Re: Nvidia support for Xen
One more on the list.
What I was thinking of was a variation of the fourth option. Running the driver dom0, while Xen installs a dummy driver in domU, which effectively acts as a HAL. This dummy driver would be the only part of the Windows (we'll assume the user is running winblows...I mean Windows in domU) environment that is aware it's running virtualized. The HAL driver would be used to talk directly to the driver running in dom0, and somewhere in the mix all the necessary calculations would be performed for the memory mapping to be done properly.
This model could actually be used for all sorts of fun hardware to run in Xen.