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,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 A3031C432C2 for ; Thu, 26 Sep 2019 01:44:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 804D3222BE for ; Thu, 26 Sep 2019 01:44:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390221AbfIZBob (ORCPT ); Wed, 25 Sep 2019 21:44:31 -0400 Received: from mga18.intel.com ([134.134.136.126]:33816 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389381AbfIZBob (ORCPT ); Wed, 25 Sep 2019 21:44:31 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Sep 2019 18:44:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,549,1559545200"; d="scan'208";a="201450212" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 25 Sep 2019 18:44:28 -0700 Cc: baolu.lu@linux.intel.com, "Raj, Ashok" , Yi Sun , "kvm@vger.kernel.org" , "Kumar, Sanjay K" , "Sun, Yi Y" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , Alex Williamson , David Woodhouse Subject: Re: [RFC PATCH 2/4] iommu/vt-d: Add first level page table interfaces To: "Tian, Kevin" , Peter Xu References: <20190923122454.9888-1-baolu.lu@linux.intel.com> <20190923122454.9888-3-baolu.lu@linux.intel.com> <20190923203102.GB21816@araj-mobl1.jf.intel.com> <9cfe6042-f0fb-ea5e-e134-f6f5bb9eb7b0@linux.intel.com> <20190925043050.GK28074@xz-x1> <20190925052402.GM28074@xz-x1> <1713f03c-4d47-34ad-f36d-882645c36389@linux.intel.com> From: Lu Baolu Message-ID: <2755a11e-1ed0-6663-2c5b-ed50be717ba7@linux.intel.com> Date: Thu, 26 Sep 2019 09:42:30 +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-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Kevin, On 9/25/19 3:32 PM, Tian, Kevin wrote: >> From: Lu Baolu [mailto:baolu.lu@linux.intel.com] >> Sent: Wednesday, September 25, 2019 2:52 PM >> >> Hi Peter and Kevin, >> >> On 9/25/19 1:24 PM, Peter Xu wrote: >>> On Wed, Sep 25, 2019 at 04:38:31AM +0000, Tian, Kevin wrote: >>>>> From: Peter Xu [mailto:peterx@redhat.com] >>>>> Sent: Wednesday, September 25, 2019 12:31 PM >>>>> >>>>> On Tue, Sep 24, 2019 at 09:38:53AM +0800, Lu Baolu wrote: >>>>>>>> intel_mmmap_range(domain, addr, end, phys_addr, prot) >>>>>>> >>>>>>> Maybe think of a different name..? mmmap seems a bit weird :-) >>>>>> >>>>>> Yes. I don't like it either. I've thought about it and haven't >>>>>> figured out a satisfied one. Do you have any suggestions? >>>>> >>>>> How about at least split the word using "_"? Like "mm_map", then >>>>> apply it to all the "mmm*" prefixes. Otherwise it'll be easily >>>>> misread as mmap() which is totally irrelevant to this... >>>>> >>>> >>>> what is the point of keeping 'mm' here? replace it with 'iommu'? >>> >>> I'm not sure of what Baolu thought, but to me "mm" makes sense itself >>> to identify this from real IOMMU page tables (because IIUC these will >>> be MMU page tables). We can come up with better names, but IMHO >>> "iommu" can be a bit misleading to let people refer to the 2nd level >>> page table. >> >> "mm" represents a CPU (first level) page table; >> >> vs. >> >> "io" represents an IOMMU (second level) page table. >> > > IOMMU first level is not equivalent to CPU page table, though you can > use the latter as the first level (e.g. in SVA). Especially here you are > making IOVA->GPA as the first level, which is not CPU page table. > > btw both levels are for "io" i.e. DMA purposes from VT-d p.o.v. They > are just hierarchical structures implemented by VT-d, with slightly > different format. The specification doesn't limit how you use them for. > In a hypothetical case, an IOMMU may implement exactly same CPU-page- > table format and support page faults for both levels. Then you can even > link the CPU page table to the 2nd level for sure. Fair enough. A good conceptual gap fix. > > Maybe we just name it from VT-d context, e.g. intel_map_first_level_range, > Intel_map_second_level_range, and then register them as dmar domain > callback as you replied in another mail. Yes. Make sense. > > Thanks > Kevin > Best regards, Baolu