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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D59CEC43334 for ; Thu, 21 Jul 2022 16:49:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232591AbiGUQtK (ORCPT ); Thu, 21 Jul 2022 12:49:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53270 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232490AbiGUQtG (ORCPT ); Thu, 21 Jul 2022 12:49:06 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D42A8812E for ; Thu, 21 Jul 2022 09:49:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658422146; x=1689958146; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=3bbPDMQI859gWFZ/CAYf4oPUAKhL1F/jX/zsW+laJyc=; b=alg1LsITR/aruPzXQ3nNqXLPLGvInDhSscy7fHm3Oj2+HtQAJ1bL2QVf eNTRlg5z6lioUUGQM3mVI8Q168VmxUIGC7i4TPXlXWkS0iFBuMfbU+Xm2 IXTIDX2uiAr+6Tbe+6giSa51VxfK/U0fD6IJIcgI0hadch91sMtVSlhJu 4YmX8MI88/j5tKnhP8Ro4UGoInzEDzgGxzcA9OldsmZxkwi/Pmy029OJO he5++AMQ+8QlflCyIa5pXzajBhHMbjTQ5NsN2Y+4trL5ikRw73SwasEdC zYn+kwUcSysI+cLgIN+RTtIfhi+co4GEzOl3wp6rTwcNaeRJkLqGWALDi Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10415"; a="285866216" X-IronPort-AV: E=Sophos;i="5.93,183,1654585200"; d="scan'208";a="285866216" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jul 2022 09:49:05 -0700 X-IronPort-AV: E=Sophos;i="5.93,183,1654585200"; d="scan'208";a="573816219" Received: from vasantgx-mobl.amr.corp.intel.com (HELO [10.212.244.191]) ([10.212.244.191]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jul 2022 09:49:04 -0700 Message-ID: <214e24f0-5236-be8d-024a-da48737d854a@intel.com> Date: Thu, 21 Jul 2022 09:49:03 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v8 5/5] x86/tdx: Add Quote generation support Content-Language: en-US To: Sathyanarayanan Kuppuswamy , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "H . Peter Anvin" , "Kirill A . Shutemov" , Tony Luck , Andi Kleen , Kai Huang , Wander Lairson Costa , Isaku Yamahata , marcelo.cerri@canonical.com, tim.gardner@canonical.com, khalid.elmously@canonical.com, philip.cox@canonical.com, linux-kernel@vger.kernel.org References: <20220609025220.2615197-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20220609025220.2615197-6-sathyanarayanan.kuppuswamy@linux.intel.com> From: Dave Hansen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/21/22 09:42, Sathyanarayanan Kuppuswamy wrote: > On 7/21/22 9:08 AM, Dave Hansen wrote: >> On 6/8/22 19:52, Kuppuswamy Sathyanarayanan wrote: >>> For shared buffer allocation, alternatives like using the DMA API is >>> also considered. Although it simpler to use, it is not preferred because >>> dma_alloc_*() APIs require a valid bus device as argument, which would >>> need converting the attestation driver into a platform device driver. >>> This is unnecessary, and since the attestation driver does not do real >>> DMA, there is no need to use real DMA APIs. >> Let's actually try to walk through the requirements for the memory >> allocation here. >> >> 1. The guest kernel needs to allocate some guest physical memory >> for the attestation data buffer > Physically contiguous memory. Remind me how large the quote structures are.