4 files changed, 336 insertions, 484 deletions

diff --git a/src/vnet/devices/devices.c b/src/vnet/devices/devices.c
index e71be602237..58c72077f24 100644
--- a/src/vnet/devices/devices.c
+++ b/src/vnet/devices/devices.c
@@ -150,6 +150,7 @@ vnet_hw_interface_assign_rx_thread (vnet_main_t * vnm, u32 hw_if_index,
   dq->dev_instance = hw->dev_instance;
   dq->queue_id = queue_id;
   dq->mode = VNET_HW_INTERFACE_RX_MODE_POLLING;
+  rt->enabled_node_state = VLIB_NODE_STATE_POLLING;
 
   vnet_device_queue_update (vnm, rt);
   vec_validate (hw->input_node_thread_index_by_queue, queue_id);
@@ -168,6 +169,7 @@ vnet_hw_interface_unassign_rx_thread (vnet_main_t * vnm, u32 hw_if_index,
   vnet_device_input_runtime_t *rt;
   vnet_device_and_queue_t *dq;
   uword old_thread_index;
+  vnet_hw_interface_rx_mode mode;
 
   if (hw->input_node_thread_index_by_queue == 0)
     return VNET_API_ERROR_INVALID_INTERFACE;
@@ -184,6 +186,7 @@ vnet_hw_interface_unassign_rx_thread (vnet_main_t * vnm, u32 hw_if_index,
   vec_foreach (dq, rt->devices_and_queues)
     if (dq->hw_if_index == hw_if_index && dq->queue_id == queue_id)
     {
+      mode = dq->mode;
       vec_del1 (rt->devices_and_queues, dq - rt->devices_and_queues);
       goto deleted;
     }
@@ -197,6 +200,23 @@ deleted:
 
   if (vec_len (rt->devices_and_queues) == 0)
     vlib_node_set_state (vm, hw->input_node_index, VLIB_NODE_STATE_DISABLED);
+  else if (mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+    {
+      /*
+       * if the deleted interface is polling, we may need to set the node state
+       * to interrupt if there is no more polling interface for this device's
+       * corresponding thread. This is because mixed interfaces
+       * (polling and interrupt), assigned to the same thread, set the
+       * thread to polling prior to the deletion.
+       */
+      vec_foreach (dq, rt->devices_and_queues)
+      {
+	if (dq->mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+	  return 0;
+      }
+      rt->enabled_node_state = VLIB_NODE_STATE_INTERRUPT;
+      vlib_node_set_state (vm, hw->input_node_index, rt->enabled_node_state);
+    }
 
   return 0;
 }
diff --git a/src/vnet/devices/virtio/vhost-user.c b/src/vnet/devices/virtio/vhost-user.c
index 451ae4342b6..231889342e8 100644
--- a/src/vnet/devices/virtio/vhost-user.c
+++ b/src/vnet/devices/virtio/vhost-user.c
@@ -362,140 +362,71 @@ vhost_user_tx_thread_placement (vhost_user_intf_t * vui)
     }
 }
 
+/**
+ * @brief Unassign existing interface/queue to thread mappings and re-assign
+ * new interface/queue to thread mappings
+ */
 static void
 vhost_user_rx_thread_placement ()
 {
   vhost_user_main_t *vum = &vhost_user_main;
   vhost_user_intf_t *vui;
-  vhost_cpu_t *vhc;
-  u32 *workers = 0;
-  u32 thread_index;
-  vlib_main_t *vm;
-
-  //Let's list all workers cpu indexes
-  u32 i;
-  for (i = vum->input_cpu_first_index;
-       i < vum->input_cpu_first_index + vum->input_cpu_count; i++)
-    {
-      vlib_node_set_state (vlib_mains[i], vhost_user_input_node.index,
-			   VLIB_NODE_STATE_DISABLED);
-      vec_add1 (workers, i);
-    }
-
-  vec_foreach (vhc, vum->cpus)
-  {
-    vec_reset_length (vhc->rx_queues);
-  }
+  vhost_user_vring_t *txvq;
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 qid;
+  int rv;
+  u16 *queue;
 
-  i = 0;
-  vhost_iface_and_queue_t iaq;
+  // Scrap all existing mappings for all interfaces/queues
   /* *INDENT-OFF* */
   pool_foreach (vui, vum->vhost_user_interfaces, {
-      u32 *vui_workers = vec_len (vui->workers) ? vui->workers : workers;
-      u32 qid;
-      for (qid = 0; qid < VHOST_VRING_MAX_N / 2; qid++)
+      vec_foreach (queue, vui->rx_queues)
 	{
-	  vhost_user_vring_t *txvq =
-	      &vui->vrings[VHOST_VRING_IDX_TX (qid)];
-	  if (!txvq->started)
-	    continue;
-
-	  i %= vec_len (vui_workers);
-	  thread_index = vui_workers[i];
-	  i++;
-	  vhc = &vum->cpus[thread_index];
-	  txvq->interrupt_thread_index = thread_index;
-
-	  iaq.qid = qid;
-	  iaq.vhost_iface_index = vui - vum->vhost_user_interfaces;
-	  vec_add1 (vhc->rx_queues, iaq);
+	  rv = vnet_hw_interface_unassign_rx_thread (vnm, vui->hw_if_index,
+						     *queue);
+	  if (rv)
+	    clib_warning ("Warning: unable to unassign interface %d, "
+			  "queue %d: rc=%d", vui->hw_if_index, *queue, rv);
 	}
+      vec_reset_length (vui->rx_queues);
   });
   /* *INDENT-ON* */
 
