dpdk: allow configure individual VMBUS devices

now startup.conf supports confuguration for VMBUS
devices as for PCI devices for whitelisting/blacklisting

dpdk { dev fa5a6e7a-cf3a-4b98-9569-addb479b84bc }
 with sub-configuration as for PCI devices
dpdk { blacklist fa5a6e7a-cf3a-4b98-9569-addb479b84bc }
 where fa5a6e7a-cf3a-4b98-9569-addb479b84bc - example of UUID

struct vlib_vmbus_addr_t changed to union with UUID described
 fields

Added device_config_index_by_vmbus_addr
      blacklist_by_vmbus_addr
to enumerate available device configs

hash_key is as_u32[0] field(last 4 bytes of UUID)
Lost of precision against full UUID, but 2^32 is enough
to handle all the devices available

Added is_blacklisted check while creating vnet devices in
order to supress creation of dev if it's blacklisted

Type: feature

Signed-off-by: Vladimir Ratnikov <vratnikov@netgate.com>
Change-Id: Id82611e54fed082190e488c7e5fbe14ecbe5b2ab
diff --git a/src/vlib/linux/vmbus.c b/src/vlib/linux/vmbus.c
index 2fc438b..d50b539 100644
--- a/src/vlib/linux/vmbus.c
+++ b/src/vlib/linux/vmbus.c
@@ -118,8 +118,8 @@
  * "f2c086b2-ff2e-11e8-88de-7bad0a57de05" and convert
  * it to u8[16]
  */
-static uword
-unformat_vlib_vmbus_addr (unformat_input_t * input, va_list * args)
+uword
+unformat_vlib_vmbus_addr (unformat_input_t *input, va_list *args)
 {
   vlib_vmbus_addr_t *addr = va_arg (*args, vlib_vmbus_addr_t *);
   uword ret = 0;
@@ -137,8 +137,8 @@
 }
 
 /* Convert bus address to standard UUID string */
-static u8 *
-format_vlib_vmbus_addr (u8 * s, va_list * va)
+u8 *
+format_vlib_vmbus_addr (u8 *s, va_list *va)
 {
   vlib_vmbus_addr_t *addr = va_arg (*va, vlib_vmbus_addr_t *);
   char tmp[40];
@@ -297,15 +297,21 @@
       vec_reset_length (s);
       s = format (s, "%s/%s/new_id%c", sysfs_vmbus_drv_path, uio_drv_name, 0);
       error = clib_sysfs_write ((char *) s, "%s", netvsc_uuid);
-
+      /* If device already exists, we can bind/unbind/override driver */
       if (error)
 	{
-	  close (fd);
-	  goto done;
+	  if (error->code == EEXIST)
+	    {
+	      clib_error_free (error);
+	    }
+	  else
+	    {
+	      close (fd);
+	      goto done;
+	    }
 	}
 
       uio_new_id_needed = 0;
-
     }
 
   error = vlib_vmbus_raise_lower (fd, ifname);