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    Subject[PATCH, RFC 14/62] x86/mm: Map zero pages into encrypted mappings correctly
    Date
    Zero pages are never encrypted. Keep KeyID-0 for them.

    Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
    ---
    arch/x86/include/asm/pgtable.h | 19 +++++++++++++++++++
    1 file changed, 19 insertions(+)

    diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
    index 50b3e2d963c9..59c3dd50b8d5 100644
    --- a/arch/x86/include/asm/pgtable.h
    +++ b/arch/x86/include/asm/pgtable.h
    @@ -803,6 +803,19 @@ static inline unsigned long pmd_index(unsigned long address)
    */
    #define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))

    +#define mk_zero_pte mk_zero_pte
    +static inline pte_t mk_zero_pte(unsigned long addr, pgprot_t prot)
    +{
    + extern unsigned long zero_pfn;
    + pte_t entry;
    +
    + prot.pgprot &= ~mktme_keyid_mask;
    + entry = pfn_pte(zero_pfn, prot);
    + entry = pte_mkspecial(entry);
    +
    + return entry;
    +}
    +
    /*
    * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
    *
    @@ -1133,6 +1146,12 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm,

    #define mk_pmd(page, pgprot) pfn_pmd(page_to_pfn(page), (pgprot))

    +#define mk_zero_pmd(zero_page, prot) \
    +({ \
    + prot.pgprot &= ~mktme_keyid_mask; \
    + pmd_mkhuge(mk_pmd(zero_page, prot)); \
    +})
    +
    #define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
    extern int pmdp_set_access_flags(struct vm_area_struct *vma,
    unsigned long address, pmd_t *pmdp,
    --
    2.20.1
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