Composition Kernel: A Multi-core Processor Virtualization Layer for Highly Functional Embedded Systems

Multi-core processors are being increasingly adopted for embedded systems because they improve performance, power consumption and lower development cost. Composing multiple operating systems on a multi-core processor enhances the reusability of software when developing rich functional embedded systems. Multiple OS environments enable the product to use two versions of an operating system at the same time. In order to build multiple OS environments, a virtualization layer specialized for embedded systems is necessary, since most of processors for embedded systems support only two protection levels, and there is no hardware support for virtualization. In traditional approaches, an OS kernel runs at the user level to isolate the respective OS kernels to increase reliability, but this approach requires heavy modifications to the guest OSes if there is no proper hardware virtualization support that is rarely used in embedded systems. Therefore existing solutions are not preferred by the embedded system industry. In this paper, we propose a composition kernel where multiple OS kernels are running on top of a very thin hardware abstraction layer. A composition kernel can reduce the engineering cost of developing an embedded system by reusing existing OS kernels and application with minimum modification without assuming special hardware supports.