Re: proxy memory objects

[Roland McGrath]

> So is it correct to just mask off the unallowed protection bit and grant the
> mapping silently, making it fail if the actual permissions the server gave
> in the proxy memory object are violated?  Or should vm_map already do some
> initial permission check and return an error?

I don't think vm_map should return an error.  There might be practical
reasons for this, but my rationale is simply that the behavior ought to
mimic what a real memory object would do.  i.e., we want io_map to return a
memory object and the user doesn't know whether the server used the proxy
object facility or just returned a port of his own.