Zero pages are never encrypted. Keep KeyID-0 for them.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@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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