diff --git a/ChangeLog b/ChangeLog
index 3f9c5a8cd..7292b1d3f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-10-16  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/kern/efi/mm.c (BYTES_TO_PAGES): Round up instead of down.
+	(grub_efi_mm_init): Take into account the memory map size increase.
+
 2010-10-16  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/term/ns8250.c (do_real_config): Set port->broken to 0.
diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index c845d7df1..6205abf9b 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -25,7 +25,7 @@
 #define NEXT_MEMORY_DESCRIPTOR(desc, size)	\
   ((grub_efi_memory_descriptor_t *) ((char *) (desc) + (size)))
 
-#define BYTES_TO_PAGES(bytes)	((bytes) >> 12)
+#define BYTES_TO_PAGES(bytes)	(((bytes) + 0xfff) >> 12)
 #define PAGES_TO_BYTES(pages)	((pages) << 12)
 
 /* The size of a memory map obtained from the firmware. This must be
@@ -447,6 +447,9 @@ grub_efi_mm_init (void)
 	((grub_efi_physical_address_t) ((grub_addr_t) memory_map),
 	 2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE));
 
+      /* Freeing/allocating operations may increase memory map size.  */
+      map_size += desc_size * 32;
+
       memory_map = grub_efi_allocate_pages (0, 2 * BYTES_TO_PAGES (map_size));
       if (! memory_map)
 	grub_fatal ("cannot allocate memory");