2 files changed, 12 insertions, 3 deletions

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 3cc06e3fceb8..16748077559a 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -2,6 +2,7 @@
 #define _ASM_X86_PGTABLE_H
 
 #include <asm/page.h>
+#include <asm/e820.h>
 
 #include <asm/pgtable_types.h>
 
@@ -269,10 +270,17 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 
 #define canon_pgprot(p) __pgprot(massage_pgprot(p))
 
-static inline int is_new_memtype_allowed(unsigned long flags,
-                                                unsigned long new_flags)
+static inline int is_new_memtype_allowed(u64 paddr, unsigned long size,
+                                         unsigned long flags,
+                                         unsigned long new_flags)
 {
         /*
+         * PAT type is always WB for ISA. So no need to check.
+         */
+        if (is_ISA_range(paddr, paddr + size - 1))
+                return 1;
+
+        /*
          * Certain new memtypes are not allowed with certain
          * requested memtype:
          * - request is uncached, return cannot be write-back
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index e6718bb28065..352aa9e927e2 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -623,7 +623,8 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
                 return ret;
 
         if (flags != want_flags) {
-                if (strict_prot || !is_new_memtype_allowed(want_flags, flags)) {
+                if (strict_prot ||
+                    !is_new_memtype_allowed(paddr, size, want_flags, flags)) {
                         free_memtype(paddr, paddr + size);
                         printk(KERN_ERR "%s:%d map pfn expected mapping type %s"
                                 " for %Lx-%Lx, got %s\n",