Operating System Extensions to Support Host Based Virtual Machines
Samuel Talmadge King, Peter M. Chen · 2000
Abstract: This paper presents two new operating system extensions that facilitate the fast execution of host based virtual machines: KTrace and MMA. KTrace provides a convenient and efficient mechanism for writing kernel modules that control the execution of user-level processes. MMA exposes more detail of the underlying memory management hardware, providing applications with access to high performance intraaddress space protection and address space overloading functionality. These extensions are applied to UMLinux, an x86 virtual machine that implements Linux as a user-mode process. As a result, overhead for UMLinux is reduced from 33 % for a CPU bound workload and 819 %- 1240 % for system call and I/O intensive workloads, to 6 % and 49 %- 24 % respectively. 1.