATCH v5 20/22] KVM: riscv: selftests: Add SBI PMU selftest

Atish Patra
2024-04-03T08:05:57Z

This test implements basic sanity test and cycle/instret event
counting tests.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/riscv/sbi_pmu_test.c | 340 ++++++++++++++++++
2 files changed, 341 insertions(+)
create mode 100644 tools/testing/selftests/kvm/riscv/sbi_pmu_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 741c7dc16afc..1cfcd2797ee4 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -189,6 +189,7 @@ TEST_GEN_PROGS_s390x += rseq_test
TEST_GEN_PROGS_s390x += set_memory_region_test
TEST_GEN_PROGS_s390x += kvm_binary_stats_test

+TEST_GEN_PROGS_riscv += riscv/sbi_pmu_test
TEST_GEN_PROGS_riscv += arch_timer
TEST_GEN_PROGS_riscv += demand_paging_test
TEST_GEN_PROGS_riscv += dirty_log_test
diff --git a/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c b/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c
new file mode 100644
index 000000000000..8e7c7a3172d8
--- /dev/null
+++ b/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sbi_pmu_test.c - Tests the riscv64 SBI PMU functionality.
+ *
+ * Copyright (c) 2024, Rivos Inc.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include "kvm_util.h"
+#include "test_util.h"
+#include "processor.h"
+#include "sbi.h"
+
+/* Maximum counters(firmware + hardware) */
+#define RISCV_MAX_PMU_COUNTERS 64
+union sbi_pmu_ctr_info ctrinfo_arr[RISCV_MAX_PMU_COUNTERS];
+
+/* Cache the available counters in a bitmask */
+static unsigned long counter_mask_available;
+
+unsigned long pmu_csr_read_num(int csr_num)
+{
+#define switchcase_csr_read(__csr_num, __val) {\
+ case __csr_num: \
+ __val = csr_read(__csr_num); \
+ break; }
+#define switchcase_csr_read_2(__csr_num, __val) {\
+ switchcase_csr_read(__csr_num + 0, __val) \
+ switchcase_csr_read(__csr_num + 1, __val)}
+#define switchcase_csr_read_4(__csr_num, __val) {\
+ switchcase_csr_read_2(__csr_num + 0, __val) \
+ switchcase_csr_read_2(__csr_num + 2, __val)}
+#define switchcase_csr_read_8(__csr_num, __val) {\
+ switchcase_csr_read_4(__csr_num + 0, __val) \
+ switchcase_csr_read_4(__csr_num + 4, __val)}
+#define switchcase_csr_read_16(__csr_num, __val) {\
+ switchcase_csr_read_8(__csr_num + 0, __val) \
+ switchcase_csr_read_8(__csr_num + 8, __val)}
+#define switchcase_csr_read_32(__csr_num, __val) {\
+ switchcase_csr_read_16(__csr_num + 0, __val) \
+ switchcase_csr_read_16(__csr_num + 16, __val)}
+
+ unsigned long ret = 0;
+
+ switch (csr_num) {
+ switchcase_csr_read_32(CSR_CYCLE, ret)
+ switchcase_csr_read_32(CSR_CYCLEH, ret)
+ default :
+ break;
+ }
+
+ return ret;
+#undef switchcase_csr_read_32
+#undef switchcase_csr_read_16
+#undef switchcase_csr_read_8
+#undef switchcase_csr_read_4
+#undef switchcase_csr_read_2
+#undef switchcase_csr_read
+}
+
+static inline void dummy_func_loop(uint64_t iter)
+{
+ int i = 0;
+
+ while (i < iter) {
+ asm volatile("nop");
+ i++;
+ }
+}
+
+static void start_counter(unsigned long counter, unsigned long start_flags,
+ unsigned long ival)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, counter, 1, start_flags,
+ ival, 0, 0);
+ __GUEST_ASSERT(ret.error == 0, "Unable to start counter %ld\n", counter);
+}
+
+/* This should be invoked only for reset counter use case */
+static void stop_reset_counter(unsigned long counter, unsigned long stop_flags)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, counter, 1,
