Messages in this thread | | | Date | Tue, 20 Feb 2018 09:32:11 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH RESEND] x86: consider effective protection attributes in W+X check |
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* Jan Beulich <JBeulich@suse.com> wrote:
> >>> On 20.02.18 at 09:10, <mingo@kernel.org> wrote: > > * Jan Beulich <JBeulich@suse.com> wrote: > >> Using just the leaf page table entry flags would cause a false warning > >> in case _PAGE_RW is clear or _PAGE_NX is set in a higher level entry. > > > > Under what circumstances did you see false positive warnings? > > As explained in the 2-patch series this was originally part of, there > continues to be that W+X warning when running under Xen, as > commit 2cc42bac1c ("x86-64/Xen: eliminate W+X mappings") has > to make the necessary adjustment in L2 rather than L1 (the > reason is explained there). I.e. _PAGE_RW is clear there in L1, > but _PAGE_NX is set in L2.
This would make an excellent additional paragraph of the v2 changelog.
Thanks,
Ingo
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