diff --git a/hmp-commands.hx b/hmp-commands.hx
index 3c647f7..38e5c95 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -798,26 +798,31 @@ ETEXI
 
     {
         .name       = "migrate",
-        .args_type  = "detach:-d,blk:-b,inc:-i,postcopy:-p,nobg:-n,uri:s",
-        .params     = "[-d] [-b] [-i] [-p [-n]] uri",
+        .args_type  = "detach:-d,blk:-b,inc:-i,postcopy:-p,nobg:-n,uri:s,"
+	              "forward:i?,backward:i?",
+        .params     = "[-d] [-b] [-i] [-p [-n] uri [forward] [backword]",
         .help       = "migrate to URI (using -d to not wait for completion)"
 		      "\n\t\t\t -b for migration without shared storage with"
 		      " full copy of disk\n\t\t\t -i for migration without "
 		      "shared storage with incremental copy of disk "
 		      "(base image shared between src and destination)"
 		      "\n\t\t\t-p for migration with postcopy mode enabled"
-		      "\n\t\t\t-n for no background transfer of postcopy mode",
+		      "\n\t\t\t-n for no background transfer of postcopy mode"
+		      "\n\t\t\tforward: the number of pages to "
+		      "forward-prefault when postcopy (default 0)"
+		      "\n\t\t\tbackward: the number of pages to "
+		      "backward-prefault when postcopy (default 0)",
         .mhandler.cmd = hmp_migrate,
     },
 
 
 STEXI
-@item migrate [-d] [-b] [-i] [-p [-n]] @var{uri}
+@item migrate [-d] [-b] [-i] [-p [-n]] @var{uri} @var{forward} @var{backward}
 @findex migrate
 Migrate to @var{uri} (using -d to not wait for completion).
 	-b for migration with full copy of disk
 	-i for migration with incremental copy of disk (base image is shared)
-	-p for migration with postcopy mode enabled
+	-p for migration with postcopy mode enabled (forward/backward is prefault size when postcopy)
 	-n for migration with postcopy mode enabled without background transfer
 ETEXI
 
diff --git a/hmp.c b/hmp.c
index d546a52..79a9c86 100644
--- a/hmp.c
+++ b/hmp.c
@@ -913,11 +913,14 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
     int inc = qdict_get_try_bool(qdict, "inc", 0);
     int postcopy = qdict_get_try_bool(qdict, "postcopy", 0);
     int nobg = qdict_get_try_bool(qdict, "nobg", 0);
+    int forward = qdict_get_try_int(qdict, "forward", 0);
+    int backward = qdict_get_try_int(qdict, "backward", 0);
     const char *uri = qdict_get_str(qdict, "uri");
     Error *err = NULL;
 
     qmp_migrate(uri, !!blk, blk, !!inc, inc, false, false,
                 !!postcopy, postcopy, !!nobg, nobg,
+                !!forward, forward, !!backward, backward,
                 &err);
     if (err) {
         monitor_printf(mon, "migrate: %s\n", error_get_pretty(err));
diff --git a/migration.c b/migration.c
index e8be0d1..e026085 100644
--- a/migration.c
+++ b/migration.c
@@ -423,6 +423,8 @@ void migrate_del_blocker(Error *reason)
 void qmp_migrate(const char *uri, bool has_blk, bool blk,
                  bool has_inc, bool inc, bool has_detach, bool detach,
                  bool has_postcopy, bool postcopy, bool has_nobg, bool nobg,
+                 bool has_forward, int64_t forward,
+                 bool has_backward, int64_t backward,
                  Error **errp)
 {
     MigrationState *s = migrate_get_current();
@@ -431,6 +433,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
         .shared = false,
         .postcopy = false,
         .nobg = false,
+        .prefault_forward = 0,
+        .prefault_backward = 0,
     };
     const char *p;
     int ret;
@@ -447,6 +451,22 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
     if (has_nobg) {
         params.nobg = nobg;
     }
+    if (has_forward) {
+        if (forward < 0) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE,
+                      "forward", "forward >= 0");
+            return;
+        }
+        params.prefault_forward = forward;
+    }
+    if (has_backward) {
+        if (backward < 0) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE,
+                      "backward", "backward >= 0");
+            return;
+        }
+        params.prefault_backward = backward;
+    }
 
     if (s->state == MIG_STATE_ACTIVE) {
         error_set(errp, QERR_MIGRATION_ACTIVE);
diff --git a/migration.h b/migration.h
index 90f3bdf..9a9b9c6 100644
--- a/migration.h
+++ b/migration.h
@@ -24,6 +24,8 @@ struct MigrationParams {
     int shared;
     int postcopy;
     int nobg;
+    int64_t prefault_forward;
+    int64_t prefault_backward;
 };
 
 typedef struct MigrationState MigrationState;
diff --git a/qapi-schema.json b/qapi-schema.json
index 5861fb9..83c2170 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1718,7 +1718,8 @@
 ##
 { 'command': 'migrate',
   'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool', '*detach': 'bool' ,
-           '*postcopy': 'bool', '*nobg': 'bool'} }
+           '*postcopy': 'bool', '*nobg': 'bool',
+           '*forward': 'int', '*backward': 'int'} }
 
 # @xen-save-devices-state:
 #
