[Qemu-devel] [PATCH for-1.3] vl.c: Fix broken -usb option

[Peter Maydell]

Commit 094b287f0b accidentally broke the "-usb" command line
option, so it would have no effect if the user had not specified
any machine options at that point. (the return value from
'qemu_opts_find(qemu_find_opts("machine"), 0);' is NULL if there
are no user specified options, so it is only to be used for
looking up an option, not when trying to set one.) Similarly,
would '-usbdevice' no longer cause USB to default to enabled.

Fix this regression by using the same style of code for forcing
the usb=on machine option that we use for other aliases such as
'-enable-kvm'.

Signed-off-by: Peter Maydell <address@hidden>
---
For 1.3 as this is a regression which would presumably cause
breakage for migrations and existing working qemu command lines.

 vl.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/vl.c b/vl.c
index c8e9c78..a3ab384 100644
--- a/vl.c
+++ b/vl.c
@@ -3273,16 +3273,12 @@ int main(int argc, char **argv, char **envp)
                 break;
             }
             case QEMU_OPTION_usb:
-                machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);
-                if (machine_opts) {
-                    qemu_opt_set_bool(machine_opts, "usb", true);
-                }
+                olist = qemu_find_opts("machine");
+                qemu_opts_parse(olist, "usb=on", 0);
                 break;
             case QEMU_OPTION_usbdevice:
-                machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);
-                if (machine_opts) {
-                    qemu_opt_set_bool(machine_opts, "usb", true);
-                }
+                olist = qemu_find_opts("machine");
+                qemu_opts_parse(olist, "usb=on", 0);
                 add_device_config(DEV_USB, optarg);
                 break;
             case QEMU_OPTION_device:
-- 
1.7.9.5