diff --git a/tools/python/xen/lowlevel/xs/xs.c b/tools/python/xen/lowlevel/xs/xs.c
index d6b5b44f85..e29d46b544 100644
--- a/tools/python/xen/lowlevel/xs/xs.c
+++ b/tools/python/xen/lowlevel/xs/xs.c
@@ -172,7 +172,7 @@ static PyObject *xspy_ls(PyObject *self, PyObject *args, PyObject *kwds)
     char *path;
 
     char **xsval;
-    int xsval_n;
+    unsigned int xsval_n;
 
     if (!parse_transaction_path(self, args, kwds, &xh, &th, &path))
         return NULL;