Why is hypervisor/OS not trustable The TCB of hypervisor contains virtualization stack larger than 9 Million LOCs TCB Size of Xen System growing ■Xen2.0 10000 ■Xen30 Contro vn Tools ■Xen4.0 5000 Kernel VMM Xen's TcB o= VMM TCB KernelWhy is hypervisor/OS not trustable • The TCB of hypervisor • contains virtualization stack • larger than 9 Million LOCs • growing … 0 5000 10000 VMM Dom0 Kernel Tools TCB KLOCs TCB Size of Xen System Xen 2.0 Xen 3.0 Xen 4.0 VMM Xen’s TCB Control VM Tools Kernel Guest VM