From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E93B5C2D0C0 for ; Mon, 16 Dec 2019 13:44:26 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C1E7720409 for ; Mon, 16 Dec 2019 13:44:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C1E7720409 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53926 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1igqfh-0006Jb-TQ for qemu-devel@archiver.kernel.org; Mon, 16 Dec 2019 08:44:25 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52380) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1igqf4-0005tr-PU for qemu-devel@nongnu.org; Mon, 16 Dec 2019 08:43:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1igqf3-0006L8-Dy for qemu-devel@nongnu.org; Mon, 16 Dec 2019 08:43:46 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:51550 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1igqf3-0006Iu-9E for qemu-devel@nongnu.org; Mon, 16 Dec 2019 08:43:45 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xBGDcSsO068746 for ; Mon, 16 Dec 2019 08:43:43 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2wwe2pb5tp-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 16 Dec 2019 08:43:43 -0500 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 16 Dec 2019 13:43:36 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xBGDhZlk46268760 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 16 Dec 2019 13:43:35 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 02997AE053; Mon, 16 Dec 2019 13:43:35 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9E2B6AE056; Mon, 16 Dec 2019 13:43:34 +0000 (GMT) Received: from [9.152.212.29] (unknown [9.152.212.29]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 16 Dec 2019 13:43:34 +0000 (GMT) Subject: Re: [RFC QEMU PATCH] pc-bios/s390-ccw: Add zipl-like "BOOT_IMAGE=x" to the kernel parameters To: Christian Borntraeger , Thomas Huth , qemu-devel@nongnu.org, Stefan Haberland References: <20191216112432.13412-1-thuth@redhat.com> From: Peter Oberparleiter Date: Mon, 16 Dec 2019 14:43:33 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19121613-0016-0000-0000-000002D564B1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19121613-0017-0000-0000-0000333798B8 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-16_05:2019-12-16,2019-12-16 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 malwarescore=0 phishscore=0 bulkscore=0 mlxscore=0 adultscore=0 priorityscore=1501 suspectscore=1 spamscore=0 impostorscore=0 mlxlogscore=999 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912160122 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390@vger.kernel.org, qemu-s390x@nongnu.org, Cornelia Huck , =?UTF-8?Q?Jan_H=c3=b6ppner?= , psundara@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 16.12.2019 12:29, Christian Borntraeger wrote: > > > On 16.12.19 12:24, Thomas Huth wrote: >> Note: I've marked the patch as RFC since I'm not quite sure whether >> this is really the right way to address this issue: It's unfortunate >> that we have to mess with different location in ZIPL which might also >> change again in the future. Having QEMU or any other tooling rely on undocumented on-disk format specifics of zipl is definitely wrong and prone to break with the next change. This is _not_ an ABI. >> As suggested by Christian on IRC last week, >> maybe it would make more sense to change ZIPL to add this parameter >> already when zipl is installed (i.e. by the Linux userspace "zipl" pro- >> gram), instead of adding it during boot time? Also, the BOOT_IMAGE para- >> meter on s390x is quite different from the BOOT_IMAGE paramter that is >> used on x86 - while s390x only uses one single number here, the x86 >> variant (added by grub2, I guess) uses the boot device + full filename >> of the kernel on the boot partition. Should we maybe make the s390x >> variant more conform to x86? If so, I think this really has to be fixed >> in zipl userspace tool, and not in the s390-ccw bios (and zipl stage3 >> bootloader). > > Yes, I actually think we should revisit the whole BOOT_IMAGE scheme on s390. > Maybe we should use the kernel name, or the name of the boot menu entry. > And maybe we should not use 0 (when the default is running) but instead > really use to what 0 points to. BOOT_IMAGE on s390 currently only exists for DASD, so any tooling that relies on it today would be broken for SCSI boot. The equivalent information for SCSI would be the boot program selector at /sys/firmware/ipl/bootprog. There is currently no other way to get this information when booting from DASD. Also note that the format of BOOT_IMAGE is dependent on the boot loader that created it. The use of the menu number (and 0 for default) has the advantage that this number can be used, e.g. to select the same number for the next boot using the LOADPARM. Changing BOOT_IMAGE to show the kernel name would take away that use case. At this time I would suggest to start by identifying any current users of BOOT_IMAGE and to understand what their actual requirement is. Once that information is available, we can think about how this requirement could best be implemented. Looking at the dracut link it seems like their requirement cannot be met at all with the information currently provided on s390 via the BOOT_IMAGE parameter. -- Peter Oberparleiter Linux on Z Development - IBM Germany