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 8AED6ECAAD2 for ; Mon, 29 Aug 2022 20:34:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229450AbiH2UeY (ORCPT ); Mon, 29 Aug 2022 16:34:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52514 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229449AbiH2UeY (ORCPT ); Mon, 29 Aug 2022 16:34:24 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 578A086064; Mon, 29 Aug 2022 13:34:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1661805263; x=1693341263; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=8uSHJfqUknE7dGMkPzrFJmVlMzuB1CY6SWhcH+woX28=; b=HW8hBwSzVC1aa8dUOkwjjM+7abDVicnEEyQlXknOcmYcRyeUwKlf0guj DRXODq1OVmq0GWW/CMXwtvLI9zw9eJ+8KPha+ol3Yad8m7tU2sm4ErLJ8 sSw7vWWCoo8R38DULXtLpkws9tWMQlczUmpSLJMDfxXkDtwogscW5EjOd iMqXrAWC96lJyoDDI+RbyKrzvaySRO2W5GYIWA0w9WtxoCthinUR+MDw2 MnFeiUstUtN42qwP9AN5k+uxkzJxhEtaod5PhiB0+JVNPQtV5zHmt1M34 EXcwym4+lRGfjSvGjWhUldHTP6RZtYc2/12IMuEAoVyFvAyYdCvV/OHVX A==; X-IronPort-AV: E=McAfee;i="6500,9779,10454"; a="295772210" X-IronPort-AV: E=Sophos;i="5.93,273,1654585200"; d="scan'208";a="295772210" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2022 13:34:22 -0700 X-IronPort-AV: E=Sophos;i="5.93,273,1654585200"; d="scan'208";a="679759317" Received: from sbhansal-mobl1.amr.corp.intel.com (HELO [10.251.30.71]) ([10.251.30.71]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2022 13:34:21 -0700 Message-ID: <9e41582a-425d-5b85-a83a-9590388a0d40@linux.intel.com> Date: Mon, 29 Aug 2022 13:34:20 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.11.0 Subject: Re: [PATCH v11 1/3] x86/tdx: Add TDX Guest attestation interface driver Content-Language: en-US To: Dave Hansen , Greg Kroah-Hartman Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Shuah Khan , "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, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org References: <20220826150638.2397576-1-sathyanarayanan.kuppuswamy@linux.intel.com> <73b375c3-97a7-5f25-5abf-48d9ec6be2db@linux.intel.com> <12ab0a8a-a286-4f21-3b44-a506a6c2d008@intel.com> From: Sathyanarayanan Kuppuswamy In-Reply-To: <12ab0a8a-a286-4f21-3b44-a506a6c2d008@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On 8/29/22 1:28 PM, Dave Hansen wrote: > On 8/29/22 13:09, Sathyanarayanan Kuppuswamy wrote: >> With the changed format, we avoided the holes, but it still adds 7 bytes of padding. >> >> Total size of struct is 32 bytes. >> >> struct tdx_report_req { >> __u64 reportdata; /* 0 8 */ >> __u64 tdreport; /* 8 8 */ >> __u32 rpd_len; /* 16 4 */ >> __u32 tdr_len; /* 20 4 */ >> __u8 subtype; /* 24 1 */ >> >> /* size: 32, cachelines: 1, members: 5 */ >> /* padding: 7 */ >> /* last cacheline: 32 bytes */ >> }; > > Might as well make some use of the padding and add: > > u8 reserved[7]; > > That will ensure that the entire structure is explicitly sized *AND* > leave you room to add flags or other fun in the future without a new ABI. Ok. I will add it in next version. -- Sathyanarayanan Kuppuswamy Linux Kernel Developer