Introduction

XMHF is a modular hypervisor platform for recent multicore x86 hardware with support for dynamic root of trust and nested (2-dimensional) paging. It is NOT a full virtual machine monitor.

XMHF takes a developer-centric approach to hypervisor design and implementation, and strives to be a comprehensible and flexible platform for performing hypervisor research and development. XMHF encapsulates common hypervisor core functionality in a framework that allows others to build custom hypervisor-based solutions (called "hypapps"). It currently supports only a single "rich" guest OS.

Included modules

The XMHF project includes several components:

• XMHF: The eXtensible Hypervisor Framework.

• TrustVisor: A special-purpose hypervisor that provides code integrity as well as data integrity and secrecy for userspace Pieces of Application Logic (PALs).

  • tee-sdk: The Trusted Execution Environment Software Development Kit. This is a set of tools and APIs for developing PALs and applications that use them.

  • tee-cred: The TEE Credential Manager (tee-cred) is an audited key-value store that is useful as a credential (e.g., password) manager. It is implemented in a PAL leveraging tee-sdk, and as a stand-alone audit server.

• Lockdown: Lockdown provides the user with a red/green system: an isolated and constrained environment for performing online transactions, as well as a high-performance, general-purpose environment for all other (non-security-sensitive) applications. An external device verifies which environment is active and allows the user to securely learn which environment is active and to switch between them.

• libbaremetal: Utility functions used across modules, including many utility function from libc, error-handling, logging, etc. As the name implies, this library is intended primarily for use in "bare metal" environments.

Copying

The XMHF project comprises code from multiple sources, under multiple open source licenses. See COPYING.md for details.

Contact and support

There are a substantial number of known technical issues with this codebase, many of them with implications for security. Please see the ticket tracker for full details. This absolutely remains EXPERIMENTAL software. Do not trust important data to this software.

For bug reports, feature requests, etc., please use the sourceforge tickets tool.

For other discussion and questions, please use the sourceforge discussion tool. Note that the discussion tool can also be used much like a traditional mailing list, if you prefer. You will still need a sourceforge account. You can subscribe to all messages or to individual message threads through the web interface, after which you will receive corresponding posts through email. You can also post by responding to such notification messages, and start new threads by sending mail to general@discussion.xmhf.p.re.sf.net. Posts via email must originate from a sourceforge account's primary email address.

Contributing

We are open to contributions. The easiest mechanism is probably to fork our git repository through the web UI, make the changes on your fork, and then issue a merge request through the sourceforge web UI.

Contributors

The core team: Amit Vasudevan, Jonathan McCune, and James Newsome.

Related Publications

• "It's an app. It's a hypervisor. It's a hypapp.": Design and Implementation of an eXtensible and Modular Hypervisor Framework. Amit Vasudevan, Jonathan M. McCune, and James Newsome. Technical Report CMU-CyLab-12-014, June 2012. pdf

• TrustVisor: Efficient TCB Reduction and Attestation. Jonathan M. McCune, Yanlin Li, Ning Qu, Zongwei Zhou, Anupam Datta, Virgil Gligor, and Adrian Perrig. IEEE Symposium on Security and Privacy, May 2010. pdf

• Lockdown: Towards a Safe and Practical Architecture for Security Applications on Commodity Platforms. Amit Vasudevan and Bryan Parno and Ning Qu and Virgil D. Gligor and Adrian Perrig. Proceedings of the 5th International Conference on Trust and Trustworthy Computing (TRUST), June 2012. pdf

• Lockdown: A Safe and Practical Environment for Security Applications (CMU-CyLab-09-011) Amit Vasudevan and Bryan Parno and Ning Qu and Virgil D. Gligor and Adrian Perrig. Technical Report CMU-CyLab-09-011, June 2009. pdf

Changelog

• 0.1 Initial Release
• 0.1.1
  • Added TPM performance profiling.
  • Stability improvements (ticket-28 fixed).
  • Intercept handling now serialized in the core.
  • XMHF now builds and runs on Ubuntu 12.04 (precise).
  • Replaced LGPL tlsf implementation with public domain implementation.
  • Added design-documents.
• 0.1.2
  • xmhf-core: stability improvements (ticket-73 fixed) - we can now handle guest NMIs gracefully
  • xmhf-core: stability improvements (ticket-10 fixed) - we now support stock MTRR-enabled (linux) guest kernels on Intel platforms
  • test-bed fixes, refactoring and improvements - now supporting 3.2.0-27-generic (and below) with ubuntu
  • added documentation generator which takes in-tree markdown files and generates html output
  • fixed build target install-bin to include correct destination path