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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 5B931C433DB for ; Thu, 4 Mar 2021 12:26:32 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 BFF3164F11 for ; Thu, 4 Mar 2021 12:26:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BFF3164F11 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 77C0442FBA; Thu, 4 Mar 2021 12:26:31 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id LP47wexfe6ef; Thu, 4 Mar 2021 12:26:30 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp2.osuosl.org (Postfix) with ESMTP id 6F8E8431CD; Thu, 4 Mar 2021 12:26:30 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 38E52C000A; Thu, 4 Mar 2021 12:26:30 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [IPv6:2605:bc80:3010::133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 398A6C0001 for ; Thu, 4 Mar 2021 12:26:28 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 2B13C431CD for ; Thu, 4 Mar 2021 12:26:28 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id NRM-fLVmeckW for ; Thu, 4 Mar 2021 12:26:27 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by smtp2.osuosl.org (Postfix) with ESMTPS id 87F4342FBA for ; Thu, 4 Mar 2021 12:26:27 +0000 (UTC) Received: by theia.8bytes.org (Postfix, from userid 1000) id BA31A447; Thu, 4 Mar 2021 13:26:24 +0100 (CET) Date: Thu, 4 Mar 2021 13:26:23 +0100 From: Joerg Roedel To: Lu Baolu Subject: Re: [PATCH 2/5] iommu/vt-d: Remove WO permissions on second-level paging entries Message-ID: <20210304122623.GD26414@8bytes.org> References: <20210225062654.2864322-1-baolu.lu@linux.intel.com> <20210225062654.2864322-3-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210225062654.2864322-3-baolu.lu@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Cc: kevin.tian@intel.com, ashok.raj@intel.com, sanjay.k.kumar@intel.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jacob.jun.pan@intel.com, Will Deacon 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 Thu, Feb 25, 2021 at 02:26:51PM +0800, Lu Baolu wrote: > When the first level page table is used for IOVA translation, it only > supports Read-Only and Read-Write permissions. The Write-Only permission > is not supported as the PRESENT bit (implying Read permission) should > always set. When using second level, we still give separate permissions > that allows WriteOnly which seems inconsistent and awkward. There is no > use case we can think off, hence remove that configuration to make it > consistent. No use-case for WriteOnly mappings? How about DMA_FROM_DEVICE mappings? _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu