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

On Thu, Feb 27, 2025 at 12:16 AM Andrew Jones ajones@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@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