qtest: Don't segfault with invalid -qtest option

This prints an error message, instead of core dump, when "-qtest"
option value is invalid, e.g.:

    $ ./x86_64-softmmu/qemu-system-x86_64 -qtest unknown
        qemu-system-x86_64: Failed to initialize device for qtest:
        "unknown"

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

1 files changed, 7 insertions, 1 deletions

diff --git a/vl.c b/vl.c
index a7b00cd..0f7d31f 100644
--- a/vl.c
+++ b/vl.c
@@ -4078,7 +4078,13 @@ int main(int argc, char **argv, char **envp)
     configure_accelerator();
 
     if (qtest_chrdev) {
-        qtest_init(qtest_chrdev, qtest_log);
+        Error *local_err = NULL;
+        qtest_init(qtest_chrdev, qtest_log, &local_err);
+        if (local_err) {
+            error_report("%s", error_get_pretty(local_err));
+            error_free(local_err);
+            exit(1);
+        }
     }
 
     machine_opts = qemu_get_machine_opts();