| Message ID | 20181109173309.25212-4-danielhb413@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | wakeup-from-suspend and system_wakeup changes | expand |
Daniel Henrique Barboza <danielhb413@gmail.com> writes: > The qmp/hmp command 'system_wakeup' is simply a direct call to > 'qemu_system_wakeup_request' from vl.c. This function verifies if > runstate is SUSPENDED and if the wake up reason is valid before > proceeding. However, no error or warning is thrown if any of those > pre-requirements isn't met. There is no way for the caller to > differentiate between a successful wakeup or an error state caused > when trying to wake up a guest that wasn't suspended. > > This means that system_wakeup is silently failing, which can be > considered a bug. Adding error handling isn't an API break in this > case - applications that didn't check the result will remain broken, > the ones that check it will have a chance to deal with it. > > Adding to that, the commit before previous created a new QMP API called > query-current-machine, with a new flag called wakeup-suspend-support, > that indicates if the guest has the capability of waking up from suspended > state. Although such guest will never reach SUSPENDED state and erroring > it out in this scenario would suffice, it is more informative for the user > to differentiate between a failure because the guest isn't suspended versus > a failure because the guest does not have support for wake up at all. > > All this considered, this patch changes qmp_system_wakeup to check if > the guest is capable of waking up from suspend, and if it is suspended. > After this patch, this is the output of system_wakeup in a guest that > does not have wake-up from suspend support (ppc64): > > (qemu) system_wakeup > wake-up from suspend is not supported by this guest > (qemu) > > And this is the output of system_wakeup in a x86 guest that has the > support but isn't suspended: > > (qemu) system_wakeup > Unable to wake up: guest is not in suspended state > (qemu) > > Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> > --- > hmp.c | 5 ++++- > hw/acpi/core.c | 4 +++- > hw/char/serial.c | 3 ++- > hw/input/ps2.c | 9 ++++++--- > hw/timer/mc146818rtc.c | 3 ++- > include/sysemu/sysemu.h | 3 ++- > migration/migration.c | 7 +++++-- > qapi/misc.json | 8 +++++++- > qmp.c | 13 ++++++++++++- > vl.c | 6 ++++-- > 10 files changed, 47 insertions(+), 14 deletions(-) > > diff --git a/hmp.c b/hmp.c > index 7828f93a39..0f5d943413 100644 > --- a/hmp.c > +++ b/hmp.c > @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) > > void hmp_system_wakeup(Monitor *mon, const QDict *qdict) > { > - qmp_system_wakeup(NULL); > + Error *err = NULL; > + > + qmp_system_wakeup(&err); > + hmp_handle_error(mon, &err); > } > > void hmp_nmi(Monitor *mon, const QDict *qdict) > diff --git a/hw/acpi/core.c b/hw/acpi/core.c > index 52e18d7810..a7073dd435 100644 > --- a/hw/acpi/core.c > +++ b/hw/acpi/core.c > @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) > static void acpi_pm_tmr_timer(void *opaque) > { > ACPIREGS *ar = opaque; > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); > + Error *err = NULL; > + > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); > ar->tmr.update_sci(ar); > } > > diff --git a/hw/char/serial.c b/hw/char/serial.c > index 02463e3388..23c5d2870c 100644 > --- a/hw/char/serial.c > +++ b/hw/char/serial.c > @@ -609,9 +609,10 @@ static int serial_can_receive1(void *opaque) > static void serial_receive1(void *opaque, const uint8_t *buf, int size) > { > SerialState *s = opaque; > + Error *err = NULL; > > if (s->wakeup) { > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); > } > if(s->fcr & UART_FCR_FE) { > int i; > diff --git a/hw/input/ps2.c b/hw/input/ps2.c > index 6c43fc2912..fc742b0061 100644 > --- a/hw/input/ps2.c > +++ b/hw/input/ps2.c > @@ -253,9 +253,10 @@ void ps2_queue_4(PS2State *s, int b1, int b2, int b3, int b4) > static void ps2_put_keycode(void *opaque, int keycode) > { > PS2KbdState *s = opaque; > + Error *err = NULL; > > trace_ps2_put_keycode(opaque, keycode); > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); > > if (s->translate) { > if (keycode == 0xf0) { > @@ -276,6 +277,7 @@ static void ps2_keyboard_event(DeviceState *dev, QemuConsole *src, > { > PS2KbdState *s = (PS2KbdState *)dev; > InputKeyEvent *key = evt->u.key.data; > + Error *err = NULL; > int qcode; > uint16_t keycode = 0; > int mod; > @@ -285,7 +287,7 @@ static void ps2_keyboard_event(DeviceState *dev, QemuConsole *src, > return; > } > > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); > assert(evt->type == INPUT_EVENT_KIND_KEY); > qcode = qemu_input_key_value_to_qcode(key->key); > > @@ -741,6 +743,7 @@ static void ps2_mouse_event(DeviceState *dev, QemuConsole *src, > static void ps2_mouse_sync(DeviceState *dev) > { > PS2MouseState *s = (PS2MouseState *)dev; > + Error *err = NULL; > > /* do not sync while disabled to prevent stream corruption */ > if (!(s->mouse_status & MOUSE_STATUS_ENABLED)) { > @@ -748,7 +751,7 @@ static void ps2_mouse_sync(DeviceState *dev) > } > > if (s->mouse_buttons) { > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); > } > if (!(s->mouse_status & MOUSE_STATUS_REMOTE)) { > /* if not remote, send event. Multiple events are sent if > diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c > index e4e4de8b8a..e65962cdb4 100644 > --- a/hw/timer/mc146818rtc.c > +++ b/hw/timer/mc146818rtc.c > @@ -443,6 +443,7 @@ static uint64_t get_next_alarm(RTCState *s) > static void rtc_update_timer(void *opaque) > { > RTCState *s = opaque; > + Error *err = NULL; > int32_t irqs = REG_C_UF; > int32_t new_irqs; > > @@ -455,7 +456,7 @@ static void rtc_update_timer(void *opaque) > if (qemu_clock_get_ns(rtc_clock) >= s->next_alarm_time) { > irqs |= REG_C_AF; > if (s->cmos_data[RTC_REG_B] & REG_B_AIE) { > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_RTC); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_RTC, &err); > } > } > > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h > index 0446adacc6..162c4b16d9 100644 > --- a/include/sysemu/sysemu.h > +++ b/include/sysemu/sysemu.h > @@ -74,7 +74,8 @@ void qemu_exit_preconfig_request(void); > void qemu_system_reset_request(ShutdownCause reason); > void qemu_system_suspend_request(void); > void qemu_register_suspend_notifier(Notifier *notifier); > -void qemu_system_wakeup_request(WakeupReason reason); > +bool qemu_wakeup_suspend_enabled(void); > +void qemu_system_wakeup_request(WakeupReason reason, Error **errp); > void qemu_system_wakeup_enable(WakeupReason reason, bool enabled); > void qemu_register_wakeup_notifier(Notifier *notifier); > void qemu_register_wakeup_support(void); > diff --git a/migration/migration.c b/migration/migration.c > index b261c1e4ce..8e9b4af71c 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -2390,6 +2390,8 @@ static int postcopy_start(MigrationState *ms) > int64_t bandwidth = migrate_max_postcopy_bandwidth(); > bool restart_block = false; > int cur_state = MIGRATION_STATUS_ACTIVE; > + Error *err = NULL; > + > if (!migrate_pause_before_switchover()) { > migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE, > MIGRATION_STATUS_POSTCOPY_ACTIVE); > @@ -2399,7 +2401,7 @@ static int postcopy_start(MigrationState *ms) > qemu_mutex_lock_iothread(); > trace_postcopy_start_set_run(); > > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); > global_state_store(); > ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); > if (ret < 0) { > @@ -2597,13 +2599,14 @@ static int migration_maybe_pause(MigrationState *s, > */ > static void migration_completion(MigrationState *s) > { > + Error *err = NULL; > int ret; > int current_active_state = s->state; > > if (s->state == MIGRATION_STATUS_ACTIVE) { > qemu_mutex_lock_iothread(); > s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); > s->vm_was_running = runstate_is_running(); > ret = global_state_store(); > > diff --git a/qapi/misc.json b/qapi/misc.json > index 9b86576e61..471f6e680c 100644 > --- a/qapi/misc.json > +++ b/qapi/misc.json > @@ -1235,12 +1235,18 @@ > ## > # @system_wakeup: > # > -# Wakeup guest from suspend. Does nothing in case the guest isn't suspended. > +# Wake-up guest from suspend. If the guest has wake-up from suspend > +# support enabled (wakeup-suspend-support flag from > +# query-current-machine), wake-up guest from suspend if the guest is "wake up guest", because wake-up is the noun, the verb is spelled wake up. > +# in SUSPENDED state. Returns an error otherwise. Imperative mood, please: "Return an error". > # > # Since: 1.1 > # > # Returns: nothing. > # > +# Note: prior to 3.2, this command does nothing in case the guest > +# isn't suspended. The next relase will be 4.0. > +# > # Example: > # > # -> { "execute": "system_wakeup" } > diff --git a/qmp.c b/qmp.c > index e7c0a2fd60..2265aa48b9 100644 > --- a/qmp.c > +++ b/qmp.c > @@ -183,7 +183,18 @@ void qmp_cont(Error **errp) > > void qmp_system_wakeup(Error **errp) > { > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); > + Error *local_err = NULL; > + > + if (!qemu_wakeup_suspend_enabled()) { > + error_setg(errp, > + "wake-up from suspend is not supported by this guest"); > + return; > + } > + > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &local_err); > + if (local_err) { > + error_propagate(errp, local_err); > + } Make that qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, errp); See error.h's big comment: * Receive an error and pass it on to the caller: * Error *err = NULL; * foo(arg, &err); * if (err) { * handle the error... * error_propagate(errp, err); * } * where Error **errp is a parameter, by convention the last one. [...] * But when all you do with the error is pass it on, please use * foo(arg, errp); * for readability. > } > > ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp) > diff --git a/vl.c b/vl.c > index 5813a8785f..b057796e48 100644 > --- a/vl.c > +++ b/vl.c > @@ -1754,11 +1754,13 @@ void qemu_register_suspend_notifier(Notifier *notifier) > notifier_list_add(&suspend_notifiers, notifier); > } > > -void qemu_system_wakeup_request(WakeupReason reason) > +void qemu_system_wakeup_request(WakeupReason reason, Error **errp) > { > trace_system_wakeup_request(reason); > > if (!runstate_check(RUN_STATE_SUSPENDED)) { > + error_setg(errp, > + "Unable to wake up: guest is not in suspended state"); > return; > } > if (!(wakeup_reason_mask & (1 << reason))) { > @@ -1788,7 +1790,7 @@ void qemu_register_wakeup_support(void) > wakeup_suspend_enabled = true; > } > > -static bool qemu_wakeup_suspend_enabled(void) > +bool qemu_wakeup_suspend_enabled(void) > { > return wakeup_suspend_enabled; > }
One more thing... Markus Armbruster <armbru@redhat.com> writes: > Daniel Henrique Barboza <danielhb413@gmail.com> writes: > >> The qmp/hmp command 'system_wakeup' is simply a direct call to >> 'qemu_system_wakeup_request' from vl.c. This function verifies if >> runstate is SUSPENDED and if the wake up reason is valid before >> proceeding. However, no error or warning is thrown if any of those >> pre-requirements isn't met. There is no way for the caller to >> differentiate between a successful wakeup or an error state caused >> when trying to wake up a guest that wasn't suspended. >> >> This means that system_wakeup is silently failing, which can be >> considered a bug. Adding error handling isn't an API break in this >> case - applications that didn't check the result will remain broken, >> the ones that check it will have a chance to deal with it. >> >> Adding to that, the commit before previous created a new QMP API called >> query-current-machine, with a new flag called wakeup-suspend-support, >> that indicates if the guest has the capability of waking up from suspended >> state. Although such guest will never reach SUSPENDED state and erroring >> it out in this scenario would suffice, it is more informative for the user >> to differentiate between a failure because the guest isn't suspended versus >> a failure because the guest does not have support for wake up at all. >> >> All this considered, this patch changes qmp_system_wakeup to check if >> the guest is capable of waking up from suspend, and if it is suspended. >> After this patch, this is the output of system_wakeup in a guest that >> does not have wake-up from suspend support (ppc64): >> >> (qemu) system_wakeup >> wake-up from suspend is not supported by this guest >> (qemu) >> >> And this is the output of system_wakeup in a x86 guest that has the >> support but isn't suspended: >> >> (qemu) system_wakeup >> Unable to wake up: guest is not in suspended state >> (qemu) >> >> Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> >> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> >> --- >> hmp.c | 5 ++++- >> hw/acpi/core.c | 4 +++- >> hw/char/serial.c | 3 ++- >> hw/input/ps2.c | 9 ++++++--- >> hw/timer/mc146818rtc.c | 3 ++- >> include/sysemu/sysemu.h | 3 ++- >> migration/migration.c | 7 +++++-- >> qapi/misc.json | 8 +++++++- >> qmp.c | 13 ++++++++++++- >> vl.c | 6 ++++-- >> 10 files changed, 47 insertions(+), 14 deletions(-) >> >> diff --git a/hmp.c b/hmp.c >> index 7828f93a39..0f5d943413 100644 >> --- a/hmp.c >> +++ b/hmp.c >> @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) >> >> void hmp_system_wakeup(Monitor *mon, const QDict *qdict) >> { >> - qmp_system_wakeup(NULL); >> + Error *err = NULL; >> + >> + qmp_system_wakeup(&err); >> + hmp_handle_error(mon, &err); >> } >> >> void hmp_nmi(Monitor *mon, const QDict *qdict) >> diff --git a/hw/acpi/core.c b/hw/acpi/core.c >> index 52e18d7810..a7073dd435 100644 >> --- a/hw/acpi/core.c >> +++ b/hw/acpi/core.c >> @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) >> static void acpi_pm_tmr_timer(void *opaque) >> { >> ACPIREGS *ar = opaque; >> - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); >> + Error *err = NULL; >> + >> + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); >> ar->tmr.update_sci(ar); >> } Leaks the error object when qemu_system_wakeup_request() fails. If it cannot fail here, pass &error_abort. If it can fail, but you want to ignore failure, pass NULL. More of the same elsewhere. [...]
