diff --git a/src/vnet/devices/virtio/vhost-user.c b/src/vnet/devices/virtio/vhost-user.c
index c16e982..b6b4c04 100644
--- a/src/vnet/devices/virtio/vhost-user.c
+++ b/src/vnet/devices/virtio/vhost-user.c
@@ -2540,7 +2540,7 @@
 		     vhost_user_intf_t * vui,
 		     int server_sock_fd,
 		     const char *sock_filename,
-		     u64 feature_mask, u32 * sw_if_index)
+		     u64 feature_mask, u32 * sw_if_index, u8 operation_mode)
 {
   vnet_sw_interface_t *sw;
   sw = vnet_get_hw_sw_interface (vnm, vui->hw_if_index);
@@ -2567,6 +2567,7 @@
   vui->feature_mask = feature_mask;
   vui->unix_file_index = ~0;
   vui->log_base_addr = 0;
+  vui->operation_mode = operation_mode;
 
   for (q = 0; q < VHOST_VRING_MAX_N; q++)
     vhost_user_vring_init (vui, q);
@@ -2594,13 +2595,17 @@
 		      u8 is_server,
 		      u32 * sw_if_index,
 		      u64 feature_mask,
-		      u8 renumber, u32 custom_dev_instance, u8 * hwaddr)
+		      u8 renumber, u32 custom_dev_instance, u8 * hwaddr,
+		      u8 operation_mode)
 {
   vhost_user_intf_t *vui = NULL;
   u32 sw_if_idx = ~0;
   int rv = 0;
   int server_sock_fd = -1;
 
+  if (operation_mode != VHOST_USER_POLLING_MODE)
+    return VNET_API_ERROR_UNIMPLEMENTED;
+
   if (sock_filename == NULL || !(strlen (sock_filename) > 0))
     {
       return VNET_API_ERROR_INVALID_ARGUMENT;
@@ -2619,7 +2624,7 @@
 
   vhost_user_create_ethernet (vnm, vm, vui, hwaddr);
   vhost_user_vui_init (vnm, vui, server_sock_fd, sock_filename,
-		       feature_mask, &sw_if_idx);
+		       feature_mask, &sw_if_idx, operation_mode);
 
   if (renumber)
     vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
@@ -2637,7 +2642,8 @@
 		      const char *sock_filename,
 		      u8 is_server,
 		      u32 sw_if_index,
-		      u64 feature_mask, u8 renumber, u32 custom_dev_instance)
+		      u64 feature_mask, u8 renumber, u32 custom_dev_instance,
+		      u8 operation_mode)
 {
   vhost_user_main_t *vum = &vhost_user_main;
   vhost_user_intf_t *vui = NULL;
@@ -2646,6 +2652,8 @@
   int rv = 0;
   vnet_hw_interface_t *hwif;
 
+  if (operation_mode != VHOST_USER_POLLING_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;
@@ -2660,7 +2668,8 @@
 
   vhost_user_term_if (vui);
   vhost_user_vui_init (vnm, vui, server_sock_fd,
-		       sock_filename, feature_mask, &sw_if_idx);
+		       sock_filename, feature_mask, &sw_if_idx,
+		       operation_mode);
 
   if (renumber)
     vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
@@ -2685,6 +2694,7 @@
   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))
@@ -2719,7 +2729,8 @@
   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)))
+				  renumber, custom_dev_instance, hw,
+				  operation_mode)))
     {
       error = clib_error_return (0, "vhost_user_create_if returned %d", rv);
       goto done;
@@ -2809,6 +2820,7 @@
       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;
diff --git a/src/vnet/devices/virtio/vhost-user.h b/src/vnet/devices/virtio/vhost-user.h
index dd23a90..6b928f0 100644
--- a/src/vnet/devices/virtio/vhost-user.h
+++ b/src/vnet/devices/virtio/vhost-user.h
@@ -42,6 +42,7 @@
 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        0x8000
 
