uvmspace_alloc
mach->vm = uvmspace_alloc(0, mach->gpa_end - mach->gpa_begin, false);
p2->p_vmspace = uvmspace_alloc(exec_vm_minaddr(VM_MIN_ADDRESS),
struct vmspace *uvmspace_alloc(vaddr_t, vaddr_t, bool);
nvm = uvmspace_alloc(start, end, topdown);
vm2 = uvmspace_alloc(vm_map_min(old_map), vm_map_max(old_map),