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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 66F69C43334 for ; Thu, 7 Jul 2022 08:02:43 +0000 (UTC) Received: from localhost ([::1]:58262 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o9MTC-0002zu-ER for qemu-devel@archiver.kernel.org; Thu, 07 Jul 2022 04:02:42 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52134) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o9MLU-0002Ym-FZ for qemu-devel@nongnu.org; Thu, 07 Jul 2022 03:54:44 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:58700) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o9MLS-0007Tu-NA for qemu-devel@nongnu.org; Thu, 07 Jul 2022 03:54:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657180482; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JX49n3pmcxTjrWe9XWUjvO3guR5PPOJFXcuBrH4E24Y=; b=UIALxlFjtS9ad1Lm6Y8JZYKotHyXk3PnEMpixBriXypQ32vxBzod2RzeZ8Lo0ALCkm1E4R g5Cs29pUHpbpNhfPHSEuD0vMK3Ms6Xrptf5vhN26h7I/L7q68VNe/cbiGEwUwGPZizhnU8 O9EScKjsa9jWu1ZIiCQivo5eLhhf6rM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-531-8bgmwj8KPResDf28YYXtBw-1; Thu, 07 Jul 2022 03:54:36 -0400 X-MC-Unique: 8bgmwj8KPResDf28YYXtBw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3FD69805AF5; Thu, 7 Jul 2022 07:54:36 +0000 (UTC) Received: from thuth.com (unknown [10.39.193.84]) by smtp.corp.redhat.com (Postfix) with ESMTP id 78B41404754C; Thu, 7 Jul 2022 07:54:35 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, Richard Henderson Cc: qemu-s390x@nongnu.org Subject: [PULL 04/18] pc-bios/s390-ccw/bootmap: Improve the guessing logic in zipl_load_vblk() Date: Thu, 7 Jul 2022 09:54:12 +0200 Message-Id: <20220707075426.1163210-5-thuth@redhat.com> In-Reply-To: <20220707075426.1163210-1-thuth@redhat.com> References: <20220707075426.1163210-1-thuth@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The logic of trying an final ISO or ECKD boot on virtio-block devices is very weird: Since the geometry hardly ever matches in virtio_disk_is_scsi(), virtio_blk_setup_device() always sets a "guessed" disk geometry via virtio_assume_scsi() (which is certainly also wrong in a lot of cases). zipl_load_vblk() then sees that there's been a "virtio_guessed_disk_nature" and tries to fix up the geometry again via virtio_assume_iso9660() before always trying to do ipl_iso_el_torito(). That's a very brain-twisting way of attempting to boot from ISO images, which won't work anymore after the following patches that will clean up the virtio_assume_scsi() mess (and thus get rid of the "virtio_guessed_disk_nature" here). Let's try a better approach instead: ISO files always have a magic string "CD001" at offset 0x8001 (see e.g. the ECMA-119 specification) which we can use to decide whether we should try to boot in ISO 9660 mode (which we should also try if we see a sector size of 2048). And if we were not able to boot in ISO mode here, the final boot attempt before panicking is to boot in ECKD mode. Since this is our last boot attempt anyway, simply always assume the ECKD geometry here (if the sector size was not 4096 yet), so that we also do not depend on the guessed disk geometry from virtio_blk_setup_device() here anymore. Message-Id: <20220704111903.62400-4-thuth@redhat.com> Signed-off-by: Thomas Huth --- pc-bios/s390-ccw/bootmap.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c index 56411ab3b6..994e59c0b0 100644 --- a/pc-bios/s390-ccw/bootmap.c +++ b/pc-bios/s390-ccw/bootmap.c @@ -780,18 +780,37 @@ static void ipl_iso_el_torito(void) } } +/** + * Detect whether we're trying to boot from an .ISO image. + * These always have a signature string "CD001" at offset 0x8001. + */ +static bool has_iso_signature(void) +{ + int blksize = virtio_get_block_size(); + + if (!blksize || virtio_read(0x8000 / blksize, sec)) { + return false; + } + + return !memcmp("CD001", &sec[1], 5); +} + /*********************************************************************** * Bus specific IPL sequences */ static void zipl_load_vblk(void) { - if (virtio_guessed_disk_nature()) { - virtio_assume_iso9660(); + int blksize = virtio_get_block_size(); + + if (blksize == VIRTIO_ISO_BLOCK_SIZE || has_iso_signature()) { + if (blksize != VIRTIO_ISO_BLOCK_SIZE) { + virtio_assume_iso9660(); + } + ipl_iso_el_torito(); } - ipl_iso_el_torito(); - if (virtio_guessed_disk_nature()) { + if (blksize != VIRTIO_DASD_DEFAULT_BLOCK_SIZE) { sclp_print("Using guessed DASD geometry.\n"); virtio_assume_eckd(); } -- 2.31.1