Allow to leave type on default in -machine

This allows to specify -machine options without setting an explicit
machine type. We will pick the default machine in this case. Requesting
the list of available machines is still possible via '-machine ?' e.g.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/vl.c b/vl.c
index a3d8d77bf8..73316cf17e 100644
--- a/vl.c
+++ b/vl.c
@@ -2724,7 +2724,10 @@ int main(int argc, char **argv, char **envp)
                     fprintf(stderr, "parse error: %s\n", optarg);
                     exit(1);
                 }
-                machine = machine_parse(qemu_opt_get(opts, "type"));
+                optarg = qemu_opt_get(opts, "type");
+                if (optarg) {
+                    machine = machine_parse(optarg);
+                }
                 break;
             case QEMU_OPTION_usb:
                 usb_enabled = 1;