[PATCH 4/4] KVM: riscv: selftests: Allow number of interrupts to be configurable

[Atish Kumar Patra]

On Thu, Feb 27, 2025 at 12:16 AM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> On Wed, Feb 26, 2025 at 12:25:06PM -0800, Atish Patra wrote:
> > It is helpful to vary the number of the LCOFI interrupts generated
> > by the overflow test. Allow additional argument for overflow test
> > to accommodate that. It can be easily cross-validated with
> > /proc/interrupts output in the host.
> >
> > Signed-off-by: Atish Patra <atishp at rivosinc.com>
> > ---
> >  tools/testing/selftests/kvm/riscv/sbi_pmu_test.c | 36 ++++++++++++++++++++----
> >  1 file changed, 30 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c b/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c
> > index 533b76d0de82..7c273a1adb17 100644
> > --- a/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c
> > +++ b/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c
> > @@ -39,8 +39,10 @@ static bool illegal_handler_invoked;
> >  #define SBI_PMU_TEST_SNAPSHOT        BIT(2)
> >  #define SBI_PMU_TEST_OVERFLOW        BIT(3)
> >
> > +#define SBI_PMU_OVERFLOW_IRQNUM_DEFAULT 5
> >  struct test_args {
> >       int disabled_tests;
> > +     int overflow_irqnum;
> >  };
> >
> >  static struct test_args targs;
> > @@ -478,7 +480,7 @@ static void test_pmu_events_snaphost(void)
> >
> >  static void test_pmu_events_overflow(void)
> >  {
> > -     int num_counters = 0;
> > +     int num_counters = 0, i = 0;
> >
> >       /* Verify presence of SBI PMU and minimum requrired SBI version */
> >       verify_sbi_requirement_assert();
> > @@ -495,11 +497,15 @@ static void test_pmu_events_overflow(void)
> >        * Qemu supports overflow for cycle/instruction.
> >        * This test may fail on any platform that do not support overflow for these two events.
> >        */
> > -     test_pmu_event_overflow(SBI_PMU_HW_CPU_CYCLES);
> > -     GUEST_ASSERT_EQ(vcpu_shared_irq_count, 1);
> > +     for (i = 0; i < targs.overflow_irqnum; i++)
> > +             test_pmu_event_overflow(SBI_PMU_HW_CPU_CYCLES);
> > +     GUEST_ASSERT_EQ(vcpu_shared_irq_count, targs.overflow_irqnum);
> > +
> > +     vcpu_shared_irq_count = 0;
> >
> > -     test_pmu_event_overflow(SBI_PMU_HW_INSTRUCTIONS);
> > -     GUEST_ASSERT_EQ(vcpu_shared_irq_count, 2);
> > +     for (i = 0; i < targs.overflow_irqnum; i++)
> > +             test_pmu_event_overflow(SBI_PMU_HW_INSTRUCTIONS);
> > +     GUEST_ASSERT_EQ(vcpu_shared_irq_count, targs.overflow_irqnum);
> >
> >       GUEST_DONE();
> >  }
> > @@ -621,8 +627,11 @@ static void test_vm_events_overflow(void *guest_code)
> >
> >  static void test_print_help(char *name)
> >  {
> > -     pr_info("Usage: %s [-h] [-t <test name>]\n", name);
> > +     pr_info("Usage: %s [-h] [-t <test name>] [-n <number of LCOFI interrupt for overflow test>]\n",
> > +             name);
> >       pr_info("\t-t: Test to run (default all). Available tests are 'basic', 'events', 'snapshot', 'overflow'\n");
> > +     pr_info("\t-n: Number of LCOFI interrupt to trigger for each event in overflow test (default: %d)\n",
> > +             SBI_PMU_OVERFLOW_IRQNUM_DEFAULT);
> >       pr_info("\t-h: print this help screen\n");
> >  }
> >
> > @@ -631,6 +640,8 @@ static bool parse_args(int argc, char *argv[])
> >       int opt;
> >       int temp_disabled_tests = SBI_PMU_TEST_BASIC | SBI_PMU_TEST_EVENTS | SBI_PMU_TEST_SNAPSHOT |
> >                                 SBI_PMU_TEST_OVERFLOW;
> > +     int overflow_interrupts = -1;
>
> Initializing to -1 made me think that '-n 0' would be valid and a way to
> disable the overflow test, but...
>

Is there any benefit ? I found it much more convenient to select a
single test and run instead of disabling
a single test.

Once you single or a set of tests, all other tests are disabled anyways.

> > +
> >       while ((opt = getopt(argc, argv, "h:t:n:")) != -1) {
> >               switch (opt) {
> >               case 't':
> > @@ -646,12 +657,24 @@ static bool parse_args(int argc, char *argv[])
> >                               goto done;
> >                       targs.disabled_tests = temp_disabled_tests;
> >                       break;
> > +             case 'n':
> > +                     overflow_interrupts = atoi_positive("Number of LCOFI", optarg);
>
> ...here we use atoi_positive() and...
>
> > +                     break;
> >               case 'h':
> >               default:
> >                       goto done;
> >               }
> >       }
> >
> > +     if (overflow_interrupts > 0) {
>
> ...here we only change from the default of 5 for nonzero.
>
> Should we allow '-n 0'? Otherwise overflow_interrupts can be initialized
> to zero (not that it matters).
>

I will change the default value to 0 to avoid ambiguity for now.
Please let me know if you strongly think we should support -n 0.
We can always support it. I just don't see the point of specifying the
test with options to disable it anymore.

> > +             if (targs.disabled_tests & SBI_PMU_TEST_OVERFLOW) {
> > +                     pr_info("-n option is only available for overflow test\n");
> > +                     goto done;
> > +             } else {
> > +                     targs.overflow_irqnum = overflow_interrupts;
> > +             }
> > +     }
> > +
> >       return true;
> >  done:
> >       test_print_help(argv[0]);
> > @@ -661,6 +684,7 @@ static bool parse_args(int argc, char *argv[])
> >  int main(int argc, char *argv[])
> >  {
> >       targs.disabled_tests = 0;
> > +     targs.overflow_irqnum = SBI_PMU_OVERFLOW_IRQNUM_DEFAULT;
> >
> >       if (!parse_args(argc, argv))
> >               exit(KSFT_SKIP);
> >
> > --
> > 2.43.0
> >
>
> Thanks,
> drew