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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 507E9C433DF for ; Wed, 8 Jul 2020 15:12:45 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 239B9206DF for ; Wed, 8 Jul 2020 15:12:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 239B9206DF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 0FC7E2045C; Wed, 8 Jul 2020 15:12:25 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id eVMEnTY4qEQ0; Wed, 8 Jul 2020 15:12:24 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id B618D2034F; Wed, 8 Jul 2020 15:12:23 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2AC66C077B; Wed, 8 Jul 2020 15:12:23 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 22035C016F for ; Wed, 8 Jul 2020 15:12:22 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 1135B88604 for ; Wed, 8 Jul 2020 15:12:22 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7cmlrvll9Z+g for ; Wed, 8 Jul 2020 15:12:21 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by hemlock.osuosl.org (Postfix) with ESMTPS id 1F987870F6 for ; Wed, 8 Jul 2020 15:12:21 +0000 (UTC) IronPort-SDR: fLZx+VJGIM6WrGmCqcpYccyP4qdXzY3Q8epMtcsZmpsU2lkRb/4dlETMeE5GqgDsx92P7TZ+ki x6Kxmu4jLAKg== X-IronPort-AV: E=McAfee;i="6000,8403,9676"; a="147823632" X-IronPort-AV: E=Sophos;i="5.75,327,1589266800"; d="scan'208";a="147823632" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2020 08:12:20 -0700 IronPort-SDR: /MVkUG8GhZH1siJlqEVBaQOSKpuUsBci6rmNU/vkTH1JLRLuD7R56lPhmqa2xMGebYejjce4y/ KN1FCGXMa4lg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,327,1589266800"; d="scan'208";a="457534824" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga005.jf.intel.com with ESMTP; 08 Jul 2020 08:12:20 -0700 Date: Wed, 8 Jul 2020 08:18:58 -0700 From: Jacob Pan To: Lu Baolu Subject: Re: [PATCH v4 3/5] iommu/uapi: Use named union for user data Message-ID: <20200708081858.37091f4b@jacob-builder> In-Reply-To: <3b36c219-4120-402b-b03e-62b076db865c@linux.intel.com> References: <1594165429-20075-1-git-send-email-jacob.jun.pan@linux.intel.com> <1594165429-20075-4-git-send-email-jacob.jun.pan@linux.intel.com> <3b36c219-4120-402b-b03e-62b076db865c@linux.intel.com> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Cc: "Tian, Kevin" , Raj Ashok , Jonathan Corbet , Jean-Philippe Brucker , Alex Williamson , LKML , Christoph Hellwig , iommu@lists.linux-foundation.org, David Woodhouse X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Wed, 8 Jul 2020 10:17:57 +0800 Lu Baolu wrote: > Hi Jacob, > > On 7/8/20 7:43 AM, Jacob Pan wrote: > > IOMMU UAPI data size is filled by the user space which must be > > validated by ther kernel. To ensure backward compatibility, user > > data can only be extended by either re-purpose padding bytes or > > extend the variable sized union at the end. No size change is > > allowed before the union. Therefore, the minimum size is the offset > > of the union. > > > > To use offsetof() on the union, we must make it named. > > > > Link:https://lkml.org/lkml/2020/6/11/834 > > Please use lore.kernel.org links. > OK. will do. > Best regards, > baolu [Jacob Pan] _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu