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

[Amit Shah]

On (Tue) Apr 27 2010 [12:37:00], Anthony Liguori wrote:
> 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?

Since we didn't have any kernel or qemu released with the older ABI,
changing the numbers isn't a bad thing (we disabled multiport support
for 2.6.34 because of this).

                Amit