diff --git a/kernel/common/sys/types.h b/kernel/common/sys/types.h
index 5efae368..ca5c338c 100644
--- a/kernel/common/sys/types.h
+++ b/kernel/common/sys/types.h
@@ -41,6 +41,8 @@ typedef uint64_t fsfilcnt_t;
 #define __socklen_t uint32_t
 typedef __socklen_t socklen_t;
 
+#define pgoff_t unsigned long
+
 struct utimbuf
 {
     time_t actime;
diff --git a/kernel/mm/mm-types.h b/kernel/mm/mm-types.h
index ab76a9cf..96891944 100644
--- a/kernel/mm/mm-types.h
+++ b/kernel/mm/mm-types.h
@@ -131,6 +131,7 @@ struct vm_area_struct
 
     struct vm_operations_t *vm_ops; // 操作方法
     atomic_t ref_count;             // 引用计数
+    pgoff_t page_offset;    // 起始地址在当前VMA所占的2M物理页中的偏移量
     void *private_data;
 };
 
diff --git a/kernel/mm/mmap.c b/kernel/mm/mmap.c
index db33f9f5..64fa0f30 100644
--- a/kernel/mm/mmap.c
+++ b/kernel/mm/mmap.c
@@ -400,7 +400,8 @@ int mm_map_vma(struct vm_area_struct *vma, uint64_t paddr)
         if (unlikely(retval != 0))
             goto failed;
     }
-
+    // 计算当前vma的起始地址在对应的物理页中的偏移量
+    vma->page_offset = paddr - (paddr & PAGE_2M_MASK);
     flush_tlb();
     return 0;
 failed:;