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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 C0D2EC43381 for ; Wed, 13 Mar 2019 02:10:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9096E217F5 for ; Wed, 13 Mar 2019 02:10:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726623AbfCMCKL (ORCPT ); Tue, 12 Mar 2019 22:10:11 -0400 Received: from mga11.intel.com ([192.55.52.93]:37412 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726411AbfCMCKL (ORCPT ); Tue, 12 Mar 2019 22:10:11 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Mar 2019 19:10:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,472,1544515200"; d="scan'208";a="126446678" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga006.jf.intel.com with ESMTP; 12 Mar 2019 19:10:05 -0700 Cc: baolu.lu@linux.intel.com, David Woodhouse , Joerg Roedel , ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com, kevin.tian@intel.com, mika.westerberg@linux.intel.com, pengfei.xu@intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jacob Pan Subject: Re: [PATCH v1 4/9] iommu/vt-d: Add bounce buffer API for domain map/unmap To: Christoph Hellwig References: <20190312060005.12189-1-baolu.lu@linux.intel.com> <20190312060005.12189-5-baolu.lu@linux.intel.com> <20190312163845.GA13141@infradead.org> From: Lu Baolu Message-ID: Date: Wed, 13 Mar 2019 10:04:41 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190312163845.GA13141@infradead.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 3/13/19 12:38 AM, Christoph Hellwig wrote: > On Tue, Mar 12, 2019 at 02:00:00PM +0800, Lu Baolu wrote: >> This adds the APIs for bounce buffer specified domain >> map() and unmap(). The start and end partial pages will >> be mapped with bounce buffered pages instead. This will >> enhance the security of DMA buffer by isolating the DMA >> attacks from malicious devices. > > Please reuse the swiotlb code instead of reinventing it. > I don't think we are doing the same thing as swiotlb here. But it's always a good thing to reuse code if possible. I considered this when writing this code, but I found it's hard to do. Do you mind pointing me to the code which I could reuse? Best regards, Lu Baolu