Support for direct inter-VM sockets? Inter-VM shared memory?

[Tyler Bletsch <tkbletsc@ncsu.edu>]

I'm interested in moving some research prototypes from Xen to KVM, but 
there are a few esoteric features I'd need to do this.

First is an efficient mechanism for direct VM-to-VM sockets...something 
that bypasses the protocol stack and minimizes overhead.  Xen has 
XenSocket, XenLoop, and others.  I found a few mentions of this idea 
dating back to 2006*, mostly saying that a few people have done 
something like this as a one-off, but nothing official has been 
released.  I haven't found anything like this more recently, though.  
Has there been any progress on this front?  Ideally, I'd want a 
character device or a special program that acts as a fast pipe to a 
different VM.

Second, what about inter-VM shared memory?

Apologies if I'm missing some well known doc...I search around google & 
the wiki to no avail.

Thanks,
Tyler Bletsch

* http://www.mail-archive.com/kvm-devel@lists.sourceforge.net/msg00304.html