It appears that UVM does not support pmap_next_page() as it
was used with the old MACHINE_NONCONTIG pmap interface, and
one feature of that interface appears to have been lost:

The ability to reserve some physical pages.

For example, all Sun3 machines (not Sun3X, but plain old Sun3)
have contiguous memory, and I would prefer represent that memory
with a single segment in the MACHINE_NEW_NONCONTIG support code.
Now, the problem is that on the Sun3/50 there are some pages of
physical memory that must be considered "in use" (by video) and
which need to be somehow marked as "already allocated" when the
initial list of free pages is created.  In the old VM code that
could be done by arranging for pmap_next_page() to not return
any of the page indicies of the reserved pages.

I would rather not represent the video ram as a "hole" (with two
physical RAM segments) because it really is memory (not a hole)
and calling it a hole makes the physical memory size wrong, etc.

So, is there any way to "pre-allocate" some pages at a specified
physical address before anything else has a chance to get them?

Thanks,
Gordon