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 7337ECCA47E for ; Thu, 16 Jun 2022 05:52:04 +0000 (UTC) Received: from localhost ([::1]:40938 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o1iQF-0006vP-51 for qemu-devel@archiver.kernel.org; Thu, 16 Jun 2022 01:52:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34716) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o1iNg-0005IN-DE for qemu-devel@nongnu.org; Thu, 16 Jun 2022 01:49:27 -0400 Received: from mga17.intel.com ([192.55.52.151]:26675) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o1iNd-00012f-Op for qemu-devel@nongnu.org; Thu, 16 Jun 2022 01:49:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655358561; x=1686894561; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=7q+liQpaS4RSq+Y+sPm5n+V8v8CGLONlUm/40d4Ij3Q=; b=ANB64+T+a1LsolE5CEzX3HlyClBS9R1uKhbRRKtoZEYwEOZdocEMA7vH SZAlxrHM33KAr6BZPGx3WARj4z2AU9Q3vTTLA1COQVcJt7xRrUBD2ZA+2 vOYB/MUuQhdAPwW299AMG68exMiZEB1NCLLcE0i/qBFqpNAdgM1/wUPzz MMoHKaXAIlTTkCexzQjkipxA8ztNpeDUUwJsuNa/2Z7hy3bDZE0XPx+Dt ZdsH/ZRHkem9622//mCSwsbmWxDjoYmHA5E58SCN2+ou8nc9lJzIfDHMh bCNXeS9RFqTM7OSngMpgYw1J3vxy6ovVHCvCMcUpyAhCiVEI/YyU8v3vo g==; X-IronPort-AV: E=McAfee;i="6400,9594,10379"; a="259635635" X-IronPort-AV: E=Sophos;i="5.91,304,1647327600"; d="scan'208";a="259635635" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 22:49:15 -0700 X-IronPort-AV: E=Sophos;i="5.91,304,1647327600"; d="scan'208";a="831415172" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.249.169.162]) ([10.249.169.162]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 22:49:13 -0700 Message-ID: <6c2f350c-61eb-825d-36b7-86c913e610b3@intel.com> Date: Thu, 16 Jun 2022 13:49:11 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.10.0 Subject: Re: New "IndustryStandard" fw_cfg? Content-Language: en-US To: Gerd Hoffmann Cc: "Xu, Min M" , Dionna Amalie Glaze , "qemu-devel@nongnu.org" , "Lendacky, Thomas" , "Yao, Jiewen" , "Aktas, Erdem" , "Yamahata, Isaku" References: <843cb055-d28e-1753-5dd5-9d4565171084@intel.com> <20220616053741.strgwe3mx3adxzui@sirius.home.kraxel.org> From: Xiaoyao Li In-Reply-To: <20220616053741.strgwe3mx3adxzui@sirius.home.kraxel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=192.55.52.151; envelope-from=xiaoyao.li@intel.com; helo=mga17.intel.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 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, HK_RANDOM_ENVFROM=0.998, HK_RANDOM_FROM=0.998, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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" On 6/16/2022 1:37 PM, Gerd Hoffmann wrote: > Hi, > >> Per my understanding, Unaccepted Memory in UEFI is introduced for >> confidential VMs, i.e., for Intel TDX and AMD SEV-SNP. The only reason >> UEFI/OVMF reports "Unaccepted Memory" to OS, is a confidential VM is >> desired. > > No. Reporting "Unaccepted Memory" to the OS is not a hard requirement > for confidential VMs, it only optimizes boot times. Instead of doing > that time-consuming process in the firmware for all memory we tell the > guest OS which memory is accepted already and which is not. So the > guest OS can go accept the remaining memory in a background process. But for non-confidential VMs, even a range of memory is reported as unaccepted nothing prevents it from being accessed without accepting it, and it's not time-consuming. Did I miss anything? > take care, > Gerd >