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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 57909C433E0 for ; Thu, 6 Aug 2020 15:06:09 +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 5722623131 for ; Thu, 6 Aug 2020 15:06:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="V5A6ROVN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5722623131 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44444 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k3hT6-0000T5-7j for qemu-devel@archiver.kernel.org; Thu, 06 Aug 2020 11:06:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44914) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k3hSW-0008NR-V4 for qemu-devel@nongnu.org; Thu, 06 Aug 2020 11:05:32 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:31687 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k3hSV-0006a3-75 for qemu-devel@nongnu.org; Thu, 06 Aug 2020 11:05:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596726330; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:content-type:content-type; bh=36NRQBFnKvLOHfTrOUCkCppYTniyv3MNt81GIJOXd7M=; b=V5A6ROVNHF23+HzAfsMlk3kThCe0fJkQGSZ/yMRQ5QU0Px3jC8MhamCjiMmOYhse2kS+Xm fK6w+gx5wq33YSqbV6FOhwcr/3EEY+zLQVTMA5+iE1LsnooCHrT92mbsqsXq/+Gghm7Bok QJX33UiibP+V8MWZxUtAz9Xxn8pYNzw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-4-rIacAZosPb63Ip5arLh3yQ-1; Thu, 06 Aug 2020 11:05:11 -0400 X-MC-Unique: rIacAZosPb63Ip5arLh3yQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0B96E19200C2; Thu, 6 Aug 2020 15:05:11 +0000 (UTC) Received: from thuth.com (ovpn-112-229.ams2.redhat.com [10.36.112.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id A6AA16FEDC; Thu, 6 Aug 2020 15:05:09 +0000 (UTC) From: Thomas Huth To: Cornelia Huck , qemu-s390x@nongnu.org Subject: [PATCH] docs/system/s390x: Add a chapter about s390x boot devices Date: Thu, 6 Aug 2020 17:05:07 +0200 Message-Id: <20200806150507.12073-1-thuth@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=thuth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Received-SPF: pass client-ip=205.139.110.120; envelope-from=thuth@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/06 00:24:10 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Booting on s390x is a little bit different compared to other architectures. Let's add some information for people who are not yet used to this. Signed-off-by: Thomas Huth --- docs/system/s390x/bootdevices.rst | 82 +++++++++++++++++++++++++++++++ docs/system/target-s390x.rst | 1 + 2 files changed, 83 insertions(+) create mode 100644 docs/system/s390x/bootdevices.rst diff --git a/docs/system/s390x/bootdevices.rst b/docs/system/s390x/bootdevices.rst new file mode 100644 index 0000000000..68f0ffd450 --- /dev/null +++ b/docs/system/s390x/bootdevices.rst @@ -0,0 +1,82 @@ +Boot devices on s390x +===================== + +Booting with bootindex parameter +-------------------------------- + +For classical mainframe guests (i.e. LPAR or z/VM installations), you always +have to exactly specify the disk where you want to boot from (or "IPL" from, +in s390x-speak -- IPL means "Initial Program Load"). Especially, there can +also be only one boot device according to the architecture specification, thus +specifying multiple boot devices is not possible (yet). + +So for booting an s390x guest in QEMU, you should always mark the +device where you want to boot from with the ``bootindex`` property, for +example:: + + qemu-system-s390x -drive if=none,id=dr1,file=guest.qcow2 \ + -device virtio-blk,drive=dr1,bootindex=1 + +For booting from a CD-ROM ISO image (which needs to include El-Torito boot +informatin for being bootable), it is recommended to specify a ``scsi-cd`` +device, for example like this:: + + qemu-system-s390x -blockdev file,node-name=c1,filename=... \ + -device virtio-scsi \ + -device scsi-cd,drive=c1,bootindex=1 + +Note that you really have to use the ``bootindex`` property to select the +boot device. The old-fashioned ``-boot order=...`` command of QEMU (and +also ``-boot once=...``) is not supported on s390x. + + +Booting without bootindex parameter +----------------------------------- + +The QEMU guest firmware (the so-called s390-ccw bios) has also some rudimentary +support for scanning through the available block devices. So in case you did +not specify a boot device with the ``bootindex`` property, there is still a +chance that it finds a bootable device on its own and starts a guest operating +system from it. However, this scanning algorithm is still very rough and may +be incomplete, so that it might fail to detect a bootable device in many cases. +It is really recommended to always specify the boot device with the +``bootindex`` property instead. + +This also means that you should avoid the classical short-cut commands like +``-hda``, ``-cdrom`` or ``-drive if=virtio``, since it is not possible to +specify the ``bootindex`` with these commands. Note that the convenience +``-cdrom`` option even does not give you a real (virtio-scsi) CD-ROM device on +s390x. Due to technical limitations in the QEMU code base, you will get a +virtio-blk device with this parameter instead, which might not be the right +device type for installing a Linux distribution via ISO image. It is +recommended to specify a CD-ROM device via ``-device scsi-cd`` (as mentioned +above) instead. + + +Booting from a network device +----------------------------- + +Beside the normal guest firmware (which is loaded from the file ``s390-ccw.img`` +in the data directory of QEMU, or via the ``-bios`` option), QEMU ships with +a small TFTP network bootloader firmware for virtio-net-ccw devices, too. This +firmware is loaded from a file called ``s390-netboot.img`` in the QEMU data +directory. In case you want to load it from a different filename instead, +you can specify it via the ``-global s390-ipl.netboot_fw=filename`` +command line option. + +The ``bootindex`` property is especially important for booting via the network. +If you don't specify the the ``bootindex`` property here, the network bootloader +firmware code won't get loaded into the guest memory so that the network boot +will fail. For a successful network boot, try something like this:: + + qemu-system-s390x -netdev user,id=n1,tftp=...,bootfile=... \ + -device virtio-net-ccw,netdev=n1,bootindex=1 + +The network bootloader firmware also has basic support for pxelinux.cfg-style +configuration files. See the `PXELINUX Configuration page +`__ +for details how to set up the configuration file on your TFTP server. +The supported configuration file entries are ``DEFAULT``, ``LABEL``, +``KERNEL``, ``INITRD`` and ``APPEND`` (see the `Syslinux Config file syntax +`__ for more +information). diff --git a/docs/system/target-s390x.rst b/docs/system/target-s390x.rst index 644e404ef9..c636f64113 100644 --- a/docs/system/target-s390x.rst +++ b/docs/system/target-s390x.rst @@ -31,4 +31,5 @@ Architectural features ====================== .. toctree:: + s390x/bootdevices s390x/protvirt -- 2.18.1