On Wed, Jul 15, 2015 at 5:34 PM, Dave Hansen
<dave.han...@linux.intel.com> wrote:
>
> The old code sized the buffer in a fully architectural way and it
> worked. The CPU *tells* you how much memory the 'xsave' instruction is
> going to scribble on. The new code just merrily calls it and let it
> scribble away. This is as clear-cut a regression as I've ever seen.
Yes, I think we'll need to revert it, or do something else drastic
like make that initial fp state allocation *much* bigger and then have
a "disable xsaves if if it's still not big enough".
setup_xstate_features() should be able to easily just say "this was
the maximum offset+size we saw", and we can take that to either do a
proper allocation, or verify that the static allocation is indeed big
enough.
Apparently a straight revert doesn't work, if only because things in
that area have been renamed very aggressively (both files and
functions and variables). Ingo?
Linus
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