| Recently, virtualization is becoming a cutting edge area due to rapid development in computer speed and performance. Xen, an open source virtualization software, leads a new way called para-virtualization in x86 which saves great overhead cost by conventional virtualization technology and achieves excellent performance almost equivalent to native one by making few modifications to hosting operating system.Throughout the design and implementation of Xen, a goal has been set to separate policy from mechanism wherever possible. The resulting architecture is one in which the hypervisor itself provides only basic control operations. However, the TCB of a current Xen-based system comprises, in addition to the VMM, a fully-fledged operating system (known as Dom0) and a set of user-space tools. Therefore, domain 0 kernel is no doubt a critical point in xen security study. Currently, Linux is selected as domain 0, which significantly increases the size of xen's trusted computing base.We present a new architecture in this paper, where L4 micro-kernel is chosen as domain 0. It takes best advantage of the small size of both xen core code and micro-kernel to achieve a more trusted computing code base. Meanwhile, taking consideration of the similarity of IPC in L4 and inter-domain communication we extended interfaces of original L4 IPC so that no copy is performed during inter-domain communication. |
