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Date: Thu, 7 Oct 2010 03:39:39 -0400 (EDT)
From: Alon Levy <alevy@redhat.com>
Message-ID: <2052681331.708791286437179606.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com>
In-Reply-To: <4CACC75B.3070401@codemonkey.ws>
Subject: Re: [Qemu-devel] [PATCH 0/2] USB CCID device
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel@nongnu.org, Gerd Hoffmann <kraxel@redhat.com>


----- "Anthony Liguori" <anthony@codemonkey.ws> wrote:

> On 10/06/2010 03:55 AM, Gerd Hoffmann wrote:
> > On 10/06/10 02:28, Alon Levy wrote:
> >>
> >>>
> >>> Does this work with live migration?  I can't see how it would.
> >>>
> >>
> >> No, it doesn't right now. It would require cooperation with the
> client,
> >> to tell it to reconnect to the target qemu (kind of like spice).
> >
> > I think until we have this migration should have pretty much the
> same 
> > effect as a chardev disconnect, i.e. detach the usb device (which
> the 
> > guest will see as unplug).
> 
> Better yet, mark the guest as unmigrateable and let the management
> tool 
> unplug the usb device before migration and replug it after migration.
> 
> It's the same principle behind device assignment.
> 

Is there any way to also get a pre_migrate callback with register_device_unmigratable?
I'd like to send a VSC_Reconnect message, then the guest sees an unplug, then migration,
then (no plug yet since the device is marked as auto_attach=0) client reconnects
(actually this happens before but to a paused machine waiting for migration), and then
causes attachement, same as a new machine.

> Regards,
> 
> Anthony Liguori
> 
> > Needs some code though, at minimum you'll have to xfer the connected
> 
> > state from the migration source and have some bits in post_load() 
> > which do attach/detach if needed.
> >
> > cheers,
> >   Gerd
> >