diff --git a/generator/actions.ml b/generator/actions.ml
index fdb35920f..37cd227e2 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -1290,7 +1290,7 @@ not all belong to a single logical operating system
 
   { defaults with
     name = "add_drive";
-    style = RErr, [String "filename"], [OBool "readonly"; OString "format"; OString "iface"; OString "name"; OString "label"; OString "protocol"; OStringList "server"; OString "username"; OString "secret"; OString "cachemode"; OString "discard"];
+    style = RErr, [String "filename"], [OBool "readonly"; OString "format"; OString "iface"; OString "name"; OString "label"; OString "protocol"; OStringList "server"; OString "username"; OString "secret"; OString "cachemode"; OString "discard"; OBool "copyonread"];
     once_had_no_optargs = true;
     blocking = false;
     fish_alias = ["add"];
@@ -1538,6 +1538,15 @@ possible, but don't mind if it doesn't work.
 
 =back
 
+=item C<copyonread>
+
+The boolean parameter C<copyonread> enables copy-on-read support.
+This only affects disk formats which have backing files, and causes
+reads to be stored in the overlay layer, speeding up multiple reads
+of the same area of disk.
+
+The default is false.
+
 =back" };
 
   { defaults with
@@ -1580,7 +1589,7 @@ not part of the formal API and can be removed or changed at any time." };
 
   { defaults with
     name = "add_domain";
-    style = RInt "nrdisks", [String "dom"], [OString "libvirturi"; OBool "readonly"; OString "iface"; OBool "live"; OBool "allowuuid"; OString "readonlydisk"; OString "cachemode"; OString "discard"];
+    style = RInt "nrdisks", [String "dom"], [OString "libvirturi"; OBool "readonly"; OString "iface"; OBool "live"; OBool "allowuuid"; OString "readonlydisk"; OString "cachemode"; OString "discard"; OBool "copyonread"];
     fish_alias = ["domain"]; config_only = true;
     shortdesc = "add the disk(s) from a named libvirt domain";
     longdesc = "\
@@ -1672,7 +1681,7 @@ C<guestfs_add_drive_opts>." };
 This interface is not quite baked yet. -- RWMJ 2010-11-11
   { defaults with
     name = "add_libvirt_dom";
-    style = RInt "nrdisks", [Pointer ("virDomainPtr", "dom")], [Bool "readonly"; String "iface"; Bool "live"; String "readonlydisk"; OString "cachemode"; OString "discard"];
+    style = RInt "nrdisks", [Pointer ("virDomainPtr", "dom")], [Bool "readonly"; String "iface"; Bool "live"; String "readonlydisk"; OString "cachemode"; OString "discard"; OBool "copyonread"];
     in_fish = false;
     shortdesc = "add the disk(s) from a libvirt domain";
     longdesc = "\
diff --git a/src/drives.c b/src/drives.c
index b92599657..307f267f9 100644
--- a/src/drives.c
+++ b/src/drives.c
@@ -62,6 +62,7 @@ struct drive_create_data {
   const char *disk_label;
   const char *cachemode;
   enum discard discard;
+  bool copyonread;
 };
 
 /* Compile all the regular expressions once when the shared library is
@@ -146,6 +147,7 @@ create_drive_file (guestfs_h *g,
   drv->disk_label = data->disk_label ? safe_strdup (g, data->disk_label) : NULL;
   drv->cachemode = data->cachemode ? safe_strdup (g, data->cachemode) : NULL;
   drv->discard = data->discard;
+  drv->copyonread = data->copyonread;
 
   if (data->readonly) {
     if (create_overlay (g, drv) == -1) {
@@ -181,6 +183,7 @@ create_drive_non_file (guestfs_h *g,
   drv->disk_label = data->disk_label ? safe_strdup (g, data->disk_label) : NULL;
   drv->cachemode = data->cachemode ? safe_strdup (g, data->cachemode) : NULL;
   drv->discard = data->discard;
+  drv->copyonread = data->copyonread;
 
   if (data->readonly) {
     if (create_overlay (g, drv) == -1) {
@@ -467,6 +470,7 @@ create_drive_dev_null (guestfs_h *g,
 
   data->exportname = tmpfile;
   data->discard = discard_disable;
+  data->copyonread = false;
 
   return create_drive_file (g, data);
 }
@@ -532,7 +536,7 @@ static char *
 drive_to_string (guestfs_h *g, const struct drive *drv)
 {
   return safe_asprintf
-    (g, "%s%s%s%s protocol=%s%s%s%s%s%s%s%s%s%s",
+    (g, "%s%s%s%s protocol=%s%s%s%s%s%s%s%s%s%s%s",
      drv->src.u.path,
      drv->readonly ? " readonly" : "",
      drv->src.format ? " format=" : "",
@@ -547,7 +551,8 @@ drive_to_string (guestfs_h *g, const struct drive *drv)
      drv->cachemode ? " cache=" : "",
      drv->cachemode ? : "",
      drv->discard == discard_disable ? "" :
-     drv->discard == discard_enable ? " discard=enable" : " discard=besteffort");
+     drv->discard == discard_enable ? " discard=enable" : " discard=besteffort",
+     drv->copyonread ? " copyonread" : "");
 }
 
