From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tetsuya Mukawa Subject: Re: [RFC PATCH 3/7] lib/librte_vhost: Add an abstraction layer tointerpret messages Date: Mon, 10 Nov 2014 14:12:35 +0900 Message-ID: <54604943.5030601@igel.co.jp> References: <1415272471-3299-1-git-send-email-mukawa@igel.co.jp> <1415272471-3299-4-git-send-email-mukawa@igel.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: "nakajima.yoshihiro-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org" , "masutani.hitoshi-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org" To: "Xie, Huawei" , "dev-VfR2kkLFssw@public.gmane.org" Return-path: In-Reply-To: List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" Hi Xie, (2014/11/08 5:43), Xie, Huawei wrote: >> -struct vhost_net_device_ops const *get_virtio_net_callbacks(void); >> +struct vhost_net_device_ops const *get_virtio_net_callbacks( >> + vhost_driver_type_t type); > Tetsuya: > I feel currently it is better we still keep the common get_virtio_net_c= allbacks().=20 > For the message flow from control layer 1 (cuse ioctl or user sock mess= age recv/xmit)---> cuse/user local message handling layer 2-> common virt= io message handling layer 3 > Layer 1 and layer 2 belong to one module. It is that module's choice w= hether to implement callbacks between internal layer1 and layer2. We don'= t need to force that. > Besides, even that module wants to define the ops between layer 1 and l= ayer2, the interface could be different between cuse/user.=20 > Refer to the following code for user: > > vhost-user-server.c: > case VHOST_USER_SET_MEM_TABLE: > user_set_mem_table(ctx, &msg) > > virtio-net-user.c: > user_set_mem_table(struct vhost_device_ctx ctx, struct VhostUserMsg *pm= sg) > { > > .... > > ops->set_mem_table(ctx, regions, memory.nregions); > } > > I may misunderstand what you say, please let me know in the case. I guess it's difficult to remove 'vhost_driver_type_t' from 'get_virtio_net_callbacks()'. In original vhost example code, there are 2 layers related with initialization as you mentioned. + Layer1: cuse ioctl handling layer. + Layer2: vhost-cuse( =3D vhost-net) message handling layer. Layer1 needs function pointers to call Layer2 functions. 'get_virtio_net_callbacks()' is used for that purpose. My RFC is based on above, but Layer1/2 are abstracted to hide vhost-cuse and vhost-user. + Layer1: device control abstraction layer. -- Layer1-a: cuse ioctl handling layer. -- Layer1-b: unix domain socket handling layer. + Layer2: message handling abstraction layer. -- Layer2-a: vhost-cuse(vhost-net) message handling layer. -- Layer2-b: vhost-user message handling layer. Still Layer1 needs function pointers of Layer2. So, anyway, we still need to implement 'get_virtio_net_callbacks()'. Also, as you mentioned, function definition and behavior are different between Layer2-a and Lanyer2-b like 'user_set_mem_table()'. Because of this, 'get_virtio_net_callbacks()' need to return collect function pointers to Layer1. So I guess 'get_virtio_net_callbacks()' needs 'vhost_driver_type_t' to know which function pointers are needed by Layer1. If someone wants to implement new vhost-backend, of course they can implement Layer2 implementation and Layer1 together. In the case, they doesn't need to call 'get_virtio_net_callbacks()'. Also they can reuse existing Layer2 implementation by calling 'get_virtio_net_callbacks()' with existing driver type, or they can implement a new Layer2 implementation for new vhost-backend. BTW, the name of 'vhost_driver_type_t' is redundant, I will change the na= me. Tetsuya