vfio/migration: Return bool type for vfio_migration_realize()

Make vfio_migration_realize() adhere to the convention of other realize()
callbacks(like qdev_realize) by returning bool instead of int.

Suggested-by: Cédric Le Goater <clg@redhat.com>
Suggested-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/migration.c

@@ -846,15 +846,20 @@ void vfio_reset_bytes_transferred(void)
     bytes_transferred = 0;
 }
 
-int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
+/*
+ * Return true when either migration initialized or blocker registered.
+ * Currently only return false when adding blocker fails which will
+ * de-register vfio device.
+ */
+bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
 {
     Error *err = NULL;
     int ret;
 
     if (vbasedev->enable_migration == ON_OFF_AUTO_OFF) {
         error_setg(&err, "%s: Migration is disabled for VFIO device",
                    vbasedev->name);
-        return vfio_block_migration(vbasedev, err, errp);
+        return !vfio_block_migration(vbasedev, err, errp);
     }
 
     ret = vfio_migration_init(vbasedev);
@@ -869,7 +874,7 @@ int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
                        vbasedev->name, ret, strerror(-ret));
         }
 
-        return vfio_block_migration(vbasedev, err, errp);
+        return !vfio_block_migration(vbasedev, err, errp);
     }
 
     if (!vbasedev->dirty_pages_supported) {
@@ -896,15 +901,15 @@ int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
     }
 
     trace_vfio_migration_realize(vbasedev->name);
-    return 0;
+    return true;
 
 add_blocker:
     ret = vfio_block_migration(vbasedev, err, errp);
 out_deinit:
     if (ret) {
         vfio_migration_deinit(vbasedev);
     }
-    return ret;
+    return !ret;
 }
 
 void vfio_migration_exit(VFIODevice *vbasedev)

hw/vfio/pci.c

@@ -3207,8 +3207,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     }
 
     if (!pdev->failover_pair_id) {
-        ret = vfio_migration_realize(vbasedev, errp);
-        if (ret) {
+        if (!vfio_migration_realize(vbasedev, errp)) {
             goto out_deregister;
         }
     }

include/hw/vfio/vfio-common.h

@@ -252,7 +252,7 @@ int vfio_spapr_create_window(VFIOContainer *container,
 int vfio_spapr_remove_window(VFIOContainer *container,
                              hwaddr offset_within_address_space);
 
-int vfio_migration_realize(VFIODevice *vbasedev, Error **errp);
+bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp);
 void vfio_migration_exit(VFIODevice *vbasedev);
 
 #endif /* HW_VFIO_VFIO_COMMON_H */