Chapter 6. Understanding Device Drivers
Device drivers are an important part of any operating system—without them, the kernel (and thus the applications) can’t communicate with physical hardware attached to the system.
Most full virtualization solutions provide emulated forms of simple devices. The emulated devices are typically chosen to be common hardware, so it is likely that drivers exist already for any given guest. Examples of hardware emulated include simple IDE hard disks and NE2000 network interfaces. This is a reasonable solution in cases where the guest cannot be modified, and is used by Xen in HVM domains where unmodified guests are run.
Paravirtualized guests, however, need to be modified in order to run anyway. As such, the requirement ...