[PATCHv2 15/59] x86/mm: Map zero pages into encrypted mappings correctly

Kirill A. Shutemov
2019-07-31T15:09:33Z

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 0bc530c4eb13..f0dd80a920a9 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -820,6 +820,19 @@ 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]
*
@@ -1153,6 +1166,12 @@ 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,
--
2.21.0