Messages in this thread | | | Date | Fri, 22 Jun 2018 18:39:50 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv3 09/17] x86/mm: Implement page_keyid() using page_ext |
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On Mon, Jun 18, 2018 at 12:54:29PM +0000, Dave Hansen wrote: > On 06/18/2018 03:07 AM, Kirill A. Shutemov wrote: > > On Wed, Jun 13, 2018 at 06:20:10PM +0000, Dave Hansen wrote: > >>> +int page_keyid(const struct page *page) > >>> +{ > >>> + if (mktme_status != MKTME_ENABLED) > >>> + return 0; > >>> + > >>> + return lookup_page_ext(page)->keyid; > >>> +} > >>> +EXPORT_SYMBOL(page_keyid); > >> Please start using a proper X86_FEATURE_* flag for this. It will give > >> you all the fancy static patching that you are missing by doing it this way. > > There's no MKTME CPU feature. > > Right. We have tons of synthetic features that have no basis in the > hardware CPUID feature.
I've tried the approach, but it doesn't fit here.
We enable MKTME relatively late during boot process -- after page_ext as page_keyid() depends on it. Enabling it earlier would make page_keyid() return garbage.
By the time page_ext initialized, CPU features is already handled and setup_force_cpu_cap() doesn't do anything.
I've implemented the enabling with static key instead.
-- Kirill A. Shutemov
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