diff --git a/tools/libxc/include/xenguest.h b/tools/libxc/include/xenguest.h
index 4f0b06e..b4f4bfb 100644
--- a/tools/libxc/include/xenguest.h
+++ b/tools/libxc/include/xenguest.h
@@ -93,7 +93,7 @@ typedef enum {
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iters,
                    uint32_t max_factor, uint32_t flags /* XCFLAGS_xxx */,
                    struct save_callbacks* callbacks, int hvm,
-                   xc_migration_stream_t stream_type);
+                   xc_migration_stream_t stream_type, int recv_fd);
 
 /* callbacks provided by xc_domain_restore */
 struct restore_callbacks {
@@ -132,7 +132,7 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                       unsigned long *console_mfn, domid_t console_domid,
                       unsigned int hvm, unsigned int pae, int superpages,
                       xc_migration_stream_t stream_type,
-                      struct restore_callbacks *callbacks);
+                      struct restore_callbacks *callbacks, int send_back_fd);
 
 /**
  * This function will create a domain for a paravirtualized Linux
diff --git a/tools/libxc/xc_nomigrate.c b/tools/libxc/xc_nomigrate.c
index 08e1f8c..15c838f 100644
--- a/tools/libxc/xc_nomigrate.c
+++ b/tools/libxc/xc_nomigrate.c
@@ -23,7 +23,7 @@
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iters,
                    uint32_t max_factor, uint32_t flags,
                    struct save_callbacks* callbacks, int hvm,
-                   xc_migration_stream_t stream_type)
+                   xc_migration_stream_t stream_type, int recv_fd)
 {
     errno = ENOSYS;
     return -1;
@@ -35,7 +35,7 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                       unsigned long *console_mfn, domid_t console_domid,
                       unsigned int hvm, unsigned int pae, int superpages,
                       xc_migration_stream_t stream_type,
-                      struct restore_callbacks *callbacks)
+                      struct restore_callbacks *callbacks, int send_back_fd)
 {
     errno = ENOSYS;
     return -1;
diff --git a/tools/libxc/xc_sr_restore.c b/tools/libxc/xc_sr_restore.c
index 819401d..2b9a0ea 100644
--- a/tools/libxc/xc_sr_restore.c
+++ b/tools/libxc/xc_sr_restore.c
@@ -726,7 +726,7 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                       unsigned long *console_gfn, domid_t console_domid,
                       unsigned int hvm, unsigned int pae, int superpages,
                       xc_migration_stream_t stream_type,
-                      struct restore_callbacks *callbacks)
+                      struct restore_callbacks *callbacks, int send_back_fd)
 {
     struct xc_sr_context ctx =
         {
diff --git a/tools/libxc/xc_sr_save.c b/tools/libxc/xc_sr_save.c
index 388ae7f..1ccdbbb 100644
--- a/tools/libxc/xc_sr_save.c
+++ b/tools/libxc/xc_sr_save.c
@@ -830,7 +830,7 @@ static int save(struct xc_sr_context *ctx, uint16_t guest_type)
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom,
                    uint32_t max_iters, uint32_t max_factor, uint32_t flags,
                    struct save_callbacks* callbacks, int hvm,
-                   xc_migration_stream_t stream_type)
+                   xc_migration_stream_t stream_type, int recv_fd)
 {
     struct xc_sr_context ctx =
         {
diff --git a/tools/libxl/libxl_save_callout.c b/tools/libxl/libxl_save_callout.c
index 06967df..f15c235 100644
--- a/tools/libxl/libxl_save_callout.c
+++ b/tools/libxl/libxl_save_callout.c
@@ -27,7 +27,7 @@
  */
 static void run_helper(libxl__egc *egc, libxl__save_helper_state *shs,
                        const char *mode_arg,
-                       int stream_fd,
+                       int stream_fd, int back_channel_fd,
                        const int *preserve_fds, int num_preserve_fds,
                        const unsigned long *argnums, int num_argnums);
 
@@ -50,6 +50,7 @@ void libxl__xc_domain_restore(libxl__egc *egc, libxl__domain_create_state *dcs,
     /* Convenience aliases */
     const uint32_t domid = dcs->guest_domid;
     const int restore_fd = dcs->libxc_fd;
+    const int send_back_fd = dcs->send_back_fd;
     libxl__domain_build_state *const state = &dcs->build_state;
 
     unsigned cbflags =
@@ -71,7 +72,7 @@ void libxl__xc_domain_restore(libxl__egc *egc, libxl__domain_create_state *dcs,
     shs->caller_state = dcs;
     shs->need_results = 1;
 
