1 files changed, 23 insertions, 43 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 85cf12219dea..4d369d5c04c5 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -512,6 +512,23 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
 #endif
 }
 
+static pgprot_t pgprot_clear_protnone_bits(pgprot_t prot)
+{
+        /*
+         * _PAGE_GLOBAL means "global page" for present PTEs.
+         * But, it is also used to indicate _PAGE_PROTNONE
+         * for non-present PTEs.
+         *
+         * This ensures that a _PAGE_GLOBAL PTE going from
+         * present to non-present is not confused as
+         * _PAGE_PROTNONE.
+         */
+        if (!(pgprot_val(prot) & _PAGE_PRESENT))
+                pgprot_val(prot) &= ~_PAGE_GLOBAL;
+
+        return prot;
+}
+
 static int
 try_preserve_large_page(pte_t *kpte, unsigned long address,
                         struct cpa_data *cpa)
@@ -577,18 +594,11 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
          * different bit positions in the two formats.
          */
         req_prot = pgprot_4k_2_large(req_prot);
-
-        /*
-         * Set the PSE and GLOBAL flags only if the PRESENT flag is
-         * set otherwise pmd_present/pmd_huge will return true even on
-         * a non present pmd. The canon_pgprot will clear _PAGE_GLOBAL
-         * for the ancient hardware that doesn't support it.
-         */
+        req_prot = pgprot_clear_protnone_bits(req_prot);
         if (pgprot_val(req_prot) & _PAGE_PRESENT)
-                pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL;
+                pgprot_val(req_prot) |= _PAGE_PSE;
         else
-                pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL);
-
+                pgprot_val(req_prot) &= ~_PAGE_PSE;
         req_prot = canon_pgprot(req_prot);
 
         /*
@@ -698,16 +708,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
                 return 1;
         }
 
-        /*
-         * Set the GLOBAL flags only if the PRESENT flag is set
-         * otherwise pmd/pte_present will return true even on a non
-         * present pmd/pte. The canon_pgprot will clear _PAGE_GLOBAL
-         * for the ancient hardware that doesn't support it.
-         */
-        if (pgprot_val(ref_prot) & _PAGE_PRESENT)
-                pgprot_val(ref_prot) |= _PAGE_GLOBAL;
-        else
-                pgprot_val(ref_prot) &= ~_PAGE_GLOBAL;
+        ref_prot = pgprot_clear_protnone_bits(ref_prot);
 
         /*
          * Get the target pfn from the original entry:
@@ -930,18 +931,7 @@ static void populate_pte(struct cpa_data *cpa,
 
         pte = pte_offset_kernel(pmd, start);
 
-        /*
-         * Set the GLOBAL flags only if the PRESENT flag is
-         * set otherwise pte_present will return true even on
-         * a non present pte. The canon_pgprot will clear
-         * _PAGE_GLOBAL for the ancient hardware that doesn't
-         * support it.
-         */
-        if (pgprot_val(pgprot) & _PAGE_PRESENT)
-                pgprot_val(pgprot) |= _PAGE_GLOBAL;
-        else
-                pgprot_val(pgprot) &= ~_PAGE_GLOBAL;
-
+        pgprot = pgprot_clear_protnone_bits(pgprot);
         pgprot = canon_pgprot(pgprot);
 
         while (num_pages-- && start < end) {
@@ -1234,17 +1224,7 @@ repeat:
 
                 new_prot = static_protections(new_prot, address, pfn);
 
-                /*
-                 * Set the GLOBAL flags only if the PRESENT flag is
-                 * set otherwise pte_present will return true even on
-                 * a non present pte. The canon_pgprot will clear
-                 * _PAGE_GLOBAL for the ancient hardware that doesn't
-                 * support it.
-                 */
-                if (pgprot_val(new_prot) & _PAGE_PRESENT)
-                        pgprot_val(new_prot) |= _PAGE_GLOBAL;
-                else
-                        pgprot_val(new_prot) &= ~_PAGE_GLOBAL;
+                new_prot = pgprot_clear_protnone_bits(new_prot);
 
                 /*
                  * We need to keep the pfn from the existing PTE,