With ARM beginning to enter the high-performance server world, virtualization support will be critical for cloud computing and ARv7+ hardware has processor extensions for supporting hardware virtualization. This Xen support is early work in enabling things work out.
"The port is based on xen-unstable (HG CS 8d6edc3d26d2) and written from scratch exploiting the latest virtualization, LPAE, GIC and generic timer support in hardware," from the mailing list message.
This work on bringing Xen to ARM began just about three months ago and is already capable of booting a Linux 3.0 kernel virtual machine.
Citrix is hoping to merge this code to xen-unstable as soon as possible. They're also looking at Xen support for the ARMv8 architecture and 64-bit ARM too.