Known issues in NVMM, low priority in most cases.

====== KERNEL NVMM DRIVER ======

 * Currently you can't modunload NVMM while a VM is running, otherwise you hit
   a panic. See TODO in nvmm_fini().

 * Maybe we will want a way to return to userland when the guest TPR changes.
   On Intel that's not complicated, but on old AMD CPUs, we need to disassemble
   the instruction, and I don't like that.

 * Maybe we shouldn't modify the INT/NMI windows during event injection. The
   virtualizer is supposed to inject the event only when these windows allow
   it. (Eg Qemu does.)

 * We need a cleaner way to handle CPUID exits. It is not complicated to solve,
   but I'm still not sure which design is the cleanest.

 * Same for the MSRs.

====== LIBNVMM ======

 * There are still a few twisted corner cases we don't handle in the instruction
   emulator. For example if the guest makes an MMIO access relative to RSP, we
   must base the GVA on %SS and not %DS. This is tiring, and in practice, no
   guest is dumb enough to perform such accesses.