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[209.132.180.67]) by mx.google.com with ESMTP id t1-v6si16141710pgg.643.2018.07.16.03.52.50; Mon, 16 Jul 2018 03:53:06 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728466AbeGPLTH (ORCPT + 99 others); Mon, 16 Jul 2018 07:19:07 -0400 Received: from foss.arm.com ([217.140.101.70]:56800 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727953AbeGPLTH (ORCPT ); Mon, 16 Jul 2018 07:19:07 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1D11418A; Mon, 16 Jul 2018 03:52:16 -0700 (PDT) Received: from [10.1.210.39] (ostrya.cambridge.arm.com [10.1.210.39]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 98BCF3F589; Mon, 16 Jul 2018 03:52:14 -0700 (PDT) Subject: Re: [PATCH 00/10] iommu/vt-d: Add scalable mode support To: Lu Baolu , Joerg Roedel , David Woodhouse Cc: ashok.raj@intel.com, sanjay.k.kumar@intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, yi.y.sun@intel.com, jacob.jun.pan@intel.com References: <1531723793-14607-1-git-send-email-baolu.lu@linux.intel.com> From: Jean-Philippe Brucker Message-ID: <07fe2e3f-4f4a-58db-ee2a-2620183d93b2@arm.com> Date: Mon, 16 Jul 2018 11:51:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1531723793-14607-1-git-send-email-baolu.lu@linux.intel.com> Content-Type: text/plain; charset=utf-8 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 16/07/18 07:49, Lu Baolu wrote: > Intel vt-d rev3.0 [1] introduces a new translation mode called > 'scalable mode', which enables PASID-granular translations for > first level, second level, nested and pass-through modes. The > vt-d scalable mode is the key ingredient to enable Scalable I/O > Virtualization (Scalable IOV) [2] [3], which allows sharing a > device in minimal possible granularity (ADI - Assignable Device > Interface). It also includes all the capabilities required to > enable Shared Virtual Addressing (SVA). As a result, previous > Extended Context (ECS) mode is deprecated (no production ever > implements ECS). > > Each scalable mode pasid table entry is 64 bytes in length, with > fields point to the first level page table and the second level > page table. The PGTT (Pasid Granular Translation Type) field is > used by hardware to determine the translation type. Looks promising! Since the 2nd level page tables are in the PASID entry, the hypervisor traps guest accesses to the PASID tables instead of passing through the whole PASID directory? Are you still planning to use the VFIO BIND_PASID_TABLE interface in this mode, or a slightly different one for individual PASIDs? Thanks, Jean