QEMU VFIO Support Is Progressing For VGA Pass-Through
Phoronix: QEMU VFIO Support Is Progressing For VGA Pass-Through
Besides virtual GPU drivers like the proprietary components within VMware and VirtualBox virtualization stacks and the under-development Virgil3D for QEMU, another option for those seeking 3D/GPU hardware acceleration support within VM guests is VGA pass-through...
Interesting. Last I tried, i could get absolutely no output through my GTX 660. I might want to try it again sometime, but I'm on 3.11 right now, so I'll probably wait some more. Meanwhile Wine is getting better all the time.
VGA passthrough also works with the old qemu pci assignment method. I have a gaming VM that uses it, and it works pretty well. You just can't use it as the machine's primary graphics adapter, but that doesn't really matter for Windows 7 and above (at least; it is a problem for XP).
It unfortunately doesn't do software reset of the card, but you can trigger that by briefly suspending the host, which usually isn't too arduous.
As an alternative to suspending the host as suggested by Dolio, try using the 'eject' button in your Windows guest. This worked well for me, and alleviated the terrible performance issues I had when not doing so. Note that this was with Xen rather than KVM.