virtio: add atomic call for kicking

Type: fix

Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
Change-Id: I41faa2ca249ff75e564a732af896e6b5d76bf665

3 files changed, 9 insertions, 20 deletions

diff --git a/src/vnet/devices/virtio/device.c b/src/vnet/devices/virtio/device.c
index 5796b1d2150..3482336b2ad 100644
--- a/src/vnet/devices/virtio/device.c
+++ b/src/vnet/devices/virtio/device.c
@@ -926,11 +926,11 @@ virtio_interface_tx_split_gso_inline (vlib_main_t * vm,
 
   if (n_left != n_vectors || n_buffers != n_buffers_left)
     {
-      CLIB_MEMORY_STORE_BARRIER ();
-      vring->avail->idx = avail;
+      clib_atomic_store_seq_cst (&vring->avail->idx, avail);
       vring->desc_next = next;
       vring->desc_in_use = used;
-      if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0)
+      if ((clib_atomic_load_seq_cst (&vring->used->flags) &
+	   VRING_USED_F_NO_NOTIFY) == 0)
 	virtio_kick (vm, vring, vif);
     }
 
@@ -997,12 +997,6 @@ VNET_DEVICE_CLASS_TX_FN (virtio_device_class) (vlib_main_t * vm,
 
   clib_spinlock_lock_if_init (&vring->lockp);
 
-  if (packed && (vring->device_event->flags != VRING_EVENT_F_DISABLE))
-    virtio_kick (vm, vring, vif);
-  else if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0 &&
-	   (vring->last_kick_avail_idx != vring->avail->idx))
-    virtio_kick (vm, vring, vif);
-
   if (vif->packet_coalesce)
     {
       n_vectors = n_left =
diff --git a/src/vnet/devices/virtio/node.c b/src/vnet/devices/virtio/node.c
index 788cc617f61..4a2e305a22e 100644
--- a/src/vnet/devices/virtio/node.c
+++ b/src/vnet/devices/virtio/node.c
@@ -135,12 +135,11 @@ more:
       n_slots--;
       used++;
     }
-  CLIB_MEMORY_STORE_BARRIER ();
-  vring->avail->idx = avail;
+  clib_atomic_store_seq_cst (&vring->avail->idx, avail);
   vring->desc_next = next;
   vring->desc_in_use = used;
-
-  if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0)
+  if ((clib_atomic_load_seq_cst (&vring->used->flags) &
+       VRING_USED_F_NO_NOTIFY) == 0)
     {
       virtio_kick (vm, vring, vif);
     }
@@ -588,9 +587,6 @@ virtio_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 
   if (vif->is_packed)
     {
-      if (vring->device_event->flags != VRING_EVENT_F_DISABLE)
-	virtio_kick (vm, vring, vif);
-
       if (vif->gso_enabled)
 	rv =
 	  virtio_device_input_gso_inline (vm, node, frame, vif, vring, type,
@@ -609,10 +605,6 @@ virtio_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
     }
   else
     {
-      if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0 &&
-	  vring->last_kick_avail_idx != vring->avail->idx)
-	virtio_kick (vm, vring, vif);
-
       if (vif->gso_enabled)
 	rv =
 	  virtio_device_input_gso_inline (vm, node, frame, vif, vring, type,
diff --git a/src/vppinfra/atomics.h b/src/vppinfra/atomics.h
index 170b54a8477..5d3c5f8d601 100644
--- a/src/vppinfra/atomics.h
+++ b/src/vppinfra/atomics.h
@@ -50,6 +50,9 @@
 #define clib_atomic_load_relax_n(a) __atomic_load_n((a), __ATOMIC_RELAXED)
 #define clib_atomic_load_acq_n(a) __atomic_load_n((a), __ATOMIC_ACQUIRE)
 #define clib_atomic_store_rel_n(a, b) __atomic_store_n ((a), (b), __ATOMIC_RELEASE)
+#define clib_atomic_store_seq_cst(a, b)                                       \
+  __atomic_store_n ((a), (b), __ATOMIC_SEQ_CST)
+#define clib_atomic_load_seq_cst(a) __atomic_load_n ((a), __ATOMIC_SEQ_CST)
 
 #define clib_atomic_swap_acq_n(a, b) __atomic_exchange_n ((a), (b), __ATOMIC_ACQUIRE)
 #define clib_atomic_swap_rel_n(a, b) __atomic_exchange_n ((a), (b), __ATOMIC_RELEASE)