device.c

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/*
 *------------------------------------------------------------------
 * Copyright (c) 2016 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.
 *------------------------------------------------------------------
 */
 
#define _GNU_SOURCE
#include <stdint.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/uio.h>
 
#include <vlib/vlib.h>
#include <vlib/unix/unix.h>
#include <vnet/ethernet/ethernet.h>
 
#include <memif/memif.h>
#include <memif/private.h>
 
#define foreach_memif_tx_func_error                                           \
  _ (NO_FREE_SLOTS, no_free_slots, ERROR, "no free tx slots")                 \
  _ (ROLLBACK, rollback, ERROR, "no enough space in tx buffers")
 
typedef enum
{
#define _(f, n, s, d) MEMIF_TX_ERROR_##f,
  foreach_memif_tx_func_error
#undef _
    MEMIF_TX_N_ERROR,
} memif_tx_func_error_t;
 
static vlib_error_desc_t memif_tx_func_error_counters[] = {
#define _(f, n, s, d) { #n, d, VL_COUNTER_SEVERITY_##s },
  foreach_memif_tx_func_error
#undef _
};
 
#ifndef CLIB_MARCH_VARIANT
u8 *
format_memif_device_name (u8 * s, va_list * args)
{
  u32 dev_instance = va_arg (*args, u32);
  memif_main_t *mm = &memif_main;
  memif_if_t *mif = pool_elt_at_index (mm->interfaces, dev_instance);
  memif_socket_file_t *msf;
 
  msf = pool_elt_at_index (mm->socket_files, mif->socket_file_index);
  s = format (s, "memif%lu/%lu", msf->socket_id, mif->id);
  return s;
}
#endif
 
static u8 *
format_memif_device (u8 * s, va_list * args)
{
  u32 dev_instance = va_arg (*args, u32);
  int verbose = va_arg (*args, int);
  u32 indent = format_get_indent (s);
 
  s = format (s, "MEMIF interface");
  if (verbose)
    {
      s = format (s, "\n%U instance %u", format_white_space, indent + 2,
                  dev_instance);
    }
  return s;
}
 
static u8 *
format_memif_tx_trace (u8 * s, va_list * args)
{
  s = format (s, "Unimplemented...");
  return s;
}
 
static_always_inline void
memif_add_copy_op (memif_per_thread_data_t * ptd, void *data, u32 len,
                   u16 buffer_offset, u16 buffer_vec_index)
{
  memif_copy_op_t *co;
  vec_add2_aligned (ptd->copy_ops, co, 1, CLIB_CACHE_LINE_BYTES);
  co->data = data;
  co->data_len = len;
  co->buffer_offset = buffer_offset;
  co->buffer_vec_index = buffer_vec_index;
}
 
static_always_inline uword
memif_interface_tx_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
                           u32 *buffers, memif_if_t *mif,
                           memif_ring_type_t type, memif_queue_t *mq,
                           memif_per_thread_data_t *ptd, u32 n_left)
{
  memif_ring_t *ring;
  u32 n_copy_op;
  u16 ring_size, mask, slot, free_slots;
  int n_retries = 5;
  vlib_buffer_t *b0, *b1, *b2, *b3;
  memif_copy_op_t *co;
  memif_region_index_t last_region = ~0;
  void *last_region_shm = 0;
  u16 head, tail;
 
  ring = mq->ring;
  ring_size = 1 << mq->log2_ring_size;
  mask = ring_size - 1;
 
retry:
 
  if (type == MEMIF_RING_S2M)
    {
      slot = head = ring->head;
      tail = __atomic_load_n (&ring->tail, __ATOMIC_ACQUIRE);
      mq->last_tail += tail - mq->last_tail;
      free_slots = ring_size - head + mq->last_tail;
    }
  else
    {
      slot = tail = ring->tail;
      head = __atomic_load_n (&ring->head, __ATOMIC_ACQUIRE);
      mq->last_tail += tail - mq->last_tail;
      free_slots = head - tail;
    }
 
  while (n_left && free_slots)
    {
      memif_desc_t *d0;
      void *mb0;
      i32 src_off;
      u32 bi0, dst_off, src_left, dst_left, bytes_to_copy;
      u32 saved_ptd_copy_ops_len = _vec_len (ptd->copy_ops);
      u32 saved_ptd_buffers_len = _vec_len (ptd->buffers);
      u16 saved_slot = slot;
 
      clib_prefetch_load (&ring->desc[(slot + 8) & mask]);
 
      d0 = &ring->desc[slot & mask];
      if (PREDICT_FALSE (last_region != d0->region))
        {
          last_region_shm = mif->regions[d0->region].shm;
          last_region = d0->region;
        }
      mb0 = last_region_shm + d0->offset;
 
      dst_off = 0;
 
