migration: switch from .vm_was_running to .vm_old_state

No logic change here, only refactoring. That's a preparation for next
commit where we finally restore the stopped vm state on migration
failure or cancellation.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230517123752.21615-5-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migration/migration.c

@@ -1402,7 +1402,7 @@ void migrate_init(MigrationState *s)
 
     s->start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
     s->total_time = 0;
-    s->vm_was_running = false;
+    s->vm_old_state = -1;
     s->iteration_initial_bytes = 0;
     s->threshold_size = 0;
 }
@@ -2287,7 +2287,8 @@ static void migration_completion(MigrationState *s)
         qemu_mutex_lock_iothread();
         s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
         qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
-        s->vm_was_running = runstate_is_running();
+
+        s->vm_old_state = runstate_get();
         global_state_store();
 
         ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
@@ -2760,12 +2761,12 @@ static void migration_iteration_finish(MigrationState *s)
     case MIGRATION_STATUS_COLO:
         assert(migrate_colo());
         migrate_start_colo_process(s);
-        s->vm_was_running = true;
+        s->vm_old_state = RUN_STATE_RUNNING;
         /* Fallthrough */
     case MIGRATION_STATUS_FAILED:
     case MIGRATION_STATUS_CANCELLED:
     case MIGRATION_STATUS_CANCELLING:
-        if (s->vm_was_running) {
+        if (s->vm_old_state == RUN_STATE_RUNNING) {
             if (!runstate_check(RUN_STATE_SHUTDOWN)) {
                 vm_start();
             }
@@ -3085,7 +3086,7 @@ static void *bg_migration_thread(void *opaque)
      * transition in vm_stop_force_state() we need to wakeup it up.
      */
     qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
-    s->vm_was_running = runstate_is_running();
+    s->vm_old_state = runstate_get();
 
     global_state_store();
     /* Forcibly stop VM before saving state of vCPUs and devices */

migration/migration.h

@@ -25,6 +25,7 @@
 #include "net/announce.h"
 #include "qom/object.h"
 #include "postcopy-ram.h"
+#include "sysemu/runstate.h"
 
 struct PostcopyBlocktimeContext;
 
@@ -317,12 +318,14 @@ struct MigrationState {
     int64_t expected_downtime;
     bool capabilities[MIGRATION_CAPABILITY__MAX];
     int64_t setup_time;
+
     /*
-     * Whether guest was running when we enter the completion stage.
+     * State before stopping the vm by vm_stop_force_state().
      * If migration is interrupted by any reason, we need to continue
-     * running the guest on source.
+     * running the guest on source if it was running or restore its stopped
+     * state.
      */
-    bool vm_was_running;
+    RunState vm_old_state;
 
     /* Flag set once the migration has been asked to enter postcopy */
     bool start_postcopy;