Re: [PATCH 4.4 103/105] Revert "x86/mm/pat: Ensure cpa->pfn only contains page frame numbers"

From: Guenter Roeck
Date: Fri Aug 24 2018 - 17:19:12 EST

+Andi Kleen <ak@xxxxxxxxxxxxxxx>

On Fri, Aug 24, 2018 at 01:04:09PM -0700, Roland Dreier wrote:
> > Ok, so what patch should be reverted? I'm seeing other reports of
> > problems all around this same area, but I can't figure out exactly what
> > to do.
> Are any of those reports public? If so can you point me at them, I'm
> curious if the symptoms match up.
> I don't think we want to revert anything. I think you should pull in
> edc3b9129cec and at least the first three patches that Ben listed:
> 21cdb6b56843 x86/mm: Page align the '_end' symbol to avoid pfn conversion bugs
> b61a76f8850d x86/efi: Map RAM into the identity page table for mixed mode
> 753b11ef8e92 x86/efi: Setup separate EFI page tables in kexec paths
> the first patch takes a bit of massaging (mostly because some of it is
> already touched by 02ff2769edbc, which keeps the changes from
> edc3b9129cec, and so we can drop a good bit when applying). The other
> three apply cleanly.
> I'm currently testing that and can send you the state of my tree in a bit.
> - R.