diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index a5826ec..88b64d8 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -592,7 +592,8 @@
 }
 
 static void add_flagname_to_bitmaps(const char *flagname,
-                                    FeatureWordArray words)
+                                    FeatureWordArray words,
+                                    Error **errp)
 {
     FeatureWord w;
     for (w = 0; w < FEATURE_WORDS; w++) {
@@ -603,7 +604,7 @@
         }
     }
     if (w == FEATURE_WORDS) {
-        fprintf(stderr, "CPU feature %s not found\n", flagname);
+        error_setg(errp, "CPU feature %s not found", flagname);
     }
 }
 
@@ -1761,9 +1762,9 @@
     while (featurestr) {
         char *val;
         if (featurestr[0] == '+') {
-            add_flagname_to_bitmaps(featurestr + 1, plus_features);
+            add_flagname_to_bitmaps(featurestr + 1, plus_features, &local_err);
         } else if (featurestr[0] == '-') {
-            add_flagname_to_bitmaps(featurestr + 1, minus_features);
+            add_flagname_to_bitmaps(featurestr + 1, minus_features, &local_err);
         } else if ((val = strchr(featurestr, '='))) {
             *val = 0; val++;
             feat2prop(featurestr);