A host operating system can take ownership of a device. The host can project the presence of a device proxy (VDP) into a guest operating system. The VDP provides a set of device functions corresponding to the particular device class. Interactions with the VDP in the guest are forwarded to a Virtual Service Provider (VSP) in the host. The VSP maps a set of device class functions onto physical devices through a hardware abstraction and emulation layer. Functions supported directly by a physical device can be delivered to the device by the hardware abstraction layer (HAL). Functions not directly supported can be implemented through the hardware emulation layer (HEL). A uniform and robust set of functions may be made available in the guest regardless of hardware changes in the host, migration to a new host, or use of the device by other competing operating systems.