The public Jailhouse announcement by Jan Kiszka reads:
We are happy to announce the Jailhouse project, now also to a broader community!
Jailhouse is a partitioning hypervisor that can create asymmetric multiprocessing (AMP) setups on Linux-based systems. That means it runs bare-metal applications or non-Linux OSes aside a standard Linux kernel on one multicore hardware platform. Jailhouse ensures isolation between these "cells", as we call them, via hardware-assisted virtualization. The typical workloads we expect to see in non-Linux cells are applications with highly demanding real-time, safety or security requirements. In contrast to comparable hypervisors, Jailhouse is loaded and configured via Linux, not the other way around. Give it a try to see and "feel" the difference.
The aim of Jailhouse is to keep the amount of code responsible for establishing and maintaining cell isolation as small as possible. And with small we mean a few thousand lines of code at the privilege level of the hypervisor. This is obviously much less than you can achieve with full-featured hypervisors like KVM.
Jailhouse right now only supports Intel x86 and has a demonstration setup inside KVM/QEMU. The code has been released by Siemens on GitHub under the GPLv2.