As another feature of the Linux 3.6 kernel is support for VFIO.
Linux VFIO allows for a secure interface for device access using IOMMU protection for cases like securely assignming a physical device to a Linux virtual machine. Support is already planned with the VFIO driver so that PCI devices can be assigned to QEMU guests in a secure manner and will eventually replace x86-specific assignment code within KVM.
The interface is more secure due to its use of IOMMU and is not specific to any particular architecture or virtualization method. The PowerPC KVM developers have already expressed interest in VFIO.
The final pull request with four patches that finally went in came from Alex Williamson on the kernel mailing list. Linus Torvalds pulled the tree over the night (merge).