I've already made a patch when I doing para-driver debugging.
see the attach patch.
Does it fit the requirement?
It will skip setupping up the loop device for ioemu image files,
but by xm vbd-list, it can still see the file bind to hda.
so  this command is still useful.


Mark Williamson wrote:
>>>Hope about an optional: vbd:/emu: prefix (or similar) on the second part
>>>of the triplet for a disk?  The default (for non VMX domains) could be
>>>"vbd" so existing behaviour would remain the same.
>>
>>Sounds good to me. How about:
>>
>>hda 		= VBD hda
>>vbd://hda 	= VBD hda
>>ioemu://hda	= IDE hda
> 
> 
> Sounds fine but I think I'd actually ditch the // to fit in with the phy: and 
> file: syntax we already have. (and as David said in another post, to avoid 
> looking like a URL).
> 
>