Messages in this thread | | | Date | Mon, 5 Sep 2016 10:48:17 +0200 | From | Borislav Petkov <> | Subject | Re: [RFC PATCH v2 07/20] x86: Provide general kernel support for memory encryption |
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On Mon, Aug 22, 2016 at 05:36:46PM -0500, Tom Lendacky wrote: > Adding general kernel support for memory encryption includes: > - Modify and create some page table macros to include the Secure Memory > Encryption (SME) memory encryption mask > - Update kernel boot support to call an SME routine that checks for and > sets the SME capability (the SME routine will grow later and for now > is just a stub routine) > - Update kernel boot support to call an SME routine that encrypts the > kernel (the SME routine will grow later and for now is just a stub > routine) > - Provide an SME initialization routine to update the protection map with > the memory encryption mask so that it is used by default > > Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> > ---
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> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h > index f1218f5..a01f0e1 100644 > --- a/arch/x86/include/asm/pgtable_types.h > +++ b/arch/x86/include/asm/pgtable_types.h > @@ -3,6 +3,7 @@ > > #include <linux/const.h> > #include <asm/page_types.h> > +#include <asm/mem_encrypt.h> > > #define FIRST_USER_ADDRESS 0UL > > @@ -121,9 +122,9 @@ > > #define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE) > > -#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \ > +#define __PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \ > _PAGE_ACCESSED | _PAGE_DIRTY)
Hmm, so this naming looks confusing and error-prone: the only difference is a single "_".
How about this instead:
#define _PAGE_TABLE_NO_ENC (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \ _PAGE_ACCESSED | _PAGE_DIRTY)
#define _PAGE_TABLE (_PAGE_TABLE_NO_ENC | _PAGE_ENC)
Or call it _PAGE_TABLE_BASE or whatever.
Ditto for __KERNPG_TABLE.
This way you can differentiate between the two and use the _NO_ENC one to define _PAGE_TABLE. And it will be absolutely clear when you use the _NO_ENC one, what you mean and that you don't want to have the enc mask in the PTE.
Should be less confusing IMO too.
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply.
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