Re: Problem with RDMA device removal architecture

Roland Dreier
2010-03-26T23:00:05Z

> >uverbs is trickier, because a userspace process will typically have some
> >hardware resources directly mmap'ed. We need a way to "revoke" that
> >mmap and have it point at a dummy page until userspace releases it --

> What exactly would the dummy page contain and could the application/library read
> it assuming that it is obtaining valid data?

It would be an all-0s page I guess (to avoid leaking kernel data).

What the device driver library would do with it is device-specific but
eg Mellanox uses it write-only. Not sure if any other devices put
something readable there -- if so I guess that driver should put a safe
value there if possible.
--
Roland Dreier <rolandd-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
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