[PULL 2/3] vfio: Fix unregister SaveVMHandler in vfio_migration_finalize

[Alex Williamson <alex.williamson@redhat.com>]

From: Kunkun Jiang <jiangkunkun@huawei.com>

In the vfio_migration_init(), the SaveVMHandler is registered for
VFIO device. But it lacks the operation of 'unregister'. It will
lead to 'Segmentation fault (core dumped)' in
qemu_savevm_state_setup(), if performing live migration after a
VFIO device is hot deleted.

Fixes: 7c2f5f75f94 (vfio: Register SaveVMHandlers for VFIO device)
Reported-by: Qixin Gan <ganqixin@huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
Message-Id: <20210527123101.289-1-jiangkunkun@huawei.com>
Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/migration.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 201642d75e6b..ef397ebe6c09 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -892,6 +892,7 @@ void vfio_migration_finalize(VFIODevice *vbasedev)
 
         remove_migration_state_change_notifier(&migration->migration_state);
         qemu_del_vm_change_state_handler(migration->vm_state);
+        unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
         vfio_migration_exit(vbasedev);
     }