diff --git a/tools/libxl/libxl_aoutils.c b/tools/libxl/libxl_aoutils.c
index 593a5754e5..124582886d 100644
--- a/tools/libxl/libxl_aoutils.c
+++ b/tools/libxl/libxl_aoutils.c
@@ -121,10 +121,10 @@ void libxl__datacopier_kill(libxl__datacopier_state *dc)
 }
 
 static void datacopier_callback(libxl__egc *egc, libxl__datacopier_state *dc,
-                                int onwrite, int errnoval)
+                                int rc, int onwrite, int errnoval)
 {
     libxl__datacopier_kill(dc);
-    dc->callback(egc, dc, onwrite, errnoval);
+    dc->callback(egc, dc, rc, onwrite, errnoval);
 }
 
 static void datacopier_writable(libxl__egc *egc, libxl__ev_fd *ev,
@@ -142,14 +142,14 @@ static void datacopier_check_state(libxl__egc *egc, libxl__datacopier_state *dc)
             if (rc) {
                 LOG(ERROR, "unable to establish write event on %s"
                     " during copy of %s", dc->writewhat, dc->copywhat);
-                datacopier_callback(egc, dc, -1, 0);
+                datacopier_callback(egc, dc, ERROR_FAIL, -1, EIO);
                 return;
             }
         }
     } else if (!libxl__ev_fd_isregistered(&dc->toread) ||
                dc->bytes_to_read == 0) {
         /* we have had eof */
-        datacopier_callback(egc, dc, 0, 0);
+        datacopier_callback(egc, dc, 0, 0, 0);
         return;
     } else {
         /* nothing buffered, but still reading */
@@ -195,7 +195,7 @@ static int datacopier_pollhup_handled(libxl__egc *egc,
             onwrite ? dc->writewhat : dc->readwhat,
             dc->copywhat);
         libxl__datacopier_kill(dc);
-        dc->callback_pollhup(egc, dc, onwrite, -1);
+        dc->callback_pollhup(egc, dc, ERROR_FAIL, onwrite, -1);
         return 1;
     }
     return 0;
@@ -213,7 +213,7 @@ static void datacopier_readable(libxl__egc *egc, libxl__ev_fd *ev,
         LOG(ERROR,
             "unexpected poll event 0x%x (expected POLLIN and/or POLLHUP)"
             " on %s during copy of %s", revents, dc->readwhat, dc->copywhat);
-        datacopier_callback(egc, dc, -1, 0);
+        datacopier_callback(egc, dc, ERROR_FAIL, -1, EIO);
         return;
     }
     assert(revents & (POLLIN|POLLHUP));
@@ -245,20 +245,21 @@ static void datacopier_readable(libxl__egc *egc, libxl__ev_fd *ev,
         }
         if (r < 0) {
             if (errno == EINTR) continue;
+            assert(errno);
             if (errno == EWOULDBLOCK) {
                 if (revents & POLLHUP) {
                     LOG(ERROR,
                         "poll reported HUP but fd read gave EWOULDBLOCK"
                         " on %s during copy of %s",
                         dc->readwhat, dc->copywhat);
-                    datacopier_callback(egc, dc, -1, 0);
+                    datacopier_callback(egc, dc, ERROR_FAIL, -1, 0);
                     return;
                 }
                 break;
             }
             LOGE(ERROR, "error reading %s during copy of %s",
                  dc->readwhat, dc->copywhat);
-            datacopier_callback(egc, dc, 0, errno);
+            datacopier_callback(egc, dc, ERROR_FAIL, 0, errno);
             return;
         }
         if (r == 0) {
@@ -287,7 +288,7 @@ static void datacopier_readable(libxl__egc *egc, libxl__ev_fd *ev,
                 assert(ferror(dc->log));
                 assert(errno);
                 LOGE(ERROR, "error logging %s", dc->copywhat);
-                datacopier_callback(egc, dc, 0, errno);
+                datacopier_callback(egc, dc, ERROR_FAIL, 0, errno);
                 return;
             }
         }
@@ -315,7 +316,7 @@ static void datacopier_writable(libxl__egc *egc, libxl__ev_fd *ev,
     if (revents & ~POLLOUT) {
         LOG(ERROR, "unexpected poll event 0x%x (should be POLLOUT)"
             " on %s during copy of %s", revents, dc->writewhat, dc->copywhat);
-        datacopier_callback(egc, dc, -1, 0);
+        datacopier_callback(egc, dc, ERROR_FAIL, -1, EIO);
         return;
     }
     assert(revents & POLLOUT);
@@ -332,9 +333,10 @@ static void datacopier_writable(libxl__egc *egc, libxl__ev_fd *ev,
         if (r < 0) {
             if (errno == EINTR) continue;
             if (errno == EWOULDBLOCK) break;
+            assert(errno);
             LOGE(ERROR, "error writing to %s during copy of %s",
                  dc->writewhat, dc->copywhat);
-            datacopier_callback(egc, dc, 1, errno);
+            datacopier_callback(egc, dc, ERROR_FAIL, 1, errno);
             return;
         }
         assert(r > 0);
diff --git a/tools/libxl/libxl_bootloader.c b/tools/libxl/libxl_bootloader.c
index 6db958e098..95dde986f2 100644
--- a/tools/libxl/libxl_bootloader.c
+++ b/tools/libxl/libxl_bootloader.c
@@ -30,9 +30,9 @@
 
