| Message ID | 20200728141005.28664-2-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | clean-ups for sleep=off behaviour | expand |
On 28/07/20 16:10, Alex Bennée wrote: > + /* > + * Check to see if we have run out of time. Most of our time > + * sources are nanoseconds since epoch (some time around the fall > + * of Babylon 5, the start of the Enterprises five year mission > + * and just before the arrival of the great evil ~ 2262CE). > + * Although icount based time is ns since the start of emulation > + * it is able to skip forward if the device is sleeping (think IoT > + * device with a very long heartbeat). Either way we don't really > + * handle running out of time so lets catch it and report it here. > + */ > + if (current_time == INT64_MAX) { > + qemu_handle_outa_time(); > + goto out; > + } > + Doing this here is a bit dangerous, I'd rather do nothing here and detect the situation in cpus.c where we can do qemu_system_shutdown_request() (and also do nothing). Paolo
Paolo Bonzini <pbonzini@redhat.com> writes: > On 28/07/20 16:10, Alex Bennée wrote: >> + /* >> + * Check to see if we have run out of time. Most of our time >> + * sources are nanoseconds since epoch (some time around the fall >> + * of Babylon 5, the start of the Enterprises five year mission >> + * and just before the arrival of the great evil ~ 2262CE). >> + * Although icount based time is ns since the start of emulation >> + * it is able to skip forward if the device is sleeping (think IoT >> + * device with a very long heartbeat). Either way we don't really >> + * handle running out of time so lets catch it and report it here. >> + */ >> + if (current_time == INT64_MAX) { >> + qemu_handle_outa_time(); >> + goto out; >> + } >> + > > Doing this here is a bit dangerous, I'd rather do nothing here and > detect the situation in cpus.c where we can do > qemu_system_shutdown_request() (and also do nothing). You mean in notify_aio_contexts()? Sure we can do that. I also figured it might be worth cleaning up the return progress stuff because AFAICT no one seems to care. > > Paolo -- Alex Bennée
On 28/07/20 18:08, Alex Bennée wrote: > > Paolo Bonzini <pbonzini@redhat.com> writes: > >> On 28/07/20 16:10, Alex Bennée wrote: >>> + /* >>> + * Check to see if we have run out of time. Most of our time >>> + * sources are nanoseconds since epoch (some time around the fall >>> + * of Babylon 5, the start of the Enterprises five year mission >>> + * and just before the arrival of the great evil ~ 2262CE). >>> + * Although icount based time is ns since the start of emulation >>> + * it is able to skip forward if the device is sleeping (think IoT >>> + * device with a very long heartbeat). Either way we don't really >>> + * handle running out of time so lets catch it and report it here. >>> + */ >>> + if (current_time == INT64_MAX) { >>> + qemu_handle_outa_time(); >>> + goto out; >>> + } >>> + >> >> Doing this here is a bit dangerous, I'd rather do nothing here and >> detect the situation in cpus.c where we can do >> qemu_system_shutdown_request() (and also do nothing). > > You mean in notify_aio_contexts()? Sure we can do that. Yes, that would work. I think qemu_clock_deadline_ns_all would already return -1 so that you'd have a zero-instruction budget from tcg_get_icount_limit. Paolo
diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h index 3c1da6a0183..7da3a5b60b5 100644 --- a/include/sysemu/cpus.h +++ b/include/sysemu/cpus.h @@ -15,6 +15,8 @@ void configure_icount(QemuOpts *opts, Error **errp); extern int use_icount; extern int icount_align_option; +void qemu_handle_outa_time(void); + /* drift information for info jit command */ extern int64_t max_delay; extern int64_t max_advance; diff --git a/softmmu/cpus.c b/softmmu/cpus.c index a802e899abb..46b6f346370 100644 --- a/softmmu/cpus.c +++ b/softmmu/cpus.c @@ -657,6 +657,19 @@ static bool shift_state_needed(void *opaque) return use_icount == 2; } +/* Handler for reaching the end of time */ +void qemu_handle_outa_time(void) +{ + static bool reported = false; + if (runstate_is_running()) { + if (!reported) { + error_report("ran out of time, suspending emulation"); + reported = true; + } + vm_stop(RUN_STATE_PAUSED); + } +} + /* * Subsection for warp timer migration is optional, because may not be created */ diff --git a/util/qemu-timer.c b/util/qemu-timer.c index f62b4feecdb..06f6818eb3d 100644 --- a/util/qemu-timer.c +++ b/util/qemu-timer.c @@ -540,6 +540,22 @@ bool timerlist_run_timers(QEMUTimerList *timer_list) * done". */ current_time = qemu_clock_get_ns(timer_list->clock->type); + + /* + * Check to see if we have run out of time. Most of our time + * sources are nanoseconds since epoch (some time around the fall + * of Babylon 5, the start of the Enterprises five year mission + * and just before the arrival of the great evil ~ 2262CE). + * Although icount based time is ns since the start of emulation + * it is able to skip forward if the device is sleeping (think IoT + * device with a very long heartbeat). Either way we don't really + * handle running out of time so lets catch it and report it here. + */ + if (current_time == INT64_MAX) { + qemu_handle_outa_time(); + goto out; + } + qemu_mutex_lock(&timer_list->active_timers_lock); while ((ts = timer_list->active_timers)) { if (!timer_expired_ns(ts, current_time)) { diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs index d42046afe4e..d363d8b551b 100644 --- a/stubs/Makefile.objs +++ b/stubs/Makefile.objs @@ -1,5 +1,6 @@ stub-obj-y += blk-commit-all.o stub-obj-y += cmos.o +stub-obj-y += cpus.o stub-obj-y += cpu-get-clock.o stub-obj-y += cpu-get-icount.o stub-obj-y += dump.o
The previous behaviour was rather user hostile as timers set for INT64_MAX would continually re-arm leaving the system locked in a loop and the console unavailable. With this patch we detect the situation and gracefully suspend the machine. NB: we need a proper fix before the 23rd century. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- include/sysemu/cpus.h | 2 ++ softmmu/cpus.c | 13 +++++++++++++ util/qemu-timer.c | 16 ++++++++++++++++ stubs/Makefile.objs | 1 + 4 files changed, 32 insertions(+) -- 2.20.1