-  vec_foreach (vhc, vum->cpus)
-  {
-    vhost_iface_and_queue_t *vhiq;
-    u8 mode = VHOST_USER_INTERRUPT_MODE;
-
-    vec_foreach (vhiq, vhc->rx_queues)
-    {
-      vui = &vum->vhost_user_interfaces[vhiq->vhost_iface_index];
-      if (vui->operation_mode == VHOST_USER_POLLING_MODE)
+  // Create the rx_queues for all interfaces
+  /* *INDENT-OFF* */
+  pool_foreach (vui, vum->vhost_user_interfaces, {
+      for (qid = 0; qid < VHOST_VRING_MAX_N / 2; qid++)
 	{
-	  /* At least one interface is polling, cpu is set to polling */
-	  mode = VHOST_USER_POLLING_MODE;
-	  break;
+	  txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
+	  if (txvq->started)
+	    {
+	      if (txvq->mode == VNET_HW_INTERFACE_RX_MODE_UNKNOWN)
+		/* Set polling as the default */
+		txvq->mode = VNET_HW_INTERFACE_RX_MODE_POLLING;
+	      vec_add1 (vui->rx_queues, qid);
+	    }
 	}
-    }
-    vhc->operation_mode = mode;
-  }
-
-  for (thread_index = vum->input_cpu_first_index;
-       thread_index < vum->input_cpu_first_index + vum->input_cpu_count;
-       thread_index++)
-    {
-      vlib_node_state_t state = VLIB_NODE_STATE_POLLING;
+  });
+  /* *INDENT-ON* */
 
-      vhc = &vum->cpus[thread_index];
-      vm = vlib_mains ? vlib_mains[thread_index] : &vlib_global_main;
-      switch (vhc->operation_mode)
+  // Assign new mappings for all interfaces/queues
+  /* *INDENT-OFF* */
+  pool_foreach (vui, vum->vhost_user_interfaces, {
+      vnet_hw_interface_set_input_node (vnm, vui->hw_if_index,
+					vhost_user_input_node.index);
+      vec_foreach (queue, vui->rx_queues)
 	{
-	case VHOST_USER_INTERRUPT_MODE:
-	  state = VLIB_NODE_STATE_INTERRUPT;
-	  break;
-	case VHOST_USER_POLLING_MODE:
-	  state = VLIB_NODE_STATE_POLLING;
-	  break;
-	default:
-	  clib_warning ("BUG: bad operation mode %d", vhc->operation_mode);
-	  break;
+	  vnet_hw_interface_assign_rx_thread (vnm, vui->hw_if_index, *queue,
+					      ~0);
+	  txvq = &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
+	  rv = vnet_hw_interface_set_rx_mode (vnm, vui->hw_if_index, *queue,
+					      txvq->mode);
+	  if (rv)
+	    clib_warning ("Warning: unable to set rx mode for interface %d, "
+			  "queue %d: rc=%d", vui->hw_if_index, *queue, rv);
 	}
-      vlib_node_set_state (vm, vhost_user_input_node.index, state);
-    }
-
-  vec_free (workers);
-}
-
-static int
-vhost_user_thread_placement (u32 sw_if_index, u32 worker_thread_index, u8 del)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-  vnet_hw_interface_t *hw;
-
-  if (worker_thread_index < vum->input_cpu_first_index ||
-      worker_thread_index >=
-      vum->input_cpu_first_index + vum->input_cpu_count)
-    return -1;
-
-  if (!(hw = vnet_get_sup_hw_interface (vnet_get_main (), sw_if_index)))
-    return -2;
-
-  vui = pool_elt_at_index (vum->vhost_user_interfaces, hw->dev_instance);
-  u32 found = ~0, *w;
-  vec_foreach (w, vui->workers)
-  {
-    if (*w == worker_thread_index)
-      {
-	found = w - vui->workers;
-	break;
-      }
-  }
-
-  if (del)
-    {
-      if (found == ~0)
-	return -3;
-      vec_del1 (vui->workers, found);
-    }
-  else if (found == ~0)
-    {
-      vec_add1 (vui->workers, worker_thread_index);
-    }
-
-  vhost_user_rx_thread_placement ();
-  return 0;
+  });
+  /* *INDENT-ON* */
 }
 
 /** @brief Returns whether at least one TX and one RX vring are enabled */
@@ -532,37 +463,17 @@ vhost_user_update_iface_state (vhost_user_intf_t * vui)
 static void
 vhost_user_set_interrupt_pending (vhost_user_intf_t * vui, u32 ifq)
 {
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_cpu_t *vhc;
-  u32 thread_index;
-  vlib_main_t *vm;
-  u32 ifq2, qid;
-  vhost_user_vring_t *txvq;
+  u32 qid;
+  vnet_main_t *vnm = vnet_get_main ();
 
   qid = ifq & 0xff;
-  if ((qid % 2) == 0)
-    /* Only care about the odd number virtqueue which is TX */
+  if ((qid & 1) == 0)
+    /* Only care about the odd number, or TX, virtqueue */
     return;
 
   if (vhost_user_intf_ready (vui))
-    {
-      txvq = &vui->vrings[qid];
-      thread_index = txvq->interrupt_thread_index;
-      vhc = &vum->cpus[thread_index];
-      if (vhc->operation_mode == VHOST_USER_INTERRUPT_MODE)
-	{
-	  vm = vlib_mains ? vlib_mains[thread_index] : &vlib_global_main;
-	  /*
-	   * Convert virtqueue number in the lower byte to vring
-	   * queue index for the input node process. Top bytes contain
-	   * the interface, lower byte contains the queue index.
-	   */
-	  ifq2 = ((ifq >> 8) << 8) | qid / 2;
-	  vhc->pending_input_bitmap =
-	    clib_bitmap_set (vhc->pending_input_bitmap, ifq2, 1);
-	  vlib_node_set_interrupt_pending (vm, vhost_user_input_node.index);
-	}
-    }
+    // qid >> 1 is to convert virtqueue number to vring queue index
+    vnet_device_input_set_interrupt_pending (vnm, vui->hw_if_index, qid >> 1);
 }
 
 static clib_error_t *
@@ -570,14 +481,10 @@ vhost_user_callfd_read_ready (unix_file_t * uf)
 {
   __attribute__ ((unused)) int n;
   u8 buff[8];
-  vhost_user_intf_t *vui =
-    pool_elt_at_index (vhost_user_main.vhost_user_interfaces,
-		       uf->private_data >> 8);
 
   n = read (uf->file_descriptor, ((char *) &buff), 8);
   DBG_SOCK ("if %d CALL queue %d", uf->private_data >> 8,
 	    uf->private_data & 0xff);
-  vhost_user_set_interrupt_pending (vui, uf->private_data);
 
   return 0;
 }
@@ -1001,12 +908,8 @@ vhost_user_socket_read (unix_file_t * uf)
 	vui->vrings[msg.state.index].last_avail_idx =
 	vui->vrings[msg.state.index].used->idx;
 
