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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 C34BAC433F5 for ; Thu, 30 Aug 2018 19:30:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8410920843 for ; Thu, 30 Aug 2018 19:30:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8410920843 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727346AbeH3Xe1 (ORCPT ); Thu, 30 Aug 2018 19:34:27 -0400 Received: from ale.deltatee.com ([207.54.116.67]:40724 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725836AbeH3Xe0 (ORCPT ); Thu, 30 Aug 2018 19:34:26 -0400 Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.89) (envelope-from ) id 1fvSeI-00071q-4U; Thu, 30 Aug 2018 13:30:34 -0600 To: Jerome Glisse 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 , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , Benjamin Herrenschmidt , Alex Williamson , =?UTF-8?Q?Christian_K=c3=b6nig?= References: <20180830185352.3369-1-logang@deltatee.com> <20180830192012.GG3529@redhat.com> From: Logan Gunthorpe Message-ID: Date: Thu, 30 Aug 2018 13:30:32 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180830192012.GG3529@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: christian.koenig@amd.com, alex.williamson@redhat.com, benh@kernel.crashing.org, dan.j.williams@intel.com, maxg@mellanox.com, jgg@mellanox.com, bhelgaas@google.com, sagi@grimberg.me, keith.busch@intel.com, 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, jglisse@redhat.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v5 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/08/18 01:20 PM, Jerome Glisse wrote: > On Thu, Aug 30, 2018 at 12:53:39PM -0600, Logan Gunthorpe wrote: > > [...] > >> >> When the PCI P2PDMA config option is selected the ACS bits in every >> bridge port in the system are turned off to allow traffic to >> pass freely behind the root port. At this time, the bit must be disabled >> at boot so the IOMMU subsystem can correctly create the groups, though >> this could be addressed in the future. There is no way to dynamically >> disable the bit and alter the groups. Oh, sorry this paragraph in the cover letter is wrong now. We now rely on the disable_acs_redir command line option introduced in aaca43fda742 ("PCI: Add "pci=disable_acs_redir=" parameter for peer-to-peer support") > Can you provide an example on how to test this ? Like kernel command > line option, the doc patch does not have any such example. It would be > nice to add. Do you mean to test the patchset or the ACS bits you quoted? Testing the patchset is a matter of having the right hardware (ie an RDMA NIC and CMB enabled NVMe behind a PCIe switch, with the ACS bits set correctly by the above command line option) and setting the p2pmem configfs attribute in an nvme-of port to 'yes'. Logan