linux-kernel - [patch 0/1] remove existing enclosed mtrr region

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Date:	Thu, 9 Oct 2008 16:17:15 +0800
From:	"bibo mao" <bibo.mao@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	akpm@...ux-foundation.org
Subject: [patch 0/1] remove existing enclosed mtrr region

Hi,
 This patch is remove enclosed mtrr region when adding new region.

 Signed-off-by: bibo mao <bibo.mao@...il.com>

 thanks
 bibo,mao


 kernel/cpu/mtrr/main.c          |   35 +++++++++++++++++++++++++++++++----
 3 files changed, 31 insertions(+), 4 deletions(-)
---------------------------------------------------------------------------------------------------------------------

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 6a1e278..6e212f3 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -303,7 +303,7 @@ static void set_mtrr(unsigned int reg, unsigned long base,
 int mtrr_add_page(unsigned long base, unsigned long size,
 		  unsigned int type, bool increment)
 {
-	int i, replace, error;
+	int i, j, replace, error;
 	mtrr_type ltype;
 	unsigned long lbase, lsize;

@@ -351,7 +351,7 @@ int mtrr_add_page(unsigned long base, unsigned long size,
 			if (base <= lbase && base + size - 1 >= lbase + lsize - 1) {
 				/*  New region encloses an existing region  */
 				if (type == ltype) {
-					replace = replace == -1 ? i : -2;
+					replace = i;
 					continue;
 				}
 				else if (types_compatible(type, ltype))
@@ -391,6 +391,20 @@ int mtrr_add_page(unsigned long base, unsigned long size,
 				set_mtrr(replace, 0, 0, 0);
 				mtrr_usage_table[replace] = 0;
 			}
+
+			/* remove existing enclosed region */
+			for (j = 0; j < num_var_ranges; ++j) {
+				if (i == j)
+					continue;
+				mtrr_if->get(j, &lbase, &lsize, &ltype);
+				if (lsize && type == ltype && base <= lbase
+					 && base + size - 1 >= lbase + lsize - 1) {
+					/*  New region encloses an existing region  */
+					mtrr_usage_table[i] += mtrr_usage_table[j];
+					set_mtrr(j, 0, 0, 0);
+					mtrr_usage_table[j]=0;
+				}	
+			}
 		}
 	} else
 		printk(KERN_INFO "mtrr: no more MTRRs available\n");
--
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