Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 2 Jun 2023 16:43:57 +0200 | From | Borislav Petkov <> | Subject | Re: [RESUBMIT][PATCH] x86/mm: Fix PAT bit missing from page protection modify mask |
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On Thu, Jun 01, 2023 at 10:47:39AM +0200, Juergen Gross wrote: > As described in the commit message, this only works on bare metal due to the > PAT bit not being needed for WC mappings. > > Making this patch Xen specific would try to cure the symptoms without fixing > the underlying problem: _PAGE_PAT should be regarded the same way as the bits > for caching mode (_PAGE_CHG_MASK).
So why isn't _PAGE_PAT part of _PAGE_CHG_MASK?
It says above it "Set of bits not changed in pte_modify."
And I don't see pte_modify() changing that bit either.
Right now this "fix" looks like, "let's OR these two masks so that we can take care of _PAGE_PAT too". But it doesn't make a whole lotta sense to me...
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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