      /* slave is the producer, so it should be able to reset buffer length */
      dst_left = (type == MEMIF_RING_S2M) ? mif->run.buffer_size : d0->length;
 
      if (PREDICT_TRUE (n_left >= 4))
        vlib_prefetch_buffer_header (vlib_get_buffer (vm, buffers[3]), LOAD);
      bi0 = buffers[0];
 
    next_in_chain:
 
      b0 = vlib_get_buffer (vm, bi0);
      src_off = b0->current_data;
      src_left = b0->current_length;
 
      while (src_left)
        {
          if (PREDICT_FALSE (dst_left == 0))
            {
              if (free_slots)
                {
                  slot++;
                  free_slots--;
                  d0->length = dst_off;
                  d0->flags = MEMIF_DESC_FLAG_NEXT;
                  d0 = &ring->desc[slot & mask];
                  dst_off = 0;
                  dst_left =
                    (type ==
                     MEMIF_RING_S2M) ? mif->run.buffer_size : d0->length;
 
                  if (PREDICT_FALSE (last_region != d0->region))
                    {
                      last_region_shm = mif->regions[d0->region].shm;
                      last_region = d0->region;
                    }
                  mb0 = last_region_shm + d0->offset;
                }
              else
                {
                  /* we need to rollback vectors before bailing out */
                  _vec_len (ptd->buffers) = saved_ptd_buffers_len;
                  _vec_len (ptd->copy_ops) = saved_ptd_copy_ops_len;
                  vlib_error_count (vm, node->node_index,
                                    MEMIF_TX_ERROR_ROLLBACK, 1);
                  slot = saved_slot;
                  goto no_free_slots;
                }
            }
          bytes_to_copy = clib_min (src_left, dst_left);
          memif_add_copy_op (ptd, mb0 + dst_off, bytes_to_copy, src_off,
                             vec_len (ptd->buffers));
          vec_add1_aligned (ptd->buffers, bi0, CLIB_CACHE_LINE_BYTES);
          src_off += bytes_to_copy;
          dst_off += bytes_to_copy;
          src_left -= bytes_to_copy;
          dst_left -= bytes_to_copy;
        }
 
      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_NEXT_PRESENT))
        {
          bi0 = b0->next_buffer;
          goto next_in_chain;
        }
 
      d0->length = dst_off;
      d0->flags = 0;
 
      free_slots -= 1;
      slot += 1;
 
      buffers++;
      n_left--;
    }
no_free_slots:
 
  /* copy data */
  n_copy_op = vec_len (ptd->copy_ops);
  co = ptd->copy_ops;
  while (n_copy_op >= 8)
    {
      clib_prefetch_load (co[4].data);
      clib_prefetch_load (co[5].data);
      clib_prefetch_load (co[6].data);
      clib_prefetch_load (co[7].data);
 
      b0 = vlib_get_buffer (vm, ptd->buffers[co[0].buffer_vec_index]);
      b1 = vlib_get_buffer (vm, ptd->buffers[co[1].buffer_vec_index]);
      b2 = vlib_get_buffer (vm, ptd->buffers[co[2].buffer_vec_index]);
      b3 = vlib_get_buffer (vm, ptd->buffers[co[3].buffer_vec_index]);
 
      clib_memcpy_fast (co[0].data, b0->data + co[0].buffer_offset,
                        co[0].data_len);
      clib_memcpy_fast (co[1].data, b1->data + co[1].buffer_offset,
                        co[1].data_len);
      clib_memcpy_fast (co[2].data, b2->data + co[2].buffer_offset,
                        co[2].data_len);
      clib_memcpy_fast (co[3].data, b3->data + co[3].buffer_offset,
                        co[3].data_len);
 
