1 files changed, 23 insertions, 15 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 39ee7182fd18..aef7af92b28b 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -565,13 +565,13 @@ pte_t xen_make_pte_debug(pteval_t pte)
         if (io_page &&
             (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
                 other_addr = pfn_to_mfn(addr >> PAGE_SHIFT) << PAGE_SHIFT;
-                WARN(addr != other_addr,
+                WARN_ONCE(addr != other_addr,
                         "0x%lx is using VM_IO, but it is 0x%lx!\n",
                         (unsigned long)addr, (unsigned long)other_addr);
         } else {
                 pteval_t iomap_set = (_pte.pte & PTE_FLAGS_MASK) & _PAGE_IOMAP;
                 other_addr = (_pte.pte & PTE_PFN_MASK);
-                WARN((addr == other_addr) && (!io_page) && (!iomap_set),
+                WARN_ONCE((addr == other_addr) && (!io_page) && (!iomap_set),
                         "0x%lx is missing VM_IO (and wasn't fixed)!\n",
                         (unsigned long)addr);
         }
@@ -1473,28 +1473,35 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 #endif
 }
 
+#ifdef CONFIG_X86_32
 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 {
-        unsigned long pfn = pte_pfn(pte);
-
-#ifdef CONFIG_X86_32
         /* If there's an existing pte, then don't allow _PAGE_RW to be set */
         if (pte_val_ma(*ptep) & _PAGE_PRESENT)
                 pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
                                pte_val_ma(pte));
-#endif
+
+        return pte;
+}
+#else /* CONFIG_X86_64 */
+static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+        unsigned long pfn = pte_pfn(pte);
 
         /*
          * If the new pfn is within the range of the newly allocated
          * kernel pagetable, and it isn't being mapped into an
-         * early_ioremap fixmap slot, make sure it is RO.
+         * early_ioremap fixmap slot as a freshly allocated page, make sure
+         * it is RO.
          */
-        if (!is_early_ioremap_ptep(ptep) &&
-            pfn >= pgt_buf_start && pfn < pgt_buf_end)
+        if (((!is_early_ioremap_ptep(ptep) &&
+                        pfn >= pgt_buf_start && pfn < pgt_buf_end)) ||
+                        (is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1)))
                 pte = pte_wrprotect(pte);
 
         return pte;
 }
+#endif /* CONFIG_X86_64 */
 
 /* Init-time set_pte while constructing initial pagetables, which
    doesn't allow RO pagetable pages to be remapped RW */
@@ -1700,9 +1707,6 @@ static __init void xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
                 for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
                         pte_t pte;
 
-                        if (pfn > max_pfn_mapped)
-                                max_pfn_mapped = pfn;
-
                         if (!pte_none(pte_page[pteidx]))
                                 continue;
 
@@ -1760,6 +1764,12 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
         pud_t *l3;
         pmd_t *l2;
 
+        /* max_pfn_mapped is the last pfn mapped in the initial memory
+         * mappings. Considering that on Xen after the kernel mappings we
+         * have the mappings of some pages that don't exist in pfn space, we
+         * set max_pfn_mapped to the last real pfn mapped. */
+        max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+
         /* Zap identity mapping */
         init_level4_pgt[0] = __pgd(0);
 
@@ -1864,9 +1874,7 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
         initial_kernel_pmd =
                 extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
 
-        max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
-                                  xen_start_info->nr_pt_frames * PAGE_SIZE +
-                                  512*1024);
+        max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
 
         kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
         memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);