On 11/29/18 4:55 PM, Markus Armbruster wrote: > One more thing... > > Markus Armbruster <armbru@redhat.com> writes: > >> Daniel Henrique Barboza <danielhb413@gmail.com> writes: >> >>> The qmp/hmp command 'system_wakeup' is simply a direct call to >>> 'qemu_system_wakeup_request' from vl.c. This function verifies if >>> runstate is SUSPENDED and if the wake up reason is valid before >>> proceeding. However, no error or warning is thrown if any of those >>> pre-requirements isn't met. There is no way for the caller to >>> differentiate between a successful wakeup or an error state caused >>> when trying to wake up a guest that wasn't suspended. >>> >>> This means that system_wakeup is silently failing, which can be >>> considered a bug. Adding error handling isn't an API break in this >>> case - applications that didn't check the result will remain broken, >>> the ones that check it will have a chance to deal with it. >>> >>> Adding to that, the commit before previous created a new QMP API called >>> query-current-machine, with a new flag called wakeup-suspend-support, >>> that indicates if the guest has the capability of waking up from suspended >>> state. Although such guest will never reach SUSPENDED state and erroring >>> it out in this scenario would suffice, it is more informative for the user >>> to differentiate between a failure because the guest isn't suspended versus >>> a failure because the guest does not have support for wake up at all. >>> >>> All this considered, this patch changes qmp_system_wakeup to check if >>> the guest is capable of waking up from suspend, and if it is suspended. >>> After this patch, this is the output of system_wakeup in a guest that >>> does not have wake-up from suspend support (ppc64): >>> >>> (qemu) system_wakeup >>> wake-up from suspend is not supported by this guest >>> (qemu) >>> >>> And this is the output of system_wakeup in a x86 guest that has the >>> support but isn't suspended: >>> >>> (qemu) system_wakeup >>> Unable to wake up: guest is not in suspended state >>> (qemu) >>> >>> Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> >>> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> >>> --- >>> hmp.c | 5 ++++- >>> hw/acpi/core.c | 4 +++- >>> hw/char/serial.c | 3 ++- >>> hw/input/ps2.c | 9 ++++++--- >>> hw/timer/mc146818rtc.c | 3 ++- >>> include/sysemu/sysemu.h | 3 ++- >>> migration/migration.c | 7 +++++-- >>> qapi/misc.json | 8 +++++++- >>> qmp.c | 13 ++++++++++++- >>> vl.c | 6 ++++-- >>> 10 files changed, 47 insertions(+), 14 deletions(-) >>> >>> diff --git a/hmp.c b/hmp.c >>> index 7828f93a39..0f5d943413 100644 >>> --- a/hmp.c >>> +++ b/hmp.c >>> @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) >>> >>> void hmp_system_wakeup(Monitor *mon, const QDict *qdict) >>> { >>> - qmp_system_wakeup(NULL); >>> + Error *err = NULL; >>> + >>> + qmp_system_wakeup(&err); >>> + hmp_handle_error(mon, &err); >>> } >>> >>> void hmp_nmi(Monitor *mon, const QDict *qdict) >>> diff --git a/hw/acpi/core.c b/hw/acpi/core.c >>> index 52e18d7810..a7073dd435 100644 >>> --- a/hw/acpi/core.c >>> +++ b/hw/acpi/core.c >>> @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) >>> static void acpi_pm_tmr_timer(void *opaque) >>> { >>> ACPIREGS *ar = opaque; >>> - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); >>> + Error *err = NULL; >>> + >>> + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); >>> ar->tmr.update_sci(ar); >>> } > Leaks the error object when qemu_system_wakeup_request() fails. > > If it cannot fail here, pass &error_abort. > > If it can fail, but you want to ignore failure, pass NULL. Good point. I'll simply pass NULL to all callers that didn't care for the error prior to this change. Thanks, Daniel > > More of the same elsewhere. > > [...]