 /* Add struct drive to the g->drives vector at the given index. */
@@ -814,6 +819,10 @@ guestfs__add_drive_opts (guestfs_h *g, const char *filename,
   else
     data.discard = discard_disable;
 
+  data.copyonread =
+    optargs->bitmask & GUESTFS_ADD_DRIVE_OPTS_COPYONREAD_BITMASK
+    ? optargs->copyonread : false;
+
   if (data.readonly && data.discard == discard_enable) {
     error (g, _("discard support cannot be enabled on read-only drives"));
     free_drive_servers (data.servers, data.nr_servers);
diff --git a/src/guestfs-internal-frontend.h b/src/guestfs-internal-frontend.h
index 20331c8e6..5c5d957d8 100644
--- a/src/guestfs-internal-frontend.h
+++ b/src/guestfs-internal-frontend.h
@@ -152,6 +152,8 @@ struct guestfs___add_libvirt_dom_argv {
   const char *cachemode;
 #define GUESTFS___ADD_LIBVIRT_DOM_DISCARD_BITMASK (UINT64_C(1)<<5)
   const char *discard;
+#define GUESTFS___ADD_LIBVIRT_DOM_COPYONREAD_BITMASK (UINT64_C(1)<<6)
+  int copyonread;
 };
 
 extern GUESTFS_DLL_PUBLIC int guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom, const struct guestfs___add_libvirt_dom_argv *optargs);
diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h
index 2e9a1d15e..69ea2dc36 100644
--- a/src/guestfs-internal.h
+++ b/src/guestfs-internal.h
@@ -262,6 +262,7 @@ struct drive {
   char *disk_label;
   char *cachemode;
   enum discard discard;
+  bool copyonread;
 };
 
 /* Extra hv parameters (from guestfs_config). */
diff --git a/src/launch-direct.c b/src/launch-direct.c
index 3a8f2b2ab..5301176a0 100644
--- a/src/launch-direct.c
+++ b/src/launch-direct.c
@@ -528,7 +528,7 @@ launch_direct (guestfs_h *g, void *datav, const char *arg)
        * the if=... at the end.
        */
       param = safe_asprintf
-        (g, "file=%s%s,cache=%s%s%s%s%s%s,id=hd%zu",
+        (g, "file=%s%s,cache=%s%s%s%s%s%s%s,id=hd%zu",
          escaped_file,
          drv->readonly ? ",snapshot=on" : "",
          drv->cachemode ? drv->cachemode : "writeback",
@@ -537,6 +537,7 @@ launch_direct (guestfs_h *g, void *datav, const char *arg)
          drv->src.format ? drv->src.format : "",
          drv->disk_label ? ",serial=" : "",
          drv->disk_label ? drv->disk_label : "",
+         drv->copyonread ? ",copy-on-read=on" : "",
          i);
     }
     else {
diff --git a/src/launch-libvirt.c b/src/launch-libvirt.c
index f86ff74f5..9bce91fd6 100644
--- a/src/launch-libvirt.c
+++ b/src/launch-libvirt.c
@@ -817,7 +817,7 @@ static int construct_libvirt_xml_devices (guestfs_h *g, const struct libvirt_xml
 static int construct_libvirt_xml_qemu_cmdline (guestfs_h *g, const struct libvirt_xml_params *params, xmlTextWriterPtr xo);
 static int construct_libvirt_xml_disk (guestfs_h *g, const struct backend_libvirt_data *data, xmlTextWriterPtr xo, struct drive *drv, size_t drv_index);
 static int construct_libvirt_xml_disk_target (guestfs_h *g, xmlTextWriterPtr xo, size_t drv_index);
-static int construct_libvirt_xml_disk_driver_qemu (guestfs_h *g, const struct backend_libvirt_data *data, struct drive *drv, xmlTextWriterPtr xo, const char *format, const char *cachemode, enum discard discard);
+static int construct_libvirt_xml_disk_driver_qemu (guestfs_h *g, const struct backend_libvirt_data *data, struct drive *drv, xmlTextWriterPtr xo, const char *format, const char *cachemode, enum discard discard, bool copyonread);
 static int construct_libvirt_xml_disk_address (guestfs_h *g, xmlTextWriterPtr xo, size_t drv_index);
 static int construct_libvirt_xml_disk_source_hosts (guestfs_h *g, xmlTextWriterPtr xo, const struct drive_source *src);
 static int construct_libvirt_xml_disk_source_seclabel (guestfs_h *g, const struct backend_libvirt_data *data, xmlTextWriterPtr xo);
@@ -1277,7 +1277,7 @@ construct_libvirt_xml_disk (guestfs_h *g,
 
