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 7A98EC678D5 for ; Tue, 7 Mar 2023 14:01:39 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pZXsB-0004h0-10; Tue, 07 Mar 2023 09:00:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pZXrm-0004U6-Af for qemu-devel@nongnu.org; Tue, 07 Mar 2023 09:00:42 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pZXrk-0001Nz-KQ for qemu-devel@nongnu.org; Tue, 07 Mar 2023 09:00:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678197631; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WVMjYIjmCmEkImB+I9IPvNSlFJfFoSPNxTVnrV3jErk=; b=AEraBYYoiNijuDBNg3HN3clxk3SM4cRliqcAKRLspG8gSHoloFSSwhd3s4c0uVEzwOLwuN OoKUawIzQ6N7Q31ZCLo0bnq9MnvvDUVhxYRhyg1mTBqlXAndEGKxaorTz+/9JtHnGgPNZR iwYWRWTcUIKndd/3XnK/keoZfZKbKmQ= 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-122-nKoHsRWJOyKqonp0pmYSZA-1; Tue, 07 Mar 2023 09:00:27 -0500 X-MC-Unique: nKoHsRWJOyKqonp0pmYSZA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 926B185CCE2; Tue, 7 Mar 2023 14:00:15 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7773A2026D4B; Tue, 7 Mar 2023 14:00:14 +0000 (UTC) Date: Tue, 7 Mar 2023 15:00:13 +0100 From: Kevin Wolf To: "Maciej S. Szmigiero" Cc: =?iso-8859-1?Q?C=E9dric?= Le Goater , qemu-block@nongnu.org, peter.maydell@linaro.org, qemu-devel@nongnu.org, Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , kraxel@redhat.com Subject: Re: [PULL 03/38] pflash: Only read non-zero parts of backend image Message-ID: References: <20230120122633.84983-1-kwolf@redhat.com> <20230120122633.84983-4-kwolf@redhat.com> <5fb3fd72-3bd8-4895-62dd-2d504188faf2@kaod.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 03.03.2023 um 23:51 hat Maciej S. Szmigiero geschrieben: > On 8.02.2023 12:19, Cédric Le Goater wrote: > > On 2/7/23 13:48, Kevin Wolf wrote: > > > Am 07.02.2023 um 10:19 hat Cédric Le Goater geschrieben: > > > > On 2/7/23 09:38, Kevin Wolf wrote: > > > > > Am 06.02.2023 um 16:54 hat Cédric Le Goater geschrieben: > > > > > > On 1/20/23 13:25, Kevin Wolf wrote: > > > > > > > From: Xiang Zheng > > > > > > > > > > > > > > Currently we fill the VIRT_FLASH memory space with two 64MB NOR images > > > > > > > when using persistent UEFI variables on virt board. Actually we only use > > > > > > > a very small(non-zero) part of the memory while the rest significant > > > > > > > large(zero) part of memory is wasted. > > > > > > > > > > > > > > So this patch checks the block status and only writes the non-zero part > > > > > > > into memory. This requires pflash devices to use sparse files for > > > > > > > backends. > > > > > > > > > > > > > > Signed-off-by: Xiang Zheng > > > > > > > > > > > > > > [ kraxel: rebased to latest master ] > > > > > > > > > > > > > > Signed-off-by: Gerd Hoffmann > > > > > > > Message-Id: <20221220084246.1984871-1-kraxel@redhat.com> > > > > > > > Reviewed-by: Daniel P. Berrangé > > > > > > > Reviewed-by: Kevin Wolf > > > > > > > Signed-off-by: Kevin Wolf > > > > > > > > > > > > This newly merged patch introduces a "regression" when booting an Aspeed > > > > > > machine. The following extra m25p80 patch (not yet merged) is required > > > > > > for the issue to show: > > > > > > > > > > > >     https://lore.kernel.org/qemu-devel/20221115151000.2080833-1-clg@kaod.org/ > > > > > > > > > > > > U-Boot fails to find the filesystem in that case. > > > > > > > > > > > > It can be easily reproduced with the witherspoon-bmc machine and seems > > > > > > to be related to the use of a UBI filesystem. Other Aspeed machines not > > > > > > using UBI are not impacted. > > > > > > > > > > > > Here is a tentative fix. I don't know enough the block layer to explain > > > > > > what is happening :/ > > > > > > > > > > I was puzzled for a moment, but... > > > > > > > > > > > @@ -39,7 +39,7 @@ static int blk_pread_nonzeroes(BlockBack > > > > > >                return ret; > > > > > >            } > > > > > >            if (!(ret & BDRV_BLOCK_ZERO)) { > > > > > > -            ret = bdrv_pread(bs->file, offset, bytes, > > > > > > > > > > 'bs->file' rather than 'bs' really looks wrong. I think replacing that > > > > > would already fix the bug you're seeing. > > > > > > > > > > Just to be sure, how did you configure the block backend? bs->file would > > > > > happen to work more or less with raw over file-posix (which is probably > > > > > what Gerd tested), but I think it breaks with anything else. > > > > > > > > The command is  : > > > > > > > >    $ qemu-system-arm -M witherspoon-bmc -net user \ > > > >     -drive file=/path/to/file.mtd,format=raw,if=mtd \ > > > >     -nographic -serial mon:stdio -snapshot > > > > > > > > If I remove '-snapshot', all works fine. > > > > > > Ok, that makes sense then. -snapshot creates a temporary qcow2 overlay, > > > and then what your guest sees with bs->file is not the virtual disk > > > content of the qcow2 image, but the qcow2 file itself. > > > > yes. Same symptom with pflash devices, TCG and KVM. The guest hangs with -snapshot. > > > > C. > > > > qemu-system-aarch64 -M virt -smp 2 -cpu max -accel tcg,thread=multi -nographic -m 2G -drive if=pflash,format=raw,file=/usr/share/edk2/aarch64/QEMU_EFI-silent-pflash.raw,readonly=on -drive if=pflash,format=raw,file=rhel9-varstore.img -device virtio-net,netdev=net0,bus=pcie.0,addr=0x3 -netdev user,id=net0 -drive file=rhel9-arm64.qcow2,if=none,id=disk,format=qcow2,cache=none -device virtio-blk-device,drive=disk -serial mon:stdio -snapshot > > > > > > > > +1 here for QEMU + KVM/x86: OVMF CODE file fails to load (is all zeroes) > with either "-snapshot" QEMU command line option or even with just "snapshot=on" > setting enabled on pflash0. > > Reverting this patch seems to fix the issue. Hm, so we know the fix, but nobody has submitted it as an actual patch? I'll send one... Kevin