Re: [Qemu-devel] [RFC 0/8]: QError v2

[Anthony Liguori]

Luiz Capitulino wrote:
> On Thu, 12 Nov 2009 08:44:03 -0600
> Anthony Liguori <address@hidden> wrote:
>
>   
> > Luiz Capitulino wrote:
> >     
> > > > #define QERR_DEVICE_ALREADY_OPEN "{'class': 'DeviceAlreadyOpen', 'data' 
> > > > : {'bus_num': %d, 'addr': %d}"
> > > >
> > > > qemu_error_new(QERR_DEVICE_ALREADY_OPEN, bus_num, addr);
> > > >     
> > > >         
> > >  What about DeviceAlreadyOpen errors with a different argument list?
> > >   
> > >       
> > Why would you have this?  That would seem like a problem to me.  I think 
> > the errors need to be very well structured (just like everything else in 
> > QMP).
> >     
>
>  This can happen with errors that carry specific info which are different
> among subsystems, eg. USB device info vs. PCI device info.
>   

This example demonstrates the problem with this.  You haven't included 
enough information in the error to properly distinguish what happened.  
I would suggest changing to:

'data' : { 'device_type' : %s, 'addr': %s }

qemu_error_new(QERR_DEVICE_ALREADY_OPEN, "pci", addr);

Or, if you really wanted to get fancy:

'data' : { 'device_type': %s, 'addr': %p }

qemu_error_new(QERR_DEVICE_ALREADY_OPEN, "pci",
                           qobject_from_jsonf("{'bus': %d, 'slot': %d, 
'function': %d}", bus, dev, fn));

Personally, I'd stick with the first one though.

--
Regards,

Anthony Liguori