VD_ACCESS_SET_PREEMPT
VD_ACCESS_SET_PREEMPT | VD_ACCESS_SET_PRESERVE);
switch (flags & (VD_ACCESS_SET_PREEMPT | VD_ACCESS_SET_PRESERVE)) {
case VD_ACCESS_SET_PREEMPT | VD_ACCESS_SET_PRESERVE:
case VD_ACCESS_SET_PREEMPT: