From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751753AbeCNOFL (ORCPT ); Wed, 14 Mar 2018 10:05:11 -0400 Received: from mail-eopbgr660099.outbound.protection.outlook.com ([40.107.66.99]:21783 "EHLO CAN01-QB1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750827AbeCNOFJ (ORCPT ); Wed, 14 Mar 2018 10:05:09 -0400 From: "Stephen Bates" To: Bjorn Helgaas , Logan Gunthorpe CC: Sinan Kaya , "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" , Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?utf-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , "Alex Williamson" Subject: Re: [PATCH v3 01/11] PCI/P2PDMA: Support peer-to-peer memory Thread-Topic: [PATCH v3 01/11] PCI/P2PDMA: Support peer-to-peer memory Thread-Index: AQHTujlZo8bTZRn+4ECdETRRU1rPhqPNgjSAgADeTICAABJggIAAD1YAgAAHVACAAAJxAIAACW8AgAAO3oCAAAopgIAACqIA//+kE4CAAG7lAIAAA38AgAA8KICAAFYtgA== Date: Wed, 14 Mar 2018 14:05:06 +0000 Message-ID: <45A47A71-B435-4DFA-8925-8EB91CEAB230@raithlin.com> References: <3e738f95-d73c-4182-2fa1-8664aafb1ab7@deltatee.com> <703aa92c-0c1c-4852-5887-6f6e6ccde0fb@codeaurora.org> <3ea80992-a0fc-08f2-d93d-ae0ec4e3f4ce@codeaurora.org> <4eb6850c-df1b-fd44-3ee0-d43a50270b53@deltatee.com> <757fca36-dee4-e070-669e-f2788bd78e41@codeaurora.org> <4f761f55-4e9a-dccb-d12f-c59d2cd689db@deltatee.com> <20180313230850.GA45763@bhelgaas-glaptop.roam.corp.google.com> <8de5d3dd-a78f-02d5-0eea-4365364143b6@deltatee.com> <20180314025639.GA50067@bhelgaas-glaptop.roam.corp.google.com> In-Reply-To: <20180314025639.GA50067@bhelgaas-glaptop.roam.corp.google.com> Accept-Language: en-CA, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/10.b.0.180311 authentication-results: spf=none (sender IP is ) smtp.mailfrom=sbates@raithlin.com; 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charset="utf-8" Content-ID: <4EAE1FFD2D16CE4CBB709CC99D67468E@CANPRD01.PROD.OUTLOOK.COM> MIME-Version: 1.0 X-OriginatorOrg: raithlin.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7e32bc84-822a-4fc1-487c-08d589b496f0 X-MS-Exchange-CrossTenant-originalarrivaltime: 14 Mar 2018 14:05:06.0991 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 18519031-7ff4-4cbb-bbcb-c3252d330f4b X-MS-Exchange-Transport-CrossTenantHeadersStamped: YTXPR0101MB1677 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id w2EE5IMN009069 >I assume you want to exclude Root Ports because of multi-function > devices and the "route to self" error. I was hoping for a reference > to that so I could learn more about it. Apologies Bjorn. This slipped through my net. I will try and get you a reference for RTS in the next couple of days. > While I was looking for it, I found sec 6.12.1.2 (PCIe r4.0), "ACS > Functions in SR-IOV Capable and Multi-Function Devices", which seems > relevant. It talks about "peer-to-peer Requests (between Functions of > the device)". Thay says to me that multi-function devices can DMA > between themselves. I will go take a look. Appreciate the link. Stephen