diff --git a/kernel/mm/mm.cc b/kernel/mm/mm.cc
index d0d8ad8..ba15fec 100644
--- a/kernel/mm/mm.cc
+++ b/kernel/mm/mm.cc
@@ -134,6 +134,9 @@ void mm_bootstrap()
         mm_map(page_base, page_base - KERNEL_OFFSET, 0, 1);
     }
 
+    /* set the page directory base register */
+    set_cr3(&page_directory);
+
     mm_use_virtual_offset = false;
 }
 
diff --git a/kernel/mm/mm.h b/kernel/mm/mm.h
index 626111e..a7ef217 100644
--- a/kernel/mm/mm.h
+++ b/kernel/mm/mm.h
@@ -29,5 +29,8 @@ int mm_map(u32_t virtual_address, u32_t physical_address,
 
 u32_t mm_page_alloc();
 
+#define set_cr3(address) \
+    __asm__ __volatile__ ("movl %0, %%cr3" : : "r" (address));
+
 #endif