[Libvir] RFC: Supporting serial & parallel ports for QEMU (and improving Xen)

[Daniel Veillard]

On Mon, May 21, 2007 at 08:18:42PM +0100, Daniel P. Berrange wrote:
> On Mon, May 21, 2007 at 10:58:02AM +0200, Gerd Hoffmann wrote:
> >   Hi,
> > 
> > >The question as ever is how to represent this in XML. For serial ports 
> > >we'll
> > >stick with '<console>', while parallel ports we might as well use a better
> > >named  '<parallel>'.
> > 
> > Hmm, I'd prefer to use '<serial>', much less confusing in the long run. 
> > And maybe alias '<console>' to '<serial port=0>' for compatibility.
> 
> There is actually one compelling reason to do this - the Xen paravirt 
> console really isn't a true serial port. It is just a dumb text console
> driver, so perhaps it is better to distinguish <console> from <serial>
> with this scenario. We already use <console> for HVM too though - so
> perhaps we should say
> 
>   - <parallel> - parallel ports
>   - <serial>  - serial ports
>   - <console>  - first text based virtual console channel
> 
> So, paravirt Xen would only ever have a <console> element. With fullyvirt
> Xen the first <serial> port element would also be exposed as a <console>
> element.

  Sounds nice to me.

> > >Next up, I think should use a 'type' attribute on this
> > >element to determine the main way ot connecting the device, and then more
> > >type specific attributes or sub-elements as needed. If 'type' was not 
> > >specified then use a default of 'pty', since that gives compatability with
> > >existing practice.
> > 
> > Also enumerate them somehow, so you can configure multiple of them.
> 
> Good point, better to have an explicit 'port' number attribute than
> to rely on implict ordering of the devices in the XML, since there's
> no other attribute in them giving uniqueness (cf device, or MAC in
> disk or network).
> 
> > >NB, whereever there are IP addresses, hostnames can be used too, hence I
> > >call the attriute 'addr' instead of 'ip'
> > 
> > s/addr/host/ + s/port/service/ to make clear that non-numeric stuff is 
> > accepted for both?
> >
> > <serial type='udp' port='0'>
> >   <sendto host='loghost' service='syslog'>
> > </serial>
> 
> Sounds reasonable.

  BTW what's the status ? wondering :-)

Daniel

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