Re: [Qemu-devel] [RFC][PATCH 14/16] kvm: x86: Add user space part for in-kernel i8259

[Avi Kivity <avi@redhat.com>]

On 12/05/2011 01:37 PM, Jan Kiszka wrote:
> On 2011-12-05 11:01, Avi Kivity wrote:
> > On 12/04/2011 11:38 PM, Jan Kiszka wrote:
> >>>
> >>> It should be also possible to migrate from non-KVM device to KVM
> >>> version, different names would prevent that for ever.
> >>
> >> It is (theoretically) possible with these patches as the vmstate names
> >> are the same. KVM to TCG migration does not work right now, so I was
> >> only able to test in-kernel <-> user space irqchip model migrations.
> > 
> > btw, for the next-gen migration protocol, we'd probably be using QOM
> > paths, not vmstate names; the QOM paths would include the device name?
>
> That would be a very bad idea IMHO. Every refactoring of your device
> tree, e.g. to model CPU hotplug and the ICC bus more accurately, would
> risk to create a migration crack.

At some point, something has to be stable.  We can't have an infinite
number of layers giving names to things.  I propose we have just one layer.

>  At least we would need some stable
> naming and/or alias concept then.

We should be able to transform a path to backward compatible names,
yes.  But if something has an unstable name, let's omit it in the first
place.

(the memory API added unstable names, hopefully the QOM can take over
the stable ones and we'll have a good way to denote the unstable ones).

-- 
error compiling committee.c: too many arguments to function