Re: [Qemu-devel] Re: [PATCH] Add -no-virtio-balloon command-line option

[Anthony Liguori]

Markus Armbruster wrote:
> Anthony Liguori <address@hidden> writes:
>
>   
> > Markus Armbruster wrote:
> >     
> > > Dor Laor <address@hidden> writes:
> > >
> > >   
> > >       
> > > > Gerd Hoffmann wrote:
> > > >     
> > > >         
> > > > > > This new option may be used to disable the virtio-balloon device.
> > > > > >
> > > > > >         
> > > > > >             
> > > > > ACK, looks good.
> > > > >
> > > > > And I can drop my lazy patch which just comments out virtio-balloon
> > > > > in the code ;)
> > > > >       
> > > > >           
> > > > Actually, I rather have the balloon disabled by default. It's like any
> > > > other pci device which needs
> > > > explicit command line specification. Why consume a pci slot if not
> > > > implicitly required?
> > > >     
> > > >         
> > > I agree.  The command line is plenty magic without implicitly added
> > > PCI devices.
> > >
> > > Besides, negative options -no-virtio-balloon lead to ugly
> > > double-negatives like if (!no_virtio_balloon).
> > >   
> > >       
> > It does no harm to add the device by default so why force the user to
> > explicitly enable it?
> >
> > Regards,
> >
> > Anthony Liguori
> >     
>
> I don't care whether it's on or off by default.  I just object to the
> ugly -no-virtio-balloon.
>
> We need to do (at least) two things to the virtio-balloon device:
> suppress it, and control its PCI address.  We can do both with one
> option, but it better not be called -no-virtio-balloon then.
>
> Options controlling devices should always be extensible to accept
> arbitrary name=value arguments.
>   
It's not in a released version of QEMU so we can remove the option and 
change it's syntax.

-balloon none
-balloon virtio
-balloon virtio,addr=00:01.3

Could be a reasonable approach.

Regards,

Anthony Liguori