Architectural virtualization extensions: A systems perspective

Owing to the increase in demand for virtualization in recent years, both Intel and AMD have added virtualization extensions to the Intel 64 architecture. These architectural extensions provide hardware support aimed at improving the performance of system virtual machines (VM). Although extensive studies on various aspects of system VMs, in particular Xen but also KVM, have been reported in the literature, there has been no work specifically focused on Intel’s virtualization extensions. The survey presented here is a comprehensive study of the Intel 64 architecture’s architectural virtualization extensions and their use in system virtual machines, as exemplified by KVM. We describe a novel evaluation environment used in this study. Using this environment, we show and explain the correlation between architectural limitations of the hardware extensions and the performance of virtualization. The present review also describes the implementation and performance of a Virtio block device.