On 2023-12-20 06:50, Haibo Xu wrote:
On Wed, Dec 20, 2023 at 2:22 AM Marc Zyngier maz@kernel.org wrote:
On Tue, 12 Dec 2023 09:31:20 +0000, Haibo Xu haibo1.xu@intel.com wrote:
@@ -216,6 +221,9 @@ static bool parse_args(int argc, char *argv[])
case 'm': test_args.migration_freq_ms = atoi_non_negative("Frequency", optarg); break;
case 'e':test_args.timer_err_margin_us = atoi_non_negative("Error Margin", optarg);break;So your error margin is always unsigned...
The error margin was supposed to be a non-negative [0, INT_MAX]. (May be need to define a Max for the input, instead of INT_MAX)
case 'o': test_args.counter_offset = strtol(optarg, NULL, 0); test_args.reserved = 0;diff --git a/tools/testing/selftests/kvm/include/timer_test.h b/tools/testing/selftests/kvm/include/timer_test.h index 968257b893a7..b1d405e7157d 100644 --- a/tools/testing/selftests/kvm/include/timer_test.h +++ b/tools/testing/selftests/kvm/include/timer_test.h @@ -22,6 +22,7 @@ struct test_args { int nr_iter; int timer_period_ms; int migration_freq_ms;
int timer_err_margin_us;... except that you are storing it as a signed value. Some consistency wouldn't hurt, really, and would avoid issues when passing large values.
Yes, it's more proper to use an unsigned int for the non-negative error margin. Storing as signed here is just to keep the type consistent with that of timer_period_ms since there will be '+' operation in other places.
tools/testing/selftests/kvm/aarch64/arch_timer.c /* Setup a timeout for the interrupt to arrive */ udelay(msecs_to_usecs(test_args.timer_period_ms) + test_args.timer_err_margin_us);
But that's exactly why using a signed quantity is wrong. What does it mean to have a huge *negative* margin?
I don't see how you can justify this.
M.