Notify all timerlists derived from vm_clock in icount warp calculations. When calculating timer delay based on vm_clock deadline, use all timerlists.
For compatibility, maintain an apparent bug where when using icount, if no vm_clock timer was set, qemu_clock_deadline would return INT32_MAX and always set an icount clock expiry about 2 seconds ahead. NB: thread safety - when different timerlists sit on different threads, this will need some locking. Signed-off-by: Alex Bligh <a...@alex.org.uk> --- cpus.c | 44 ++++++++++++++++++++++++++++++++++++-------- include/qemu/timer.h | 1 + qemu-timer.c | 16 ++++++++++++++++ 3 files changed, 53 insertions(+), 8 deletions(-) diff --git a/cpus.c b/cpus.c index 0f65e76..55b9550 100644 --- a/cpus.c +++ b/cpus.c @@ -262,7 +262,7 @@ static void icount_warp_rt(void *opaque) qemu_icount_bias += MIN(warp_delta, delta); } if (qemu_clock_expired(vm_clock)) { - qemu_notify_event(); + qemu_clock_notify(vm_clock); } } vm_clock_warp_start = -1; @@ -279,7 +279,7 @@ void qtest_clock_warp(int64_t dest) qemu_run_timers(vm_clock); clock = qemu_get_clock_ns(vm_clock); } - qemu_notify_event(); + qemu_clock_notify(vm_clock); } void qemu_clock_warp(QEMUClock *clock) @@ -314,7 +314,18 @@ void qemu_clock_warp(QEMUClock *clock) } vm_clock_warp_start = qemu_get_clock_ns(rt_clock); - deadline = qemu_clock_deadline(vm_clock); + /* We want to use the earliest deadline from ALL vm_clocks */ + deadline = qemu_clock_deadline_ns_all(vm_clock); + + /* Maintain prior (possibly buggy) behaviour where if no deadline + * was set (as there is no vm_clock timer) or it is more than + * INT32_MAX nanoseconds ahead, we still use INT32_MAX + * nanoseconds. + */ + if ((deadline < 0) || (deadline > INT32_MAX)) { + deadline = INT32_MAX; + } + if (deadline > 0) { /* * Ensure the vm_clock proceeds even when the virtual CPU goes to @@ -333,8 +344,8 @@ void qemu_clock_warp(QEMUClock *clock) * packets continuously instead of every 100ms. */ qemu_mod_timer(icount_warp_timer, vm_clock_warp_start + deadline); - } else { - qemu_notify_event(); + } else if (deadline == 0) { + qemu_clock_notify(vm_clock); } } @@ -866,8 +877,13 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) while (1) { tcg_exec_all(); - if (use_icount && qemu_clock_deadline(vm_clock) <= 0) { - qemu_notify_event(); + + if (use_icount) { + int64_t deadline = qemu_clock_deadline_ns_all(vm_clock); + + if (deadline == 0) { + qemu_clock_notify(vm_clock); + } } qemu_tcg_wait_io_event(); } @@ -1145,11 +1161,23 @@ static int tcg_cpu_exec(CPUArchState *env) #endif if (use_icount) { int64_t count; + int64_t deadline; int decr; qemu_icount -= (env->icount_decr.u16.low + env->icount_extra); env->icount_decr.u16.low = 0; env->icount_extra = 0; - count = qemu_icount_round(qemu_clock_deadline(vm_clock)); + deadline = qemu_clock_deadline_ns_all(vm_clock); + + /* Maintain prior (possibly buggy) behaviour where if no deadline + * was set (as there is no vm_clock timer) or it is more than + * INT32_MAX nanoseconds ahead, we still use INT32_MAX + * nanoseconds. + */ + if ((deadline < 0) || (deadline > INT32_MAX)) { + deadline = INT32_MAX; + } + + count = qemu_icount_round(deadline); qemu_icount += count; decr = (count > 0xffff) ? 0xffff : count; count -= decr; diff --git a/include/qemu/timer.h b/include/qemu/timer.h index d3d4701..b6e5efd 100644 --- a/include/qemu/timer.h +++ b/include/qemu/timer.h @@ -60,6 +60,7 @@ int64_t qemu_clock_has_timers(QEMUClock *clock); int64_t qemu_clock_expired(QEMUClock *clock); int64_t qemu_clock_deadline(QEMUClock *clock); int64_t qemu_clock_deadline_ns(QEMUClock *clock); +int64_t qemu_clock_deadline_ns_all(QEMUClock *clock); bool qemu_clock_use_for_deadline(QEMUClock *clock); QEMUTimerList *qemu_clock_get_default_timerlist(QEMUClock *clock); void qemu_clock_notify(QEMUClock *clock); diff --git a/qemu-timer.c b/qemu-timer.c index 5f65455..a7ef047 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -389,6 +389,22 @@ int64_t qemu_clock_deadline_ns(QEMUClock *clock) return timerlist_deadline_ns(clock->default_timerlist); } +/* Calculate the soonest deadline across all timerlists attached + * to the clock. This is used for the icount timeout so we + * ignore whether or not the clock should be used in deadline + * calculations. + */ +int64_t qemu_clock_deadline_ns_all(QEMUClock *clock) +{ + int64_t deadline = -1; + QEMUTimerList *tl; + QLIST_FOREACH(tl, &clock->timerlists, list) { + deadline = qemu_soonest_timeout(deadline, + timerlist_deadline_ns(tl)); + } + return deadline; +} + QEMUClock *timerlist_get_clock(QEMUTimerList *tl) { return tl->clock; -- 1.7.9.5