Re: [Qemu-devel] [PATCH v4 3/9] cli: add -preconfig option

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 29 Mar 2018 13:57:54 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

[...]
> > As for the future, I agree it would be much more flexible
> > to allow both -preconfig and -incoming at the same time,
> > so we could start target with empty CLI, and then feed it
> > options from source. It would require audit/refactoring of
> > INMIGRATE state and making 'all' current CLI options
> > available via QMP interface.
> > 
> > But for now I'd prefer to keep using old way to start target.  
> 
> Well, if management software developers tell us that -preconfig
> will be already useful without -incoming support, I won't object.
As Peter said, mgmt can/will use -preconfig even without -incoming,
since it lets deal with initial (source) start-up problem (i.e.
avoid restarting QEMU) and lets us make numa configuration work
in qemu/libvirt stack without guess work. (that's the end goal of
the series)

> But it would be very nice for management software if they can
> simply assume that -preconfig and -incoming will work together
> since the first version.  Can we have this as a goal for 2.13?
I can't promise to refactor -incoming in near future, as I'm working
on ARM cpu-hotplug currently and next in queue is ARM memory hotplug.

Peter suggested an alternative idea, to abandon -incoming and
enable incoming migration from QMP after all configuration is done.
Amount of refactoring need probably would be the same but at least
interface and runstate transitions wise it looks cleaner.

[...]