-      if (vui->operation_mode == VHOST_USER_POLLING_MODE)
-	/* tell driver that we don't want interrupts */
-	vui->vrings[msg.state.index].used->flags = VRING_USED_F_NO_NOTIFY;
-      else
-	/* tell driver that we want interrupts */
-	vui->vrings[msg.state.index].used->flags = 0;
+      /* tell driver that we don't want interrupts */
+      vui->vrings[msg.state.index].used->flags = VRING_USED_F_NO_NOTIFY;
       break;
 
     case VHOST_USER_SET_OWNER:
@@ -1315,8 +1218,6 @@ vhost_user_init (vlib_main_t * vm)
   clib_error_t *error;
   vhost_user_main_t *vum = &vhost_user_main;
   vlib_thread_main_t *tm = vlib_get_thread_main ();
-  vlib_thread_registration_t *tr;
-  uword *p;
 
   error = vlib_call_init_function (vm, ip4_init);
   if (error)
@@ -1335,18 +1236,6 @@ vhost_user_init (vlib_main_t * vm)
     cpu->rx_buffers_len = 0;
   }
 
-  /* find out which cpus will be used for input */
-  vum->input_cpu_first_index = 0;
-  vum->input_cpu_count = 1;
-  p = hash_get_mem (tm->thread_registrations_by_name, "workers");
-  tr = p ? (vlib_thread_registration_t *) p[0] : 0;
-
-  if (tr && tr->count > 0)
-    {
-      vum->input_cpu_first_index = tr->first_index;
-      vum->input_cpu_count = tr->count;
-    }
-
   vum->random = random_default_seed ();
 
   mhash_init_c_string (&vum->if_index_by_sock_name, sizeof (uword));
@@ -1447,9 +1336,16 @@ vhost_user_send_call (vlib_main_t * vm, vhost_user_vring_t * vq)
   vhost_user_main_t *vum = &vhost_user_main;
   u64 x = 1;
   int fd = UNIX_GET_FD (vq->callfd_idx);
-  int rv __attribute__ ((unused));
-  /* TODO: pay attention to rv */
+  int rv;
+
   rv = write (fd, &x, sizeof (x));
+  if (rv <= 0)
+    {
+      clib_unix_warning
+	("Error: Could not write to unix socket for callfd %d", fd);
+      return;
+    }
+
   vq->n_since_last_int = 0;
   vq->int_deadline = vlib_time_now (vm) + vum->coalesce_time;
 }
@@ -1564,7 +1460,8 @@ static u32
 vhost_user_if_input (vlib_main_t * vm,
 		     vhost_user_main_t * vum,
 		     vhost_user_intf_t * vui,
-		     u16 qid, vlib_node_runtime_t * node)
+		     u16 qid, vlib_node_runtime_t * node,
+		     vnet_hw_interface_rx_mode mode)
 {
   vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
   u16 n_rx_packets = 0;
@@ -1590,6 +1487,26 @@ vhost_user_if_input (vlib_main_t * vm,
       vhost_user_send_call (vm, rxvq);
   }
 
+  /*
+   * For adaptive mode, it is optimized to reduce interrupts.
+   * If the scheduler switches the input node to polling due
+   * to burst of traffic, we tell the driver no interrupt.
+   * When the traffic subsides, the scheduler switches the node back to
+   * interrupt mode. We must tell the driver we want interrupt.
+   */
+  if (PREDICT_FALSE (mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE))
+    {
+      if ((node->flags &
+	   VLIB_NODE_FLAG_SWITCH_FROM_POLLING_TO_INTERRUPT_MODE) ||
+	  !(node->flags &
+	    VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE))
+	/* Tell driver we want notification */
+	txvq->used->flags = 0;
+      else
+	/* Tell driver we don't want notification */
+	txvq->used->flags = VRING_USED_F_NO_NOTIFY;
+    }
+
   if (PREDICT_FALSE (txvq->avail->flags & 0xFFFE))
     return 0;
 
@@ -1926,34 +1843,23 @@ vhost_user_input (vlib_main_t * vm,
 {
   vhost_user_main_t *vum = &vhost_user_main;
   uword n_rx_packets = 0;
-  u32 thread_index = vlib_get_thread_index ();
-  vhost_iface_and_queue_t *vhiq;
   vhost_user_intf_t *vui;
-  vhost_cpu_t *vhc;
+  vnet_device_input_runtime_t *rt =
+    (vnet_device_input_runtime_t *) node->runtime_data;
+  vnet_device_and_queue_t *dq;
 
-  vhc = &vum->cpus[thread_index];
-  if (PREDICT_TRUE (vhc->operation_mode == VHOST_USER_POLLING_MODE))
-    {
-      vec_foreach (vhiq, vum->cpus[thread_index].rx_queues)
+  vec_foreach (dq, rt->devices_and_queues)
+  {
+    if (clib_smp_swap (&dq->interrupt_pending, 0) ||
+	(node->state == VLIB_NODE_STATE_POLLING))
       {
-	vui = &vum->vhost_user_interfaces[vhiq->vhost_iface_index];
-	n_rx_packets += vhost_user_if_input (vm, vum, vui, vhiq->qid, node);
+	vui =
+	  pool_elt_at_index (vum->vhost_user_interfaces, dq->dev_instance);
+	n_rx_packets = vhost_user_if_input (vm, vum, vui, dq->queue_id, node,
+					    dq->mode);
       }
-    }
-  else
-    {
-      int i;
-
-      /* *INDENT-OFF* */
-      clib_bitmap_foreach (i, vhc->pending_input_bitmap, ({
-	int qid = i & 0xff;
+  }
 
-	clib_bitmap_set (vhc->pending_input_bitmap, i, 0);
-	vui = pool_elt_at_index (vum->vhost_user_interfaces, i >> 8);
-	n_rx_packets += vhost_user_if_input (vm, vum, vui, qid, node);
-      }));
-      /* *INDENT-ON* */
-    }
   return n_rx_packets;
 }
 
