Taming Hosted Hypervisors with (Mostly) Deprivileged Execution.

摘要: Recent years have witnessed increased adoption of hosted hypervisors in virtualized computer systems. By non-intrusively extending commodity OSs, can effectively take advantage a variety mature and stable features as well the existing broad user base OSs. However, virtualizing system is still rather complex task. As result, typically large code (e.g., 33.6K SLOC for KVM), which inevitably introduces exploitable software bugs. Unfortunately, any compromised hypervisor immediately jeopardize host subsequently affect all running guests same physical machine. In this paper, we present that aims to dramatically reduce exposed attack surface by deprivileging its execution mode. essence, decoupling from OS execution, our demotes mostly user-level library, not only substantially reduces (with much smaller TCB), but also brings additional benefits allowing better development debugging concurrent multiple To evaluate effectiveness, developed proof-ofconcept prototype successfully deprivileges ∼ 93.2% loadable KVM module mode while adding small TCB (2.3K SLOC) kernel. Additional evaluation results with number benchmark programs further demonstrate practicality efficiency.