+ stop_flags | SBI_PMU_STOP_FLAG_RESET, 0, 0, 0);
+ __GUEST_ASSERT(ret.error == SBI_ERR_ALREADY_STOPPED,
+ "Unable to stop counter %ld\n", counter);
+}
+
+static void stop_counter(unsigned long counter, unsigned long stop_flags)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, counter, 1, stop_flags,
+ 0, 0, 0);
+ __GUEST_ASSERT(ret.error == 0, "Unable to stop counter %ld error %ld\n",
+ counter, ret.error);
+}
+
+static void guest_illegal_exception_handler(struct ex_regs *regs)
+{
+ __GUEST_ASSERT(regs->cause == EXC_INST_ILLEGAL,
+ "Unexpected exception handler %lx\n", regs->cause);
+
+ /* skip the trapping instruction */
+ regs->epc += 4;
+}
+
+static unsigned long get_counter_index(unsigned long cbase, unsigned long cmask,
+ unsigned long cflags,
+ unsigned long event)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_CFG_MATCH, cbase, cmask,
+ cflags, event, 0, 0);
+ __GUEST_ASSERT(ret.error == 0, "config matching failed %ld\n", ret.error);
+ GUEST_ASSERT(ret.value < RISCV_MAX_PMU_COUNTERS);
+ GUEST_ASSERT(BIT(ret.value) & counter_mask_available);
+
+ return ret.value;
+}
+
+static unsigned long get_num_counters(void)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_NUM_COUNTERS, 0, 0, 0, 0, 0, 0);
+
+ __GUEST_ASSERT(ret.error == 0, "Unable to retrieve number of counters from SBI PMU");
+ __GUEST_ASSERT(ret.value < RISCV_MAX_PMU_COUNTERS,
+ "Invalid number of counters %ld\n", ret.value);
+
+ return ret.value;
+}
+
+static void update_counter_info(int num_counters)
+{
+ int i = 0;
+ struct sbiret ret;
+
+ for (i = 0; i < num_counters; i++) {
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_GET_INFO, i, 0, 0, 0, 0, 0);
+
+ /* There can be gaps in logical counter indicies*/
+ if (ret.error)
+ continue;
+ GUEST_ASSERT_NE(ret.value, 0);
+
+ ctrinfo_arr[i].value = ret.value;
+ counter_mask_available |= BIT(i);
+ }
+
+ GUEST_ASSERT(counter_mask_available > 0);
+}
+
+static unsigned long read_counter(int idx, union sbi_pmu_ctr_info ctrinfo)
+{
+ unsigned long counter_val = 0;
+ struct sbiret ret;
+
+ __GUEST_ASSERT(ctrinfo.type < 2, "Invalid counter type %d", ctrinfo.type);
+
+ if (ctrinfo.type == SBI_PMU_CTR_TYPE_HW) {
+ counter_val = pmu_csr_read_num(ctrinfo.csr);
+ } else if (ctrinfo.type == SBI_PMU_CTR_TYPE_FW) {
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ, idx, 0, 0, 0, 0, 0);
+ GUEST_ASSERT(ret.error == 0);
+ counter_val = ret.value;
+ }
+
+ return counter_val;
+}
+
+static void test_pmu_event(unsigned long event)
+{
+ unsigned long counter;
+ unsigned long counter_value_pre, counter_value_post;
+ unsigned long counter_init_value = 100;
+
+ counter = get_counter_index(0, counter_mask_available, 0, event);
+ counter_value_pre = read_counter(counter, ctrinfo_arr[counter]);
+
+ /* Do not set the initial value */
+ start_counter(counter, 0, counter_init_value);
+ dummy_func_loop(10000);
+ stop_counter(counter, 0);
+
+ counter_value_post = read_counter(counter, ctrinfo_arr[counter]);
+ __GUEST_ASSERT(counter_value_post > counter_value_pre,
+ "counter_value_post %lx counter_value_pre %lx\n",
+ counter_value_post, counter_value_pre);
+
+ /* Now set the initial value and compare */
+ start_counter(counter, SBI_PMU_START_FLAG_SET_INIT_VALUE, counter_init_value);
+ dummy_func_loop(10000);
