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_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 13FA7C432C1 for ; Wed, 25 Sep 2019 02:50:44 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 CEC5F20673 for ; Wed, 25 Sep 2019 02:50:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CEC5F20673 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 mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 99042C7C; Wed, 25 Sep 2019 02:50:43 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 21C21B8F for ; Wed, 25 Sep 2019 02:50:42 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 0C38B8A for ; Wed, 25 Sep 2019 02:50:32 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Sep 2019 19:50:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,546,1559545200"; d="scan'208";a="201100050" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 24 Sep 2019 19:50:29 -0700 Subject: Re: [RFC PATCH 0/4] Use 1st-level for DMA remapping in guest To: "Tian, Kevin" , "Raj, Ashok" , Jacob Pan References: <20190923122454.9888-1-baolu.lu@linux.intel.com> <20190923122715.53de79d0@jacob-builder> <20190923202552.GA21816@araj-mobl1.jf.intel.com> From: Lu Baolu Message-ID: Date: Wed, 25 Sep 2019 10:48:32 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Cc: "kvm@vger.kernel.org" , "Kumar, Sanjay K" , "Sun, Yi Y" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , Alex Williamson , David Woodhouse X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Hi Kevin, On 9/24/19 3:00 PM, Tian, Kevin wrote: >>>> '-----------' >>>> '-----------' >>>> >>>> This patch series only aims to achieve the first goal, a.k.a using > first goal? then what are other goals? I didn't spot such information. > The overall goal is to use IOMMU nested mode to avoid shadow page table and VMEXIT when map an gIOVA. This includes below 4 steps (maybe not accurate, but you could get the point.) 1) GIOVA mappings over 1st-level page table; 2) binding vIOMMU 1st level page table to the pIOMMU; 3) using pIOMMU second level for GPA->HPA translation; 4) enable nested (a.k.a. dual stage) translation in host. This patch set aims to achieve 1). > Also earlier you mentioned the new approach (nested) is more secure > than shadowing. why? > My bad! After reconsideration, I realized that it's not "more secure". Thanks for pointing this out. Best regards, Baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu