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=-8.9 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=unavailable 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 B4C72C433E2 for ; Wed, 9 Sep 2020 08:42:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60078215A4 for ; Wed, 9 Sep 2020 08:42:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bHjGmcvq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729298AbgIIImU (ORCPT ); Wed, 9 Sep 2020 04:42:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:20947 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728584AbgIIImL (ORCPT ); Wed, 9 Sep 2020 04:42:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599640929; 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=DtMgeTKjCn17clYv2JEnI3ffDcOPCVRLd/V3CjCE3+4=; b=bHjGmcvqF0tE71baoI3XsazFtb7Y1uRgSepgFwfvZVBUz2TXHY8Z/uH6eebU85ovLLOVAz 8Nqr+bGQj37LIpdfjuv1znQF6+mxZvW2ANflJEEkIPlnQsSYLPWcy89D/Y/TxGeQPqjGSH KjlZ03LQQkKXOnZ+4HXNy1MWu3PbLgY= 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-23-_Ya4rfJ9P0yaQlRETl-ZPw-1; Wed, 09 Sep 2020 04:42:06 -0400 X-MC-Unique: _Ya4rfJ9P0yaQlRETl-ZPw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D592981F02E; Wed, 9 Sep 2020 08:42:03 +0000 (UTC) Received: from [10.72.12.24] (ovpn-12-24.pek2.redhat.com [10.72.12.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9D6F760C15; Wed, 9 Sep 2020 08:41:46 +0000 (UTC) Subject: Re: [RFC PATCH 00/22] Enhance VHOST to enable SoC-to-SoC communication To: Cornelia Huck Cc: Kishon Vijay Abraham I , "Michael S. Tsirkin" , Ohad Ben-Cohen , Bjorn Andersson , Jon Mason , Dave Jiang , Allen Hubbe , Lorenzo Pieralisi , Bjorn Helgaas , Paolo Bonzini , Stefan Hajnoczi , Stefano Garzarella , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-ntb@googlegroups.com, linux-pci@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org References: <20200702082143.25259-1-kishon@ti.com> <20200702055026-mutt-send-email-mst@kernel.org> <603970f5-3289-cd53-82a9-aa62b292c552@redhat.com> <14c6cad7-9361-7fa4-e1c6-715ccc7e5f6b@ti.com> <59fd6a0b-8566-44b7-3dae-bb52b468219b@redhat.com> <45a8a97c-2061-13ee-5da8-9877a4a3b8aa@ti.com> <20200828123409.4cd2a812.cohuck@redhat.com> <9cd58cd1-0041-3d98-baf7-6e5bc2e7e317@redhat.com> <20200908183701.60b93441.cohuck@redhat.com> From: Jason Wang Message-ID: Date: Wed, 9 Sep 2020 16:41:44 +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: <20200908183701.60b93441.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2020/9/9 上午12:37, Cornelia Huck wrote: >> Then you need something that is functional equivalent to virtio PCI >> which is actually the concept of vDPA (e.g vDPA provides alternatives if >> the queue_sel is hard in the EP implementation). > It seems I really need to read up on vDPA more... do you have a pointer > for diving into this alternatives aspect? See vpda_config_ops in include/linux/vdpa.h Especially this part:     int (*set_vq_address)(struct vdpa_device *vdev,                   u16 idx, u64 desc_area, u64 driver_area,                   u64 device_area); This means for the devices (e.g endpoint device) that is hard to implement virtio-pci layout, it can use any other register layout or vendor specific way to configure the virtqueue. > >>> "Virtio Over NTB" should anyways be a new transport. >>>> Does that make any sense? >>> yeah, in the approach I used the initial features are hard-coded in >>> vhost-rpmsg (inherent to the rpmsg) but when we have to use adapter >>> layer (vhost only for accessing virtio ring and use virtio drivers on >>> both front end and backend), based on the functionality (e.g, rpmsg), >>> the vhost should be configured with features (to be presented to the >>> virtio) and that's why additional layer or APIs will be required. >> A question here, if we go with vhost bus approach, does it mean the >> virtio device can only be implemented in EP's userspace? > Can we maybe implement an alternative bus as well that would allow us > to support different virtio device implementations (in addition to the > vhost bus + userspace combination)? That should be fine, but I'm not quite sure that implementing the device in kerne (kthread) is the good approach. Thanks >