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 C24F0C636CD for ; Tue, 7 Feb 2023 12:49:08 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pPNOk-0005dN-Hp; Tue, 07 Feb 2023 07:48:34 -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 1pPNOj-0005c2-DN for qemu-devel@nongnu.org; Tue, 07 Feb 2023 07:48:33 -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 1pPNOh-0004Tb-Ly for qemu-devel@nongnu.org; Tue, 07 Feb 2023 07:48:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1675774110; 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=VMifq9Evo8eqLEbPwQqX66hipue5IvpYnnM0U2CL0hM=; b=EBY9LXC8iWIHht5f5yqA3nCbTqvvIMOplY93UyDC4bpMQvfy+edDgRpMsv5yTMsB3YUNq4 dBZhOI5IUasu8p9TefHHqeUOEfr77/enHA+CaW0lMv44jRBdT1io/hY5EuQFv2q8XB8uf4 5VhlHunbLvMsGMrE8/hLq5/AkRbKH+4= 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-518-wodIGuXVNYil7fg9j4pwog-1; Tue, 07 Feb 2023 07:48:27 -0500 X-MC-Unique: wodIGuXVNYil7fg9j4pwog-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 059DF101A52E; Tue, 7 Feb 2023 12:48:27 +0000 (UTC) Received: from redhat.com (unknown [10.39.195.39]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C698E404BEF3; Tue, 7 Feb 2023 12:48:23 +0000 (UTC) Date: Tue, 7 Feb 2023 13:48:22 +0100 From: Kevin Wolf To: =?iso-8859-1?Q?C=E9dric?= Le Goater Cc: 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> 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 10.11.54.1 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=ham 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 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. Kevin