Re: [Qemu-devel] [PATCH v2 10/10] qdev: Do not let the user try to device_add when it cannot work

[Marcel Apfelbaum <marcel.a@redhat.com>]

On Tue, 2013-10-29 at 17:08 +0100, armbru@redhat.com wrote:
> From: Markus Armbruster <armbru@redhat.com>
> 
> Such devices have always been unavailable and omitted from the list of
> available devices shown by device_add help.  Until commit 18b6dad
> silently broke the former, setting up nasty traps for unwary users,
> like this one:
> 
>     $ qemu-system-x86_64 -nodefaults -monitor stdio -display none
>     QEMU 1.6.50 monitor - type 'help' for more information
>     (qemu) device_add apic
>     Segmentation fault (core dumped)
> 
> I call that a regression.  Fix it.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  qdev-monitor.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/qdev-monitor.c b/qdev-monitor.c
> index 36f6f09..c538fec 100644
> --- a/qdev-monitor.c
> +++ b/qdev-monitor.c
> @@ -477,7 +477,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
>          }
>      }
>  
> -    if (!obj) {
> +    if (!obj || DEVICE_CLASS(obj)->cannot_instantiate_with_device_add_yet) {
>          qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver", "device type");
>          return NULL;
>      }
Minor comment, if you move the if statement after
 k = DEVICE_CLASS(obj);
you don't need the cast anymore.


Seems OK to me.
Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>