      co += 4;
      n_copy_op -= 4;
    }
  while (n_copy_op)
    {
      b0 = vlib_get_buffer (vm, ptd->buffers[co[0].buffer_vec_index]);
      clib_memcpy_fast (co[0].data, b0->data + co[0].buffer_offset,
                        co[0].data_len);
      co += 1;
      n_copy_op -= 1;
    }
 
  vec_reset_length (ptd->copy_ops);
  vec_reset_length (ptd->buffers);
 
  if (type == MEMIF_RING_S2M)
    __atomic_store_n (&ring->head, slot, __ATOMIC_RELEASE);
  else
    __atomic_store_n (&ring->tail, slot, __ATOMIC_RELEASE);
 
  if (n_left && n_retries--)
    goto retry;
 
  return n_left;
}
 
static_always_inline uword
memif_interface_tx_zc_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
                              u32 *buffers, memif_if_t *mif, memif_queue_t *mq,
                              memif_per_thread_data_t *ptd, u32 n_left)
{
  memif_ring_t *ring = mq->ring;
  u16 slot, free_slots, n_free;
  u16 ring_size = 1 << mq->log2_ring_size;
  u16 mask = ring_size - 1;
  int n_retries = 5;
  vlib_buffer_t *b0;
  u16 head, tail;
 
retry:
  tail = __atomic_load_n (&ring->tail, __ATOMIC_ACQUIRE);
  slot = head = ring->head;
 
  n_free = tail - mq->last_tail;
  if (n_free >= 16)
    {
      vlib_buffer_free_from_ring_no_next (vm, mq->buffers,
                                          mq->last_tail & mask,
                                          ring_size, n_free);
      mq->last_tail += n_free;
    }
 
  free_slots = ring_size - head + mq->last_tail;
 
  while (n_left && free_slots)
    {
      u16 s0;
      u16 slots_in_packet = 1;
      memif_desc_t *d0;
      u32 bi0;
 
      clib_prefetch_store (&ring->desc[(slot + 8) & mask]);
 
      if (PREDICT_TRUE (n_left >= 4))
        vlib_prefetch_buffer_header (vlib_get_buffer (vm, buffers[3]), LOAD);
 
      bi0 = buffers[0];
 
    next_in_chain:
      s0 = slot & mask;
      d0 = &ring->desc[s0];
      mq->buffers[s0] = bi0;
      b0 = vlib_get_buffer (vm, bi0);
 
      d0->region = b0->buffer_pool_index + 1;
      d0->offset = (void *) b0->data + b0->current_data -
        mif->regions[d0->region].shm;
      d0->length = b0->current_length;
 
      free_slots--;
      slot++;
 
      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_NEXT_PRESENT))
        {
          if (PREDICT_FALSE (free_slots == 0))
            {
              /* revert to last fully processed packet */
              free_slots += slots_in_packet;
              slot -= slots_in_packet;
              goto no_free_slots;
            }
 
          d0->flags = MEMIF_DESC_FLAG_NEXT;
          bi0 = b0->next_buffer;
 
          /* next */
          slots_in_packet++;
          goto next_in_chain;
        }
 
      d0->flags = 0;
 
      /* next from */
      buffers++;
      n_left--;
    }
no_free_slots:
 
  __atomic_store_n (&ring->head, slot, __ATOMIC_RELEASE);
 
  if (n_left && n_retries--)
    goto retry;
 
  return n_left;
}
 
VNET_DEVICE_CLASS_TX_FN (memif_device_class) (vlib_main_t * vm,
                                              vlib_node_runtime_t * node,
                                              vlib_frame_t * frame)
{
  memif_main_t *nm = &memif_main;
  vnet_interface_output_runtime_t *rund = (void *) node->runtime_data;
  memif_if_t *mif = pool_elt_at_index (nm->interfaces, rund->dev_instance);
  memif_queue_t *mq;
  u32 *from, thread_index = vm->thread_index;
  memif_per_thread_data_t *ptd = vec_elt_at_index (memif_main.per_thread_data,
                                                   thread_index);
  u8 tx_queues = vec_len (mif->tx_queues);
  uword n_left;
 
  if (tx_queues < vlib_get_n_threads ())
    {
      ASSERT (tx_queues > 0);
      mq = vec_elt_at_index (mif->tx_queues, thread_index % tx_queues);
    }
  else
    mq = vec_elt_at_index (mif->tx_queues, thread_index);
 
