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 EE353C432C2 for ; Tue, 24 Sep 2019 04:29:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE97020872 for ; Tue, 24 Sep 2019 04:29:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391822AbfIXE3L (ORCPT ); Tue, 24 Sep 2019 00:29:11 -0400 Received: from mga06.intel.com ([134.134.136.31]:14675 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725308AbfIXE3L (ORCPT ); Tue, 24 Sep 2019 00:29:11 -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 orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Sep 2019 21:29:09 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,542,1559545200"; d="scan'208";a="200773565" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 23 Sep 2019 21:29:07 -0700 Cc: baolu.lu@linux.intel.com, Joerg Roedel , David Woodhouse , Alex Williamson , ashok.raj@intel.com, sanjay.k.kumar@intel.com, kevin.tian@intel.com, yi.l.liu@intel.com, yi.y.sun@intel.com, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/4] Use 1st-level for DMA remapping in guest To: Jacob Pan References: <20190923122454.9888-1-baolu.lu@linux.intel.com> <20190923122715.53de79d0@jacob-builder> From: Lu Baolu Message-ID: Date: Tue, 24 Sep 2019 12:27:11 +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: <20190923122715.53de79d0@jacob-builder> 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 Jacob, On 9/24/19 3:27 AM, Jacob Pan wrote: > Hi Baolu, > > On Mon, 23 Sep 2019 20:24:50 +0800 > Lu Baolu wrote: > >> This patchset aims to move IOVA (I/O Virtual Address) translation >> to 1st-level page table under scalable mode. The major purpose of >> this effort is to make guest IOVA support more efficient. >> >> As Intel VT-d architecture offers caching-mode, guest IOVA (GIOVA) >> support is now implemented in a shadow page manner. The device >> simulation software, like QEMU, has to figure out GIOVA->GPA mapping >> and writes to a shadowed page table, which will be used by pIOMMU. >> Each time when mappings are created or destroyed in vIOMMU, the >> simulation software will intervene. The change on GIOVA->GPA will be >> shadowed to host, and the pIOMMU will be updated via VFIO/IOMMU >> interfaces. >> >> >> .-----------. >> | vIOMMU | >> |-----------| .--------------------. >> | |IOTLB flush trap | QEMU | >> .-----------. (map/unmap) |--------------------| >> | GVA->GPA |---------------->| .----------. | >> '-----------' | | GPA->HPA | | >> | | | '----------' | >> '-----------' | | >> | | >> '--------------------' >> | >> <------------------------------------ >> | >> v VFIO/IOMMU API >> .-----------. >> | pIOMMU | >> |-----------| >> | | >> .-----------. >> | GVA->HPA | >> '-----------' >> | | >> '-----------' >> >> In VT-d 3.0, scalable mode is introduced, which offers two level >> translation page tables and nested translation mode. Regards to >> GIOVA support, it can be simplified by 1) moving the GIOVA support >> over 1st-level page table to store GIOVA->GPA mapping in vIOMMU, >> 2) binding vIOMMU 1st level page table to the pIOMMU, 3) using pIOMMU >> second level for GPA->HPA translation, and 4) enable nested (a.k.a. >> dual stage) translation in host. Compared with current shadow GIOVA >> support, the new approach is more secure and software is simplified >> as we only need to flush the pIOMMU IOTLB and possible device-IOTLB >> when an IOVA mapping in vIOMMU is torn down. >> >> .-----------. >> | vIOMMU | >> |-----------| .-----------. >> | |IOTLB flush trap | QEMU | >> .-----------. (unmap) |-----------| >> | GVA->GPA |---------------->| | >> '-----------' '-----------' >> | | | >> '-----------' | >> <------------------------------ >> | VFIO/IOMMU >> | cache invalidation and >> | guest gpd bind interfaces >> v > For vSVA, the guest PGD bind interface will mark the PASID as guest > PASID and will inject page request into the guest. In FL gIOVA case, I > guess we are assuming there is no page fault for GIOVA. I will need to > add a flag in the gpgd bind such that any PRS will be auto responded > with invalid. There should be no page fault. The pages should have been pinned. > > Also, native use of IOVA FL map is not to be supported? i.e. IOMMU API > and DMA API for native usage will continue to be SL only? Yes. There isn't such use case as far as I can see. Best regards, Baolu >> .-----------. >> | pIOMMU | >> |-----------| >> .-----------. >> | GVA->GPA |<---First level >> '-----------' >> | GPA->HPA |<---Scond level >> '-----------' >> '-----------' >> >> This patch series only aims to achieve the first goal, a.k.a using >> first level translation for IOVA mappings in vIOMMU. I am sending >> it out for your comments. Any comments, suggestions and concerns are >> welcomed. >> > > >> Based-on-idea-by: Ashok Raj >> Based-on-idea-by: Kevin Tian >> Based-on-idea-by: Liu Yi L >> Based-on-idea-by: Lu Baolu >> Based-on-idea-by: Sanjay Kumar >> >> Lu Baolu (4): >> iommu/vt-d: Move domain_flush_cache helper into header >> iommu/vt-d: Add first level page table interfaces >> iommu/vt-d: Map/unmap domain with mmmap/mmunmap >> iommu/vt-d: Identify domains using first level page table >> >> drivers/iommu/Makefile | 2 +- >> drivers/iommu/intel-iommu.c | 142 ++++++++++-- >> drivers/iommu/intel-pgtable.c | 342 >> +++++++++++++++++++++++++++++ include/linux/intel-iommu.h | >> 31 ++- include/trace/events/intel_iommu.h | 60 +++++ >> 5 files changed, 553 insertions(+), 24 deletions(-) >> create mode 100644 drivers/iommu/intel-pgtable.c >> > > [Jacob Pan] >