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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 C161DC43463 for ; Fri, 18 Sep 2020 12:03:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E9502311A for ; Fri, 18 Sep 2020 12:03:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600430626; bh=EO90FkAcyHdLTcPE+7fKS87YRHUsQQ2e1yJv4hbuiFY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=lvgOhRAfI9kvO7F4Xy9BT/P5d/Ws0YRZiLJamBORwyyyT3C6DJtUDwe7hSmLeEyZ7 gWgVfaTCpPd4yucsFmaFePSnUslq1xsKc9kvZzJ9quFV+C35hjjSE6feGgQ2uBiSif ek6pGJrCLGE37SzGDUTNEMmMCOg8+xmWj9x540M8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726239AbgIRMDp (ORCPT ); Fri, 18 Sep 2020 08:03:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:41500 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726064AbgIRMDp (ORCPT ); Fri, 18 Sep 2020 08:03:45 -0400 Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7247321582; Fri, 18 Sep 2020 12:03:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600430625; bh=EO90FkAcyHdLTcPE+7fKS87YRHUsQQ2e1yJv4hbuiFY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=1+anVRzL9lCTOsGOPzkUU2dkPuADzZxYoQ3S4wt1SR2qxmDAFpiat9nznjFrf8CBa VkMKdh34cz9iH/LIpLxn1XFCMzwtcobtRquPt3T2PPKh2HY0kLykUeK90/k7mEdvb3 vG5wNuOgk2BhcfBYPGzVXoyX2qRt8yIt6SrlsZ1o= Date: Fri, 18 Sep 2020 15:03:40 +0300 From: Leon Romanovsky To: Oded Gabbay Cc: Gal Pressman , Jason Gunthorpe , Jakub Kicinski , "Linux-Kernel@Vger. Kernel. Org" , netdev@vger.kernel.org, SW_Drivers , Greg Kroah-Hartman , "David S. Miller" , Andrew Lunn , Florian Fainelli , linux-rdma@vger.kernel.org Subject: Re: [PATCH v3 00/14] Adding GAUDI NIC code to habanalabs driver Message-ID: <20200918120340.GT869610@unreal> References: <20200915171022.10561-1-oded.gabbay@gmail.com> <20200915133556.21268811@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20200917171833.GJ8409@ziepe.ca> <0b21db8d-1061-6453-960b-8043951b3bad@amazon.com> <20200918115227.GR869610@unreal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Sep 18, 2020 at 02:56:09PM +0300, Oded Gabbay wrote: > On Fri, Sep 18, 2020 at 2:52 PM Leon Romanovsky wrote: > > > > On Fri, Sep 18, 2020 at 02:36:10PM +0300, Gal Pressman wrote: > > > On 17/09/2020 20:18, Jason Gunthorpe wrote: > > > > On Tue, Sep 15, 2020 at 11:46:58PM +0300, Oded Gabbay wrote: > > > >> infrastructure for communication between multiple accelerators. Same > > > >> as Nvidia uses NVlink, we use RDMA that we have inside our ASIC. > > > >> The RDMA implementation we did does NOT support some basic RDMA > > > >> IBverbs (such as MR and PD) and therefore, we can't use the rdma-core > > > >> library or to connect to the rdma infrastructure in the kernel. > > > > > > > > You can't create a parallel RDMA subsystem in netdev, or in misc, and > > > > you can't add random device offloads as IOCTL to nedevs. > > > > > > > > RDMA is the proper home for all the networking offloads that don't fit > > > > into netdev. > > > > > > > > EFA was able to fit into rdma-core/etc and it isn't even RoCE at > > > > all. I'm sure this can too. > > > > > > Well, EFA wasn't welcomed to the RDMA subsystem with open arms ;), initially it > > > was suggested to go through the vfio subsystem instead. > > > > > > I think this comes back to the discussion we had when EFA was upstreamed, which > > > is what's the bar to get accepted to the RDMA subsystem. > > > IIRC, what we eventually agreed on is having a userspace rdma-core provider and > > > ibv_{ud,rc}_pingpong working (or just supporting one of the IB spec's QP types?). > > > > > > Does GAUDI fit these requirements? If not, should it be in a different subsystem > > > or should we open the "what qualifies as an RDMA device" question again? > > > > I want to remind you that rdma-core requirement came to make sure that > > anything exposed from the RDMA to the userspace is strict with proper > > UAPI header hygiene. > > > > I doubt that Havana's ioctls are backed by anything like this. > > > > Thanks > > Why do you doubt that ? Have you looked at our code ? > Our uapi and IOCTLs interface is based on drm subsystem uapi interface > and it is very safe and protected. Yes, I looked and didn't find open-source users of your UAPI headers. It is not related to being safe or protected by to the common request to present userspace that relies on those exported interfaces. > Otherwise Greg would have never allowed me to go upstream in the first place. Nice, can we get a link? > > We have a single function which is the entry point for all the IOCTLs > of our drivers (only one IOCTL is RDMA related, all the others are > compute related). > That function is almost 1:1 copy of the function in drm. DRM has same rules as RDMA, no kernel code will be merged without seeing open-source userspace. Thanks > > Thanks, > Oded