diff --git a/tools/python/xen/xm/XenAPI.py b/tools/python/xen/xm/XenAPI.py
index 1c1bc41e94..5cf929f48c 100644
--- a/tools/python/xen/xm/XenAPI.py
+++ b/tools/python/xen/xm/XenAPI.py
@@ -84,23 +84,23 @@ class Session(xen.util.xmlrpclib2.ServerProxy):
 
     def xenapi_request(self, methodname, params):
         if methodname.startswith('login'):
-            self._login(methodname, *params)
+            self._login(methodname, params)
             return None
         else:
             full_params = (self._session,) + params
             return _parse_result(getattr(self, methodname)(*full_params))
 
 
-    def _login(self, method, username, password):
+    def _login(self, method, params):
         self._session = _parse_result(
-            getattr(self, 'session.%s' % method)(username, password))
+            getattr(self, 'session.%s' % method)(*params))
 
 
     def __getattr__(self, name):
         if name == 'xenapi':
             return _Dispatcher(self.xenapi_request, None)
         elif name.startswith('login'):
-            return lambda u, p: self._login(name, u, p)
+            return lambda *params: self._login(name, params)
         else:
             return xen.util.xmlrpclib2.ServerProxy.__getattr__(self, name)