Pull up following revision(s) (requested by nonaka in ticket #700):
sys/dev/acpi/acpi_mcfg.c: 1.6
Change the iteration, to make sure the ACPI_MCFG_ALLOCATION structure we're
reading fits the table we allocated. Linux does the same.
I have a laptop which, for some reason, reports a table size of 62 bytes.
Clearly that's incorrect, it should be 60 (44 + 16). Because of the stray
+2, here the kernel reads past the end of the allocated buffer, hits an
unmapped VA, and panics at boot time. So the laptop can't boot.
Now it boots fine.

(snj)