x86: mtrr_cleanup hole size should be less than half of chunk_size, v2

v2: should check with half of range0 size instead of chunk_size

So don't have silly big hole.

in hpa's case we could auto detect instead of adding mtrr_chunk_size in
command line.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 43 insertions, 31 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index aff46b99ff01..bccf57f5b615 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -992,22 +992,17 @@ range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
         /* only cut back, when it is not the last */
         if (sizek) {
                 while (range0_basek + range0_sizek > (basek + sizek)) {
-                        range0_sizek -= chunk_sizek;
+                        if (range0_sizek >= chunk_sizek)
+                                range0_sizek -= chunk_sizek;
+                        else
+                                range0_sizek = 0;
+
                         if (!range0_sizek)
                                 break;
                 }
         }
 
-        if (range0_sizek) {
-                if (debug_print)
-                        printk(KERN_DEBUG "range0: %016lx - %016lx\n",
-                                range0_basek<<10,
-                                (range0_basek + range0_sizek)<<10);
-                state->reg = range_to_mtrr(state->reg, range0_basek,
-                                range0_sizek, MTRR_TYPE_WRBACK);
-
-        }
-
+second_try:
         range_basek = range0_basek + range0_sizek;
 
         /* one hole in the middle */
@@ -1015,33 +1010,50 @@ range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
                 second_sizek = range_basek - basek;
 
         if (range0_sizek > state->range_sizek) {
-                unsigned long hole_basek, hole_sizek;
 
                 /* one hole in middle or at end */
                 hole_sizek = range0_sizek - state->range_sizek - second_sizek;
-                if (hole_sizek) {
-                        hole_basek = range_basek - hole_sizek - second_sizek;
-                        if (debug_print)
-                                printk(KERN_DEBUG "hole: %016lx - %016lx\n",
-                                         hole_basek<<10,
-                                         (hole_basek + hole_sizek)<<10);
-                        state->reg = range_to_mtrr(state->reg, hole_basek,
-                                                   hole_sizek,
-                                                   MTRR_TYPE_UNCACHABLE);
+
+                /* hole size should be less than half of range0 size */
+                if (hole_sizek > (range0_sizek >> 1) &&
+                    range0_sizek >= chunk_sizek) {
+                        range0_sizek -= chunk_sizek;
+                        second_sizek = 0;
+                        hole_sizek = 0;
+
+                        goto second_try;
                 }
-        } else  {
+        }
+
+        if (range0_sizek) {
+                if (debug_print)
+                        printk(KERN_DEBUG "range0: %016lx - %016lx\n",
+                                range0_basek<<10,
+                                (range0_basek + range0_sizek)<<10);
+                state->reg = range_to_mtrr(state->reg, range0_basek,
+                                range0_sizek, MTRR_TYPE_WRBACK);
+        }
+
+        if (range0_sizek < state->range_sizek) {
                 /* need to handle left over */
                 range_sizek = state->range_sizek - range0_sizek;
 
-                if (range_sizek) {
-                        if (debug_print)
-                                printk(KERN_DEBUG "range: %016lx - %016lx\n",
-                                         range_basek<<10,
-                                         (range_basek + range_sizek)<<10);
-                        state->reg = range_to_mtrr(state->reg, range_basek,
-                                         range_sizek,
-                                         MTRR_TYPE_WRBACK);
-                }
+                if (debug_print)
+                        printk(KERN_DEBUG "range: %016lx - %016lx\n",
+                                 range_basek<<10,
+                                 (range_basek + range_sizek)<<10);
+                state->reg = range_to_mtrr(state->reg, range_basek,
+                                 range_sizek, MTRR_TYPE_WRBACK);
+        }
+
+        if (hole_sizek) {
+                hole_basek = range_basek - hole_sizek - second_sizek;
+                if (debug_print)
+                        printk(KERN_DEBUG "hole: %016lx - %016lx\n",
+                                 hole_basek<<10,
+                                 (hole_basek + hole_sizek)<<10);
+                state->reg = range_to_mtrr(state->reg, hole_basek,
+                                 hole_sizek, MTRR_TYPE_UNCACHABLE);
         }
 
         return second_sizek;