-    run_helper(egc, shs, "--restore-domain", restore_fd, 0, 0,
+    run_helper(egc, shs, "--restore-domain", restore_fd, send_back_fd, 0, 0,
                argnums, ARRAY_SIZE(argnums));
 }
 
@@ -95,7 +96,7 @@ void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_save_state *dss,
     shs->caller_state = dss;
     shs->need_results = 0;
 
-    run_helper(egc, shs, "--save-domain", dss->fd,
+    run_helper(egc, shs, "--save-domain", dss->fd, dss->recv_fd,
                NULL, 0,
                argnums, ARRAY_SIZE(argnums));
     return;
@@ -141,12 +142,14 @@ static int dup_cloexec(libxl__gc *gc, int fd, const char *what)
  * 1) Path to libxl-save-helper.
  * 2) --[restore|save]-domain.
  * 3) stream file descriptor.
+ * 4) back channel file descriptor.
  * n) save/restore specific parameters.
- * 4) A \0 at the end.
+ * 5) A \0 at the end.
  */
-#define HELPER_NR_ARGS 4
+#define HELPER_NR_ARGS 5
 static void run_helper(libxl__egc *egc, libxl__save_helper_state *shs,
-                       const char *mode_arg, int stream_fd,
+                       const char *mode_arg,
+                       int stream_fd, int back_channel_fd,
                        const int *preserve_fds, int num_preserve_fds,
                        const unsigned long *argnums, int num_argnums)
 {
@@ -179,6 +182,7 @@ static void run_helper(libxl__egc *egc, libxl__save_helper_state *shs,
     *arg++ = getenv("LIBXL_SAVE_HELPER") ?: LIBEXEC_BIN "/" "libxl-save-helper";
     *arg++ = mode_arg;
     const char **stream_fd_arg = arg++;
+    const char **back_channel_fd_arg = arg++;
     for (i=0; i<num_argnums; i++)
         *arg++ = GCSPRINTF("%lu", argnums[i]);
     *arg++ = 0;
@@ -206,6 +210,11 @@ static void run_helper(libxl__egc *egc, libxl__save_helper_state *shs,
         stream_fd = dup_cloexec(gc, stream_fd, "migration stream fd");
         *stream_fd_arg = GCSPRINTF("%d", stream_fd);
 
+        if (back_channel_fd >= 0)
+            back_channel_fd = dup_cloexec(gc, back_channel_fd,
+                                          "migration back channel fd");
+        *back_channel_fd_arg = GCSPRINTF("%d", back_channel_fd);
+
         for (i=0; i<num_preserve_fds; i++)
             if (preserve_fds[i] >= 0) {
                 assert(preserve_fds[i] > 2);
diff --git a/tools/libxl/libxl_save_helper.c b/tools/libxl/libxl_save_helper.c
index 0fd7022..5fe642a 100644
--- a/tools/libxl/libxl_save_helper.c
+++ b/tools/libxl/libxl_save_helper.c
@@ -238,6 +238,7 @@ static struct restore_callbacks helper_restore_callbacks;
 int main(int argc, char **argv)
 {
     int r;
+    int send_back_fd, recv_fd;
 
 #define NEXTARG (++argv, assert(*argv), *argv)
 
@@ -247,6 +248,7 @@ int main(int argc, char **argv)
     if (!strcmp(mode,"--save-domain")) {
 
         io_fd =                             atoi(NEXTARG);
+        recv_fd =                           atoi(NEXTARG);
         uint32_t dom =                      strtoul(NEXTARG,0,10);
         uint32_t max_iters =                strtoul(NEXTARG,0,10);
         uint32_t max_factor =               strtoul(NEXTARG,0,10);
@@ -262,12 +264,14 @@ int main(int argc, char **argv)
         setup_signals(save_signal_handler);
 
         r = xc_domain_save(xch, io_fd, dom, max_iters, max_factor, flags,
-                           &helper_save_callbacks, hvm, stream_type);
+                           &helper_save_callbacks, hvm, stream_type,
+                           recv_fd);
         complete(r);
 
     } else if (!strcmp(mode,"--restore-domain")) {
 
         io_fd =                             atoi(NEXTARG);
+        send_back_fd =                      atoi(NEXTARG);
         uint32_t dom =                      strtoul(NEXTARG,0,10);
         unsigned store_evtchn =             strtoul(NEXTARG,0,10);
         domid_t store_domid =               strtoul(NEXTARG,0,10);
@@ -292,7 +296,7 @@ int main(int argc, char **argv)
                               store_domid, console_evtchn, &console_mfn,
                               console_domid, hvm, pae, superpages,
                               stream_type,
-                              &helper_restore_callbacks);
+                              &helper_restore_callbacks, send_back_fd);
         helper_stub_restore_results(store_mfn,console_mfn,0);
         complete(r);
 
