Re: [Qemu-devel] Boot order problem and disable iPXE/gPXE

[Gleb Natapov <gleb@redhat.com>]

On Sat, Jan 07, 2012 at 11:28:44AM -0500, Kevin O'Connor wrote:
> On Sat, Jan 07, 2012 at 10:00:56AM +0100, Gerhard Wiesinger wrote:
> > On Fri, 6 Jan 2012, Kevin O'Connor wrote:
> > >I'm not sure what a SCSI rom would do with a CD drive.  My guess is
> > >that it wouldn't map it to a BIOS visible drive id at all, as there's
> > >no way to select an id with any assurance that it wont conflict with
> > >one chosen by the BIOS or another rom.  If QEMU can simulate this (and
> > >someone knows the command-line to do such) it would be an interesting
> > >test to see what the rom does.
> > 
> > As far as I remember from SCSI only systems one can just boot from
> > CD drives, too. Order is SCSI id (starting with SCSI id 0, up to 7,
> > 15, etc. depending on host adapeter).
> > 
> > Tried:
> > -drive file=KNOPPIX_V6.2CD-2009-11-18-DE.iso,media=cdrom,if=scsi,bus=0,unit=0
> > all other drives are afterwards.
> > 
> > Registers as CDROM, selecting Legacy Option ROM from boot menu, but
> > can't boot:
> > Screen:
> > Booting from DVD/CD...
> 
> This is SeaBIOS attempting to boot from its internal CD code which
> wont work for SCSI.  (The "Legacy Option ROM" seletion is probably the
> KVM vapic.bin rom.)  The question is, what will the 8xx_64.rom do with
> a cdrom on a scsi adapter...
> 
> I downloaded 8xx_64.rom and tried the above command line.
> Interestingly, it will register a BEV for a CD drive - which confirms
> my suspicion that it wont use a BCV.  Also interesting is that if both
> a harddrive and a CD are found, both a BEV and a BCV will be present -
> SeaBIOS doesn't support this, but I don't see any reason it couldn't.
> 
Cool! What about non pnp roms that also register bcv? Should we use HD
priority for those too?

--
			Gleb.