mtrr, x86: fix MTRR lookup to handle inclusive entry

[karo-tx-linux.git] / arch / x86 / kernel / cpu / mtrr / generic.c

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 7d74f7b3c6ba49ee5f3ef9baa93e9eb03a906992..a82e370493738fab1db0cd1ea90abfb3c09e6412 100644 (file)
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -154,7 +154,7 @@ static u8 __mtrr_type_lookup(u64 start, u64 end, u64 *partial_end, int *repeat)
 
        prev_match = 0xFF;
        for (i = 0; i < num_var_ranges; ++i) {
-               unsigned short start_state, end_state;
+               unsigned short start_state, end_state, inclusive;
 
                if (!(mtrr_state.var_ranges[i].mask_lo & (1 << 11)))
                        continue;
@@ -166,15 +166,16 @@ static u8 __mtrr_type_lookup(u64 start, u64 end, u64 *partial_end, int *repeat)
 
                start_state = ((start & mask) == (base & mask));
                end_state = ((end & mask) == (base & mask));
+               inclusive = ((start < base) && (end > base));
 
-               if (start_state != end_state) {
+               if ((start_state != end_state) || inclusive) {
                        /*
                         * We have start:end spanning across an MTRR.
-                        * We split the region into
-                        * either
-                        * (start:mtrr_end) (mtrr_end:end)
-                        * or
-                        * (start:mtrr_start) (mtrr_start:end)
+                        * We split the region into either
+                        * - start_state:1
+                        *     (start:mtrr_end) (mtrr_end:end)
+                        * - end_state:1 or inclusive:1
+                        *     (start:mtrr_start) (mtrr_start:end)
                         * depending on kind of overlap.
                         * Return the type for first region and a pointer to
                         * the start of second region so that caller will
@@ -195,7 +196,7 @@ static u8 __mtrr_type_lookup(u64 start, u64 end, u64 *partial_end, int *repeat)
                        *repeat = 1;
                }
 
-               if ((start & mask) != (base & mask))
+               if (!start_state)
                        continue;
 
                curr_match = mtrr_state.var_ranges[i].base_lo & 0xff;