| From | Roland Dreier <> | Date | Wed, 22 Aug 2018 17:48:32 -0700 | Subject | Re: [PATCH 4.4 103/105] Revert "x86/mm/pat: Ensure cpa->pfn only contains page frame numbers" |
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On Fri, Dec 15, 2017 at 2:20 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > This reverts commit 87e2bd898d3a79a8c609f183180adac47879a2a4 which is > commit edc3b9129cecd0f0857112136f5b8b1bc1d45918 upstream. > > Turns there was too many other issues with this patch to make it viable > for the stable tree.
This was sort of a long time ago, but does anyone remember why this needed to be reverted from 4.4?
The reason I ask is that without this, commit 02ff2769edbc / "x86/mm/pat: Make set_memory_np() L1TF safe" in 4.4.148 is broken. That patch has
- set_pud(pud, __pud(cpa->pfn | _PAGE_PSE | - massage_pgprot(pud_pgprot))); + set_pud(pud, pud_mkhuge(pfn_pud(cpa->pfn, + canon_pgprot(pud_pgprot))));
(and similarly for pmds) but pfn_pud() is operating on page frame numbers and __pud(cpa->pfn... in the old code is operating on physical addresses.
This is bad enough that 4.4.148 and all newer 4.4.y crash early in boot on some EFI systems that I have.
For now I am re-applying the "ensure cpa->pfn only contains page frame numbers" patch, ported on top of 4.4.151.
- R.
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