@@ -2371,6 +2277,161 @@ done3:
   return frame->n_vectors;
 }
 
+static uword
+vhost_user_send_interrupt_process (vlib_main_t * vm,
+				   vlib_node_runtime_t * rt, vlib_frame_t * f)
+{
+  vhost_user_intf_t *vui;
+  f64 timeout = 3153600000.0 /* 100 years */ ;
+  uword event_type, *event_data = 0;
+  vhost_user_main_t *vum = &vhost_user_main;
+  u16 *queue;
+  f64 now, poll_time_remaining;
+  f64 next_timeout;
+  u8 stop_timer = 0;
+
+  while (1)
+    {
+      poll_time_remaining =
+	vlib_process_wait_for_event_or_clock (vm, timeout);
+      event_type = vlib_process_get_events (vm, &event_data);
+      vec_reset_length (event_data);
+
+      /*
+       * Use the remaining timeout if it is less than coalesce time to avoid
+       * resetting the existing timer in the middle of expiration
+       */
+      timeout = poll_time_remaining;
+      if (vlib_process_suspend_time_is_zero (timeout) ||
+	  (timeout > vum->coalesce_time))
+	timeout = vum->coalesce_time;
+
+      now = vlib_time_now (vm);
+      switch (event_type)
+	{
+	case VHOST_USER_EVENT_STOP_TIMER:
+	  stop_timer = 1;
+	  break;
+
+	case VHOST_USER_EVENT_START_TIMER:
+	  stop_timer = 0;
+	  if (!vlib_process_suspend_time_is_zero (poll_time_remaining))
+	    break;
+	  /* fall through */
+
+	case ~0:
+	  /* *INDENT-OFF* */
+	  pool_foreach (vui, vum->vhost_user_interfaces, {
+	      next_timeout = timeout;
+	      vec_foreach (queue, vui->rx_queues)
+		{
+		  vhost_user_vring_t *rxvq =
+		    &vui->vrings[VHOST_VRING_IDX_RX (*queue)];
+		  vhost_user_vring_t *txvq =
+		    &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
+
+		  if (txvq->n_since_last_int)
+		    {
+		      if (now >= txvq->int_deadline)
+			vhost_user_send_call (vm, txvq);
+		      else
+			next_timeout = txvq->int_deadline - now;
+		    }
+
+		  if (rxvq->n_since_last_int)
+		    {
+		      if (now >= rxvq->int_deadline)
+			vhost_user_send_call (vm, rxvq);
+		      else
+			next_timeout = rxvq->int_deadline - now;
+		    }
+
+		  if ((next_timeout < timeout) && (next_timeout > 0.0))
+		    timeout = next_timeout;
+		}
+	  });
+          /* *INDENT-ON* */
+	  break;
+
+	default:
+	  clib_warning ("BUG: unhandled event type %d", event_type);
+	  break;
+	}
+      /* No less than 1 millisecond */
+      if (timeout < 1e-3)
+	timeout = 1e-3;
+      if (stop_timer)
+	timeout = 3153600000.0;
+    }
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (vhost_user_send_interrupt_node,static) = {
+    .function = vhost_user_send_interrupt_process,
+    .type = VLIB_NODE_TYPE_PROCESS,
+    .name = "vhost-user-send-interrupt-process",
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+vhost_user_interface_rx_mode_change (vnet_main_t * vnm, u32 hw_if_index,
+				     u32 qid, vnet_hw_interface_rx_mode mode)
+{
+  vlib_main_t *vm = vnm->vlib_main;
+  vnet_hw_interface_t *hif = vnet_get_hw_interface (vnm, hw_if_index);
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui =
+    pool_elt_at_index (vum->vhost_user_interfaces, hif->dev_instance);
+  vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
+
+  if ((mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
+      (mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE))
+    {
+      if (txvq->mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+	{
+	  vum->ifq_count++;
+	  // Start the timer if this is the first encounter on interrupt
+	  // interface/queue
+	  if ((vum->ifq_count == 1) &&
+	      (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
+	    vlib_process_signal_event (vm,
+				       vhost_user_send_interrupt_node.index,
+				       VHOST_USER_EVENT_START_TIMER, 0);
+	}
+    }
+  else if (mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+    {
+      if (((txvq->mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
+	   (txvq->mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE)) &&
+	  vum->ifq_count)
+	{
+	  vum->ifq_count--;
+	  // Stop the timer if there is no more interrupt interface/queue
+	  if ((vum->ifq_count == 0) &&
+	      (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
+	    vlib_process_signal_event (vm,
+				       vhost_user_send_interrupt_node.index,
+				       VHOST_USER_EVENT_STOP_TIMER, 0);
+	}
+    }
+
+  txvq->mode = mode;
+  if (mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+    txvq->used->flags = VRING_USED_F_NO_NOTIFY;
+  else if ((mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE) ||
+	   (mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT))
+    txvq->used->flags = 0;
+  else
+    {
+      clib_warning ("BUG: unhandled mode %d changed for if %d queue %d", mode,
+		    hw_if_index, qid);
+      return clib_error_return (0, "unsupported");
+    }
+
+  return 0;
+}
+
 static clib_error_t *
 vhost_user_interface_admin_up_down (vnet_main_t * vnm, u32 hw_if_index,
 				    u32 flags)
@@ -2399,6 +2460,7 @@ VNET_DEVICE_CLASS (vhost_user_dev_class,static) = {
   .format_device_name = format_vhost_user_interface_name,
   .name_renumber = vhost_user_name_renumber,
   .admin_up_down_function = vhost_user_interface_admin_up_down,
+  .rx_mode_change_function = vhost_user_interface_rx_mode_change,
   .format_tx_trace = format_vhost_trace,
 };
 
@@ -2523,8 +2585,6 @@ vhost_user_term_if (vhost_user_intf_t * vui)
   int q;
   vhost_user_main_t *vum = &vhost_user_main;
 
-  // Delete configured thread pinning
-  vec_reset_length (vui->workers);
   // disconnect interface sockets
   vhost_user_if_disconnect (vui);
   vhost_user_update_iface_state (vui);
@@ -2555,6 +2615,7 @@ vhost_user_delete_if (vnet_main_t * vnm, vlib_main_t * vm, u32 sw_if_index)
   vhost_user_intf_t *vui;
   int rv = 0;
   vnet_hw_interface_t *hwif;
+  u16 *queue;
 
   if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
       hwif->dev_class_index != vhost_user_dev_class.index)
@@ -2565,6 +2626,28 @@ vhost_user_delete_if (vnet_main_t * vnm, vlib_main_t * vm, u32 sw_if_index)
 
   vui = pool_elt_at_index (vum->vhost_user_interfaces, hwif->dev_instance);
 
