From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id 6F5766B6B0F for ; Mon, 3 Sep 2018 22:12:47 -0400 (EDT) Received: by mail-pg1-f199.google.com with SMTP id f13-v6so960910pgs.15 for ; Mon, 03 Sep 2018 19:12:47 -0700 (PDT) Received: from huawei.com (szxga04-in.huawei.com. [45.249.212.190]) by mx.google.com with ESMTPS id h9-v6si20583360pgr.260.2018.09.03.19.12.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Sep 2018 19:12:46 -0700 (PDT) Subject: Re: [PATCH v2 13/40] vfio: Add support for Shared Virtual Addressing References: <20180511190641.23008-1-jean-philippe.brucker@arm.com> <20180511190641.23008-14-jean-philippe.brucker@arm.com> <5B83B11E.7010807@huawei.com> <1d5b6529-4e5a-723c-3f1b-dd5a9adb490c@arm.com> <5B89F818.7060300@huawei.com> <3a961aff-e830-64bb-b6a9-14e08de1abf5@arm.com> From: Xu Zaibo Message-ID: <5B8DEA15.7020404@huawei.com> Date: Tue, 4 Sep 2018 10:12:37 +0800 MIME-Version: 1.0 In-Reply-To: <3a961aff-e830-64bb-b6a9-14e08de1abf5@arm.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jean-Philippe Brucker , "linux-arm-kernel@lists.infradead.org" , "linux-pci@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "devicetree@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "linux-mm@kvack.org" Cc: "joro@8bytes.org" , Will Deacon , Robin Murphy , "alex.williamson@redhat.com" , "tn@semihalf.com" , "liubo95@huawei.com" , "thunder.leizhen@huawei.com" , "xieyisheng1@huawei.com" , "ilias.apalodimas@linaro.org" , "jonathan.cameron@huawei.com" , "liudongdong3@huawei.com" , "shunyong.yang@hxt-semitech.com" , "nwatters@codeaurora.org" , "okaya@codeaurora.org" , "jcrouse@codeaurora.org" , "rfranz@cavium.com" , "dwmw2@infradead.org" , "jacob.jun.pan@linux.intel.com" , "yi.l.liu@intel.com" , "ashok.raj@intel.com" , "kevin.tian@intel.com" , "baolu.lu@linux.intel.com" , "robdclark@gmail.com" , "christian.koenig@amd.com" , "bharatku@xilinx.com" , "rgummal@xilinx.com" , =?UTF-8?B?57Gz57Gz?= , wangzhou1 , "liguozhu@hisilicon.com" , fanghao11 On 2018/9/3 18:34, Jean-Philippe Brucker wrote: > On 01/09/18 03:23, Xu Zaibo wrote: >> As one application takes a whole function while using VFIO-PCI, why do >> the application and the >> function need to enable PASID capability? (Since just one I/O page table >> is enough for them.) > At the moment the series doesn't provide support for SVA without PASID > (on the I/O page fault path, 08/40). In addition the BIND ioctl could be > used by the owner application to bind other processes (slaves) and > perform sub-assignment. But that feature is incomplete because we don't > send stop_pasid notification to the owner when a slave dies. > So, Could I understand like this? 1. While the series are finished well, VFIO-PCI device can be held by only one process through binding IOCTL command without PASID (without PASID being exposed user space). 2. While using VFIO-PCI device to support multiple processes with SVA series, a primary process with multiple secondary processes must be deployed just like DPDK(https://www.dpdk.org/). And, the PASID still has to be exposed to user land. Thanks, Zaibo .