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

[Kevin O'Connor]

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.

-Kevin