diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index c621686131..1fcfdb0997 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -188,7 +188,7 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
     }
 
     exp = nbd_export_new(bs, 0, len, name, NULL, bitmap,
-                         writable ? 0 : NBD_FLAG_READ_ONLY,
+                         writable ? 0 : NBD_FLAG_READ_ONLY, !writable,
                          NULL, false, on_eject_blk, errp);
     if (!exp) {
         return;
diff --git a/docs/interop/nbd.txt b/docs/interop/nbd.txt
index fc64473e02..6dfec7f476 100644
--- a/docs/interop/nbd.txt
+++ b/docs/interop/nbd.txt
@@ -53,3 +53,4 @@ the operation of that feature.
 * 2.12: NBD_CMD_BLOCK_STATUS for "base:allocation"
 * 3.0: NBD_OPT_STARTTLS with TLS Pre-Shared Keys (PSK),
 NBD_CMD_BLOCK_STATUS for "qemu:dirty-bitmap:", NBD_CMD_CACHE
+* 4.2: NBD_FLAG_CAN_MULTI_CONN for sharable read-only exports
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 7b36d672f0..991fd52a51 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -326,7 +326,7 @@ typedef struct NBDClient NBDClient;
 
 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
                           uint64_t size, const char *name, const char *desc,
-                          const char *bitmap, uint16_t nbdflags,
+                          const char *bitmap, uint16_t nbdflags, bool shared,
                           void (*close)(NBDExport *), bool writethrough,
                           BlockBackend *on_eject_blk, Error **errp);
 void nbd_export_close(NBDExport *exp);
diff --git a/nbd/server.c b/nbd/server.c
index f55ccf8edf..0fb41c6c50 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1461,7 +1461,7 @@ static void nbd_eject_notifier(Notifier *n, void *data)
 
 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
                           uint64_t size, const char *name, const char *desc,
-                          const char *bitmap, uint16_t nbdflags,
+                          const char *bitmap, uint16_t nbdflags, bool shared,
                           void (*close)(NBDExport *), bool writethrough,
                           BlockBackend *on_eject_blk, Error **errp)
 {
@@ -1487,6 +1487,8 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
     perm = BLK_PERM_CONSISTENT_READ;
     if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
         perm |= BLK_PERM_WRITE;
+    } else if (shared) {
+        nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
     }
     blk = blk_new(bdrv_get_aio_context(bs), perm,
                   BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 83b6c32d73..2403ef3d0f 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -1173,7 +1173,7 @@ int main(int argc, char **argv)
     }
 
     export = nbd_export_new(bs, dev_offset, fd_size, export_name,
-                            export_description, bitmap, nbdflags,
+                            export_description, bitmap, nbdflags, shared > 1,
                             nbd_export_closed, writethrough, NULL,
                             &error_fatal);
 
diff --git a/tests/qemu-iotests/223.out b/tests/qemu-iotests/223.out
index d5201b2356..2bca28ae72 100644
--- a/tests/qemu-iotests/223.out
+++ b/tests/qemu-iotests/223.out
@@ -40,7 +40,7 @@ exports available: 0
 exports available: 2
  export: 'n'
   size:  4194304
-  flags: 0x4ef ( readonly flush fua trim zeroes df cache )
+  flags: 0x5ef ( readonly flush fua trim zeroes df multi cache )
   min block: 1
   opt block: 4096
   max block: 33554432