[Qemu-devel] Re: [PATCH v6 05/18] virtio-serial: Use control messages to notify guest of new ports

[Anthony Liguori]

On 04/27/2010 07:33 AM, Amit Shah wrote:
> Allow the port 'id's to be set by a user on the command line. This is
> needed by management apps that will want a stable port numbering scheme
> for hot-plug/unplug and migration.
>
> Since the port numbers are shared with the guest (to identify ports in
> control messages), we just send a control message to the guest
> indicating addition of new ports (hot-plug) or notifying the guest of
> the available ports when the guest sends us a DEVICE_READY control
> message.
>
> Signed-off-by: Amit Shah<address@hidden>
>    

If you're introducing a new message type, don't you need to negotiate 
that feature with the guest?

Regards,

Anthony Liguori