On Tue, Jun 12, 2018 at 4:09 PM Nicholas Piggin <npiggin@xxxxxxxxx> wrote:
>
> Sorry I mean Intel needs the existing behaviour of range flush expanded
> to cover page table pages.... right?
Right. Intel depends on the current thing, ie if a page table
*itself* is freed, we will will need to do a flush, but it's the exact
same flush as if there had been a regular page there.
That's already handled by (for example) pud_free_tlb() doing the
__tlb_adjust_range().
Again, I may be missing entirely what you're talking about, because it
feels like we're talking across each other.
My argument is that your new patches in (2-3 in the series - patch #1
looks ok) seem to be fundamentally specific to things that have a
*different* tlb invalidation for the directory entries than for the
leaf entries.
But that's not what at least x86 has, and not what the generic code has done.
I think it might be fine to introduce a few new helpers that end up
being no-ops for the traditional cases.
I just don't think it makes sense to maintain a set of range values
that then aren't actually used in the general case.
Linus