On Tue, Dec 04, 2018 at 04:36:56PM -0200, Daniel Henrique Barboza wrote: > > > On 11/29/18 4:55 PM, Markus Armbruster wrote: > > One more thing... > > > > Markus Armbruster <armbru@redhat.com> writes: > > > > > Daniel Henrique Barboza <danielhb413@gmail.com> writes: > > > > > > > The qmp/hmp command 'system_wakeup' is simply a direct call to > > > > 'qemu_system_wakeup_request' from vl.c. This function verifies if > > > > runstate is SUSPENDED and if the wake up reason is valid before > > > > proceeding. However, no error or warning is thrown if any of those > > > > pre-requirements isn't met. There is no way for the caller to > > > > differentiate between a successful wakeup or an error state caused > > > > when trying to wake up a guest that wasn't suspended. > > > > > > > > This means that system_wakeup is silently failing, which can be > > > > considered a bug. Adding error handling isn't an API break in this > > > > case - applications that didn't check the result will remain broken, > > > > the ones that check it will have a chance to deal with it. > > > > > > > > Adding to that, the commit before previous created a new QMP API called > > > > query-current-machine, with a new flag called wakeup-suspend-support, > > > > that indicates if the guest has the capability of waking up from suspended > > > > state. Although such guest will never reach SUSPENDED state and erroring > > > > it out in this scenario would suffice, it is more informative for the user > > > > to differentiate between a failure because the guest isn't suspended versus > > > > a failure because the guest does not have support for wake up at all. > > > > > > > > All this considered, this patch changes qmp_system_wakeup to check if > > > > the guest is capable of waking up from suspend, and if it is suspended. > > > > After this patch, this is the output of system_wakeup in a guest that > > > > does not have wake-up from suspend support (ppc64): > > > > > > > > (qemu) system_wakeup > > > > wake-up from suspend is not supported by this guest > > > > (qemu) > > > > > > > > And this is the output of system_wakeup in a x86 guest that has the > > > > support but isn't suspended: > > > > > > > > (qemu) system_wakeup > > > > Unable to wake up: guest is not in suspended state > > > > (qemu) > > > > > > > > Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> > > > > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> > > > > --- > > > > hmp.c | 5 ++++- > > > > hw/acpi/core.c | 4 +++- > > > > hw/char/serial.c | 3 ++- > > > > hw/input/ps2.c | 9 ++++++--- > > > > hw/timer/mc146818rtc.c | 3 ++- > > > > include/sysemu/sysemu.h | 3 ++- > > > > migration/migration.c | 7 +++++-- > > > > qapi/misc.json | 8 +++++++- > > > > qmp.c | 13 ++++++++++++- > > > > vl.c | 6 ++++-- > > > > 10 files changed, 47 insertions(+), 14 deletions(-) > > > > > > > > diff --git a/hmp.c b/hmp.c > > > > index 7828f93a39..0f5d943413 100644 > > > > --- a/hmp.c > > > > +++ b/hmp.c > > > > @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) > > > > void hmp_system_wakeup(Monitor *mon, const QDict *qdict) > > > > { > > > > - qmp_system_wakeup(NULL); > > > > + Error *err = NULL; > > > > + > > > > + qmp_system_wakeup(&err); > > > > + hmp_handle_error(mon, &err); > > > > } > > > > void hmp_nmi(Monitor *mon, const QDict *qdict) > > > > diff --git a/hw/acpi/core.c b/hw/acpi/core.c > > > > index 52e18d7810..a7073dd435 100644 > > > > --- a/hw/acpi/core.c > > > > +++ b/hw/acpi/core.c > > > > @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) > > > > static void acpi_pm_tmr_timer(void *opaque) > > > > { > > > > ACPIREGS *ar = opaque; > > > > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); > > > > + Error *err = NULL; > > > > + > > > > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); > > > > ar->tmr.update_sci(ar); > > > > } > > Leaks the error object when qemu_system_wakeup_request() fails. > > > > If it cannot fail here, pass &error_abort. > > > > If it can fail, but you want to ignore failure, pass NULL. > > Good point. I'll simply pass NULL to all callers that didn't care > for the error prior to this change. Most times I saw QEMU code ignoring errors, it actually didn't expect any errors to happen and was supposed to be using &error_abort instead. This makes NULL errp always look like a bug to be fixed. If you are sure you really want to ignore an error, I'd recommend adding a comment making your intention explicit.
On 12/4/18 5:15 PM, Eduardo Habkost wrote: > On Tue, Dec 04, 2018 at 04:36:56PM -0200, Daniel Henrique Barboza wrote: >> >> On 11/29/18 4:55 PM, Markus Armbruster wrote: >>> One more thing... >>> >>> Markus Armbruster <armbru@redhat.com> writes: >>> >>>> Daniel Henrique Barboza <danielhb413@gmail.com> writes: >>>> >>>>> The qmp/hmp command 'system_wakeup' is simply a direct call to >>>>> 'qemu_system_wakeup_request' from vl.c. This function verifies if >>>>> runstate is SUSPENDED and if the wake up reason is valid before >>>>> proceeding. However, no error or warning is thrown if any of those >>>>> pre-requirements isn't met. There is no way for the caller to >>>>> differentiate between a successful wakeup or an error state caused >>>>> when trying to wake up a guest that wasn't suspended. >>>>> >>>>> This means that system_wakeup is silently failing, which can be >>>>> considered a bug. Adding error handling isn't an API break in this >>>>> case - applications that didn't check the result will remain broken, >>>>> the ones that check it will have a chance to deal with it. >>>>> >>>>> Adding to that, the commit before previous created a new QMP API called >>>>> query-current-machine, with a new flag called wakeup-suspend-support, >>>>> that indicates if the guest has the capability of waking up from suspended >>>>> state. Although such guest will never reach SUSPENDED state and erroring >>>>> it out in this scenario would suffice, it is more informative for the user >>>>> to differentiate between a failure because the guest isn't suspended versus >>>>> a failure because the guest does not have support for wake up at all. >>>>> >>>>> All this considered, this patch changes qmp_system_wakeup to check if >>>>> the guest is capable of waking up from suspend, and