Single Graphic Card only for KVM-Guest, not Linux?

Hi,

I'm also interested in this possibilty of graphic card passthrough to a client. As it seems impossible to share the graphic card between multiple systems, does it work with high performance if using a second graphic card for the host system? I've read that Xen can handle the passthrough in that case, but I didn' find any confirmation that it will work using KVM.

Thanks.

Regards
Chris