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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 E1443C3404F for ; Wed, 19 Feb 2020 05:36:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB373208E4 for ; Wed, 19 Feb 2020 05:36:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SYM+a0sG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726604AbgBSFf7 (ORCPT ); Wed, 19 Feb 2020 00:35:59 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:23394 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725842AbgBSFf7 (ORCPT ); Wed, 19 Feb 2020 00:35:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582090557; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FnMyrS2ffrGzjTv2kAsMGrfcVGfLXQvqbV7CHWKXWPg=; b=SYM+a0sGlezWhDA11SWSOykhpntWmgm55zDD1vWYe1XfjOBr+pXoBvvbW+C/6jUw1e8UNt +mSmKwt2PZRWekgFIGRm7jqR+1z8er1NJb3evbQ6EvYD5VoCfL9LuuUL+XwpGszzsTem0d g866ccK2XYY2MX/FV/QLRp4aVo9WQ14= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-193-wJx9yaKzM8O55fVO3NXE4Q-1; Wed, 19 Feb 2020 00:35:52 -0500 X-MC-Unique: wJx9yaKzM8O55fVO3NXE4Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6E95B1085925; Wed, 19 Feb 2020 05:35:49 +0000 (UTC) Received: from [10.72.13.212] (ovpn-13-212.pek2.redhat.com [10.72.13.212]) by smtp.corp.redhat.com (Postfix) with ESMTP id 44D3D87B1A; Wed, 19 Feb 2020 05:35:27 +0000 (UTC) Subject: Re: [PATCH V2 3/5] vDPA: introduce vDPA bus To: Jason Gunthorpe Cc: "mst@redhat.com" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "tiwei.bie@intel.com" , "maxime.coquelin@redhat.com" , "cunming.liang@intel.com" , "zhihong.wang@intel.com" , "rob.miller@broadcom.com" , "xiao.w.wang@intel.com" , "haotian.wang@sifive.com" , "lingshan.zhu@intel.com" , "eperezma@redhat.com" , "lulu@redhat.com" , Parav Pandit , "kevin.tian@intel.com" , "stefanha@redhat.com" , "rdunlap@infradead.org" , "hch@infradead.org" , "aadam@redhat.com" , Jiri Pirko , Shahaf Shuler , "hanand@xilinx.com" , "mhabets@solarflare.com" References: <20200211134746.GI4271@mellanox.com> <20200212125108.GS4271@mellanox.com> <12775659-1589-39e4-e344-b7a2c792b0f3@redhat.com> <20200213134128.GV4271@mellanox.com> <20200213150542.GW4271@mellanox.com> <8b3e6a9c-8bfd-fb3c-12a8-2d6a3879f1ae@redhat.com> <20200214135232.GB4271@mellanox.com> <01c86ebb-cf4b-691f-e682-2d6f93ddbcf7@redhat.com> <20200218135608.GS4271@mellanox.com> From: Jason Wang Message-ID: Date: Wed, 19 Feb 2020 13:35:25 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20200218135608.GS4271@mellanox.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/2/18 =E4=B8=8B=E5=8D=889:56, Jason Gunthorpe wrote: > On Mon, Feb 17, 2020 at 02:08:03PM +0800, Jason Wang wrote: > >> I thought you were copied in the patch [1], maybe we can move vhost re= lated >> discussion there to avoid confusion. >> >> [1] https://lwn.net/Articles/811210/ > Wow, that is .. confusing. > > So this is supposed to duplicate the uAPI of vhost-user? It tries to reuse the uAPI of vhost with some extension. > But it is > open coded and duplicated because .. vdpa? I'm not sure I get here, vhost module is reused for vhost-vdpa and all=20 current vhost device (e.g net) uses their own char device. > >> So it's cheaper and simpler to introduce a new bus instead of refactor= ing a >> well known bus and API where brunches of drivers and devices had been >> implemented for years. > If you reason for this approach is to ease the implementation then you > should talk about it in the cover letters/etc I will add more rationale in both cover letter and this patch. Thanks > > Maybe it is reasonable to do this because the rework is too great, I > don't know, but to me this whole thing looks rather messy. > > Remember this stuff is all uAPI as it shows up in sysfs, so you can > easilly get stuck with it forever. > > Jason >