Taming Virtualization

Although the term virtualization has been around for decades, only recently has it become a buzzword in the computer systems community with the revival of virtual machines (VMs), driven by efforts in industry and academia. VMs are software entities that emulate a real machine's functionality; they execute under the control of a hypervisor that virtualizes and multiplexes low-level hardware resources. Hypervisors come in two flavors: non-hosted, which run directly on top of the hardware, and hosted, which are integrated with a host operating system (OS). The presence of a hypervisor makes VMs subject to a level of visibility and control that's hard to achieve with real machines. The small size, isolation, and mediation power of an ideal hypervisor over VMs make it an interesting candidate for a trusted computing base, with applications in security research fields such as intrusion detection, integrity protection, and malware analysis, among others.