Looks like Sun is making moves to allow its UltraSPARC T1 to work with Xen.

Quoting from The Register:

The server maker has plans to offer the Linux set a bit of Niagara Viagra. Sun's engineers have been beavering away on a hypervisor layer that sits on the company's UltraSPARC T1 - aka Niagara - processor and allows operating systems such as Linux and BSD to run on the chip. More impressively, perhaps, Sun plans to merge its own hypervisor work with the open source Xen code.

Read the full article here.