From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:48861) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rijq9-0002O5-Im for qemu-devel@nongnu.org; Thu, 05 Jan 2012 04:42:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Rijq6-0001qU-4g for qemu-devel@nongnu.org; Thu, 05 Jan 2012 04:42:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39450) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rijq5-0001qH-LR for qemu-devel@nongnu.org; Thu, 05 Jan 2012 04:42:25 -0500 Date: Thu, 5 Jan 2012 11:42:23 +0200 From: Gleb Natapov Message-ID: <20120105094222.GC31206@redhat.com> References: <4F055827.50202@redhat.com> <20120105083239.GR2072@redhat.com> <20120105092037.GA31206@redhat.com> <20120105092957.GB31206@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] Boot order problem and disable iPXE/gPXE List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerhard Wiesinger Cc: Gerd Hoffmann , qemu-devel@nongnu.org On Thu, Jan 05, 2012 at 10:36:29AM +0100, Gerhard Wiesinger wrote: > On Thu, 5 Jan 2012, Gleb Natapov wrote: > > >On Thu, Jan 05, 2012 at 10:27:44AM +0100, Gerhard Wiesinger wrote: > >>On Thu, 5 Jan 2012, Gleb Natapov wrote: > >> > >>>On Thu, Jan 05, 2012 at 10:09:44AM +0100, Gerhard Wiesinger wrote: > >>>>On Thu, 5 Jan 2012, Gleb Natapov wrote: > >>>> > >>>>>On Thu, Jan 05, 2012 at 09:23:02AM +0100, Gerhard Wiesinger wrote: > >>>>>>On Thu, 5 Jan 2012, Gerd Hoffmann wrote: > >>>>>> > >>>>>>>On 01/04/12 19:02, Gerhard Wiesinger wrote: > >>>>>>>>Hello, > >>>>>>>> > >>>>>>>>I'm having the following boot order problem using an SCSI option ROM: > >>>>>>>> > >>>>>>> > >>>>>>>>Still boots the cdrom instead of harddisk. So it is impossible to have a > >>>>>>>>bootable CDROM in the VM without booting from it. > >>>>>>> > >>>>>>>-option-rom romfile=/root/roms/8xx_64.rom,bootindex=1 > >>>>>> > >>>>>>Ok, works well, but I think than "-boot order=c" is buggy, right? > >>>>>> > >>>>>Wrong. "-boot order=c" tells seabios to boot from a HD, but for that > >>>>>Seabios needs to actually know what is HD and what is not. Since Seabios > >>>>>does not support scsi controller natively it only sees pci device and > >>>>>has no idea that you have scsi disk there. It uses pci option rom to > >>>>>boot from this unknown device. > >>>> > >>>>But as far as I remember therefore the option ROM registers through > >>>>BIOS for INT 19h booting. So Seabios should know it that this is a > >>>>harddisk. > >>>It registers BEV. Otherwise you wouldn't be able to boot at all. In fact > >>>it registers multiple BEVs (one for each attached scsi device). But BIOS > >>>knows nothing about the device behind the BEV. It just jumps to BEV > >>>address to boot from it when INT 19h is called. There may be scsi cdrom > >>>there or even tape. > >> > >>But to get rid of this problem typical BIOSes have an option whether > >>they prefer to BOOT from SCSI (with an option ROM) or > >>from the other devices. Then the option ROM typically boots from the > >>first registered device. > >> > >>I think this is a missing feature in Seabios. > >> > >How is it missing if you just used it and confirmed that it worked? > > It had to specify it on the option ROM itself. But I think a generic > way would be e.g.: > boot=SCSI,c,a > boot option is deprecated in favor of bootindex. The later has much more fine grained control of boot sequence. What if you have 5 SCSI controllers? Even boot=c does not tell you much if you have more then one disk. -- Gleb.