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author | Daniel Henrique Barboza <danielhb413@gmail.com> | 2018-12-05 17:46:59 -0200 |
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committer | Markus Armbruster <armbru@redhat.com> | 2018-12-18 07:55:47 +0100 |
commit | 46ea94ca9cfcd56c27efafd2ff32281360e0267f (patch) | |
tree | 0ea689cac4cc897a38969a880ce18d5b0dc7dcf7 /vl.c | |
parent | 9254893882139b9a7738214d669958df4dfeee2f (diff) | |
download | qemu-46ea94ca9cfcd56c27efafd2ff32281360e0267f.zip qemu-46ea94ca9cfcd56c27efafd2ff32281360e0267f.tar.gz qemu-46ea94ca9cfcd56c27efafd2ff32281360e0267f.tar.bz2 |
qmp: query-current-machine with wakeup-suspend-support
When issuing the qmp/hmp 'system_wakeup' command, what happens in a
nutshell is:
- qmp_system_wakeup_request set runstate to RUNNING, sets a wakeup_reason
and notify the event
- in the main_loop, all vcpus are paused, a system reset is issued, all
subscribers of wakeup_notifiers receives a notification, vcpus are then
resumed and the wake up QAPI event is fired
Note that this procedure alone doesn't ensure that the guest will awake
from SUSPENDED state - the subscribers of the wake up event must take
action to resume the guest, otherwise the guest will simply reboot. At
this moment, only the ACPI machines via acpi_pm1_cnt_init and xen_hvm_init
have wake-up from suspend support.
However, only the presence of 'system_wakeup' is required for QGA to
support 'guest-suspend-ram' and 'guest-suspend-hybrid' at this moment.
This means that the user/management will expect to suspend the guest using
one of those suspend commands and then resume execution using system_wakeup,
regardless of the support offered in system_wakeup in the first place.
This patch creates a new API called query-current-machine [1], that holds
a new flag called 'wakeup-suspend-support' that indicates if the guest
supports wake up from suspend via system_wakeup. The machine is considered
to implement wake-up support if a call to a new 'qemu_register_wakeup_support'
is made during its init, as it is now being done inside acpi_pm1_cnt_init
and xen_hvm_init. This allows for any other machine type to declare wake-up
support regardless of ACPI state or wakeup_notifiers subscription, making easier
for newer implementations that might have their own mechanisms in the future.
This is the expected output of query-current-machine when running a x86
guest:
{"execute" : "query-current-machine"}
{"return": {"wakeup-suspend-support": true}}
Running the same x86 guest, but with the --no-acpi option:
{"execute" : "query-current-machine"}
{"return": {"wakeup-suspend-support": false}}
This is the output when running a pseries guest:
{"execute" : "query-current-machine"}
{"return": {"wakeup-suspend-support": false}}
With this extra tool, management can avoid situations where a guest
that does not have proper suspend/wake capabilities ends up in
inconsistent state (e.g.
https://github.com/open-power-host-os/qemu/issues/31).
[1] the decision of creating the query-current-machine API is based
on discussions in the QEMU mailing list where it was decided that
query-target wasn't a proper place to store the wake-up flag, neither
was query-machines because this isn't a static property of the
machine object. This new API can then be used to store other
dynamic machine properties that are scattered around the code
ATM. More info at:
https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg04235.html
Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20181205194701.17836-2-danielhb413@gmail.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Diffstat (limited to 'vl.c')
-rw-r--r-- | vl.c | 19 |
1 files changed, 19 insertions, 0 deletions
@@ -192,6 +192,7 @@ bool boot_strict; uint8_t *boot_splash_filedata; size_t boot_splash_filedata_size; uint8_t qemu_extra_params_fw[2]; +bool wakeup_suspend_enabled; int icount_align_option; @@ -1780,6 +1781,24 @@ void qemu_register_wakeup_notifier(Notifier *notifier) notifier_list_add(&wakeup_notifiers, notifier); } +void qemu_register_wakeup_support(void) +{ + wakeup_suspend_enabled = true; +} + +static bool qemu_wakeup_suspend_enabled(void) +{ + return wakeup_suspend_enabled; +} + +CurrentMachineParams *qmp_query_current_machine(Error **errp) +{ + CurrentMachineParams *params = g_malloc0(sizeof(*params)); + params->wakeup_suspend_support = qemu_wakeup_suspend_enabled(); + + return params; +} + void qemu_system_killed(int signal, pid_t pid) { shutdown_signal = signal; |