diff --git a/u2mfn/u2mfnlib.c b/u2mfn/u2mfnlib.c
index 998f47e9..dff06e43 100644
--- a/u2mfn/u2mfnlib.c
+++ b/u2mfn/u2mfnlib.c
@@ -31,11 +31,24 @@ static int u2mfn_fd = -1;
 
 static int get_fd()
 {
-	if (u2mfn_fd == -1) {
-		u2mfn_fd = open("/proc/u2mfn", O_RDWR);
-		if (u2mfn_fd < 0)
-			return -1;
-	}
+	if (u2mfn_fd == -1)
+		u2mfn_fd = u2mfn_get_fd();
+	if (u2mfn_fd < 0)
+		return -1;
+	return 0;
+}
+
+int u2mfn_get_fd()
+{
+	return open("/proc/u2mfn", O_RDWR);
+}
+
+int u2mfn_get_mfn_for_page_with_fd(int fd, long va, int *mfn)
+{
+	*mfn = ioctl(fd, U2MFN_GET_MFN_FOR_PAGE, va);
+	if (*mfn == -1)
+		return -1;
+
 	return 0;
 }
 
@@ -43,7 +56,12 @@ int u2mfn_get_mfn_for_page(long va, int *mfn)
 {
 	if (get_fd())
 		return -1;
-	*mfn = ioctl(u2mfn_fd, U2MFN_GET_MFN_FOR_PAGE, va);
+	return u2mfn_get_mfn_for_page_with_fd(u2mfn_fd, va, mfn);
+}
+
+int u2mfn_get_last_mfn_with_fd(int fd, int *mfn)
+{
+	*mfn = ioctl(fd, U2MFN_GET_LAST_MFN, 0);
 	if (*mfn == -1)
 		return -1;
 
@@ -54,22 +72,20 @@ int u2mfn_get_last_mfn(int *mfn)
 {
 	if (get_fd())
 		return -1;
-
-	*mfn = ioctl(u2mfn_fd, U2MFN_GET_LAST_MFN, 0);
-	if (*mfn == -1)
-		return -1;
-
-	return 0;
+	return u2mfn_get_last_mfn_with_fd(u2mfn_fd, mfn);
 }
 
-
+char *u2mfn_alloc_kpage_with_fd(int fd)
+{
+	char *ret;
+	ret =
+	    mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	return ret;
+}
 
 char *u2mfn_alloc_kpage()
 {
-	char *ret;
 	if (get_fd())
 		return MAP_FAILED;
-	ret =
-	    mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, u2mfn_fd, 0);
-	return ret;
+	return u2mfn_alloc_kpage_with_fd(u2mfn_fd);
 }
diff --git a/u2mfn/u2mfnlib.h b/u2mfn/u2mfnlib.h
index e64431af..a7c20972 100644
--- a/u2mfn/u2mfnlib.h
+++ b/u2mfn/u2mfnlib.h
@@ -19,6 +19,10 @@
  *
  */
 
+int u2mfn_get_fd();
 int u2mfn_get_mfn_for_page(long va, int *mfn) ;
+int u2mfn_get_mfn_for_page_with_fd(int fd, long va, int *mfn) ;
 int u2mfn_get_last_mfn(int *mfn) ;
-char *u2mfn_alloc_kpage(void) ;
+int u2mfn_get_last_mfn_with_fd(int fd, int *mfn) ;
+char *u2mfn_alloc_kpage(void);
+char *u2mfn_alloc_kpage_with_fd(int fd);