Re: UVM and the NULL page

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Sat, Jul 30, 2016 at 12:29:10PM -0400, Thor Lancelot Simon wrote:
> 4) Some people think your proposal to fix this by adding a pair of MD
>    constants to UVM and making the VA checks generic across platforms
>    does not adequately encapsulate this change which seems to benefit
>    only a single architecture.  They would prefer such changes to be
>    made in the existing MD component of the VM system (the pmap) rather
>    than in the MI components.
> 
> 5) You think your proposed fix is small and is appropriately MD and do
>    not think it is worth fully encapsulating your change in the pmap
>    layer.  For what it's worth, if any other architecture suffers from
>    this problem, I think I agree.

For what it is worth, I do believe that the handling of the 0 page
should be part of UVM and not pmap. I am only objection to forcing it
unconditionally.

Joerg