vmbus: not having uio_hv_generic is not an error

If uio_hv_generic is not loaded, then the startup code will
fallback to the older failsafe/tap method of initialization
in DPDK.  Therefore don't put out scary message in the log.

Also, reorder startup to avoid manipulating lower device until/unless
uio is going to work.

Change-Id: Ie1cc77b4b5359c04f00a93d01a772eccf3bbab37
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

1 files changed, 20 insertions, 7 deletions

diff --git a/src/vlib/linux/vmbus.c b/src/vlib/linux/vmbus.c
index 2dba8025326..a359c10a71f 100644
--- a/src/vlib/linux/vmbus.c
+++ b/src/vlib/linux/vmbus.c
@@ -199,6 +199,16 @@ done:
   return error;
 }
 
+static int
+directory_exists (char *path)
+{
+  struct stat s = { 0 };
+  if (stat (path, &s) == -1)
+    return 0;
+
+  return S_ISDIR (s.st_mode);
+}
+
 clib_error_t *
 vlib_vmbus_bind_to_uio (vlib_vmbus_addr_t * addr)
 {
@@ -223,6 +233,10 @@ vlib_vmbus_bind_to_uio (vlib_vmbus_addr_t * addr)
   if (!driver_name || strcmp ("hv_netvsc", (char *) driver_name) != 0)
     goto done;
 
+  /* if uio_hv_generic is not loaded, then can't use native DPDK driver. */
+  if (!directory_exists ("/sys/module/uio_hv_generic"))
+    goto done;
+
   s = format (s, "%v/net%c", dev_dir_name, 0);
   dir = opendir ((char *) s);
   vec_reset_length (s);
@@ -277,13 +291,6 @@ vlib_vmbus_bind_to_uio (vlib_vmbus_addr_t * addr)
       goto done;
     }
 
-  error = vlib_vmbus_raise_lower (fd, ifname);
-  close (fd);
-
-  if (error)
-    goto done;
-
-
   /* tell uio_hv_generic about netvsc device type */
   if (uio_new_id_needed)
     {
@@ -298,6 +305,12 @@ vlib_vmbus_bind_to_uio (vlib_vmbus_addr_t * addr)
 
     }
 
+  error = vlib_vmbus_raise_lower (fd, ifname);
+  close (fd);
+
+  if (error)
+    goto done;
+
   /* prefer the simplier driver_override model */
   vec_reset_length (s);
   s = format (s, "%/driver_override%c", dev_dir_name, 0);