+  vec_foreach (queue, vui->rx_queues)
+  {
+    vhost_user_vring_t *txvq;
+
+    txvq = &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
+    if ((vum->ifq_count > 0) &&
+	((txvq->mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
+	 (txvq->mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE)))
+      {
+	vum->ifq_count--;
+	// Stop the timer if there is no more interrupt interface/queue
+	if ((vum->ifq_count == 0) &&
+	    (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
+	  {
+	    vlib_process_signal_event (vm,
+				       vhost_user_send_interrupt_node.index,
+				       VHOST_USER_EVENT_STOP_TIMER, 0);
+	    break;
+	  }
+      }
+  }
+
   // Disable and reset interface
   vhost_user_term_if (vui);
 
@@ -2687,13 +2770,15 @@ vhost_user_vui_init (vnet_main_t * vnm,
 		     vhost_user_intf_t * vui,
 		     int server_sock_fd,
 		     const char *sock_filename,
-		     u64 feature_mask, u32 * sw_if_index, u8 operation_mode)
+		     u64 feature_mask, u32 * sw_if_index)
 {
   vnet_sw_interface_t *sw;
-  sw = vnet_get_hw_sw_interface (vnm, vui->hw_if_index);
   int q;
   vhost_user_main_t *vum = &vhost_user_main;
+  vnet_hw_interface_t *hw;
 
+  hw = vnet_get_hw_interface (vnm, vui->hw_if_index);
+  sw = vnet_get_hw_sw_interface (vnm, vui->hw_if_index);
   if (server_sock_fd != -1)
     {
       unix_file_t template = { 0 };
@@ -2715,7 +2800,6 @@ vhost_user_vui_init (vnet_main_t * vnm,
   vui->feature_mask = feature_mask;
   vui->unix_file_index = ~0;
   vui->log_base_addr = 0;
-  vui->operation_mode = operation_mode;
   vui->if_index = vui - vum->vhost_user_interfaces;
   mhash_set_mem (&vum->if_index_by_sock_name, vui->sock_filename,
 		 &vui->if_index, 0);
@@ -2723,6 +2807,7 @@ vhost_user_vui_init (vnet_main_t * vnm,
   for (q = 0; q < VHOST_VRING_MAX_N; q++)
     vhost_user_vring_init (vui, q);
 
+  hw->flags |= VNET_HW_INTERFACE_FLAG_SUPPORTS_INT_MODE;
   vnet_hw_interface_set_flags (vnm, vui->hw_if_index, 0);
 
   if (sw_if_index)
@@ -2740,106 +2825,13 @@ vhost_user_vui_init (vnet_main_t * vnm,
   vhost_user_tx_thread_placement (vui);
 }
 
-static uword
-vhost_user_send_interrupt_process (vlib_main_t * vm,
-				   vlib_node_runtime_t * rt, vlib_frame_t * f)
-{
-  vhost_user_intf_t *vui;
-  f64 timeout = 3153600000.0 /* 100 years */ ;
-  uword event_type, *event_data = 0;
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_iface_and_queue_t *vhiq;
-  vhost_cpu_t *vhc;
-  f64 now, poll_time_remaining;
-
-  while (1)
-    {
-      poll_time_remaining =
-	vlib_process_wait_for_event_or_clock (vm, timeout);
-      event_type = vlib_process_get_events (vm, &event_data);
-      vec_reset_length (event_data);
-
-      /*
-       * Use the remaining timeout if it is less than coalesce time to avoid
-       * resetting the existing timer in the middle of expiration
-       */
-      timeout = poll_time_remaining;
-      if (vlib_process_suspend_time_is_zero (timeout) ||
-	  (timeout > vum->coalesce_time))
-	timeout = vum->coalesce_time;
-
-      now = vlib_time_now (vm);
-      switch (event_type)
-	{
-	case VHOST_USER_EVENT_START_TIMER:
-	  if (!vlib_process_suspend_time_is_zero (poll_time_remaining))
-	    break;
-	  /* fall through */
-
-	case ~0:
-	  vec_foreach (vhc, vum->cpus)
-	  {
-	    u32 thread_index = vhc - vum->cpus;
-	    f64 next_timeout;
-
-	    next_timeout = timeout;
-	    vec_foreach (vhiq, vum->cpus[thread_index].rx_queues)
-	    {
-	      vui = &vum->vhost_user_interfaces[vhiq->vhost_iface_index];
-	      vhost_user_vring_t *rxvq =
-		&vui->vrings[VHOST_VRING_IDX_RX (vhiq->qid)];
-	      vhost_user_vring_t *txvq =
-		&vui->vrings[VHOST_VRING_IDX_TX (vhiq->qid)];
-
-	      if (txvq->n_since_last_int)
-		{
-		  if (now >= txvq->int_deadline)
-		    vhost_user_send_call (vm, txvq);
-		  else
-		    next_timeout = txvq->int_deadline - now;
-		}
-
-	      if (rxvq->n_since_last_int)
-		{
-		  if (now >= rxvq->int_deadline)
-		    vhost_user_send_call (vm, rxvq);
-		  else
-		    next_timeout = rxvq->int_deadline - now;
-		}
-
-	      if ((next_timeout < timeout) && (next_timeout > 0.0))
-		timeout = next_timeout;
-	    }
-	  }
-	  break;
-
-	default:
-	  clib_warning ("BUG: unhandled event type %d", event_type);
-	  break;
-	}
-      /* No less than 1 millisecond */
-      if (timeout < 1e-3)
-	timeout = 1e-3;
-    }
-  return 0;
-}
-
-/* *INDENT-OFF* */
-VLIB_REGISTER_NODE (vhost_user_send_interrupt_node,static) = {
-    .function = vhost_user_send_interrupt_process,
-    .type = VLIB_NODE_TYPE_PROCESS,
-    .name = "vhost-user-send-interrupt-process",
-};
-/* *INDENT-ON* */
-
 int
 vhost_user_create_if (vnet_main_t * vnm, vlib_main_t * vm,
 		      const char *sock_filename,
 		      u8 is_server,
 		      u32 * sw_if_index,
 		      u64 feature_mask,
-		      u8 renumber, u32 custom_dev_instance, u8 * hwaddr,
-		      u8 operation_mode)
+		      u8 renumber, u32 custom_dev_instance, u8 * hwaddr)
 {
   vhost_user_intf_t *vui = NULL;
   u32 sw_if_idx = ~0;
@@ -2848,10 +2840,6 @@ vhost_user_create_if (vnet_main_t * vnm, vlib_main_t * vm,
   vhost_user_main_t *vum = &vhost_user_main;
   uword *if_index;
 
-  if ((operation_mode != VHOST_USER_POLLING_MODE) &&
-      (operation_mode != VHOST_USER_INTERRUPT_MODE))
-    return VNET_API_ERROR_UNIMPLEMENTED;
-
   if (sock_filename == NULL || !(strlen (sock_filename) > 0))
     {
       return VNET_API_ERROR_INVALID_ARGUMENT;
@@ -2881,7 +2869,7 @@ vhost_user_create_if (vnet_main_t * vnm, vlib_main_t * vm,
 
   vhost_user_create_ethernet (vnm, vm, vui, hwaddr);
   vhost_user_vui_init (vnm, vui, server_sock_fd, sock_filename,
-		       feature_mask, &sw_if_idx, operation_mode);
+		       feature_mask, &sw_if_idx);
 
   if (renumber)
     vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
@@ -2892,14 +2880,6 @@ vhost_user_create_if (vnet_main_t * vnm, vlib_main_t * vm,
   // Process node must connect
   vlib_process_signal_event (vm, vhost_user_process_node.index, 0, 0);
 
-  if ((operation_mode == VHOST_USER_INTERRUPT_MODE) &&
-      !vum->interrupt_mode && (vum->coalesce_time > 0.0) &&
-      (vum->coalesce_frames > 0))
-    {
-      vum->interrupt_mode = 1;
-      vlib_process_signal_event (vm, vhost_user_send_interrupt_node.index,
-				 VHOST_USER_EVENT_START_TIMER, 0);
-    }
   return rv;
 }
 
@@ -2908,8 +2888,7 @@ vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
 		      const char *sock_filename,
 		      u8 is_server,
 		      u32 sw_if_index,
-		      u64 feature_mask, u8 renumber, u32 custom_dev_instance,
-		      u8 operation_mode)
+		      u64 feature_mask, u8 renumber, u32 custom_dev_instance)
 {
   vhost_user_main_t *vum = &vhost_user_main;
   vhost_user_intf_t *vui = NULL;
@@ -2919,9 +2898,6 @@ vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
   vnet_hw_interface_t *hwif;
   uword *if_index;
 
-  if ((operation_mode != VHOST_USER_POLLING_MODE) &&
-      (operation_mode != VHOST_USER_INTERRUPT_MODE))
-    return VNET_API_ERROR_UNIMPLEMENTED;
   if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
       hwif->dev_class_index != vhost_user_dev_class.index)
     return VNET_API_ERROR_INVALID_SW_IF_INDEX;
@@ -2947,8 +2923,7 @@ vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
 
   vhost_user_term_if (vui);
   vhost_user_vui_init (vnm, vui, server_sock_fd,
-		       sock_filename, feature_mask, &sw_if_idx,
-		       operation_mode);
+		       sock_filename, feature_mask, &sw_if_idx);
 
   if (renumber)
     vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
@@ -2956,33 +2931,9 @@ vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
   // Process node must connect
   vlib_process_signal_event (vm, vhost_user_process_node.index, 0, 0);
 
-  if ((operation_mode == VHOST_USER_INTERRUPT_MODE) &&
-      !vum->interrupt_mode && (vum->coalesce_time > 0.0) &&
-      (vum->coalesce_frames > 0))
-    {
-      vum->interrupt_mode = 1;
-      vlib_process_signal_event (vm, vhost_user_send_interrupt_node.index,
-				 VHOST_USER_EVENT_START_TIMER, 0);
-    }
   return rv;
 }
 
-static uword
-unformat_vhost_user_operation_mode (unformat_input_t * input, va_list * args)
-{
-  u8 *operation_mode = va_arg (*args, u8 *);
-  uword rc = 1;
-
-  if (unformat (input, "interrupt"))
-    *operation_mode = VHOST_USER_INTERRUPT_MODE;
-  else if (unformat (input, "polling"))
-    *operation_mode = VHOST_USER_POLLING_MODE;
-  else
-    rc = 0;
-
-  return rc;
-}
-
 clib_error_t *
 vhost_user_connect_command_fn (vlib_main_t * vm,
 			       unformat_input_t * input,
@@ -2998,7 +2949,6 @@ vhost_user_connect_command_fn (vlib_main_t * vm,
   u8 hwaddr[6];
   u8 *hw = NULL;
   clib_error_t *error = NULL;
-  u8 operation_mode = VHOST_USER_POLLING_MODE;
 
   /* Get a line of input. */
   if (!unformat_user (input, unformat_line_input, line_input))
@@ -3020,9 +2970,6 @@ vhost_user_connect_command_fn (vlib_main_t * vm,
 	{
 	  renumber = 1;
 	}
-      else if (unformat (line_input, "mode %U",
-			 unformat_vhost_user_operation_mode, &operation_mode))
-	;
       else
 	{
 	  error = clib_error_return (0, "unknown input `%U'",
@@ -3036,8 +2983,7 @@ vhost_user_connect_command_fn (vlib_main_t * vm,
   int rv;
   if ((rv = vhost_user_create_if (vnm, vm, (char *) sock_filename,
 				  is_server, &sw_if_index, feature_mask,
-				  renumber, custom_dev_instance, hw,
-				  operation_mode)))
+				  renumber, custom_dev_instance, hw)))
     {
       error = clib_error_return (0, "vhost_user_create_if returned %d", rv);
       goto done;
@@ -3127,7 +3073,6 @@ vhost_user_dump_ifs (vnet_main_t * vnm, vlib_main_t * vm,
       vui = pool_elt_at_index (vum->vhost_user_interfaces, hi->dev_instance);
 
       vec_add2 (r_vuids, vuid, 1);
-      vuid->operation_mode = vui->operation_mode;
       vuid->sw_if_index = vui->sw_if_index;
       vuid->virtio_net_hdr_sz = vui->virtio_net_hdr_sz;
       vuid->features = vui->features;
@@ -3152,25 +3097,6 @@ vhost_user_dump_ifs (vnet_main_t * vnm, vlib_main_t * vm,
   return rv;
 }
 
