While the early AArch64 support has been apart of the Linux kernel for a few releases now, there's still being new functionality brought up. ARM 32-bit has supported Xen/KVM virtualization and now with Linux 3.11 it's been extended to the 64-bit ARM world.
Beyond the Xen/KVM ports for AArch64, the 64-bit ARM architecture now also handles Hugetlbfs and transparent huge-pages. There's also been cache flishing improvements and other fixes.
More details on the Linux 3.11 ARM64 improvements can be found via the mail pull request.