Re: [Qemu-devel] KVM call agenda for tuesday 31

[Anthony Liguori]

On 01/31/2012 08:09 AM, Avi Kivity wrote:
> On 01/31/2012 03:59 PM, Anthony Liguori wrote:
> > On 01/30/2012 05:41 PM, Andreas Färber wrote:
> > > Am 30.01.2012 19:55, schrieb Juan Quintela:
> > > > Please send in any agenda items you are interested in covering.
> > >
> > > QOM roadmap update:
> > > * Series 3/4 is on the list.
> > > ->   Please officially designate a merge date (Friday?).
> > > ->   To make review sensible, I ask for a hard device freeze until
> > > merged.
> > >      I.e., no new devices and no conflicting changes to DeviceInfo.
> >
> > I put together a few slides to help this discussion:
> >
> > http://www.codemonkey.ws/files/qom-overview.pdf
>
> That was helpful, thanks.
>
> Can you clarify
>
> - Types and their properties will be ABI  compatible
> - Types and properties will not be backwards  compatible
> – We can re-examine this as the device model  matures and stabilizes
>
> the first two seem very similar, except for the "not".

I guess I really mean QMP compatible.  The expectation is that well written 
management code does:

if (check_for_command("qom-list")) {
   run_command("qom-list", "/");
}

ABI compatible means that if qom-list is there, it's semantics never change. 
Backwards compatibility would mean that once qom-list is introduced, it never 
goes away.

In terms of QOM types, we won't guarantee that a Type will stick around forever, 
but we will guarantee if it's there, it'll behave in a certain way.

When the device model stabilizes over time, we can revisit this, but in the 1.x 
series, I'm sure we're going to go through a few significant refactorings that 
change types significantly.

Regards,

Anthony Liguori

>