From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755581AbeEHTOM (ORCPT ); Tue, 8 May 2018 15:14:12 -0400 Received: from ale.deltatee.com ([207.54.116.67]:60412 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751464AbeEHTOJ (ORCPT ); Tue, 8 May 2018 15:14:09 -0400 To: =?UTF-8?Q?Christian_K=c3=b6nig?= , Bjorn Helgaas , Alex Williamson Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-block@vger.kernel.org, Stephen Bates , Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt References: <20180423233046.21476-1-logang@deltatee.com> <20180423233046.21476-5-logang@deltatee.com> <20180507231306.GG161390@bhelgaas-glaptop.roam.corp.google.com> <0b4183ef-e720-204b-9e85-b9eaf7a4136a@deltatee.com> From: Logan Gunthorpe Message-ID: <3584a6ac-95c7-5d23-1859-aee30605776e@deltatee.com> Date: Tue, 8 May 2018 13:13:40 -0600 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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: benh@kernel.crashing.org, jglisse@redhat.com, dan.j.williams@intel.com, maxg@mellanox.com, jgg@mellanox.com, bhelgaas@google.com, sagi@grimberg.me, keith.busch@intel.com, axboe@kernel.dk, hch@lst.de, sbates@raithlin.com, linux-block@vger.kernel.org, linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, alex.williamson@redhat.com, helgaas@kernel.org, christian.koenig@amd.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v4 04/14] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/05/18 10:50 AM, Christian König wrote: > E.g. transactions are initially send to the root complex for > translation, that's for sure. But at least for AMD GPUs the root complex > answers with the translated address which is then cached in the device. > > So further transactions for the same address range then go directly to > the destination. Sounds like you are referring to Address Translation Services (ATS). This is quite separate from ACS and, to my knowledge, isn't widely supported by switch hardware. Logan