vfio: Set the priority of the VFIO VM state change handler explicitly

In the VFIO VM state change handler when stopping the VM, the _RUNNING
bit in device_state is cleared which makes the VFIO device stop, including
no longer generating interrupts. Then we can save the pending states of
all interrupts in the GIC VM state change handler (on ARM).

So we have to set the priority of the VFIO VM state change handler
explicitly (like virtio devices) to ensure it is called before the
GIC's in saving.

Signed-off-by: Shenming Lu <lushenming@huawei.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20210310030233.1133-3-lushenming@huawei.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

hw/vfio/migration.c

@@ -862,7 +862,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
     register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
                          vbasedev);
 
-    migration->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change,
+    migration->vm_state = qdev_add_vm_change_state_handler(vbasedev->dev,
+                                                           vfio_vmstate_change,
                                                            vbasedev);
     migration->migration_state.notify = vfio_migration_state_notifier;
     add_migration_state_change_notifier(&migration->migration_state);