Communicating between Dom0 and DomU without a network

[Hajime Inoue <hinoue@ccsl.carleton.ca>]

I'm looking for a way to communicate, without a network,
between Dom0 and DomU, at speeds approaching typical
bandwidth.

In August of last year, there was a discussion on this
list about the best way to communicate between Dom0 and
DomU without a network.  Using the console was suggested,
but some of the responders complained about its lack of
speed.  Someone mentioned a proposal for high speed byte
transfers between VMs, but I cannot find a record of it
being implemented.

I'd appreciate any advice on this.  What's the best way
to send large amounts of data from an HVM guest to Dom0
without a network?

Thanks,
-Hajime Inoue