Hardware drivers are the most failure-prone part of an operating system. It would be good for safety if you could isolate a driver from the rest of the system so that, when it failed, it could just be restarted without affecting the rest of the machine. Driver domains allow this. A driver domain is a DomU that has been given responsibility for a particular piece of hardware. It runs a minimal kernel with only that hardware driver and the BackendDriver for that device class. Thus, if the hardware driver fails, the other domains (including Dom0) will survive and, when the driver domain is restarted, will be able to use the hardware again.
No, it is not a domU but essentially a dom0 with the backend driver part plus actual hardware driver. domUs can communicate with the driver domain just like they communicate with the dom0.
PS: Some Xen guru, please add/remove last two lines after ratification.
xen.org,
