[Libvir] Updated patch for hvm guests

Daniel P. Berrange berrange at redhat.com
Mon Jul 10 17:59:03 UTC 2006

On Mon, Jul 10, 2006 at 09:02:32AM -0400, Daniel Veillard wrote:
> On Mon, Jul 10, 2006 at 06:22:39AM -0400, Daniel Veillard wrote:
> > I have made changes to the XML conversion code to reflect this, I will commit
> > whithin one hour or two. Attached is one example of the XML for HVM.
>   Okay, I commited it, I also extended the page describing the XML format
> to cover the new HVM domains. I was able to launch a domain and attach to
> the vnc server so it seems to work for me at least in a minimal canonical
> configuration.

On the subject of VNC server, the element currently just contains

 <graphics type='vnc'/>

Now the (undocumented) assumption is that the VNC server is listening on
a port number 5900+<domain id>. eg, Domain 3 listens on port 5903. This 
may be fine for dev / testing purposes, but this is not really a acceptable
assumption to make long term. Xen could quite easily change to allocate
arbitrary ports to each domain on a first-come, first-serve basis. When
libVirt is ported to QEMU, there will be no correlation between domain
ID and vnc port number. Thus I'd suggest we extend the XML for VNC thus:

 <graphics type='vnc'>
   <listen port="5903"/>

XenD doesn't currently give us the port number in the SEXPR it returns
so we'll have to have code to explicitly  insert a suitable <listen/>
tag manually, but its well worth it, avoiding need to hardcode port number
assumptions in application code.

On a similar theme, Xen provides a serial console for each guest domain.
Curently people access it with 'xm console <blah>', however, the actual
console is just a psuedo TTY, so if one knows the /dev/pts/<N>  path
there is no need to use 'xm console' at all. Thus I think we could have
another TODO item, to add '<serial port="/dev/pts/3"/>'  element to the
<devices> section of the XML.

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