Unmodified device driver reuse and improved system dependability via virtual machines

We propose a method to reuse unmodified device drivers and to improve system dependability using vir-tual machines. We run the unmodified device driver, with its original operating system, in a virtual machine. This approach enables extensive reuse of existing and unmod-ified drivers, independent of the OS or device vendor, significantly reducing the barrier to building new OS en-deavors. By allowing distinct device drivers to reside in separate virtual machines, this technique isolates faults caused by defective or malicious drivers, thus improving a system’s dependability. We show that our technique requires minimal support infrastructure and provides strong fault isolation. Our prototype’s network performance is within 3–8 % of a native Linux system. Each additional virtual machine in-creases the CPU utilization by about 0.12%. We have successfully reused a wide variety of unmodified Linux network, disk, and PCI device drivers.