Add RDMA ibverb driver plugin

RDMA ibverb is a userspace API to efficiently rx/tx packets. This is an
initial, unoptimized driver targeting Mellanox cards.
Next steps should include batching, multiqueue and additional cards.

Change-Id: I0309c7a543f75f2f9317eaf63ca502ac7a093ef9
Signed-off-by: Benoît Ganne <bganne@cisco.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/src/plugins/rdma/output.c b/src/plugins/rdma/output.c
new file mode 100644
index 00000000000..410784308f3
--- /dev/null
+++ b/src/plugins/rdma/output.c
@@ -0,0 +1,133 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <vlib/vlib.h>
+#include <vlib/unix/unix.h>
+#include <vlib/pci/pci.h>
+#include <vppinfra/ring.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/devices/devices.h>
+
+#include <rdma/rdma.h>
+
+static_always_inline u16
+rdma_device_output_tx (vlib_main_t * vm, rdma_device_t * rd, rdma_txq_t * txq,
+		       u32 * buffers, u16 n_left, u32 * n_tx_packets,
+		       u32 * n_tx_bytes)
+{
+  struct ibv_sge sg_entry;
+  struct ibv_send_wr wr, *bad_wr;
+  u16 i;
+
+  for (i = 0; i < n_left; i++)
+    {
+      vlib_buffer_t *b = vlib_get_buffer (vm, buffers[i]);
+      sg_entry.addr = vlib_buffer_get_current_va (b);
+      sg_entry.length = b->current_length;
+      sg_entry.lkey = rd->mr->lkey;
+
+      memset (&wr, 0, sizeof (wr));
+      wr.num_sge = 1;
+      wr.sg_list = &sg_entry;
+      wr.opcode = IBV_WR_SEND;
+      wr.send_flags = IBV_SEND_SIGNALED;
+      wr.wr_id = buffers[i];
+
+      if (ibv_post_send (txq->qp, &wr, &bad_wr) != 0)
+	break;
+
+      *n_tx_bytes += b->current_length;
+    }
+
+  *n_tx_packets += i;
+  return i;
+}
+
+static_always_inline void
+rdma_device_output_free (vlib_main_t * vm, rdma_txq_t * txq)
+{
+  struct ibv_wc wc[VLIB_FRAME_SIZE];
+  u32 to_free[VLIB_FRAME_SIZE];
+  int n_free;
+  int i;
+
+  n_free = ibv_poll_cq (txq->cq, VLIB_FRAME_SIZE, wc);
+  if (n_free <= 0)
+    return;
+
+  for (i = 0; i < n_free; i++)
+    to_free[i] = wc[i].wr_id;
+
+  vlib_buffer_free (vm, to_free, n_free);
+}
+
+VNET_DEVICE_CLASS_TX_FN (rdma_device_class) (vlib_main_t * vm,
+					     vlib_node_runtime_t * node,
+					     vlib_frame_t * frame)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  rdma_main_t *rm = &rdma_main;
+  vnet_interface_output_runtime_t *ord = (void *) node->runtime_data;
+  rdma_device_t *rd = pool_elt_at_index (rm->devices, ord->dev_instance);
+  u32 thread_index = vm->thread_index;
+  u8 qid = thread_index;
+  rdma_txq_t *txq = vec_elt_at_index (rd->txqs, qid % vec_len (rd->txqs));
+  u32 *buffers = vlib_frame_vector_args (frame);
+  u16 n_left;
+  u16 n_retry = 5;
+  u32 n_tx_packets = 0, n_tx_bytes = 0;
+
+  clib_spinlock_lock_if_init (&txq->lock);
+
+  n_left = frame->n_vectors;
+
+  while (n_left)
+    {
+      u16 n;
+      rdma_device_output_free (vm, txq);
+      n =
+	rdma_device_output_tx (vm, rd, txq, buffers, n_left, &n_tx_packets,
+			       &n_tx_bytes);
+      n_left -= n;
+      buffers += n;
+
+      if (n_left && n_retry--)
+	{
+	  vlib_buffer_free (vm, buffers, n_left);
+	  vlib_error_count (vm, node->node_index,
+			    RDMA_TX_ERROR_NO_FREE_SLOTS, n_left);
+	  break;
+	}
+    }
+
+  clib_spinlock_unlock_if_init (&txq->lock);
+
+  vlib_increment_combined_counter
+    (vnm->interface_main.combined_sw_if_counters +
+     VNET_INTERFACE_COUNTER_TX, thread_index,
+     rd->hw_if_index, n_tx_packets, n_tx_bytes);
+
+  return frame->n_vectors - n_left;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */