From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Daniel P. Berrange" Subject: Re: [PATCH/RFC 7/9] Virtual network guest device driver Date: Wed, 16 May 2007 18:38:22 +0100 Message-ID: <20070516173822.GD16863@redhat.com> References: <1178903957.25135.13.camel@cotte.boeblingen.de.ibm.com> <1178904965.25135.34.camel@cotte.boeblingen.de.ibm.com> <13426df10705111244w1578ebedy8259bc42ca1f588d@mail.gmail.com> <4644CE15.6080505@us.ibm.com> <4644E456.2060507@us.ibm.com> <464B3F20.4030904@us.ibm.com> Reply-To: "Daniel P. Berrange" Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jimi Xenidis , "jmk-zzFmDc4TPjtKvsKVC3L/VUEOCMrvLtNR@public.gmane.org" , Christian Borntraeger , Martin Schwidefsky , "kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" To: Anthony Liguori Return-path: Content-Disposition: inline In-Reply-To: <464B3F20.4030904-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org On Wed, May 16, 2007 at 12:28:00PM -0500, Anthony Liguori wrote: > Eric Van Hensbergen wrote: > > On 5/11/07, Anthony Liguori wrote: > >> > >> There's definitely a conversation to have here. There are going to be a > >> lot of small devices that would benefit from a common transport > >> mechanism. Someone mentioned a PV entropy device on LKML. A > >> host=>guest filesystem is another consumer of such an interface. > >> > >> I'm inclined to think though that the abstraction point should be the > >> transport and not the actual protocol. My concern with standardizing on > >> a protocol like 9p would be that one would lose some potential > >> optimizations (like passing PFN's directly between guest and host). > >> > > > > I think that there are two layers - having a standard, well defined, > > simple shared memory transport between partitions (or between > > emulators and the host system) is certainly a prerequisite. There are > > lots of different decisions to made here: > > What do you think about a socket interface? I'm not sure how discovery > would work yet, but there are a few PV socket implementations for Xen at > the moment. As a userspace apps service, I'd very much like to see a common sockets interface for inter-VM communication that is portable across virt systems like Xen & KVM. I'd see it as similar to UNIX domain sockets in style. So basically any app which could do UNIX domain sockets, could be ported to inter-VM sockets by just changing PF_UNIX to say, PF_VIRT Lots of interesting details around impl & security (what VMs are allowed to talk to each other, whether this policy should be controlled by the host, or allow VMs to decide for themselves). > > a) does it communicate with userspace, kernelspace, or both? > > sockets are usable for both userspace/kernespace. For userspace, it would be very easy to adapt existing sockets based apps using IP or UNIX sockets to use inter-VM sockets, which is a big positive. > > d) can all of these parameters be something controllable from userspace? > > e) I'm sure there are many others that I can't be bothered to think > > of on a Friday > > The biggest point of contention would probably be what goes in the > sockaddr structure. Keeping it very simple would be some arbitrary 'path', similar to UNIX domain sockets in the abstract namespace ? Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=| ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/