Re: [Qemu-devel] [PATCH] hw/qdev-monitor: report error for -device <not-a-device-type>

[Luiz Capitulino <lcapitulino@redhat.com>]

On Wed, 28 Nov 2012 13:19:36 +0100
Andreas Färber <afaerber@suse.de> wrote:

> Am 28.11.2012 13:14, schrieb Luiz Capitulino:
> > On Wed, 28 Nov 2012 13:02:26 +0100
> > Paolo Bonzini <pbonzini@redhat.com> wrote:
> > 
> >> Il 28/11/2012 12:54, Luiz Capitulino ha scritto:
> >>> On Wed, 28 Nov 2012 10:54:33 +0200
> >>> Alon Levy <alevy@redhat.com> wrote:
> >>>
> >>>> Instead of aborting immediately after at DEVICE_CLASS(obj)
> >>>>
> >>>> Signed-off-by: Alon Levy <alevy@redhat.com>
> >>>> ---
> >>>>  hw/qdev-monitor.c | 5 +++++
> >>>>  1 file changed, 5 insertions(+)
> >>>>
> >>>> diff --git a/hw/qdev-monitor.c b/hw/qdev-monitor.c
> >>>> index 479eecd..3b70cdb 100644
> >>>> --- a/hw/qdev-monitor.c
> >>>> +++ b/hw/qdev-monitor.c
> >>>> @@ -426,6 +426,11 @@ DeviceState *qdev_device_add(QemuOpts *opts)
> >>>>          return NULL;
> >>>>      }
> >>>>  
> >>>> +    if (!object_class_dynamic_cast(obj, "device")) {
> >>>> +        qerror_report(QERR_INVALID_PARAMETER_TYPE, "driver", "device type");
> >>>> +        return NULL;
> >>>> +    }
> >>>
> >>> Gives me the impression that something is wrong before this, but it's
> >>> better to ask a QOM guy (CC'ing them).
> >>
> >> I would reuse the same error message as for "if (!obj)", and also use
> >> TYPE_DEVICE instead of the hardcoded string, but the patch is ok.
> > 
> > It's a bit weird to me that you check for a condition and right next
> > you also assert it (it's what DEVICE_CLASS() will do). But I'm not familiar
> > with QOM, so I'll just trust you.
> 
> We could just as well do:
> 
> k = object_class_dynamic_cast(obj, TYPE_DEVICE);
> if (k == NULL) {
>     // do the error reporting
>     return ...;
> }

Yeah, was reaching this solution after some code reading :)

> 
> /* find bus */
> ...
> 
> Andreas
>