From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com. [216.205.24.124]) by gmr-mx.google.com with ESMTPS id k6si134553qkg.1.2020.09.09.01.42.09 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Sep 2020 01:42:09 -0700 (PDT) Subject: Re: [RFC PATCH 00/22] Enhance VHOST to enable SoC-to-SoC communication 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 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 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 List-ID: 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 >