migration: MigrationEvent for notifiers

Passing MigrationState to notifiers is unsound because they could access
unstable migration state internals or even modify the state.  Instead, pass
the minimal info needed in a new MigrationEvent struct, which could be
extended in the future if needed.

Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-5-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 6b6acc4140..869d8417d6 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -757,18 +757,14 @@ static void vfio_vmstate_change(void *opaque, bool running, RunState state)
 static int vfio_migration_state_notifier(NotifierWithReturn *notifier,
                                          void *data, Error **errp)
 {
-    MigrationState *s = data;
+    MigrationEvent *e = data;
     VFIOMigration *migration = container_of(notifier, VFIOMigration,
                                             migration_state);
     VFIODevice *vbasedev = migration->vbasedev;
 
-    trace_vfio_migration_state_notifier(vbasedev->name,
-                                        MigrationStatus_str(s->state));
+    trace_vfio_migration_state_notifier(vbasedev->name, e->type);
 
-    switch (s->state) {
-    case MIGRATION_STATUS_CANCELLING:
-    case MIGRATION_STATUS_CANCELLED:
-    case MIGRATION_STATUS_FAILED:
+    if (e->type == MIG_EVENT_PRECOPY_FAILED) {
         vfio_migration_set_state_or_reset(vbasedev, VFIO_DEVICE_STATE_RUNNING);
     }
     return 0;