-static u8 *
-format_vhost_user_operation_mode (u8 * s, va_list * va)
-{
-  int operation_mode = va_arg (*va, int);
-
-  switch (operation_mode)
-    {
-    case VHOST_USER_POLLING_MODE:
-      s = format (s, "%s", "polling");
-      break;
-    case VHOST_USER_INTERRUPT_MODE:
-      s = format (s, "%s", "interrupt");
-      break;
-    default:
-      s = format (s, "%s", "invalid");
-    }
-  return s;
-}
-
 clib_error_t *
 show_vhost_user_command_fn (vlib_main_t * vm,
 			    unformat_input_t * input,
@@ -3182,10 +3108,8 @@ show_vhost_user_command_fn (vlib_main_t * vm,
   vhost_user_intf_t *vui;
   u32 hw_if_index, *hw_if_indices = 0;
   vnet_hw_interface_t *hi;
-  vhost_cpu_t *vhc;
-  vhost_iface_and_queue_t *vhiq;
+  u16 *queue;
   u32 ci;
-
   int i, j, q;
   int show_descr = 0;
   struct feat_struct
@@ -3238,6 +3162,8 @@ show_vhost_user_command_fn (vlib_main_t * vm,
   vlib_cli_output (vm, "Virtio vhost-user interfaces");
   vlib_cli_output (vm, "Global:\n  coalesce frames %d time %e",
 		   vum->coalesce_frames, vum->coalesce_time);
+  vlib_cli_output (vm, "  number of rx virtqueues in interrupt mode: %d",
+		   vum->ifq_count);
 
   for (i = 0; i < vec_len (hw_if_indices); i++)
     {
@@ -3279,23 +3205,21 @@ show_vhost_user_command_fn (vlib_main_t * vm,
 		       (vui->unix_server_index != ~0) ? "server" : "client",
 		       strerror (vui->sock_errno));
 
-      vlib_cli_output (vm, " configured mode: %U\n",
-		       format_vhost_user_operation_mode, vui->operation_mode);
       vlib_cli_output (vm, " rx placement: ");
-      vec_foreach (vhc, vum->cpus)
+
+      vec_foreach (queue, vui->rx_queues)
       {
-	vec_foreach (vhiq, vhc->rx_queues)
-	{
-	  if (vhiq->vhost_iface_index == vui - vum->vhost_user_interfaces)
-	    {
-	      vlib_cli_output (vm, "   thread %d on vring %d\n",
-			       vhc - vum->cpus,
-			       VHOST_VRING_IDX_TX (vhiq->qid));
-	      vlib_cli_output (vm, "   mode: %U\n",
-			       format_vhost_user_operation_mode,
-			       vhc->operation_mode);
-	    }
-	}
+	vnet_main_t *vnm = vnet_get_main ();
+	uword thread_index;
+	vnet_hw_interface_rx_mode mode;
+
+	thread_index = vnet_get_device_input_thread_index (vnm,
+							   vui->hw_if_index,
+							   *queue);
+	vnet_hw_interface_get_rx_mode (vnm, vui->hw_if_index, *queue, &mode);
+	vlib_cli_output (vm, "   thread %d on vring %d, %U\n",
+			 thread_index, VHOST_VRING_IDX_TX (*queue),
+			 format_vnet_hw_interface_rx_mode, mode);
       }
 
       vlib_cli_output (vm, " tx placement: %s\n",
@@ -3444,8 +3368,7 @@ done:
 VLIB_CLI_COMMAND (vhost_user_connect_command, static) = {
     .path = "create vhost-user",
     .short_help = "create vhost-user socket <socket-filename> [server] "
-    "[feature-mask <hex>] [hwaddr <mac-addr>] [renumber <dev_instance>] "
-    "[mode {interrupt | polling}]",
+    "[feature-mask <hex>] [hwaddr <mac-addr>] [renumber <dev_instance>] ",
     .function = vhost_user_connect_command_fn,
 };
 /* *INDENT-ON* */
@@ -3648,69 +3571,6 @@ vhost_user_unmap_all (void)
     }
 }
 
-static clib_error_t *
-vhost_thread_command_fn (vlib_main_t * vm,
-			 unformat_input_t * input, vlib_cli_command_t * cmd)
-{
-  unformat_input_t _line_input, *line_input = &_line_input;
-  u32 worker_thread_index;
-  u32 sw_if_index;
-  u8 del = 0;
-  int rv;
-  clib_error_t *error = NULL;
-
-  /* Get a line of input. */
-  if (!unformat_user (input, unformat_line_input, line_input))
-    return 0;
-
-  if (!unformat
-      (line_input, "%U %d", unformat_vnet_sw_interface, vnet_get_main (),
-       &sw_if_index, &worker_thread_index))
-    {
-      error = clib_error_return (0, "unknown input `%U'",
-				 format_unformat_error, line_input);
-      goto done;
-    }
-
-  if (unformat (line_input, "del"))
-    del = 1;
-
-  if ((rv =
-       vhost_user_thread_placement (sw_if_index, worker_thread_index, del)))
-    {
-      error = clib_error_return (0, "vhost_user_thread_placement returned %d",
-				 rv);
-      goto done;
-    }
-
-done:
-  unformat_free (line_input);
-
-  return error;
-}
-
-
-/*?
- * This command is used to move the RX processing for the given
- * interfaces to the provided thread. If the '<em>del</em>' option is used,
- * the forced thread assignment is removed and the thread assigment is
- * reassigned automatically. Use '<em>show vhost-user <interface></em>'
- * to see the thread assignment.
- *
- * @cliexpar
- * Example of how to move the RX processing for a given interface to a given thread:
- * @cliexcmd{vhost thread VirtualEthernet0/0/0 1}
- * Example of how to remove the forced thread assignment for a given interface:
- * @cliexcmd{vhost thread VirtualEthernet0/0/0 1 del}
-?*/
-/* *INDENT-OFF* */
-VLIB_CLI_COMMAND (vhost_user_thread_command, static) = {
-    .path = "vhost thread",
-    .short_help = "vhost thread <iface> <worker-index> [del]",
-    .function = vhost_thread_command_fn,
-};
-/* *INDENT-ON* */
-
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vnet/devices/virtio/vhost-user.h b/src/vnet/devices/virtio/vhost-user.h
index 56b65477b19..ceced342c92 100644
--- a/src/vnet/devices/virtio/vhost-user.h
+++ b/src/vnet/devices/virtio/vhost-user.h
@@ -66,13 +66,11 @@ typedef enum
 int vhost_user_create_if (vnet_main_t * vnm, vlib_main_t * vm,
 			  const char *sock_filename, u8 is_server,
 			  u32 * sw_if_index, u64 feature_mask,
-			  u8 renumber, u32 custom_dev_instance, u8 * hwaddr,
-			  u8 operation_mode);
+			  u8 renumber, u32 custom_dev_instance, u8 * hwaddr);
 int vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
 			  const char *sock_filename, u8 is_server,
 			  u32 sw_if_index, u64 feature_mask,
-			  u8 renumber, u32 custom_dev_instance,
-			  u8 operation_mode);
+			  u8 renumber, u32 custom_dev_instance);
 int vhost_user_delete_if (vnet_main_t * vnm, vlib_main_t * vm,
 			  u32 sw_if_index);
 
