diff --git a/qubes/ext/block.py b/qubes/ext/block.py
index 913fd7b1c..37f024708 100644
--- a/qubes/ext/block.py
+++ b/qubes/ext/block.py
@@ -360,7 +360,9 @@ def get_device_attachments(vm_):
                 info = _try_get_block_device_info(vm.app, disk)
                 if not info:
                     continue
-                _backend_domain, port_id = info
+                backend_domain, port_id = info
+                if backend_domain != vm_:
+                    continue
 
                 result[port_id] = vm
         return result