       if (construct_libvirt_xml_disk_driver_qemu (g, data, drv,
                                                   xo, "qcow2", "unsafe",
-                                                  discard_disable)
+                                                  discard_disable, false)
           == -1)
         return -1;
     }
@@ -1416,7 +1416,7 @@ construct_libvirt_xml_disk (guestfs_h *g,
 
       if (construct_libvirt_xml_disk_driver_qemu (g, data, drv, xo, format,
                                                   drv->cachemode ? : "writeback",
-                                                  drv->discard)
+                                                  drv->discard, false)
           == -1)
         return -1;
     }
@@ -1458,7 +1458,8 @@ construct_libvirt_xml_disk_driver_qemu (guestfs_h *g,
                                         xmlTextWriterPtr xo,
                                         const char *format,
                                         const char *cachemode,
-                                        enum discard discard)
+                                        enum discard discard,
+                                        bool copyonread)
 {
   bool discard_unmap = false;
 
@@ -1492,6 +1493,8 @@ construct_libvirt_xml_disk_driver_qemu (guestfs_h *g,
     attribute ("cache", cachemode);
     if (discard_unmap)
       attribute ("discard", "unmap");
+    if (copyonread)
+      attribute ("copy_on_read", "on");
   } end_element ();
 
   return 0;
@@ -1578,7 +1581,7 @@ construct_libvirt_xml_appliance (guestfs_h *g,
 
     if (construct_libvirt_xml_disk_driver_qemu (g, params->data, NULL, xo,
                                                 "qcow2", "unsafe",
-                                                discard_disable) == -1)
+                                                discard_disable, false) == -1)
       return -1;
 
     if (construct_libvirt_xml_disk_address (g, xo, params->appliance_index)
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index d148d4aaa..7e0a0d9f5 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -65,6 +65,7 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
   const char *iface;
   const char *cachemode;
   const char *discard;
+  bool copyonread;
   struct guestfs___add_libvirt_dom_argv optargs2 = { .bitmask = 0 };
 
   libvirturi = optargs->bitmask & GUESTFS_ADD_DOMAIN_LIBVIRTURI_BITMASK
@@ -83,6 +84,8 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
             ? optargs->cachemode : NULL;
   discard = optargs->bitmask & GUESTFS_ADD_DOMAIN_DISCARD_BITMASK
           ? optargs->discard : NULL;
+  copyonread = optargs->bitmask & GUESTFS_ADD_DOMAIN_COPYONREAD_BITMASK
+               ? optargs->copyonread : false;
 
   if (live && readonly) {
     error (g, _("you cannot set both live and readonly flags"));
@@ -143,6 +146,10 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
     optargs2.bitmask |= GUESTFS___ADD_LIBVIRT_DOM_DISCARD_BITMASK;
     optargs2.discard = discard;
   }
+  if (copyonread) {
+    optargs2.bitmask |= GUESTFS___ADD_LIBVIRT_DOM_COPYONREAD_BITMASK;
+    optargs2.copyonread = copyonread;
+  }
 
   r = guestfs___add_libvirt_dom (g, dom, &optargs2);
 
@@ -179,6 +186,7 @@ guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom,
   const char *iface;
   const char *cachemode;
   const char *discard;
+  bool copyonread;
   int live;
   /* Default for back-compat reasons: */
   enum readonlydisk readonlydisk = readonlydisk_write;
@@ -220,6 +228,10 @@ guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom,
     optargs->bitmask & GUESTFS___ADD_LIBVIRT_DOM_DISCARD_BITMASK
     ? optargs->discard : NULL;
 
+  copyonread =
+    optargs->bitmask & GUESTFS___ADD_LIBVIRT_DOM_COPYONREAD_BITMASK
+    ? optargs->copyonread : false;
+
   if (live && readonly) {
     error (g, _("you cannot set both live and readonly flags"));
     return -1;
@@ -289,6 +301,10 @@ guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom,
     data.optargs.bitmask |= GUESTFS_ADD_DRIVE_OPTS_DISCARD_BITMASK;
     data.optargs.discard = discard;
   }
+  if (copyonread) {
+    data.optargs.bitmask |= GUESTFS_ADD_DRIVE_OPTS_COPYONREAD_BITMASK;
+    data.optargs.copyonread = copyonread;
+  }
 
   /* Checkpoint the command line around the operation so that either
    * all disks are added or none are added.