1 files changed, 23 insertions, 10 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index de807c9daad1..6c8e3fdaf077 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -485,14 +485,23 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
 
         /*
          * We are safe now. Check whether the new pgprot is the same:
+         * Convert protection attributes to 4k-format, as cpa->mask* are set
+         * up accordingly.
          */
         old_pte = *kpte;
-        old_prot = req_prot = pte_pgprot(old_pte);
+        old_prot = req_prot = pgprot_large_2_4k(pte_pgprot(old_pte));
 
         pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr);
         pgprot_val(req_prot) |= pgprot_val(cpa->mask_set);
 
         /*
+         * req_prot is in format of 4k pages. It must be converted to large
+         * page format: the caching mode includes the PAT bit located at
+         * 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
@@ -585,13 +594,10 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
 
         paravirt_alloc_pte(&init_mm, page_to_pfn(base));
         ref_prot = pte_pgprot(pte_clrhuge(*kpte));
-        /*
-         * If we ever want to utilize the PAT bit, we need to
-         * update this function to make sure it's converted from
-         * bit 12 to bit 7 when we cross from the 2MB level to
-         * the 4K level:
-         */
-        WARN_ON_ONCE(pgprot_val(ref_prot) & _PAGE_PAT_LARGE);
+
+        /* promote PAT bit to correct position */
+        if (level == PG_LEVEL_2M)
+                ref_prot = pgprot_large_2_4k(ref_prot);
 
 #ifdef CONFIG_X86_64
         if (level == PG_LEVEL_1G) {
@@ -879,6 +885,7 @@ static int populate_pmd(struct cpa_data *cpa,
 {
         unsigned int cur_pages = 0;
         pmd_t *pmd;
+        pgprot_t pmd_pgprot;
 
         /*
          * Not on a 2M boundary?
@@ -910,6 +917,8 @@ static int populate_pmd(struct cpa_data *cpa,
         if (num_pages == cur_pages)
                 return cur_pages;
 
+        pmd_pgprot = pgprot_4k_2_large(pgprot);
+
         while (end - start >= PMD_SIZE) {
 
                 /*
@@ -921,7 +930,8 @@ static int populate_pmd(struct cpa_data *cpa,
 
                 pmd = pmd_offset(pud, start);
 
-                set_pmd(pmd, __pmd(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot)));
+                set_pmd(pmd, __pmd(cpa->pfn | _PAGE_PSE |
+                                   massage_pgprot(pmd_pgprot)));
 
                 start     += PMD_SIZE;
                 cpa->pfn  += PMD_SIZE;
@@ -949,6 +959,7 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd,
         pud_t *pud;
         unsigned long end;
         int cur_pages = 0;
+        pgprot_t pud_pgprot;
 
         end = start + (cpa->numpages << PAGE_SHIFT);
 
@@ -986,12 +997,14 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd,
                 return cur_pages;
 
         pud = pud_offset(pgd, start);
+        pud_pgprot = pgprot_4k_2_large(pgprot);
 
         /*
          * Map everything starting from the Gb boundary, possibly with 1G pages
          */
         while (end - start >= PUD_SIZE) {
-                set_pud(pud, __pud(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot)));
+                set_pud(pud, __pud(cpa->pfn | _PAGE_PSE |
+                                   massage_pgprot(pud_pgprot)));
 
                 start     += PUD_SIZE;
                 cpa->pfn  += PUD_SIZE;