While the KVM changes for Linux 4.6 are numerous, they are mostly architecture-specific changes for this important piece of the open-source Linux virtualization puzzle.
In the ARM space there is VHE support, PMU support for guests, 32-bit world switch rewritten in C, and various optimizations. Over in the PowerPC world there is KVM-VFIO integration, optimizations to speed up IPIs between vCPUs, in-kernel handling of IOMMU hypercalls, and support for dynamic DMA windows.
Of interest to most people will be the KVM x86 changes. Ready for Linux 4.6 in the KVM x86 world is Hyper-V VMBus hypercall user-space exit support, an alternative implementation of lowest-priority interrupts, fixed guest debugging with nested virtualization, improved interrupt tracking, generic infrastructure for tracking writes to guest memory, and many code clean-ups.
More details on the KVM changes for Linux 4.6 can be found via this morning's pull request.