From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH] RFC: V4V Linux Driver Date: Fri, 17 Aug 2012 10:08:12 -0400 Message-ID: <20120817140812.GC8093@phenom.dumpdata.com> References: <1344032660-1251-1-git-send-email-jean.guyader@citrix.com> <20120806152815.GE8967@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jean Guyader Cc: Jean Guyader , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Fri, Aug 10, 2012 at 09:37:15AM +0100, Jean Guyader wrote: > On 6 August 2012 16:28, Konrad Rzeszutek Wilk wrote: > > On Fri, Aug 03, 2012 at 11:24:20PM +0100, Jean Guyader wrote: > >> This is a Linux driver for the V4V inter VM communication system. > >> > >> I've posted the V4V Xen patches for comments, to find more info about > >> V4V you can check out this link. > >> http://osdir.com/ml/general/2012-08/msg05904.html > >> > >> This linux driver exposes two char devices one for TCP one for UDP. > >> The interface exposed to userspace are made of IOCTLs, one per > >> network operation (listen, bind, accept, send, recv, ...). > > > > I haven't had a chance to take a look at this and won't until next > > week. But just a couple of quick questions: > > > > - Is there a test application for this? If so where can I get it > > I have a userspace library that talks to it, I'm in the process of > cleaning it up. > I'll send a patch series today that would add it in xen/tools. > > > - Is there any code in the Xen repository that uses it. > > The Xen support is being upstream right now, but because it needs some > userspace kernel to be useful it's kind a chicken and a egg problem, so I'm > trying to upstream both at the same time. > > You can find the last version of the Xen patches here: > http://lists.xen.org/archives/html/xen-devel/2012-08/msg00385.html > > > - Who are the users? > > Right now we use a close but not compatible version in XenClient. > Potentially the users > would be anyone that is looking to for a easy way to communicate > between VMs with > that has a feel of TCP/UDP. > > Some background info about V4V could be found here: > http://lists.xen.org/archives/html/xen-devel/2012-05/msg01866.html > > > - Why .. TCP and UDP ? Does that mean it masquarades as an Ethernet > > device? Why the choice of using a char device? > > > > Because of security concerns we didn't want to rely on the Linux > networking code because it would > have been hard for us to prove that a V4V packet could never end up on > your network card. > Although we understand that there is a need for a network like driver > and we are working on a version > of the V4V driver that will use SKBs and expose itself as a new socket type. > > In fact we asked on the LKML if it would be acceptable to add a new > type of socket in linux for > inter-VM communication but we are still waiting for an answer. > http://comments.gmane.org/gmane.linux.kernel/1337472 I saw that and wasn't sure what it meant. .. Why a new family? You didn't really explain why it is neccessary and why you could not create message sockets for example? Or just make your driver be an network driver. > > The really nice feature about V4V is it's ability leverage all the > existing networking programs. > We have a libc interposer library that wraps all the networking > functions. Here is an example > to access a ssh server running in another domain (domid=16) > > LD_PRELOAD=/usr/lib/libv4v.so ssh 1.0.0.16 Wouldn't it be just easier to not have an interposer? I mean, it all sounds like it is for networking, so.. it would seem like doing the full networking (or even a partial simple implemenation) would be the way to go? > > Thanks, > Jean > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel