[PATCH V5 07/12] migration: preserve suspended for bg_migration

[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 because bg migration forces RUN_STATE_PAUSED to
save the precopy device state.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 migration/migration.c | 7 +------
 system/runstate.c     | 3 +++
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 29ed901..49ec836 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -3394,7 +3394,7 @@ 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);
 }
 
@@ -3466,11 +3466,6 @@ 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 f1d4bc7..68cc485 100644
--- a/system/runstate.c
+++ b/system/runstate.c
@@ -112,6 +112,7 @@ static const RunStateTransition runstate_transitions_def[] = {
     { RUN_STATE_PAUSED, RUN_STATE_COLO},
     { RUN_STATE_PAUSED, RUN_STATE_SAVE_VM},
     { RUN_STATE_PAUSED, RUN_STATE_RESTORE_VM},
+    { RUN_STATE_PAUSED, RUN_STATE_SUSPENDED},
 
     { RUN_STATE_POSTMIGRATE, RUN_STATE_RUNNING },
     { RUN_STATE_POSTMIGRATE, RUN_STATE_FINISH_MIGRATE },
@@ -171,6 +172,8 @@ static const RunStateTransition runstate_transitions_def[] = {
     { RUN_STATE_SUSPENDED, RUN_STATE_COLO},
     { RUN_STATE_SUSPENDED, RUN_STATE_SAVE_VM },
     { RUN_STATE_SUSPENDED, RUN_STATE_RESTORE_VM },
+    { RUN_STATE_SUSPENDED, RUN_STATE_PAUSED },
+    { RUN_STATE_SUSPENDED, RUN_STATE_SHUTDOWN },
 
     { RUN_STATE_WATCHDOG, RUN_STATE_RUNNING },
     { RUN_STATE_WATCHDOG, RUN_STATE_FINISH_MIGRATE },
-- 
1.8.3.1