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=-4.1 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 29436C4363D for ; Fri, 2 Oct 2020 11:45:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD56E206FA for ; Fri, 2 Oct 2020 11:45:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601639150; bh=Pz95HEQOu00LREcKTfrLQ1OFE1RN0p/e2FOjSN+3YCM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=NCo94iRSlNXf46FWg/mp6/Mit/N8yh2EYg4FKfKTMeLbVr4EeGtxlE8QYVR+xD0Gy zPOFQHlFRyqNAlVkB+8+FR1hw6pqkLT9qGNSBtKGdIwU5H8lnUoIaJM3Civf8OMdQC hw7O3nx0Kg2oIu50OnZ8dcbmn/no70Xl0QFgr0HE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726017AbgJBLpu (ORCPT ); Fri, 2 Oct 2020 07:45:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:40682 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726010AbgJBLpu (ORCPT ); Fri, 2 Oct 2020 07:45:50 -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 DB03E206E3; Fri, 2 Oct 2020 11:45:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601639149; bh=Pz95HEQOu00LREcKTfrLQ1OFE1RN0p/e2FOjSN+3YCM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ekKbSGUw21UaYEvRUV8yiPQcmwJGbCvnn3sA7Jtpmf6oQGlslma7PUp3G5OrzYMtu 5ZmOe++epRlOk5iKUX39fNShoZ9ZE3C/63XLMkorII6aI/Hvb2aQt6VTA9BA7eRfDD zRBE+/etpWIfm7KbA3+nAb56EacOoK6zOtM12r68= Date: Fri, 2 Oct 2020 14:45:45 +0300 From: Leon Romanovsky To: Parav Pandit Cc: "Ertman, David M" , "linux-rdma@vger.kernel.org" Subject: Re: [PATCH 1/6] Add ancillary bus support Message-ID: <20201002114545.GB3094@unreal> References: <20201001083229.GV3094@unreal> <20201001174025.GW3094@unreal> <20201001193211.GX3094@unreal> <20201002062011.GY3094@unreal> <20201002111354.GZ3094@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, Oct 02, 2020 at 11:27:43AM +0000, Parav Pandit wrote: > > > > From: Leon Romanovsky > > Sent: Friday, October 2, 2020 4:44 PM > > [..] > > > > ../../../devices/pci0000:00/0000:00:0b.0/mlx5_core.eth.2 > > > This gives you the ability to not load the netdevice and rdma device of a VF > > and only load the vdpa device. > > > These are real use case that users have asked for. > > > In use case one, they are only interested in rdma device. > > > In second use case only vdpa device. > > > How shall one achieve that without spinning of the device for each class? > > > > Why will it be different if ancillary device is small PCI core? > > If you want RDMA, you will use specific ancillary driver that connects to that > > small PCI logic. > > I didn't follow, wwhat is PCI core and PCI logic in this context? mlx5_core is PCI core/logic - ancillary device mlx5_ib/mlx5_en/mlx5_vdpa - ancillary drivers > > Not sure if you understood the use case. > Let me try again. > Let say there are 4 VFs enabled. > User would not like to create netdev for 3 VFs (0 to 2) ; user only wants rdma device for these VFs 0 to 2. > User wants only vdpa device for 4th VF. > User doesn't want to create rdma device and netdevice for the 4th VF. > How one shall achieve this? It depends on how N-to-1 bus will be implemented. For example, devlink already allows to disable RoCE on specific function, nothing prohibits to extend it to support other classes. > It is easily achievable with current ancillary device instantiation per class proposal. It is byproduct of 1-to-1 connection and not specific design decision. > > > Being nice to the users and provide clean abstraction are important goals too. > Which part of this makes not_nice_to_users and what is not abstracted. > I lost you. Your use case perfectly presented not_nice_to_users thing. Users are interested to work on functions (VF/PF/SF) and configure them without need to dig into the sysfs directories to connect ancillary classes and their indexes to the real functions. Thanks