 static void bootloader_gotptys(libxl__egc *egc, libxl__openpty_state *op);
 static void bootloader_keystrokes_copyfail(libxl__egc *egc,
-       libxl__datacopier_state *dc, int onwrite, int errnoval);
+       libxl__datacopier_state *dc, int rc, int onwrite, int errnoval);
 static void bootloader_display_copyfail(libxl__egc *egc,
-       libxl__datacopier_state *dc, int onwrite, int errnoval);
+       libxl__datacopier_state *dc, int rc, int onwrite, int errnoval);
 static void bootloader_domaindeath(libxl__egc*, libxl__domaindeathcheck *dc,
                                    int rc);
 static void bootloader_finished(libxl__egc *egc, libxl__ev_child *child,
@@ -579,10 +579,10 @@ static void bootloader_gotptys(libxl__egc *egc, libxl__openpty_state *op)
 
 /* perhaps one of these will be called, but perhaps not */
 static void bootloader_copyfail(libxl__egc *egc, const char *which,
-        libxl__bootloader_state *bl, int ondisplay, int onwrite, int errnoval)
+        libxl__bootloader_state *bl, int ondisplay,
+        int rc, int onwrite, int errnoval)
 {
     STATE_AO_GC(bl->ao);
-    int rc = ERROR_FAIL;
 
     if (errnoval==-1) {
         /* POLLHUP */
@@ -593,22 +593,24 @@ static void bootloader_copyfail(libxl__egc *egc, const char *which,
             LOG(ERROR, "unexpected POLLHUP on %s", which);
         }
     }
-    if (!onwrite && !errnoval)
+    if (!rc) {
         LOG(ERROR, "unexpected eof copying %s", which);
+        rc = ERROR_FAIL;
+    }
 
     bootloader_stop(egc, bl, rc);
 }
 static void bootloader_keystrokes_copyfail(libxl__egc *egc,
-       libxl__datacopier_state *dc, int onwrite, int errnoval)
+       libxl__datacopier_state *dc, int rc, int onwrite, int errnoval)
 {
     libxl__bootloader_state *bl = CONTAINER_OF(dc, *bl, keystrokes);
-    bootloader_copyfail(egc, "bootloader input", bl, 0, onwrite, errnoval);
+    bootloader_copyfail(egc, "bootloader input", bl, 0, rc,onwrite,errnoval);
 }
 static void bootloader_display_copyfail(libxl__egc *egc,
-       libxl__datacopier_state *dc, int onwrite, int errnoval)
+       libxl__datacopier_state *dc, int rc, int onwrite, int errnoval)
 {
     libxl__bootloader_state *bl = CONTAINER_OF(dc, *bl, display);
-    bootloader_copyfail(egc, "bootloader output", bl, 1, onwrite, errnoval);
+    bootloader_copyfail(egc, "bootloader output", bl, 1, rc,onwrite,errnoval);
 }
 
