Hello, everybody!

I knew recently that xl doesn't yet work with GFX passthrough for HVM 
guest. It makes me consider that main job for GFX passthrough are going 
for xm toolstack. My company is very interested to use xl tool, but we 
need also GFX passthrough.

The issue is not very hard to solve. It just needs to teach xl to 
recognize 'gfx_passthru' in config file and pass it to qemu-dm. And 
qemu-dm will choose the specific VGA bios to load into domain's memory 
in case of this option.  

I attached the patch, addressing this issue.

Please, consider to push it to main repository.

Thank you.

Sergey.