@@ -210,14 +208,13 @@ typedef struct
   u32 callfd_idx;
   u32 kickfd_idx;
   u64 log_guest_addr;
-  u32 interrupt_thread_index;
-} vhost_user_vring_t;
 
-#define VHOST_USER_POLLING_MODE   0
-#define VHOST_USER_INTERRUPT_MODE 1
-#define VHOST_USER_ADAPTIVE_MODE  2
+  /* The rx queue policy (interrupt/adaptive/polling) for this queue */
+  u32 mode;
+} vhost_user_vring_t;
 
 #define VHOST_USER_EVENT_START_TIMER 1
+#define VHOST_USER_EVENT_STOP_TIMER  2
 
 typedef struct
 {
@@ -258,20 +255,12 @@ typedef struct
   u8 use_tx_spinlock;
   u16 *per_cpu_tx_qid;
 
-  /* Vector of workers for this interface */
-  u32 *workers;
-
-  u8 operation_mode;
+  /* Vector of active rx queues for this interface */
+  u16 *rx_queues;
 } vhost_user_intf_t;
 
 typedef struct
 {
-  u16 vhost_iface_index;
-  u16 qid;
-} vhost_iface_and_queue_t;
-
-typedef struct
-{
   uword dst;
   uword src;
   u32 len;
@@ -292,7 +281,6 @@ typedef struct
 
 typedef struct
 {
-  vhost_iface_and_queue_t *rx_queues;
   u32 rx_buffers_len;
   u32 rx_buffers[VHOST_USER_RX_BUFFERS_N];
 
@@ -302,12 +290,6 @@ typedef struct
   /* This is here so it doesn't end-up
    * using stack or registers. */
   vhost_trace_t *current_trace;
-
-  /* bitmap of pending rx interfaces */
-  uword *pending_input_bitmap;
-
-  /* The operation mode computed per cpu based on interface setting */
-  u8 operation_mode;
 } vhost_cpu_t;
 
 typedef struct
@@ -320,20 +302,14 @@ typedef struct
   f64 coalesce_time;
   int dont_dump_vhost_user_memory;
 
-  /** first cpu index */
-  u32 input_cpu_first_index;
-
-  /** total cpu count */
-  u32 input_cpu_count;
-
   /** Per-CPU data for vhost-user */
   vhost_cpu_t *cpus;
 
   /** Pseudo random iterator */
   u32 random;
 
-  /* Node is in interrupt mode */
-  u8 interrupt_mode;
+  /* The number of rx interface/queue pairs in interrupt mode */
+  u32 ifq_count;
 } vhost_user_main_t;
 
 typedef struct
@@ -346,7 +322,6 @@ typedef struct
   u8 sock_filename[256];
   u32 num_regions;
   int sock_errno;
-  u8 operation_mode;
 } vhost_user_intf_details_t;
 
 int vhost_user_dump_ifs (vnet_main_t * vnm, vlib_main_t * vm,
diff --git a/src/vnet/devices/virtio/vhost_user_api.c b/src/vnet/devices/virtio/vhost_user_api.c
index ac7afa611b6..8dbd032b117 100644
--- a/src/vnet/devices/virtio/vhost_user_api.c
+++ b/src/vnet/devices/virtio/vhost_user_api.c
@@ -81,8 +81,7 @@ vl_api_create_vhost_user_if_t_handler (vl_api_create_vhost_user_if_t * mp)
   rv = vhost_user_create_if (vnm, vm, (char *) mp->sock_filename,
 			     mp->is_server, &sw_if_index, (u64) ~ 0,
 			     mp->renumber, ntohl (mp->custom_dev_instance),
-			     (mp->use_custom_mac) ? mp->mac_address : NULL,
-			     mp->operation_mode);
+			     (mp->use_custom_mac) ? mp->mac_address : NULL);
 
   /* Remember an interface tag for the new interface */
   if (rv == 0)
@@ -117,8 +116,7 @@ vl_api_modify_vhost_user_if_t_handler (vl_api_modify_vhost_user_if_t * mp)
 
   rv = vhost_user_modify_if (vnm, vm, (char *) mp->sock_filename,
 			     mp->is_server, sw_if_index, (u64) ~ 0,
-			     mp->renumber, ntohl (mp->custom_dev_instance),
-			     mp->operation_mode);
+			     mp->renumber, ntohl (mp->custom_dev_instance));
 
   REPLY_MACRO (VL_API_MODIFY_VHOST_USER_IF_REPLY);
 }
@@ -164,7 +162,6 @@ send_sw_interface_vhost_user_details (vpe_api_main_t * am,
   mp->virtio_net_hdr_sz = ntohl (vui->virtio_net_hdr_sz);
   mp->features = clib_net_to_host_u64 (vui->features);
   mp->is_server = vui->is_server;
-  mp->operation_mode = vui->operation_mode;
   mp->num_regions = ntohl (vui->num_regions);
   mp->sock_errno = ntohl (vui->sock_errno);
   mp->context = context;