Re: [PATCH v4 13/15] KVM: riscv: selftests: Add SBI PMU selftest

[Atish Kumar Patra]

On Thu, Feb 29, 2024 at 8:47 PM Anup Patel <anup@xxxxxxxxxxxxxx> wrote:
>
> On Thu, Feb 29, 2024 at 6:32 AM Atish Patra <atishp@xxxxxxxxxxxx> wrote:
> >
> > This test implements basic sanity test and cycle/instret event
> > counting tests.
> >
> > Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
>
> I feel the test should have been called sbi_pmu_test but no need to
> revise this series. I will take care of it at the time of merging.
>

Sure. I am going to send v5 anyway. I have changed the name there.

> Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
>
> Regards,
> Anup
>
> > ---
> >  tools/testing/selftests/kvm/Makefile        |   1 +
> >  tools/testing/selftests/kvm/riscv/sbi_pmu.c | 340 ++++++++++++++++++++
> >  2 files changed, 341 insertions(+)
> >  create mode 100644 tools/testing/selftests/kvm/riscv/sbi_pmu.c
> >
> > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> > index 426f85798aea..b2dce6843b9e 100644
> > --- a/tools/testing/selftests/kvm/Makefile
> > +++ b/tools/testing/selftests/kvm/Makefile
> > @@ -195,6 +195,7 @@ TEST_GEN_PROGS_riscv += kvm_create_max_vcpus
> >  TEST_GEN_PROGS_riscv += kvm_page_table_test
> >  TEST_GEN_PROGS_riscv += set_memory_region_test
> >  TEST_GEN_PROGS_riscv += steal_time
> > +TEST_GEN_PROGS_riscv += riscv/sbi_pmu
> >
> >  SPLIT_TESTS += arch_timer
> >  SPLIT_TESTS += get-reg-list
> > diff --git a/tools/testing/selftests/kvm/riscv/sbi_pmu.c b/tools/testing/selftests/kvm/riscv/sbi_pmu.c
> > new file mode 100644
> > index 000000000000..fc1fc5eea99e
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/riscv/sbi_pmu.c
> > @@ -0,0 +1,340 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * arch_timer.c - Tests the riscv64 sstc timer IRQ functionality
> > + *
> > + * The test validates the sstc timer IRQs using vstimecmp registers.
> > + * It's ported from the aarch64 arch_timer test.
> > + *
> > + * 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"
> > +
> > +/* 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(int iter)
> > +{
> > +       int i = 0;
> > +
> > +       while (i < iter) {
> > +               asm volatile("nop");
> > +               i++;
> > +       }
> > +}
> > +
> > +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) &&
> > +                   ((1UL << 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)
> > +                       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 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);
> > +}
> > +
> > +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);
> > +       if (stop_flags & SBI_PMU_STOP_FLAG_RESET)
> > +               __GUEST_ASSERT(ret.error == SBI_ERR_ALREADY_STOPPED,
> > +                              "Unable to stop counter %ld\n", counter);
> > +       else
> > +               __GUEST_ASSERT(ret.error == 0, "Unable to stop counter %ld error %ld\n",
> > +                              counter, ret.error);
> > +}
> > +
> > +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_counter(counter, SBI_PMU_STOP_FLAG_RESET);
> > +}
> > +
> > +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(int cpu)
> > +{
> > +       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 guranteed 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(int cpu)
> > +{
> > +       long out_val = 0;
> > +       bool probe;
> > +       struct sbiret ret;
> > +       int num_counters = 0, i;
> > +       unsigned long counter_val = -1;
> > +       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)
> > +                       GUEST_ASSERT_NE(ret.value, 0);
> > +               else
> > +                       continue;
> > +
> > +               ctrinfo.value = ret.value;
> > +
> > +               /* Accesibility check of hardware and read capability of firmware counters */
> > +               counter_val = read_counter(i, ctrinfo);
> > +               /* The spec doesn't mandate any initial value. Verify if a sane value */
> > +               GUEST_ASSERT_NE(counter_val, -1);
> > +       }
> > +
> > +       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_ext(vcpu, RISCV_ISA_EXT_REG(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);
> > +       vcpu_args_set(vcpu, 1, 0);
> > +       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_ext(vcpu, RISCV_ISA_EXT_REG(KVM_RISCV_SBI_EXT_PMU)),
> > +                                  "SBI PMU not available, skipping test");
> > +       vcpu_args_set(vcpu, 1, 0);
> > +       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
> >