Re: [Qemu-devel] [PATCH v5 00/16] uq/master: Introduce basic irqchip support

[Anthony Liguori]

On 12/19/2011 06:37 PM, Jan Kiszka wrote:
> On 2011-12-20 01:32, Anthony Liguori wrote:
> > On 12/19/2011 05:49 PM, Jan Kiszka wrote:
> > > On 2011-12-19 23:24, Anthony Liguori wrote:
> > > > On 12/19/2011 03:17 PM, Marcelo Tosatti wrote:
> > > > > Anthony,
> > > > >
> > > > > Can you please review&    ACK?
> > > > >
> > > > > You could even apply directly but well do a kvm-autotest run through
> > > > > uq/master. Still, your review is needed.
> > > >
> > > > Overall, it looks good except for the backend/frontend split.  This
> > > > should be done in terms of qdev inheritance.
> > >
> > > I cannot follow your idea here yet. There is no inheritance as we end up
> > > with only a single class that permutes (selects a different backend) on
> > > creation. I'm not sure how to model two classes that will still only
> > > mean a single qdev registration.
> >
> > See other reply in thread.
> >
> > We should model this as two separate qdev devices.  We can avoid
> > regressing migration in qemu-kvm by just having a common vmstate name.
> >
> > apic is a no-user device so there's no way that changing the name of it
> > in qemu-kvm can affect users.
>
> Look down http://thread.gmane.org/gmane.comp.emulators.kvm.devel/82598
> for the discussion of that model.

Let me say that I know this is the last bit of qemu-kvm that needs merging and 
that this has been an epic effort.  I wouldn't refuse to merge a pull request 
that came in with this in its current form.

If we merged this now, I would be submitting patches in the not too distant 
future to remove all of this backend stuff in favor of proper modeling 
(including using two separate devices).

There's lot of inconsistency in qdev already today so adding a little more isn't 
the end of the world.  We're going to need to eventually have this debate soon 
so it's up to you whether you want to just get this merged now and worry about 
this another day or resolve this before merge.

I don't see any compatibility issues here so I'm not really concerned about 
introducing a regression by breaking it into two devices.

Regards,

Anthony Liguori

> Jan