A variety of tools and architectures have been developed to detect security violations to Operating System kernels. However, they all have fundamental flaw in the design so that they fail to discover kernel-level attack. Few hardware solutions have been proposed to address the outstanding problem, but unfortunately they are not widely accepted. This paper presents a software-based method to detect intrusion to kernel. The proposed tool named XenKIMONO, which is based on Xen Virtual Machine, is able to detect many kernel rootkits in virtual machines with small penalty to the system's performance. In contrast with the traditional approaches, XenKIMONO is isolated with the kernel being monitored, thus it can still function correctly even if the observed kernel is compromised. Moreover, XenKIMONO is flexible and easy to deploy as it absolutely does not require any modification to the monitored systems.