  clib_spinlock_lock_if_init (&mif->lockp);
 
  from = vlib_frame_vector_args (frame);
  n_left = frame->n_vectors;
  if (mif->flags & MEMIF_IF_FLAG_ZERO_COPY)
    n_left =
      memif_interface_tx_zc_inline (vm, node, from, mif, mq, ptd, n_left);
  else if (mif->flags & MEMIF_IF_FLAG_IS_SLAVE)
    n_left = memif_interface_tx_inline (vm, node, from, mif, MEMIF_RING_S2M,
                                        mq, ptd, n_left);
  else
    n_left = memif_interface_tx_inline (vm, node, from, mif, MEMIF_RING_M2S,
                                        mq, ptd, n_left);
 
  clib_spinlock_unlock_if_init (&mif->lockp);
 
  if (n_left)
    vlib_error_count (vm, node->node_index, MEMIF_TX_ERROR_NO_FREE_SLOTS,
                      n_left);
 
  if ((mq->ring->flags & MEMIF_RING_FLAG_MASK_INT) == 0 && mq->int_fd > -1)
    {
      u64 b = 1;
      int __clib_unused r = write (mq->int_fd, &b, sizeof (b));
      mq->int_count++;
    }
 
  if ((mif->flags & MEMIF_IF_FLAG_ZERO_COPY) == 0)
    vlib_buffer_free (vm, from, frame->n_vectors);
  else if (n_left)
    vlib_buffer_free (vm, from + frame->n_vectors - n_left, n_left);
 
  return frame->n_vectors - n_left;
}
 
static void
memif_set_interface_next_node (vnet_main_t * vnm, u32 hw_if_index,
                               u32 node_index)
{
  memif_main_t *apm = &memif_main;
  vnet_hw_interface_t *hw = vnet_get_hw_interface (vnm, hw_if_index);
  memif_if_t *mif = pool_elt_at_index (apm->interfaces, hw->dev_instance);
 
  /* Shut off redirection */
  if (node_index == ~0)
    {
      mif->per_interface_next_index = node_index;
      return;
    }
 
  mif->per_interface_next_index =
    vlib_node_add_next (vlib_get_main (), memif_input_node.index, node_index);
}
 
static void
memif_clear_hw_interface_counters (u32 instance)
{
  /* Nothing for now */
}
 
static clib_error_t *
memif_interface_rx_mode_change (vnet_main_t * vnm, u32 hw_if_index, u32 qid,
                                vnet_hw_if_rx_mode mode)
{
  memif_main_t *mm = &memif_main;
  vnet_hw_interface_t *hw = vnet_get_hw_interface (vnm, hw_if_index);
  memif_if_t *mif = pool_elt_at_index (mm->interfaces, hw->dev_instance);
  memif_queue_t *mq = vec_elt_at_index (mif->rx_queues, qid);
 
  if (mode == VNET_HW_IF_RX_MODE_POLLING)
    mq->ring->flags |= MEMIF_RING_FLAG_MASK_INT;
  else
    mq->ring->flags &= ~MEMIF_RING_FLAG_MASK_INT;
 
  return 0;
}
 
static clib_error_t *
memif_subif_add_del_function (vnet_main_t * vnm,
                              u32 hw_if_index,
                              struct vnet_sw_interface_t *st, int is_add)
{
  /* Nothing for now */
  return 0;
}
 
/* *INDENT-OFF* */
VNET_DEVICE_CLASS (memif_device_class) = {
  .name = "memif",
  .format_device_name = format_memif_device_name,
  .format_device = format_memif_device,
  .format_tx_trace = format_memif_tx_trace,
  .tx_function_n_errors = MEMIF_TX_N_ERROR,
  .tx_function_error_counters = memif_tx_func_error_counters,
  .rx_redirect_to_node = memif_set_interface_next_node,
  .clear_counters = memif_clear_hw_interface_counters,
  .admin_up_down_function = memif_interface_admin_up_down,
  .subif_add_del_function = memif_subif_add_del_function,
  .rx_mode_change_function = memif_interface_rx_mode_change,
};
 
/* *INDENT-ON* */
 
/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */