>
>	- A "virtual address" type.  This may need to be split into:
>		- kernel virtual address (kva_t?)
>		- user virtual address (uva_t?)

One small comment- a virtual address is meaningless without knowing
which context to apply it in. This is really the same sort of thing
with physical addresses that have tag bits that identify which
type of physical address they are.

At any rate, there are far too many machine classes that it would
be desirable or necessary to know how the "virtual" space applies.
And, btw, we should really plan for more than one kernel virtual
address (for trying to do loosely coupled machines).