diff --git a/cpus.c b/cpus.c
index c232265..c8bc8ad 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1278,7 +1278,7 @@
 
     f = fopen(filename, "wb");
     if (!f) {
-        error_set(errp, QERR_OPEN_FILE_FAILED, filename);
+        error_setg_file_open(errp, errno, filename);
         return;
     }
 
@@ -1308,7 +1308,7 @@
 
     f = fopen(filename, "wb");
     if (!f) {
-        error_set(errp, QERR_OPEN_FILE_FAILED, filename);
+        error_setg_file_open(errp, errno, filename);
         return;
     }