diff --git a/scripts/march-to-cpu-opt b/scripts/march-to-cpu-opt
index 44511eabd7f..0f3f08de2a6 100755
--- a/scripts/march-to-cpu-opt
+++ b/scripts/march-to-cpu-opt
@@ -103,10 +103,10 @@ def get_vlen(ext_dict):
         if ext == 'v':
             vlen = max(vlen, 128)
         elif (ext.startswith('zvl') and ext[-1] == 'b'):
-            zvlen = int(arch[3:-1])
+            zvlen = int(ext[3:-1])
             vlen = max(vlen, zvlen)
         elif ext.startswith("zve"):
-            zvelen = int(arch[3:-1])
+            zvelen = int(ext[3:-1])
             vlen = max(vlen, zvelen)
     return vlen