Re: error message for invalid mapping?

[Joshua Haberman]
> How should a programmer who has made this mistake diagnose the
> problem?  Currently the only way is to make a lucky guess.  If
> nothing else, could you add a note to the reference manual that
> pages that are not mapped in the mapper's address space will not be
> mapped in the mappee's?

> I'm just trying to save the next person who encounters this problem
> the several days I spent debugging it.  :)

Personally, I thought it would be clear that one can not map something
which one does not already have access to.  Anyhow, the reference
manual does state that a flexpage consists of all the pages actually
mapped into the region specified (except KIP and UTCBs).  The whole
mapping functionality is pretty unclear in the reference manual,
though.  I have some writeups on an abstract model that I have been
thinking about including as an appendix (similar to what you'll find
in the "On u-Kernel Construction" paper).  This model does handle
holes in fpages as well as superpages.

	eSk