Virtualization Layer Security in Cloud Architecture

Abstract

Cloud Computing is a type of service based computing or utility computing. Cloud computing is based on virtualization technology. Virtualization architecture is categorized as hypervisor architecture, para virtualization and host based virtualization depending on the position of the virtualization layer. The hypervisor supports hardware-level virtualization on devices like CPU, disk, memory etc. The hypervisor provides hyper calls for the guest operating systems and applications. The architecture of processor supports the ability to run number of virtual machine instructions on one CPU after virtualization. Virtual machine instructions can be categorized as privileged and unprivileged instructions. Privileged instructions must be run in supervisor mode in Hypervisor. To provide reliable computing in cloud, virtualization layer security is a major concern. Hypervisor is a program responsible for allocation and de allocation of resources to each virtual machine (VM) connected to the cloud. Hypervisor security compromise affects all the privileged and sensitive instructions. Hypervisor is very small program compare to the operating system so it is easy to attack . A set of additional instructions must be added to control the hypervisor attacks and regular CPU state checking must be done in each virtual machine.