 #define VRING_USED_F_NO_NOTIFY  1
+#define VRING_AVAIL_F_NO_INTERRUPT 1
 
 #define foreach_virtio_net_feature      \
  _ (VIRTIO_NET_F_MRG_RXBUF, 15)         \
@@ -65,11 +66,13 @@
 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 renumber, u32 custom_dev_instance, u8 * hwaddr,
+			  u8 operation_mode);
 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 renumber, u32 custom_dev_instance,
+			  u8 operation_mode);
 int vhost_user_delete_if (vnet_main_t * vnm, vlib_main_t * vm,
 			  u32 sw_if_index);
 
@@ -209,6 +212,10 @@
   u64 log_guest_addr;
 } vhost_user_vring_t;
 
+#define VHOST_USER_POLLING_MODE   0
+#define VHOST_USER_INTERRUPT_MODE 1
+#define VHOST_USER_ADAPTIVE_MODE  2
+
 typedef struct
 {
   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
@@ -249,6 +256,8 @@
 
   /* Vector of workers for this interface */
   u32 *workers;
+
+  u8 operation_mode;
 } vhost_user_intf_t;
 
 typedef struct
@@ -323,6 +332,7 @@
   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 b/src/vnet/devices/virtio/vhost_user.api
index 21e4229..4f604e4 100644
--- a/src/vnet/devices/virtio/vhost_user.api
+++ b/src/vnet/devices/virtio/vhost_user.api
@@ -19,6 +19,7 @@
     @param sock_filename - unix socket filename, used to speak with frontend
     @param use_custom_mac - enable or disable the use of the provided hardware address
     @param mac_address - hardware address to use if 'use_custom_mac' is set
+    @param operation_mode - polling=0, interrupt=1, or adaptive=2
 */
 define create_vhost_user_if
 {
@@ -31,6 +32,7 @@
   u8 use_custom_mac;
   u8 mac_address[6];
   u8 tag[64];
+  u8 operation_mode;
 };
 
 /** \brief vhost-user interface create response
@@ -49,6 +51,7 @@
     @param client_index - opaque cookie to identify the sender
     @param is_server - our side is socket server
     @param sock_filename - unix socket filename, used to speak with frontend
+    @param operation_mode - polling=0, interrupt=1, or adaptive=2
 */
 define modify_vhost_user_if
 {
@@ -59,6 +62,7 @@
   u8 sock_filename[256];
   u8 renumber;
   u32 custom_dev_instance;
+  u8 operation_mode;
 };
 
 /** \brief vhost-user interface modify response
@@ -99,6 +103,7 @@
     @param is_server - vhost-user server socket
     @param sock_filename - socket filename
     @param num_regions - number of used memory regions
+    @param operation_mode - polling=0, interrupt=1, or adaptive=2
 */
 define sw_interface_vhost_user_details
 {
@@ -111,6 +116,7 @@
   u8 sock_filename[256];
   u32 num_regions;
   i32 sock_errno;
+  u8 operation_mode;
 };
 
 define sw_interface_vhost_user_dump
diff --git a/src/vnet/devices/virtio/vhost_user_api.c b/src/vnet/devices/virtio/vhost_user_api.c
index 8dbd032..ac7afa6 100644
--- a/src/vnet/devices/virtio/vhost_user_api.c
+++ b/src/vnet/devices/virtio/vhost_user_api.c
@@ -81,7 +81,8 @@
   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->use_custom_mac) ? mp->mac_address : NULL,
+			     mp->operation_mode);
 
   /* Remember an interface tag for the new interface */
   if (rv == 0)
@@ -116,7 +117,8 @@
 
   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->renumber, ntohl (mp->custom_dev_instance),
+			     mp->operation_mode);
 
   REPLY_MACRO (VL_API_MODIFY_VHOST_USER_IF_REPLY);
 }
@@ -162,6 +164,7 @@
   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;