if it is suspended. >>>>> After this patch, this is the output of system_wakeup in a guest that >>>>> does not have wake-up from suspend support (ppc64): >>>>> >>>>> (qemu) system_wakeup >>>>> wake-up from suspend is not supported by this guest >>>>> (qemu) >>>>> >>>>> And this is the output of system_wakeup in a x86 guest that has the >>>>> support but isn't suspended: >>>>> >>>>> (qemu) system_wakeup >>>>> Unable to wake up: guest is not in suspended state >>>>> (qemu) >>>>> >>>>> Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> >>>>> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> >>>>> --- >>>>> hmp.c | 5 ++++- >>>>> hw/acpi/core.c | 4 +++- >>>>> hw/char/serial.c | 3 ++- >>>>> hw/input/ps2.c | 9 ++++++--- >>>>> hw/timer/mc146818rtc.c | 3 ++- >>>>> include/sysemu/sysemu.h | 3 ++- >>>>> migration/migration.c | 7 +++++-- >>>>> qapi/misc.json | 8 +++++++- >>>>> qmp.c | 13 ++++++++++++- >>>>> vl.c | 6 ++++-- >>>>> 10 files changed, 47 insertions(+), 14 deletions(-) >>>>> >>>>> diff --git a/hmp.c b/hmp.c >>>>> index 7828f93a39..0f5d943413 100644 >>>>> --- a/hmp.c >>>>> +++ b/hmp.c >>>>> @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) >>>>> void hmp_system_wakeup(Monitor *mon, const QDict *qdict) >>>>> { >>>>> - qmp_system_wakeup(NULL); >>>>> + Error *err = NULL; >>>>> + >>>>> + qmp_system_wakeup(&err); >>>>> + hmp_handle_error(mon, &err); >>>>> } >>>>> void hmp_nmi(Monitor *mon, const QDict *qdict) >>>>> diff --git a/hw/acpi/core.c b/hw/acpi/core.c >>>>> index 52e18d7810..a7073dd435 100644 >>>>> --- a/hw/acpi/core.c >>>>> +++ b/hw/acpi/core.c >>>>> @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) >>>>> static void acpi_pm_tmr_timer(void *opaque) >>>>> { >>>>> ACPIREGS *ar = opaque; >>>>> - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); >>>>> + Error *err = NULL; >>>>> + >>>>> + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); >>>>> ar->tmr.update_sci(ar); >>>>> } >>> Leaks the error object when qemu_system_wakeup_request() fails. >>> >>> If it cannot fail here, pass &error_abort. >>> >>> If it can fail, but you want to ignore failure, pass NULL. >> Good point. I'll simply pass NULL to all callers that didn't care >> for the error prior to this change. > Most times I saw QEMU code ignoring errors, it actually didn't > expect any errors to happen and was supposed to be using > &error_abort instead. In this particular case, the existing code wouldn't be expecting errors because qemu_system_wakeup_request wasn't reporting any. Prior to this patch, the function would either change the runstate and notify the wake up event or fail silently. The idea of the patch is to add the extra Error pointer into qemu_system_wakeup_request, so qmp_system_wakeup can propagate the runstate_check error back to hmp_system_wakeup, instead of duplicating this runstate verification inside qmp_system_wakeup (like I was doing in some earlier version). With this idea in mind, passing NULL in the errp of the remaining qemu_system_wakeup_request calls will not improve the existing usage or fix potential bugs, sure, but doesn't make it worse either. I don't see any problems with re-evaluating every existing qemu_system_wakeup_request call and judge f qemu should error_abort out of it in case of error. It's just out of scope of this patch series, IMO. Thanks, Daniel > > This makes NULL errp always look like a bug to be fixed. If you > are sure you really want to ignore an error, I'd recommend adding > a comment making your intention explicit. >
Daniel Henrique Barboza <danielhb413@gmail.com> writes: > On 12/4/18 5:15 PM, Eduardo Habkost wrote: >> On Tue, Dec 04, 2018 at 04:36:56PM -0200, Daniel Henrique Barboza wrote: >>> >>> On 11/29/18 4:55 PM, Markus Armbruster wrote: >>>> One more thing... >>>> >>>> Markus Armbruster <armbru@redhat.com> writes: >>>> >>>>> Daniel Henrique Barboza <danielhb413@gmail.com> writes: >>>>> >>>>>> The qmp/hmp command 'system_wakeup' is simply a direct call to >>>>>> 'qemu_system_wakeup_request' from vl.c. This function verifies if >>>>>> runstate is SUSPENDED and if the wake up reason is valid before >>>>>> proceeding. However, no error or warning is thrown if any of those >>>>>> pre-requirements isn't met. There is no way for the caller to >>>>>> differentiate between a successful wakeup or an error state caused >>>>>> when trying to wake up a guest that wasn't suspended. >>>>>> >>>>>> This means that system_wakeup is silently failing, which can be >>>>>> considered a bug. Adding error handling isn't an API break in this >>>>>> case - applications that didn't check the result will remain broken, >>>>>> the ones that check it will have a chance to deal with it. >>>>>> >>>>>> Adding to that, the commit before previous created a new QMP API called >>>>>> query-current-machine, with a new flag called wakeup-suspend-support, >>>>>> that indicates if the guest has the capability of waking up from suspended >>>>>> state. Although such guest will never reach SUSPENDED state and erroring >>>>>> it out in this scenario would suffice, it is more informative for the user >>>>>> to differentiate between a failure because the guest isn't suspended versus >>>>>> a failure because the guest does not have support for wake up at all. >>>>>> >>>>>> All this considered, this patch changes qmp_system_wakeup to check if >>>>>> the guest is capable of waking up from suspend, and if it is suspended. >>>>>> After this patch, this is the output of system_wakeup in a guest that >>>>>> does not have wake-up from suspend support (ppc64): >>>>>> >>>>>> (qemu) system_wakeup >>>>>> wake-up from suspend is not supported by this guest >>>>>> (qemu) >>>>>> >>>>>> And this is the output of system_wakeup in a x86 guest that has the >>>>>> support but isn't suspended: >>>>>> >>>>>> (qemu) system_wakeup >>>>>> Unable to wake up: guest is not in suspended state >>>>>> (qemu) >>>>>> >>>>>> Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> >>>>>> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> >>>>>> --- >>>>>> hmp.c | 5 ++++- >>>>>> hw/acpi/core.c | 4 +++- >>>>>> hw/char/serial.c | 3 ++- >>>>>> hw/input/ps2.c | 9 ++++++--- >>>>>> hw/timer/mc146818rtc.c | 3 ++- >>>>>> include/sysemu/sysemu.h | 3 ++- >>>>>> migration/migration.c | 7 +++++-- >>>>>> qapi/misc.json | 8 +++++++- >>>>>> qmp.c | 13 ++++++++++++- >>>>>> vl.c | 6 ++++-- >>>>>> 10 files changed, 47 insertions(+), 14 deletions(-) >>>>>> >>>>>> diff --git a/hmp.c b/hmp.c >>>>>> index 7828f93a39..0f5d943413 100644 >>>>>> --- a/hmp.c >>>>>> +++ b/hmp.c >>>>>> @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) >>>>>> void hmp_system_wakeup(Monitor *mon, const QDict *qdict) >>>>>> { >>>>>> - qmp_system_wakeup(NULL); >>>>>> + Error *err = NULL; >>>>>> + >>>>>> + qmp_system_wakeup(&err); >>>>>> + hmp_handle_error(mon, &err); >>>>>> } >>>>>> void hmp_nmi(Monitor *mon, const QDict *qdict) >>>>>> diff --git a/hw/acpi/core.c b/hw/acpi/core.c >>>>>> index 52e18d7810..a7073dd435 100644 >>>>>> --- a/hw/acpi/core.c >>>>>> +++ b/hw/acpi/core.c >>>>>> @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) >>>>>> static void acpi_pm_tmr_timer(void *opaque) >>>>>> { >>>>>> ACPIREGS *ar = opaque; >>>>>> - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); >>>>>> + Error *err = NULL; >>>>>> + >>>>>> + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); >>>>>> ar->tmr.update_sci(ar); >>>>>> } >>>> Leaks the error object when qemu_system_wakeup_request() fails. >>>> >>>> If it cannot fail here, pass &error_abort. >>>> >>>> If it can fail, but you want to ignore failure, pass NULL. >>> Good point. I'll simply pass NULL to all callers that didn't care >>> for the error prior to this change. >> Most times I saw QEMU code ignoring errors, it actually didn't >> expect any errors to happen and was supposed to be using >> &error_abort instead. >> >> This makes NULL errp always look like a bug to be fixed. If you >> are sure you really want to ignore an error, I'd recommend adding >> a comment making your intention explicit. I agree the "ignore errors" feature is widely abused. I don't agree with adding "I mean it" comments. I think the proper remedy is to flag abuses in patch review, and clean them up wherever we find them. > In this particular case, the existing code wouldn't be expecting > errors because > qemu_system_wakeup_request wasn't reporting any. Prior to this patch, > the function > would either change the runstate and notify the wake up event or fail > silently. > > The idea of the patch is to add the extra Error pointer into > qemu_system_wakeup_request, > so qmp_system_wakeup can propagate the runstate_check error back to > hmp_system_wakeup, > instead of duplicating this runstate verification inside > qmp_system_wakeup (like I was > doing in some earlier version). With this idea in mind, passing NULL > in the errp > of the remaining qemu_system_wakeup_request calls will not improve the > existing usage > or fix potential bugs, sure, but doesn't make it worse either. > > I don't see any problems with re-evaluating every existing > qemu_system_wakeup_request > call and judge f qemu should error_abort out of it in case of > error. It's just out of scope of > this patch series, IMO. Okay. I asked you to eliminate the code duplication, and I don't want to punish your good deed there by demanding further cleanup. That said, further cleanup is always welcome :)
On 12/5/18 5:35 AM, Markus Armbruster wrote: > Daniel Henrique Barboza <danielhb413@gmail.com> writes: > >> On 12/4/18 5:15 PM, Eduardo Habkost wrote: >>> On Tue, Dec 04, 2018 at 04:36:56PM -0200, Daniel Henrique Barboza wrote: >>>> On 11/29/18 4:55 PM, Markus Armbruster wrote: >>>>> One more thing... >>>>> >>>>> Markus Armbruster <armbru@redhat.com> writes: >>>>> >>>>>> Daniel Henrique Barboza <danielhb413@gmail.com> writes: >>>>>> >>>>>>> The qmp/hmp command 'system_wakeup' is simply a direct call to >>>>>>> 'qemu_system_wakeup_request' from vl.c. This function verifies if >>>>>>> runstate is SUSPENDED and if the wake up reason is valid before >>>>>>> proceeding. However, no error or warning is thrown if any of those >>>>>>> pre-requirements isn't met. There is no way for the caller to >>>>>>> differentiate between a successful wakeup or an error state caused >>>>>>> when trying to wake up a guest that wasn't suspended. >>>>>>> >>>>>>> This means that system_wakeup is silently failing, which can be >>>>>>> considered a bug. Adding error handling isn't an API break in this >>>>>>> case - applications that didn't check the result will remain broken, >>>>>>> the ones that check it will have a chance to deal with it. >>>>>>> >>>>>>> Adding to that, the commit before previous created a new QMP API called >>>>>>> query-current-machine, with a new flag called wakeup-suspend-support, >>>>>>> that indicates if the guest has the capability of waking up from suspended >>>>>>> state. Although such guest will never reach SUSPENDED state and erroring >>>>>>> it out in this scenario would suffice, it is more informative for the user >>>>>>> to differentiate between a failure because the guest isn't suspended versus >>>>>>> a failure because the guest does not have support for wake up at all. >>>>>>> >>>>>>> All this considered, this patch changes qmp_system_wakeup to check if >>>>>>> the guest is capable of waking up from suspend, and if it is suspended. >>>>>>> After this patch, this is the output of system_wakeup in a guest that >>>>>>> does not have wake-up from suspend support (ppc64): >>>>>>> >>>>>>> (qemu) system_wakeup >>>>>>> wake-up from suspend is not supported by this guest >>>>>>> (qemu) >>>>>>> >>>>>>> And this is the output of system_wakeup in a x86 guest that has the >>>>>>> support but isn't suspended: >>>>>>> >>>>>>> (qemu) system_wakeup >>>>>>> Unable to wake up: guest is not in suspended state >>>>>>> (qemu) >>>>>>> >>>>>>> Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> >>>>>>> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> >>>>>>> --- >>>>>>> hmp.c | 5 ++++- >>>>>>> hw/acpi/core.c | 4 +++- >>>>>>> hw/char/serial.c | 3 ++- >>>>>>> hw/input/ps2.c | 9 ++++++--- >>>>>>> hw/timer/mc146818rtc.c | 3 ++- >>>>>>> include/sysemu/sysemu.h | 3 ++- >>>>>>> migration/migration.c | 7 +++++-- >>>>>>> qapi/misc.json | 8 +++++++- >>>>>>> qmp.c | 13 ++++++++++++- >>>>>>> vl.c | 6 ++++-- >>>>>>> 10 files changed, 47 insertions(+), 14 deletions(-) >>>>>>> >>>>>>> diff --git a/hmp.c b/hmp.c >>>>>>> index 