qemu/migration
Daniel Henrique Barboza fb06411210 qmp hmp: Make system_wakeup check wake-up support and run state
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>
Message-Id: <20181205194701.17836-4-danielhb413@gmail.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2018-12-18 07:55:47 +01:00
..
block-dirty-bitmap.c dirty-bitmaps: clean-up bitmaps loading and migration logic 2018-10-29 16:23:17 -04:00
block.c migration/block: compare only read blocks against the rate limiter 2018-03-23 16:45:18 +00:00
block.h migration: disable auto-converge during bulk block migration 2017-09-27 11:27:14 +01:00
channel.c Migration+TLS: Fix crash due to double cleanup 2018-05-15 22:13:08 +02:00
channel.h migration: Route errors down through migration_channel_connect 2018-02-06 10:55:12 +00:00
colo-failover.c qapi/migration.json: Rename COLO unknown mode to none mode. 2018-10-19 11:15:03 +08:00
colo.c qapi: add conditions to REPLICATION type/commands on the schema 2018-12-14 06:52:48 +01:00
exec.c migration: unify incoming processing 2018-07-10 12:48:53 +01:00
exec.h migration: Export exec.c functions in its own file 2017-06-01 18:49:22 +02:00
fd.c migration: unify incoming processing 2018-07-10 12:48:53 +01:00
fd.h migration: Export fd.c functions in its own file 2017-06-01 18:49:22 +02:00
global_state.c migration: pre_save return int 2017-09-27 11:35:59 +01:00
Makefile.objs COLO: Remove colo_state migration struct 2018-10-19 11:15:03 +08:00
migration.c qmp hmp: Make system_wakeup check wake-up support and run state 2018-12-18 07:55:47 +01:00
migration.h migration: avoid segmentfault when take a snapshot of a VM which being migrated 2018-10-31 09:38:59 +00:00
page_cache.c migration: use local path for local headers 2018-06-01 19:20:38 +03:00
page_cache.h migration: Make cache_init() take an error parameter 2017-10-23 18:03:25 +02:00
postcopy-ram.c migration: Stop postcopy fault thread before notifying 2018-10-11 19:58:26 +01:00
postcopy-ram.h postcopy: drop ram_pages parameter from postcopy_ram_incoming_init() 2018-06-27 13:28:31 +02:00
qemu-file-channel.c migration: invoke qio_channel_yield only when qemu_in_coroutine() 2018-08-22 12:13:59 +02:00
qemu-file-channel.h migration: Export qemu-file-channel.c functions in its own file 2017-05-18 19:20:50 +02:00
qemu-file.c migration: disable RDMA WRITE after postcopy started 2018-08-22 12:12:07 +02:00
qemu-file.h migration: stop compression to allocate and free memory frequently 2018-04-25 18:04:06 +01:00
qjson.c qobject: Replace qobject_incref/QINCREF qobject_decref/QDECREF 2018-05-04 08:27:53 +02:00
qjson.h typedefs: add QJSON 2018-06-15 14:40:56 +01:00
ram.c COLO: flush host dirty ram from cache 2018-10-19 11:15:03 +08:00
ram.h COLO: Load dirty pages into SVM's RAM cache firstly 2018-10-19 11:15:03 +08:00
rdma.c migration/rdma: Fix uninitialised rdma_return_path 2018-09-26 12:21:33 +01:00
rdma.h migration: Export rdma.c functions in its own file 2017-06-01 18:49:23 +02:00
savevm.c vmstate: constify VMStateField 2018-11-27 15:35:15 +01:00
savevm.h savevm: split the process of different stages for loadvm/savevm 2018-10-19 11:15:03 +08:00
socket.c migration: unify incoming processing 2018-07-10 12:48:53 +01:00
socket.h migration: Export functions to create send channels 2018-05-15 20:24:27 +02:00
tls.c qio: non-default context for TLS handshake 2018-03-06 10:19:07 +00:00
tls.h migration: Export tls.c functions in its own file 2017-06-01 18:49:23 +02:00
trace-events COLO: Flush memory data from ram cache 2018-10-19 11:15:03 +08:00
vmstate-types.c vmstate: constify VMStateField 2018-11-27 15:35:15 +01:00
vmstate.c vmstate: constify VMStateField 2018-11-27 15:35:15 +01:00
xbzrle.c migration: Create migration/xbzrle.h 2017-05-18 18:04:54 +02:00
xbzrle.h migration: Create migration/xbzrle.h 2017-05-18 18:04:54 +02:00