Re: [Qemu-devel] [PATCH - V3] Port codes from qemu-kvm to support booting from SCSI disk image

[Gleb Natapov <gleb@redhat.com>]

On Wed, Aug 18, 2010 at 05:16:56PM +0200, Alexander Graf wrote:
> 
> On 18.08.2010, at 17:08, Paul Brook wrote:
> 
> >> The qemu-kvm could boot from SCSI disk image by utilizing seabios, this
> >> patch ported codes
> >> from qemu-kvm to let upstream qemu to support booting from SCSI disk image.
> > 
> > No. This has nothing to do with SCSI.
> > 
> > What it does is add a really cheap and nasty block storage device that aliases 
> > one of the other block devices in the system. This is bad. The OS has no way 
> > of knowing which devices are aliased, and we really don't want yet another 
> > braindead guest visible interface (c.f. recent performance issues where -
> > kernel/fw_cfg were being abused)
> > 
> > This has been discussed several times before. The proper solution is to teach 
> > the bios how to boot off SCSI devices. IIRC support for virtio devices already 
> > exists, implementing support for the SCSI controller shouldn't be that much 
> > harder.
> 
> Couldn't we just have an option rom for the SCSI controller? The same way the VGABIOS is a rewrite of a VGA BIOS for the Cirrus Logic...
> 
> 
Of course we could, but it should not be extboot, but proper scsi driver. gpxe has
src/drivers/block/scsi.c so may be it already supports qemu scsi device?

--
			Gleb.