7828f93a39..0f5d943413 100644 >>>>>>> --- a/hmp.c >>>>>>> +++ b/hmp.c >>>>>>> @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) >>>>>>> void hmp_system_wakeup(Monitor *mon, const QDict *qdict) >>>>>>> { >>>>>>> - qmp_system_wakeup(NULL); >>>>>>> + Error *err = NULL; >>>>>>> + >>>>>>> + qmp_system_wakeup(&err); >>>>>>> + hmp_handle_error(mon, &err); >>>>>>> } >>>>>>> void hmp_nmi(Monitor *mon, const QDict *qdict) >>>>>>> diff --git a/hw/acpi/core.c b/hw/acpi/core.c >>>>>>> index 52e18d7810..a7073dd435 100644 >>>>>>> --- a/hw/acpi/core.c >>>>>>> +++ b/hw/acpi/core.c >>>>>>> @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) >>>>>>> static void acpi_pm_tmr_timer(void *opaque) >>>>>>> { >>>>>>> ACPIREGS *ar = opaque; >>>>>>> - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); >>>>>>> + Error *err = NULL; >>>>>>> + >>>>>>> + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); >>>>>>> ar->tmr.update_sci(ar); >>>>>>> } >>>>> Leaks the error object when qemu_system_wakeup_request() fails. >>>>> >>>>> If it cannot fail here, pass &error_abort. >>>>> >>>>> If it can fail, but you want to ignore failure, pass NULL. >>>> Good point. I'll simply pass NULL to all callers that didn't care >>>> for the error prior to this change. >>> Most times I saw QEMU code ignoring errors, it actually didn't >>> expect any errors to happen and was supposed to be using >>> &error_abort instead. >>> >>> This makes NULL errp always look like a bug to be fixed. If you >>> are sure you really want to ignore an error, I'd recommend adding >>> a comment making your intention explicit. > I agree the "ignore errors" feature is widely abused. I don't agree > with adding "I mean it" comments. I think the proper remedy is to flag > abuses in patch review, and clean them up wherever we find them. > >> In this particular case, the existing code wouldn't be expecting >> errors because >> qemu_system_wakeup_request wasn't reporting any. Prior to this patch, >> the function >> would either change the runstate and notify the wake up event or fail >> silently. >> >> The idea of the patch is to add the extra Error pointer into >> qemu_system_wakeup_request, >> so qmp_system_wakeup can propagate the runstate_check error back to >> hmp_system_wakeup, >> instead of duplicating this runstate verification inside >> qmp_system_wakeup (like I was >> doing in some earlier version). With this idea in mind, passing NULL >> in the errp >> of the remaining qemu_system_wakeup_request calls will not improve the >> existing usage >> or fix potential bugs, sure, but doesn't make it worse either. >> >> I don't see any problems with re-evaluating every existing >> qemu_system_wakeup_request >> call and judge f qemu should error_abort out of it in case of >> error. It's just out of scope of >> this patch series, IMO. > Okay. I asked you to eliminate the code duplication, and I don't want > to punish your good deed there by demanding further cleanup. That said, > further cleanup is always welcome :) I agree! Let's see if we can get this series pushed first, then we can get back to all these new "ignore errors" we just added here. Daniel
diff --git a/hmp.c b/hmp.c index 7828f93a39..0f5d943413 100644 --- a/hmp.c +++ b/hmp.c @@ -1220,7 +1220,10 @@ void hmp_cont(Monitor *mon, const QDict *qdict) void hmp_system_wakeup(Monitor *mon, const QDict *qdict) { - qmp_system_wakeup(NULL); + Error *err = NULL; + + qmp_system_wakeup(&err); + hmp_handle_error(mon, &err); } void hmp_nmi(Monitor *mon, const QDict *qdict) diff --git a/hw/acpi/core.c b/hw/acpi/core.c index 52e18d7810..a7073dd435 100644 --- a/hw/acpi/core.c +++ b/hw/acpi/core.c @@ -514,7 +514,9 @@ static uint32_t acpi_pm_tmr_get(ACPIREGS *ar) static void acpi_pm_tmr_timer(void *opaque) { ACPIREGS *ar = opaque; - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER); + Error *err = NULL; + + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, &err); ar->tmr.update_sci(ar); } diff --git a/hw/char/serial.c b/hw/char/serial.c index 02463e3388..23c5d2870c 100644 --- a/hw/char/serial.c +++ b/hw/char/serial.c @@ -609,9 +609,10 @@ static int serial_can_receive1(void *opaque) static void serial_receive1(void *opaque, const uint8_t *buf, int size) { SerialState *s = opaque; + Error *err = NULL; if (s->wakeup) { - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); } if(s->fcr & UART_FCR_FE) { int i; diff --git a/hw/input/ps2.c b/hw/input/ps2.c index 6c43fc2912..fc742b0061 100644 --- a/hw/input/ps2.c +++ b/hw/input/ps2.c @@ -253,9 +253,10 @@ void ps2_queue_4(PS2State *s, int b1, int b2, int b3, int b4) static void ps2_put_keycode(void *opaque, int keycode) { PS2KbdState *s = opaque; + Error *err = NULL; trace_ps2_put_keycode(opaque, keycode); - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); if (s->translate) { if (keycode == 0xf0) { @@ -276,6 +277,7 @@ static void ps2_keyboard_event(DeviceState *dev, QemuConsole *src, { PS2KbdState *s = (PS2KbdState *)dev; InputKeyEvent *key = evt->u.key.data; + Error *err = NULL; int qcode; uint16_t keycode = 0; int mod; @@ -285,7 +287,7 @@ static void ps2_keyboard_event(DeviceState *dev, QemuConsole *src, return; } - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); assert(evt->type == INPUT_EVENT_KIND_KEY); qcode = qemu_input_key_value_to_qcode(key->key); @@ -741,6 +743,7 @@ static void ps2_mouse_event(DeviceState *dev, QemuConsole *src, static void ps2_mouse_sync(DeviceState *dev) { PS2MouseState *s = (PS2MouseState *)dev; + Error *err = NULL; /* do not sync while disabled to prevent stream corruption */ if (!(s->mouse_status & MOUSE_STATUS_ENABLED)) { @@ -748,7 +751,7 @@ static void ps2_mouse_sync(DeviceState *dev) } if (s->mouse_buttons) { - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); } if (!