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 DAD32C61DA4 for ; Thu, 16 Feb 2023 15:26:32 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pSg8y-0005ig-KM; Thu, 16 Feb 2023 10:25:56 -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 1pSg8w-0005fb-3r; Thu, 16 Feb 2023 10:25:54 -0500 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pSg8t-0005JZ-Gh; Thu, 16 Feb 2023 10:25:53 -0500 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 8881B47381; Thu, 16 Feb 2023 16:25:47 +0100 (CET) Message-ID: Date: Thu, 16 Feb 2023 16:25:46 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: Lost partition tables on ide-hd + ahci drive Content-Language: en-US To: Mike Maslenkin Cc: John Snow , QEMU Developers , "open list:Network Block Dev..." , Thomas Lamprecht , Aaron Lauterer References: From: Fiona Ebner In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.351, 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 16.02.23 um 15:17 schrieb Mike Maslenkin: > Does additional comparison make a sense here: check for LBA == 0 and > then check MBR signature bytes. > Additionally it’s easy to check buffer_is_zero() result or even print > FIS contents under these conditions. > Data looks like a part of guest memory of 64bit Windows. Thank you for the suggestion! I'll think about adding such a check and dumping of FIS contents in a custom build for affected users. But in general it would be too much noise for non-MBR cases: e.g. on a disk formatted with ext4 (without any partitions), Linux will write to sector 0 on every startup and shutdown. Best Regards, Fiona