x86: introduce max_low_pfn_mapped for 64-bit

when more than 4g memory is installed, don't map the big hole below 4g.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 17 insertions, 2 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index afd40054d157..0389cb8f6b1a 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -536,8 +536,14 @@ static int split_large_page(pte_t *kpte, unsigned long address)
                 set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
 
         if (address >= (unsigned long)__va(0) &&
+                address < (unsigned long)__va(max_low_pfn_mapped << PAGE_SHIFT))
+                split_page_count(level);
+
+#ifdef CONFIG_X86_64
+        if (address >= (unsigned long)__va(1UL<<32) &&
                 address < (unsigned long)__va(max_pfn_mapped << PAGE_SHIFT))
                 split_page_count(level);
+#endif
 
         /*
          * Install the new, split up pagetable. Important details here:
@@ -655,12 +661,21 @@ static int cpa_process_alias(struct cpa_data *cpa)
         if (cpa->pfn > max_pfn_mapped)
                 return 0;
 
+#ifdef CONFIG_X86_64
+        if (cpa->pfn > max_low_pfn_mapped && cpa->pfn < (1UL<<(32-PAGE_SHIFT)))
+                return 0;
+#endif
         /*
          * No need to redo, when the primary call touched the direct
          * mapping already:
          */
-        if (!within(cpa->vaddr, PAGE_OFFSET,
-                    PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))) {
+        if (!(within(cpa->vaddr, PAGE_OFFSET,
+                    PAGE_OFFSET + (max_low_pfn_mapped << PAGE_SHIFT))
+#ifdef CONFIG_X86_64
+                || within(cpa->vaddr, PAGE_OFFSET + (1UL<<32),
+                    PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))
+#endif
+        )) {
 
                 alias_cpa = *cpa;
                 alias_cpa.vaddr = (unsigned long) __va(cpa->pfn << PAGE_SHIFT);