Cooperative Linux

In this paper I'll describe Cooperative Linux, a port of the Linux kernel that allows it to run as an unprivileged lightweight virtual machine in kernel mode, on top of another OS kernel. It allows Linux to run under any operating system that supports loading drivers, such as Windows or Linux, after minimal porting efforts. The paper includes the present and future implementation details, its applications, and its comparison with other Linux virtualization methods. Among the technical details I'll present the CPU-complete context switch code, hardware interrupt forwarding, the interface between the host OS and Linux, and the management of the VM's pseudo physical RAM.