Re: [Qemu-devel] [PATCH V7 1/5] runstate: introduce prelaunch-migrate state

[Jiri Denemark <jdenemar@redhat.com>]

On Thu, Mar 07, 2013 at 08:37:17 -0700, Eric Blake wrote:
> On 03/07/2013 01:23 AM, Jason Wang wrote:
> > Sometimes, we need track the state when guest is just about to start after
> > migration. There's not a accurate state available which do this accurately
> > (consider qemu may started with -S in destination).
> 
> s/may/may be/
> 
> and yes, libvirt _always_ starts qemu with -S in the destination.
> 
> > 
> > So this patch introduces a new state prelaunch-migrate which just tracks this
> > state, it covers the case both w/ and w/o -S in destination. The first user of
> > this is the support of doing announce by guest.
> > 
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> >  migration.c      |    3 +--
> >  qapi-schema.json |    5 ++++-
> >  vl.c             |    4 +++-
> >  3 files changed, 8 insertions(+), 4 deletions(-)
> 
> I'm not sure if this patch will have any negative effects on existing
> libvirt migration or state reporting; adding Jirka to cc.

I don't see any issues this patch could cause to libvirt. The only place
where we ask qemu for its current state is when we reconnect to existing
qemu processes after libvirtd restart. And the only thing we care about
is whether the guest is running or not. We use our own state information
to detect if we were migrating or not.

Jirka