[PULL 10/26] migration: preserve suspended for bg_migration

[peterx@redhat.com]

From: Steve Sistare <steven.sistare@oracle.com>

Do not wake a suspended guest during bg_migration, and restore the prior
state at finish rather than unconditionally running.  Allow the additional
state transitions that occur.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-9-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c | 7 +------
 system/runstate.c     | 1 +
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 8124811045..2cc7e2a56c 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -3390,7 +3390,7 @@ static void bg_migration_vm_start_bh(void *opaque)
     qemu_bh_delete(s->vm_start_bh);
     s->vm_start_bh = NULL;
 
-    vm_start();
+    vm_resume(s->vm_old_state);
     migration_downtime_end(s);
 }
 
@@ -3462,11 +3462,6 @@ static void *bg_migration_thread(void *opaque)
 
     qemu_mutex_lock_iothread();
 
-    /*
-     * If VM is currently in suspended state, then, to make a valid runstate
-     * transition in vm_stop_force_state() we need to wakeup it up.
-     */
-    qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
     s->vm_old_state = runstate_get();
 
     global_state_store();
diff --git a/system/runstate.c b/system/runstate.c
index ca9eb54cde..621a023120 100644
--- a/system/runstate.c
+++ b/system/runstate.c
@@ -168,6 +168,7 @@ static const RunStateTransition runstate_transitions_def[] = {
     { RUN_STATE_SUSPENDED, RUN_STATE_PAUSED},
     { RUN_STATE_SUSPENDED, RUN_STATE_SAVE_VM },
     { RUN_STATE_SUSPENDED, RUN_STATE_RESTORE_VM },
+    { RUN_STATE_SUSPENDED, RUN_STATE_SHUTDOWN },
 
     { RUN_STATE_WATCHDOG, RUN_STATE_RUNNING },
     { RUN_STATE_WATCHDOG, RUN_STATE_FINISH_MIGRATE },
-- 
2.41.0