+ stop_counter(counter, 0);
+
+ counter_value_post = read_counter(counter, ctrinfo_arr[counter]);
+ __GUEST_ASSERT(counter_value_post > counter_init_value,
+ "counter_value_post %lx counter_init_value %lx\n",
+ counter_value_post, counter_init_value);
+
+ stop_reset_counter(counter, 0);
+}
+
+static void test_invalid_event(void)
+{
+ struct sbiret ret;
+ unsigned long event = 0x1234; /* A random event */
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_CFG_MATCH, 0,
+ counter_mask_available, 0, event, 0, 0);
+ GUEST_ASSERT_EQ(ret.error, SBI_ERR_NOT_SUPPORTED);
+}
+
+static void test_pmu_events(void)
+{
+ int num_counters = 0;
+
+ /* Get the counter details */
+ num_counters = get_num_counters();
+ update_counter_info(num_counters);
+
+ /* Sanity testing for any random invalid event */
+ test_invalid_event();
+
+ /* Only these two events are guaranteed to be present */
+ test_pmu_event(SBI_PMU_HW_CPU_CYCLES);
+ test_pmu_event(SBI_PMU_HW_INSTRUCTIONS);
+
+ GUEST_DONE();
+}
+
+static void test_pmu_basic_sanity(void)
+{
+ long out_val = 0;
+ bool probe;
+ struct sbiret ret;
+ int num_counters = 0, i;
+ union sbi_pmu_ctr_info ctrinfo;
+
+ probe = guest_sbi_probe_extension(SBI_EXT_PMU, &out_val);
+ GUEST_ASSERT(probe && out_val == 1);
+
+ num_counters = get_num_counters();
+
+ for (i = 0; i < num_counters; i++) {
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_GET_INFO, i,
+ 0, 0, 0, 0, 0);
+
+ /* There can be gaps in logical counter indicies*/
+ if (ret.error)
+ continue;
+ GUEST_ASSERT_NE(ret.value, 0);
+
+ ctrinfo.value = ret.value;
+
+ /**
+ * Accesibillity check of hardware and read capability of firmware counters.
+ * The spec doesn't mandate any initial value. No need to check any value.
+ */
+ read_counter(i, ctrinfo);
+ }
+
+ GUEST_DONE();
+}
+
+static void run_vcpu(struct kvm_vcpu *vcpu)
+{
+ struct ucall uc;
+
+ vcpu_run(vcpu);
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT(uc);
+ break;
+ case UCALL_DONE:
+ case UCALL_SYNC:
+ break;
+ default:
+ TEST_FAIL("Unknown ucall %lu", uc.cmd);
+ break;
+ }
+}
+
+void test_vm_destroy(struct kvm_vm *vm)
+{
+ memset(ctrinfo_arr, 0, sizeof(union sbi_pmu_ctr_info) * RISCV_MAX_PMU_COUNTERS);
+ counter_mask_available = 0;
+ kvm_vm_free(vm);
+}
+
+static void test_vm_basic_test(void *guest_code)
+{
+ struct kvm_vm *vm;
+ struct kvm_vcpu *vcpu;
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ __TEST_REQUIRE(__vcpu_has_sbi_ext(vcpu, KVM_RISCV_SBI_EXT_PMU),
+ "SBI PMU not available, skipping test");
+ vm_init_vector_tables(vm);
+ /* Illegal instruction handler is required to verify read access without configuration */
+ vm_install_exception_handler(vm, EXC_INST_ILLEGAL, guest_illegal_exception_handler);
+
+ vcpu_init_vector_tables(vcpu);
+ run_vcpu(vcpu);
+
+ test_vm_destroy(vm);
+}
+
+static void test_vm_events_test(void *guest_code)
+{
+ struct kvm_vm *vm = NULL;
+ struct kvm_vcpu *vcpu = NULL;
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ __TEST_REQUIRE(__vcpu_has_sbi_ext(vcpu, KVM_RISCV_SBI_EXT_PMU),
+ "SBI PMU not available, skipping test");
+ run_vcpu(vcpu);
+
+ test_vm_destroy(vm);
+}
+
+int main(void)
+{
+ test_vm_basic_test(test_pmu_basic_sanity);
+ pr_info("SBI PMU basic test : PASS\n");
+
+ test_vm_events_test(test_pmu_events);
+ pr_info("SBI PMU event verification test : PASS\n");
+
+ return 0;
+}
--
2.34.1