The first and foremost requirement of any virtualization solution that no guest error / crash can ever penetrate and bring down the host.
Originally Posted by project_phelius
Once you start doing direct 3D pass-through without any type of marshaling, a malformed Direct3D or OpenGL call can and will bring down the host.
Beyond that, virtualized 3D more-or-less requires that multiple guests will be able to run 3D application simultaneously which makes pass-through 3D even more complicated.
As other pointed out, in the short term, wine is a far better option.
In the long term, I would imagine that a combination of multiple GPU cards, pass-through-PCI capable drivers and smart management will give host-like performance to guests, without endangering the stability of the host.
On my side, I'm waiting for the full integration of Xen PCI-backend to the 2.6.40 kernel and hopefully, nVidia binary support for Xen. (E.g. use low-end GPU for the host, and let the guests use the high-end GPU's)
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