syscall hooking freezes Windows when stopping the hypervisor

Hi, I'm enabling syscall hooking via:

```c++
auto efer = msr::read<msr::efer_t>();
efer.syscall_enable = false;
msr::write(efer);

auto exception_bitmap = vp.exception_bitmap();
exception_bitmap.invalid_opcode = true;
vp.exception_bitmap(exception_bitmap);
  ```

Whenever I `sc.exe stop` my service the entire OS freezes