diff --git a/arch/i386/kernel/cpu/mtrr/generic.c b/arch/i386/kernel/cpu/mtrr/generic.c
index 0b61eed8bbd819cb3f4d71a59feec3376acec5c6..ee8dc6753953ea20d7e675be55274214c9e6ed26 100644
--- a/arch/i386/kernel/cpu/mtrr/generic.c
+++ b/arch/i386/kernel/cpu/mtrr/generic.c
@@ -366,7 +366,7 @@ int generic_validate_add_page(unsigned long base, unsigned long size, unsigned i
 			printk(KERN_WARNING "mtrr: base(0x%lx000) is not 4 MiB aligned\n", base);
 			return -EINVAL;
 		}
-		if (!(base + size < 0x70000000 || base > 0x7003FFFF) &&
+		if (!(base + size < 0x70000 || base > 0x7003F) &&
 		    (type == MTRR_TYPE_WRCOMB
 		     || type == MTRR_TYPE_WRBACK)) {
 			printk(KERN_WARNING "mtrr: writable mtrr between 0x70000000 and 0x7003FFFF may hang the CPU.\n");
@@ -374,7 +374,7 @@ int generic_validate_add_page(unsigned long base, unsigned long size, unsigned i
 		}
 	}
 
-	if (base + size < 0x100) {
+	if (base < 0x100) {
 		printk(KERN_WARNING "mtrr: cannot set region below 1 MiB (0x%lx000,0x%lx000)\n",
 		       base, size);
 		return -EINVAL;
diff --git a/arch/i386/kernel/cpu/mtrr/main.c b/arch/i386/kernel/cpu/mtrr/main.c
index fff90bda473323a7fd0364d6db35475bbb862cd8..2b8b0b361ccb410564aae2c5a9340a708abf2da7 100644
--- a/arch/i386/kernel/cpu/mtrr/main.c
+++ b/arch/i386/kernel/cpu/mtrr/main.c
@@ -263,8 +263,8 @@ static void set_mtrr(unsigned int reg, unsigned long base,
 
 /**
  *	mtrr_add_page - Add a memory type region
- *	@base: Physical base address of region in pages (4 KB)
- *	@size: Physical size of region in pages (4 KB)
+ *	@base: Physical base address of region in pages (in units of 4 kB!)
+ *	@size: Physical size of region in pages (4 kB)
  *	@type: Type of MTRR desired
  *	@increment: If this is true do usage counting on the region
  *