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=-8.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 4B026C64E7C for ; Wed, 2 Dec 2020 05:50:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE594221FE for ; Wed, 2 Dec 2020 05:50:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728599AbgLBFuI (ORCPT ); Wed, 2 Dec 2020 00:50:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:21641 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726986AbgLBFuH (ORCPT ); Wed, 2 Dec 2020 00:50:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606888121; 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=mCYBZnVFwcJcfwEuD0pQ/djq4n14JKN2dFyCj8tmsog=; b=F/K4mLZmS7VLK2r2pu8HGRsp6IknLjKaN17T6y/BiSfFinvCKMP982Y1fPHj/uUz3BVo/e ywIWgYi1NbZnsV+oSngN+i/1cQEY+0SCrVTVzhVP/eJ5LHliec4XavFbHM9Sy2kbjOsIRf 9JbYAD+HumrV5OlQmwK3/j7IbKbnoMo= 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-532-JnDDeUHHMruWjKpDLQ1-8A-1; Wed, 02 Dec 2020 00:48:39 -0500 X-MC-Unique: JnDDeUHHMruWjKpDLQ1-8A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 225CE18C89DE; Wed, 2 Dec 2020 05:48:38 +0000 (UTC) Received: from [10.72.13.145] (ovpn-13-145.pek2.redhat.com [10.72.13.145]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4611D5C1B4; Wed, 2 Dec 2020 05:48:31 +0000 (UTC) Subject: Re: [External] Re: [PATCH 0/7] Introduce vdpa management tool To: Yongji Xie Cc: Parav Pandit , virtualization@lists.linux-foundation.org, "Michael S. Tsirkin" , elic@nvidia.com, netdev@vger.kernel.org References: <20201112064005.349268-1-parav@nvidia.com> <5b2235f6-513b-dbc9-3670-e4c9589b4d1f@redhat.com> <182708df-1082-0678-49b2-15d0199f20df@redhat.com> <7f80eeed-f5d3-8c6f-1b8c-87b7a449975c@redhat.com> From: Jason Wang Message-ID: <594b2086-802f-1053-2866-a25d4a327876@redhat.com> Date: Wed, 2 Dec 2020 13:48:30 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Archived-At: List-Archive: List-Post: On 2020/12/1 下午5:55, Yongji Xie wrote: > On Tue, Dec 1, 2020 at 2:25 PM Jason Wang wrote: >> >> On 2020/11/30 下午3:07, Yongji Xie wrote: >>>>> Thanks for adding me, Jason! >>>>> >>>>> Now I'm working on a v2 patchset for VDUSE (vDPA Device in Userspace) >>>>> [1]. This tool is very useful for the vduse device. So I'm considering >>>>> integrating this into my v2 patchset. But there is one problem： >>>>> >>>>> In this tool, vdpa device config action and enable action are combined >>>>> into one netlink msg: VDPA_CMD_DEV_NEW. But in vduse case, it needs to >>>>> be splitted because a chardev should be created and opened by a >>>>> userspace process before we enable the vdpa device (call >>>>> vdpa_register_device()). >>>>> >>>>> So I'd like to know whether it's possible (or have some plans) to add >>>>> two new netlink msgs something like: VDPA_CMD_DEV_ENABLE and >>>>> VDPA_CMD_DEV_DISABLE to make the config path more flexible. >>>>> >>>> Actually, we've discussed such intermediate step in some early >>>> discussion. It looks to me VDUSE could be one of the users of this. >>>> >>>> Or I wonder whether we can switch to use anonymous inode(fd) for VDUSE >>>> then fetching it via an VDUSE_GET_DEVICE_FD ioctl? >>>> >>> Yes, we can. Actually the current implementation in VDUSE is like >>> this. But seems like this is still a intermediate step. The fd should >>> be binded to a name or something else which need to be configured >>> before. >> >> The name could be specified via the netlink. It looks to me the real >> issue is that until the device is connected with a userspace, it can't >> be used. So we also need to fail the enabling if it doesn't opened. >> > Yes, that's true. So you mean we can firstly try to fetch the fd > binded to a name/vduse_id via an VDUSE_GET_DEVICE_FD, then use the > name/vduse_id as a attribute to create vdpa device? It looks fine to > me. Yes, something like this. The anonymous fd will be created during dev_add() and the fd will be carried in the msg to userspace. Thanks > > Thanks, > Yongji >