(s->mouse_status & MOUSE_STATUS_REMOTE)) { /* if not remote, send event. Multiple events are sent if diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c index e4e4de8b8a..e65962cdb4 100644 --- a/hw/timer/mc146818rtc.c +++ b/hw/timer/mc146818rtc.c @@ -443,6 +443,7 @@ static uint64_t get_next_alarm(RTCState *s) static void rtc_update_timer(void *opaque) { RTCState *s = opaque; + Error *err = NULL; int32_t irqs = REG_C_UF; int32_t new_irqs; @@ -455,7 +456,7 @@ static void rtc_update_timer(void *opaque) if (qemu_clock_get_ns(rtc_clock) >= s->next_alarm_time) { irqs |= REG_C_AF; if (s->cmos_data[RTC_REG_B] & REG_B_AIE) { - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_RTC); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_RTC, &err); } } diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index 0446adacc6..162c4b16d9 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -74,7 +74,8 @@ void qemu_exit_preconfig_request(void); void qemu_system_reset_request(ShutdownCause reason); void qemu_system_suspend_request(void); void qemu_register_suspend_notifier(Notifier *notifier); -void qemu_system_wakeup_request(WakeupReason reason); +bool qemu_wakeup_suspend_enabled(void); +void qemu_system_wakeup_request(WakeupReason reason, Error **errp); void qemu_system_wakeup_enable(WakeupReason reason, bool enabled); void qemu_register_wakeup_notifier(Notifier *notifier); void qemu_register_wakeup_support(void); diff --git a/migration/migration.c b/migration/migration.c index b261c1e4ce..8e9b4af71c 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -2390,6 +2390,8 @@ static int postcopy_start(MigrationState *ms) int64_t bandwidth = migrate_max_postcopy_bandwidth(); bool restart_block = false; int cur_state = MIGRATION_STATUS_ACTIVE; + Error *err = NULL; + if (!migrate_pause_before_switchover()) { migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_POSTCOPY_ACTIVE); @@ -2399,7 +2401,7 @@ static int postcopy_start(MigrationState *ms) qemu_mutex_lock_iothread(); trace_postcopy_start_set_run(); - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); global_state_store(); ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); if (ret < 0) { @@ -2597,13 +2599,14 @@ static int migration_maybe_pause(MigrationState *s, */ static void migration_completion(MigrationState *s) { + Error *err = NULL; int ret; int current_active_state = s->state; if (s->state == MIGRATION_STATUS_ACTIVE) { qemu_mutex_lock_iothread(); s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &err); s->vm_was_running = runstate_is_running(); ret = global_state_store(); diff --git a/qapi/misc.json b/qapi/misc.json index 9b86576e61..471f6e680c 100644 --- a/qapi/misc.json +++ b/qapi/misc.json @@ -1235,12 +1235,18 @@ ## # @system_wakeup: # -# Wakeup guest from suspend. Does nothing in case the guest isn't suspended. +# Wake-up guest from suspend. If the guest has wake-up from suspend +# support enabled (wakeup-suspend-support flag from +# query-current-machine), wake-up guest from suspend if the guest is +# in SUSPENDED state. Returns an error otherwise. # # Since: 1.1 # # Returns: nothing. # +# Note: prior to 3.2, this command does nothing in case the guest +# isn't suspended. +# # Example: # # -> { "execute": "system_wakeup" } diff --git a/qmp.c b/qmp.c index e7c0a2fd60..2265aa48b9 100644 --- a/qmp.c +++ b/qmp.c @@ -183,7 +183,18 @@ void qmp_cont(Error **errp) void qmp_system_wakeup(Error **errp) { - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + Error *local_err = NULL; + + if (!qemu_wakeup_suspend_enabled()) { + error_setg(errp, + "wake-up from suspend is not supported by this guest"); + return; + } + + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &local_err); + if (local_err) { + error_propagate(errp, local_err); + } } ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp) diff --git a/vl.c b/vl.c index 5813a8785f..b057796e48 100644 --- a/vl.c +++ b/vl.c @@ -1754,11 +1754,13 @@ void qemu_register_suspend_notifier(Notifier *notifier) notifier_list_add(&suspend_notifiers, notifier); } -void qemu_system_wakeup_request(WakeupReason reason) +void qemu_system_wakeup_request(WakeupReason reason, Error **errp) { trace_system_wakeup_request(reason); if (!runstate_check(RUN_STATE_SUSPENDED)) { + error_setg(errp, + "Unable to wake up: guest is not in suspended state"); return; } if (!(wakeup_reason_mask & (1 << reason))) { @@ -1788,7 +1790,7 @@ void qemu_register_wakeup_support(void) wakeup_suspend_enabled = true; } -static bool qemu_wakeup_suspend_enabled(void) +bool qemu_wakeup_suspend_enabled(void) { return wakeup_suspend_enabled; }
The qmp/hmp command 'system_wakeup' is simply a direct call to 'qemu_system_wakeup_request' from vl.c. This function verifies if runstate is SUSPENDED and if the wake up reason is valid before proceeding. However, no error or warning is thrown if any of those pre-requirements isn't met. There is no way for the caller to differentiate between a successful wakeup or an error state caused when trying to wake up a guest that wasn't suspended. This means that system_wakeup is silently failing, which can be considered a bug. Adding error handling isn't an API break in this case - applications that didn't check the result will remain broken, the ones that check it will have a chance to deal with it. Adding to that, the commit before previous created a new QMP API called query-current-machine, with a new flag called wakeup-suspend-support, that indicates if the guest has the capability of waking up from suspended state. Although such guest will never reach SUSPENDED state and erroring it out in this scenario would suffice, it is more informative for the user to differentiate between a failure because the guest isn't suspended versus a failure because the guest does not have support for wake up at all. All this considered, this patch changes qmp_system_wakeup to check if the guest is capable of waking up from suspend, and if it is suspended. After this patch, this is the output of system_wakeup in a guest that does not have wake-up from suspend support (ppc64): (qemu) system_wakeup wake-up from suspend is not supported by this guest (qemu) And this is the output of system_wakeup in a x86 guest that has the support but isn't suspended: (qemu) system_wakeup Unable to wake up: guest is not in suspended state (qemu) Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> --- hmp.c | 5 ++++- hw/acpi/core.c | 4 +++- hw/char/serial.c | 3 ++- hw/input/ps2.c | 9 ++++++--- hw/timer/mc146818rtc.c | 3 ++- include/sysemu/sysemu.h | 3 ++- migration/migration.c | 7 +++++-- qapi/misc.json | 8 +++++++- qmp.c | 13 ++++++++++++- vl.c | 6 ++++-- 10 files changed, 47 insertions(+), 14 deletions(-)