[libvirt] [PATCH] qemu: Add support for SGA video

Daniel P. Berrange berrange at redhat.com
Mon Jul 4 13:40:36 UTC 2011

On Mon, Jul 04, 2011 at 03:21:25PM +0200, Michal Privoznik wrote:
> This patch extends possible values for <video> element. Serial Graphics
> Adapter allows users to see BIOS messages from the very first moment
> domain boots up. Therefore, users can choose boot medium, set PXE, etc.

This isn't really the right way todo this. '-sga' is not actually a
new type of video card. It isn't even a guest device. It is just a
hack QEMU uses for loading an option ROM via their qdev infrastructure.
This in turn causes the QEMU BIOS to use a serial port for outputting

IMHO we should do one of

 - Automatically enable it if no <graphics> is set, but there
   is a <serial> set (ie no XML additions at all)
 - Add a attribute to the <serial> element to allow use of SGA
   to be toggled on/off
 - Add an attribute on the <boot> element to redirect BIOS
   to SGA.

One thing about options 2/3 there is that they could allow
a user to request the BIOS to use the serial port even when
their guest *does* have a <graphics> element present.

|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|

More information about the libvir-list mailing list