[Libvir] Fix handling of HVM boot parameters

[Daniel P. Berrange]

On Thu, Aug 10, 2006 at 08:02:20AM -0400, Jeremy Katz wrote:
> On Thu, 2006-08-10 at 05:08 -0400, Daniel Veillard wrote:
> >   There is the read-only attribute. For example UML has no specific way
> > to indicate an emulated CD-ROM, there is just a read-only command line 
> > flag.
> > 
> >      <disk type='file'>
> >        <source file='/root/boot.iso'/>
> >        <target dev='hdc'/>
> >        <readonly/>
> >      </disk>
> > 
> >   After all since we don't have hardware to tell us what kind of device
> > it is, it is really a matter of what kind of accesses are allowed. How
> > it is mapped underneath depends on the engine used, but should probably
> > not affect the XML format.
> 
> But read-only isn't all that you want -- think about giving access to a
> CD-R drive.  It's not read-only, but we still need to have it exposed as
> a CD device.  And with things like the bios for qemu and HVM guests, if
> a device is a CD-ROM or a hard drive makes a large difference.
> 
> Thinking out loud, what if we went with something like
>   <cdrom type='file'>
>     <source file='/root/boot.iso'/>
>     <target dev='hdc'/>
>   </cdrom>
> for CDs and then similarly <floppy .../> for floppies

I wouldn't do this for CDROMs, since they basically share the same device
namespace as disks already - with versions Xen / QEMU any hda -> hdd
can be labelled as a cdrom by appending :cdrom - so they're best handled
under same XML tag as disks

For floppy disks though we could certainly have a separate <floppy>
tag name instead of <disk> - it would be clearer than distinguishing
based on the value of the 'dev' attribute.

Regards,
Dan.
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