An Effective Memory Optimization for Virtual Machine-Based Systems

Utilizing the popular virtualization technology (VT), users can benefit from server consolidation on high-end systems and flexible programming interfaces on low-end systems. In these virtualization environments, the intensive memory multiplexing for I/O of Virtual Machines (VMs) significantly degrades system performance. In this paper, we present a new technique, called Batmem, to effectively reduce the memory multiplexing overhead of VMs and emulated devices by optimizing the operations of the conventional emulated Memory Mapped I/O in Virtual Machine Monitor (VMM)/hypervisor. To demonstrate the feasibility of Batmem, we conduct a detailed taxonomy of the memory optimization on selected virtual devices. We evaluate the effectiveness of Batmem in Windows and Linux systems. Our experimental results show that 1) for high-end systems, Batmem operates as a component of the hypervisor and significantly improves the performance of the virtual environment, and 2) for low-end systems, Batmem could be exploited as a component of the VM-based malware/rootkit (VMBR) and cloak malicious activities from users' awareness.