From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 9 Jan 2018 10:10:08 -0700 From: Jason Gunthorpe Subject: Re: [PATCH 06/12] IB/core: Add optional PCI P2P flag to rdma_rw_ctx_[init|destroy]() Message-ID: <20180109171008.GB4518@ziepe.ca> References: <20180104221337.GV11348@ziepe.ca> <3e8391a9-8924-be6d-8c43-162a360d75b6@deltatee.com> <20180105045031.GX11348@ziepe.ca> <20180108145901.GA10743@lst.de> <20180108180917.GF11348@ziepe.ca> <20180108183434.GA15549@lst.de> <20180108185743.GA15936@lst.de> <20180108194950.GK11348@ziepe.ca> <20180109164640.GA12159@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180109164640.GA12159@lst.de> Sender: linux-kernel-owner@vger.kernel.org To: Christoph Hellwig Cc: Logan Gunthorpe , open list , linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-rdma , linux-nvdimm@lists.01.org, linux-block@vger.kernel.org, Stephen Bates , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Max Gurtovoy , Dan Williams , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Benjamin Herrenschmidt List-ID: On Tue, Jan 09, 2018 at 05:46:40PM +0100, Christoph Hellwig wrote: > On Mon, Jan 08, 2018 at 12:49:50PM -0700, Jason Gunthorpe wrote: > > Pretty sure P2P capable IOMMU hardware exists. > > > > With SOC's we also have the scenario that an DMA originated from an > > on-die device wishes to target an off-die PCI BAR (through the IOMMU), > > that definitely exists today, and people care about it :) > > Then people will have to help and contribute support for it. Sure. But my point was all this will have to migrate under the dma_ops for that to work, so why the resistance to using dma_ops right away? Jason