Program an unmasked timer whose cval sits within long_wait_ms of the counter's wrap while the guest's counter is at wait_ms, and expect no interrupt. The guest's counter can't reach it, but a host that applies the timer's offset by adding it to cval wraps the sum into the past and fires at once. The one existing case with a cval past the wrap, in the sanity checks, runs with the timer masked and can't see that.
Signed-off-by: Fuad Tabba <[email protected]> --- .../kvm/arm64/arch_timer_edge_cases.c | 25 +++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c b/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c index d9c9377a63256..69986a7f0d37d 100644 --- a/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c +++ b/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c @@ -787,6 +787,30 @@ static void test_timers_in_the_past(enum arch_timer timer) } } +/* + * With the counter at wait_ms, a tval of -(wait_ms + long_wait_ms) puts cval + * within long_wait_ms of the counter's wrap: a deadline further away than the + * counter can reach. Unmasked, so an early ISTATUS shows up as an IRQ. + */ +static void test_timers_past_counter_wrap(enum arch_timer timer) +{ + s32 tval = -(s32)msec_to_cycles(test_args.wait_ms + test_args.long_wait_ms); + int i; + + for (i = 0; i < ARRAY_SIZE(sleep_method); i++) { + sleep_method_t sm = sleep_method[i]; + + local_irq_disable(); + set_counter(timer, msec_to_cycles(test_args.wait_ms)); + set_tval_irq(timer, tval, CTL_ENABLE); + sm(timer, msecs_to_usecs(test_args.wait_ms) + TIMEOUT_NO_IRQ_US); + local_irq_enable(); + isb(); + assert_irqs_handled(0); + timer_set_ctl(timer, CTL_IMASK); + } +} + static void test_long_timer_delays(enum arch_timer timer) { s32 tval = (s32)msec_to_cycles(test_args.long_wait_ms); @@ -806,6 +830,7 @@ static void guest_run_iteration(enum arch_timer timer) test_basic_functionality(timer); test_timers_sanity_checks(timer); + test_timers_past_counter_wrap(timer); test_timers_above_tval_max(timer); test_timers_in_the_past(timer); -- 2.39.5
