xen/m2p: Check whether the MFN has IDENTITY_FRAME bit set..

[platform/adaptation/renesas_rcar/renesas_kernel.git] / arch / x86 / include / asm / xen / page.h

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 1957070..c61934f 100644 (file)
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -81,6 +81,7 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn)
 static inline unsigned long mfn_to_pfn(unsigned long mfn)
 {
        unsigned long pfn;
+       int ret = 0;
 
        if (xen_feature(XENFEAT_auto_translated_physmap))
                return mfn;
@@ -95,15 +96,29 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
         * In such cases it doesn't matter what we return (we return garbage),
         * but we must handle the fault without crashing!
         */
-       __get_user(pfn, &machine_to_phys_mapping[mfn]);
+       ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
 try_override:
-       /*
-        * If this appears to be a foreign mfn (because the pfn
-        * doesn't map back to the mfn), then check the local override
-        * table to see if there's a better pfn to use.
+       /* ret might be < 0 if there are no entries in the m2p for mfn */
+       if (ret < 0)
+               pfn = ~0;
+       else if (get_phys_to_machine(pfn) != mfn)
+               /*
+                * If this appears to be a foreign mfn (because the pfn
+                * doesn't map back to the mfn), then check the local override
+                * table to see if there's a better pfn to use.
+                *
+                * m2p_find_override_pfn returns ~0 if it doesn't find anything.
+                */
+               pfn = m2p_find_override_pfn(mfn, ~0);
+
+       /* 
+        * pfn is ~0 if there are no entries in the m2p for mfn or if the
+        * entry doesn't map back to the mfn and m2p_override doesn't have a
+        * valid entry for it.
         */
-       if (get_phys_to_machine(pfn) != mfn)
-               pfn = m2p_find_override_pfn(mfn, pfn);
+       if (pfn == ~0 &&
+                       get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn))
+               pfn = mfn;
 
        return pfn;
 }