From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NDDLo-0002C0-Sy for qemu-devel@nongnu.org; Wed, 25 Nov 2009 03:35:48 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NDDLk-00029T-IM for qemu-devel@nongnu.org; Wed, 25 Nov 2009 03:35:48 -0500 Received: from [199.232.76.173] (port=58480 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NDDLk-00029L-3Z for qemu-devel@nongnu.org; Wed, 25 Nov 2009 03:35:44 -0500 Received: from cantor2.suse.de ([195.135.220.15]:50489 helo=mx2.suse.de) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NDDLi-0000S2-80 for qemu-devel@nongnu.org; Wed, 25 Nov 2009 03:35:43 -0500 Date: Wed, 25 Nov 2009 09:35:37 +0100 From: Hannes Reinecke Subject: Re: [Qemu-devel] [PATCH 12/13] Add zipl bootloader interpreter Message-ID: <20091125083537.GA25731@ochil.suse.de> References: <1259083781-14642-1-git-send-email-agraf@suse.de> <4B0C3375.4010206@codemonkey.ws> <200911242039.55345.maw48@cantab.net> <4B0C4BC0.7070006@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4B0C4BC0.7070006@codemonkey.ws> Content-Transfer-Encoding: quoted-printable List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Carsten Otte , Alexander Graf , qemu-devel@nongnu.org, Aurelien Jarno , Mark Williamson On Tue, Nov 24, 2009 at 03:10:24PM -0600, Anthony Liguori wrote: > Hi Mark! > > Mark Williamson wrote: >> Way back in the mists of time (uh, something like that 2004-05) I had = some=20 >> discussions with some of the S390 people about using kboot for more=20 >> flexible boot, since it tallied with their interests. Although at tha= t=20 >> point I had the impression that zipl was restricted to only one boot=20 >> option anyhow, so if it can now choose from a list then maybe they jus= t=20 >> enhanced what they had. >> >> Anthony, you might remember these discussions? I don't know if they w= ent=20 >> anywhere with it. >> =20 > > I do, that's why I brought it up. AFAICT, there hasn't been a lot of=20 > progress with kboot. Carsten or Alex would probably know better if any= one=20 > is actually using it on s390s. > No, not to my knowledge. There have been some discussion as if kboot would be beneficial here, but especially for s390 it doesn't make a lot of sense. kboot is okay for scenarios where you have a _lot_ of modules in the defa= ult kernel, but need only a very small subset to get the system bootstrapped. Then you can built a kboot kernel with the driver subset for bootstrappin= g and have that loading the 'normal' kernel which then loads all remaining modules. If you have (like s390) only about 8 driver modules to care about it's pretty much pointless as the kboot kernel will have the same configuratio= n than the normal kernel. So you'll end up with loading the same kernel twi= ce. And won't change the situation here, as you still have to do the initial bootstrap somehow. And as this should be quite close to the original syst= em you'll end up having to support zipl anyway. So back to the zipl question, it might be an idea to support initially the SCSI disk layout only. This has the advantage of being far simpler as the DASD disk layout and should be pretty straightforward to handle. But that's me talking with no real knowledge of qemu bootstrap internals. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: Markus Rex, HRB 16746 (AG N=FCrnberg)