From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=43026 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Olkhu-0000qR-WE for qemu-devel@nongnu.org; Wed, 18 Aug 2010 11:37:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Olkhm-0005Y4-PU for qemu-devel@nongnu.org; Wed, 18 Aug 2010 11:37:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26475) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Olkhm-0005Xu-JD for qemu-devel@nongnu.org; Wed, 18 Aug 2010 11:37:30 -0400 Date: Wed, 18 Aug 2010 18:37:20 +0300 From: Gleb Natapov Subject: Re: [Qemu-devel] [PATCH - V3] Port codes from qemu-kvm to support booting from SCSI disk image Message-ID: <20100818153720.GG10499@redhat.com> References: <201008181608.55759.paul@codesourcery.com> <632E0D52-7618-4184-990D-2918E51A61BC@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <632E0D52-7618-4184-990D-2918E51A61BC@suse.de> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: Paul Brook , Hai Shan Bai , qemu-devel@nongnu.org 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.