Re: x86/mm/pageattr: Code without effect?

From: Borislav Petkov
Date: Mon Apr 08 2013 - 08:52:10 EST


On Mon, Apr 08, 2013 at 02:28:47PM +0200, Stefan Bader wrote:
> To enforce the PSE bit here sounds reasonably right. And also apply
> canon_pgprot, too. GLOBAL I don't know for sure.

Well sure, you don't want to flush those from the TLB if it is kernel
memory since it is mapped in every process AFAICT.

> By the way there is a usage of new_prot a bit down of
> try_preserve_large_page which probably should be changed into
> req_prot, too. That was enforcing the canon_pgprot before the change.
> So that may be considered a regression to before.

Which one?

Actually, after Andrea's patch it all makes sense - we initialize
new_prot from req_prot *after* all protections checks. new_prot are,
IMHO, the final protection bits which we are actually going to change.

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
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