[Qemu-devel] [PATCH v6] vl.c: Output error on invalid machine type

[mrezanin]

From: Miroslav Rezanina <address@hidden>

Output error message using qemu's error_report() function when user
provides the invalid machine type on the command line. This also saves
time to find what issue is when you downgrade from one version of qemu
to another that doesn't support required machine type yet (the version
user downgraded to have to have this patch applied too, of course).

Signed-off-by: Miroslav Rezanina <address@hidden>
---
v6:
 - print help instead of list supported machines on error
 vl.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/vl.c b/vl.c
index 383be1b..3297c0a 100644
--- a/vl.c
+++ b/vl.c
@@ -2600,13 +2600,19 @@ static QEMUMachine *machine_parse(const char *name)
     if (machine) {
         return machine;
     }
-    printf("Supported machines are:\n");
-    for (m = first_machine; m != NULL; m = m->next) {
-        if (m->alias) {
-            printf("%-20s %s (alias of %s)\n", m->alias, m->desc, m->name);
+
+    if (name && !is_help_option(name)) {
+        error_report("Unsupported machine type");
+        printf("\nUse '-M help' to list supported machines!\n");
+    } else {
+        printf("Supported machines are:\n");
+        for (m = first_machine; m != NULL; m = m->next) {
+            if (m->alias) {
+                printf("%-20s %s (alias of %s)\n", m->alias, m->desc, m->name);
+            }
+            printf("%-20s %s%s\n", m->name, m->desc,
+                   m->is_default ? " (default)" : "");
         }
-        printf("%-20s %s%s\n", m->name, m->desc,
-               m->is_default ? " (default)" : "");
     }
     exit(!name || !is_help_option(name));
 }
-- 
1.8.5.3