 static void bootloader_domaindeath(libxl__egc *egc,
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index b081ef7af5..bdc04657fa 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -2158,7 +2158,7 @@ out:
 }
 
 static void save_device_model_datacopier_done(libxl__egc *egc,
-     libxl__datacopier_state *dc, int onwrite, int errnoval);
+     libxl__datacopier_state *dc, int rc, int onwrite, int errnoval);
 
 void libxl__domain_save_device_model(libxl__egc *egc,
                                      libxl__domain_suspend_state *dss,
@@ -2218,11 +2218,11 @@ void libxl__domain_save_device_model(libxl__egc *egc,
     return;
 
  out:
-    save_device_model_datacopier_done(egc, dc, -1, 0);
+    save_device_model_datacopier_done(egc, dc, rc, -1, EIO);
 }
 
 static void save_device_model_datacopier_done(libxl__egc *egc,
-     libxl__datacopier_state *dc, int onwrite, int errnoval)
+     libxl__datacopier_state *dc, int our_rc, int onwrite, int errnoval)
 {
     libxl__domain_suspend_state *dss =
         CONTAINER_OF(dc, *dss, save_dm_datacopier);
@@ -2230,14 +2230,10 @@ static void save_device_model_datacopier_done(libxl__egc *egc,
 
     /* Convenience aliases */
     const char *const filename = dss->dm_savefile;
-    int our_rc = 0;
     int rc;
 
     libxl__datacopier_kill(dc);
 
-    if (onwrite || errnoval)
-        our_rc = ERROR_FAIL;
-
     if (dc->readfd >= 0) {
         close(dc->readfd);
         dc->readfd = -1;
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index ad20168746..140725199b 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2620,17 +2620,21 @@ _hidden void libxl__device_disk_local_initiate_detach(libxl__egc *egc,
 typedef struct libxl__datacopier_state libxl__datacopier_state;
 typedef struct libxl__datacopier_buf libxl__datacopier_buf;
 
-/* onwrite==1 means failure happened when writing, logged, errnoval is valid
- * onwrite==0 means failure happened when reading
- *     errnoval==0 means we got eof and all data was written
- *     errnoval!=0 means we had a read error, logged
- * onwrite==-1 means some other internal failure, errnoval not valid, logged
- * If we get POLLHUP, we call callback_pollhup(..., onwrite, -1);
+/* onwrite==1 means problem happened when writing
+ *     rc==FAIL    errnoval >0    we had a write error, logged
+ * onwrite==0 means problem happened when reading
+ *     rc==0       errnoval==0    we got eof and all data was written
+ *     rc==FAIL    errnoval >0    we had a read error, logged
+ * onwrite==-1 means some other internal problem
+ *     rc==FAIL    errnoval==EIO  some other internal failure, logged
+ *     rc==ABORTED errnoval==0    abort requested, not logged
+ * If we get POLLHUP, we call callback_pollhup with
+ *     rc==FAIL    errnoval==-1   POLLHUP signalled
  * or if callback_pollhup==0 this is treated as eof (if POLLIN|POLLHUP
  * on the reading fd) or an internal failure (otherwise), as above.
  * In all cases copier is killed before calling this callback */
 typedef void libxl__datacopier_callback(libxl__egc *egc,
-     libxl__datacopier_state *dc, int onwrite, int errnoval);
+     libxl__datacopier_state *dc, int rc, int onwrite, int errnoval);
 
 struct libxl__datacopier_buf {
     /* private to datacopier */