From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Subject: Re: IOAT DMA w/IOMMU To: Logan Gunthorpe , Eric Pilmore Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, David Woodhouse , Alex Williamson , iommu@lists.linux-foundation.org References: <20180809184331.GB113140@bhelgaas-glaptop.roam.corp.google.com> <7068db44-af31-4462-f966-2dd2340ba0f0@deltatee.com> <695826a6-e10c-5a30-a51f-7cc61ba6e640@gigaio.com> <0d3f48c3-8c4f-4dfb-e883-23c168f12b9b@deltatee.com> From: Kit Chow Message-ID: <14db6acb-da4f-9604-7359-1671210fcb8b@gigaio.com> Date: Thu, 16 Aug 2018 11:53:53 -0700 MIME-Version: 1.0 In-Reply-To: <0d3f48c3-8c4f-4dfb-e883-23c168f12b9b@deltatee.com> Content-Type: text/plain; charset=utf-8; format=flowed List-ID: On 08/16/2018 10:21 AM, Logan Gunthorpe wrote: > > On 16/08/18 11:16 AM, Kit Chow wrote: >> I only have access to intel hosts for testing (and possibly an AMD >> host currently collecting dust) and am not sure how to go about getting >> the proper test coverage for other architectures. > Well, I thought you were only changing the Intel IOMMU implementation... > So testing on Intel hardware seems fine to me. For the ntb change, I wasn't sure if there was some other arch where ntb_async_tx_submit would work ok with the pci bar address but would break with the dma map (assuming map_resource has been implemented). If its all x86 at the moment, I guess I'm good to go. Please confirm. Thanks Kit >> Any suggestions? Do you anticipate any issues with dma mapping the pci bar >> address in ntb_async_tx_submit on non-x86 archs?  Do you or know of folks >> who have ntb test setups with non-x86 hosts who might be able to help? > I expect other IOMMUs will need to be updated to properly support > dma_map_resource but that will probably need to be done on a case by > case basis as the need arises. Unfortunately it seems the work to add > dma_map_resource() didn't really consider that the IOMMUs had to have > proper support and probably should have errored out instead of just > passing along the physical address if the IOMMU didn't have support. > > I don't know of anyone with an NTB setup on anything but x86 at the moment. > > Logan