Did this ever work?
For me, the kernel memory allocation (uvm_km_alloc()) from
the amd64 specific lkm_map always fails.
The problem is appearently that the addresses in the lkm_map
are not within VM_{MIN,MAX}_KERNEL_ADDRESS.

Why is the special map needed, and what is the intention
behind
lkm_end = KERNBASE + NKL2_KIMG_ENTRIES * NBPD_L2; ?

best regards
Matthias