Re: [PATCH] qmp: Stabilize preconfig

[Paolo Bonzini]

> On 11/3/21 09:02, Markus Armbruster wrote:
> > I wonder whether we really have to step through three states
> >
> >           x-exit-preconfig  cont
> >      preconfig ---> pre run ---> run
> >
> > and not two
> >
> >              cont
> >      pre run ---> run

Devices would be hotplugged between x-exit-preconfig and cont, and part 
of the machine until x-exit-preconfig; so there is a need for something 
like x-exit-preconfig.

In my prototype of a QMP-only binary, the idea would be that there 
wouldn't be a single x-exit-preconfig command, but "cont", 
"migrate-incoming", "finish-machine-init" (the stable replacement for 
x-exit-preconfig) and "loadvm" would all complete the configuration of 
the machine.  "finish-machine-init" would do nothing else, the others 
would continue with whatever they were supposed to do.

> > Which of the queries you need work only between x-exit-preconfig and -S?
>
> Well before x-exit-preconfig, QMP only permits a very small number
> of commands - QEMU has loosened that up a bit, but I don't think anyone
> has checked whether there's enough to cover libvirt's current usage yet.

Indeed I looked at the commands that operate on the backends, but not 
that much at query commands.

Paolo