From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:49393) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SRptz-0008CD-Fx for qemu-devel@nongnu.org; Tue, 08 May 2012 15:16:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SRptx-0000nH-My for qemu-devel@nongnu.org; Tue, 08 May 2012 15:16:51 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:50099) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SRptx-0000my-IW for qemu-devel@nongnu.org; Tue, 08 May 2012 15:16:49 -0400 Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 May 2012 15:16:44 -0400 Received: from d01relay05.pok.ibm.com (d01relay05.pok.ibm.com [9.56.227.237]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 7D20138C8067 for ; Tue, 8 May 2012 15:16:40 -0400 (EDT) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q48JGeuT090564 for ; Tue, 8 May 2012 15:16:40 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q48JGeoo027222 for ; Tue, 8 May 2012 16:16:40 -0300 Message-ID: <4FA97111.8@us.ibm.com> Date: Tue, 08 May 2012 14:16:33 -0500 From: Anthony Liguori MIME-Version: 1.0 References: <1336139040-16628-1-git-send-email-borntraeger@de.ibm.com> <1336139040-16628-2-git-send-email-borntraeger@de.ibm.com> <16456C5E-6C77-4976-8F09-A122C0FE0943@suse.de> <4FA3E108.9040204@de.ibm.com> <4FA3E15D.20804@de.ibm.com> <72DBB625-871D-4B0F-8139-A8F941448905@suse.de> <4FA91267.5050306@de.ibm.com> In-Reply-To: <4FA91267.5050306@de.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/1] s390: IPL device for s390 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christian Borntraeger Cc: Cornelia Huck , Jens Freimann , Heinz Graalfs , Alexander Graf , qemu-devel Developers On 05/08/2012 07:32 AM, Christian Borntraeger wrote: > On 04/05/12 20:12, Alexander Graf wrote: >> >> On 04.05.2012, at 16:02, Christian Borntraeger wrote: >> >>> On 04/05/12 16:00, Christian Borntraeger wrote: >>>>>> An IPL (booting) on s390 of SCSI disks is done by a firmware component. >>>>>> Lets implement this scheme as an qemu device that also allows to >>>>>> configure the IPL like the HMC. We have a parameter iplid that >>>>>> refers to a disk device and a load parm that specifies the entry >>>>>> on the disk to be ipled. We also provide a default device >>>>>> if no -device s390-ipl statement is given. >>>>> >>>>> Any reason we can't do this in guest firmware code? >>>> >>>> Conceptually guest firmware does not exist in the guest address space >>>> on s390. It is separate in a storage area called HSA. >>>> (you could say the existing hardware is semi-hosted, you cant buy it bare >>>> metal. >>>> Doing the boot code in guest address space will fail if the guest firmware >>>> address collides with the addresses specified by a bootmap. >>> >>> Or in other words, this code is closer to the real s390 boxes. >> >> Yeah, I see the point. I'd really like to get Anthony's comments on this one first though. > > Right. > > Anthony, this is the prototype of the IPL device that we have talked about some weeks > ago. Is an external device to do the IPL process for s390 still ok with you? I don't really understand the point about collision. If you chain load carefully, you ought to be able to relocate or something like that I would imagine. But at any rate, for these semi-hosted platforms, I don't see a lot better choices than doing these things as devices since there's no "real hardware" to model. So doing this as a device and limiting it to s390 seems like the right strategy to me. Regards, Anthony Liguori > > Christian >