drivers/net/virtio/virtio_rxtx.c

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   5  *   All rights reserved.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following conditions
   9  *   are met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <stdint.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <errno.h>
  39
  40 #include <rte_cycles.h>
  41 #include <rte_memory.h>
  42 #include <rte_memzone.h>
  43 #include <rte_branch_prediction.h>
  44 #include <rte_mempool.h>
  45 #include <rte_malloc.h>
  46 #include <rte_mbuf.h>
  47 #include <rte_ether.h>
  48 #include <rte_ethdev.h>
  49 #include <rte_prefetch.h>
  50 #include <rte_string_fns.h>
  51 #include <rte_errno.h>
  52 #include <rte_byteorder.h>
  53 #include <rte_cpuflags.h>
  54 #include <rte_net.h>
  55 #include <rte_ip.h>
  56 #include <rte_udp.h>
  57 #include <rte_tcp.h>
  58
  59 #include "virtio_logs.h"
  60 #include "virtio_ethdev.h"
  61 #include "virtio_pci.h"
  62 #include "virtqueue.h"
  63 #include "virtio_rxtx.h"
  64
  65 #ifdef RTE_LIBRTE_VIRTIO_DEBUG_DUMP
  66 #define VIRTIO_DUMP_PACKET(m, len) rte_pktmbuf_dump(stdout, m, len)
  67 #else
  68 #define  VIRTIO_DUMP_PACKET(m, len) do { } while (0)
  69 #endif
  70
  71
  72 #define VIRTIO_SIMPLE_FLAGS ((uint32_t)ETH_TXQ_FLAGS_NOMULTSEGS | \
  73         ETH_TXQ_FLAGS_NOOFFLOADS)
  74
  75 static void
  76 vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx)
  77 {
  78         struct vring_desc *dp, *dp_tail;
  79         struct vq_desc_extra *dxp;
  80         uint16_t desc_idx_last = desc_idx;
  81
  82         dp  = &vq->vq_ring.desc[desc_idx];
  83         dxp = &vq->vq_descx[desc_idx];
  84         vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt + dxp->ndescs);
  85         if ((dp->flags & VRING_DESC_F_INDIRECT) == 0) {
  86                 while (dp->flags & VRING_DESC_F_NEXT) {
  87                         desc_idx_last = dp->next;
  88                         dp = &vq->vq_ring.desc[dp->next];
  89                 }
  90         }
  91         dxp->ndescs = 0;
  92
  93         /*
  94          * We must append the existing free chain, if any, to the end of
  95          * newly freed chain. If the virtqueue was completely used, then
  96          * head would be VQ_RING_DESC_CHAIN_END (ASSERTed above).
  97          */
  98         if (vq->vq_desc_tail_idx == VQ_RING_DESC_CHAIN_END) {
  99                 vq->vq_desc_head_idx = desc_idx;
 100         } else {
 101                 dp_tail = &vq->vq_ring.desc[vq->vq_desc_tail_idx];
 102                 dp_tail->next = desc_idx;
 103         }
 104
 105         vq->vq_desc_tail_idx = desc_idx_last;
 106         dp->next = VQ_RING_DESC_CHAIN_END;
 107 }
 108
 109 static uint16_t
 110 virtqueue_dequeue_burst_rx(struct virtqueue *vq, struct rte_mbuf **rx_pkts,
 111                            uint32_t *len, uint16_t num)
 112 {
 113         struct vring_used_elem *uep;
 114         struct rte_mbuf *cookie;
 115         uint16_t used_idx, desc_idx;
 116         uint16_t i;
 117
 118         /*  Caller does the check */
 119         for (i = 0; i < num ; i++) {
 120                 used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
 121                 uep = &vq->vq_ring.used->ring[used_idx];
 122                 desc_idx = (uint16_t) uep->id;
 123                 len[i] = uep->len;
 124                 cookie = (struct rte_mbuf *)vq->vq_descx[desc_idx].cookie;
 125
 126                 if (unlikely(cookie == NULL)) {
 127                         PMD_DRV_LOG(ERR, "vring descriptor with no mbuf cookie at %u\n",
 128                                 vq->vq_used_cons_idx);
 129                         break;
 130                 }
 131
 132                 rte_prefetch0(cookie);
 133                 rte_packet_prefetch(rte_pktmbuf_mtod(cookie, void *));
 134                 rx_pkts[i]  = cookie;
 135                 vq->vq_used_cons_idx++;
 136                 vq_ring_free_chain(vq, desc_idx);
 137                 vq->vq_descx[desc_idx].cookie = NULL;
 138         }
 139
 140         return i;
 141 }
 142
 143 #ifndef DEFAULT_TX_FREE_THRESH
 144 #define DEFAULT_TX_FREE_THRESH 32
 145 #endif
 146
 147 /* Cleanup from completed transmits. */
 148 static void
 149 virtio_xmit_cleanup(struct virtqueue *vq, uint16_t num)
 150 {
 151         uint16_t i, used_idx, desc_idx;
 152         for (i = 0; i < num; i++) {
 153                 struct vring_used_elem *uep;
 154                 struct vq_desc_extra *dxp;
 155
 156                 used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
 157                 uep = &vq->vq_ring.used->ring[used_idx];
 158
 159                 desc_idx = (uint16_t) uep->id;
 160                 dxp = &vq->vq_descx[desc_idx];
 161                 vq->vq_used_cons_idx++;
 162                 vq_ring_free_chain(vq, desc_idx);
 163
 164                 if (dxp->cookie != NULL) {
 165                         rte_pktmbuf_free(dxp->cookie);
 166                         dxp->cookie = NULL;
 167                 }
 168         }
 169 }
 170
 171
 172 static inline int
 173 virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
 174 {
 175         struct vq_desc_extra *dxp;
 176         struct virtio_hw *hw = vq->hw;
 177         struct vring_desc *start_dp;
 178         uint16_t needed = 1;
 179         uint16_t head_idx, idx;
 180
 181         if (unlikely(vq->vq_free_cnt == 0))
 182                 return -ENOSPC;
 183         if (unlikely(vq->vq_free_cnt < needed))
 184                 return -EMSGSIZE;
 185
 186         head_idx = vq->vq_desc_head_idx;
 187         if (unlikely(head_idx >= vq->vq_nentries))
 188                 return -EFAULT;
 189
 190         idx = head_idx;
 191         dxp = &vq->vq_descx[idx];
 192         dxp->cookie = (void *)cookie;
 193         dxp->ndescs = needed;
 194
 195         start_dp = vq->vq_ring.desc;
 196         start_dp[idx].addr =
 197                 VIRTIO_MBUF_ADDR(cookie, vq) +
 198                 RTE_PKTMBUF_HEADROOM - hw->vtnet_hdr_size;
 199         start_dp[idx].len =
 200                 cookie->buf_len - RTE_PKTMBUF_HEADROOM + hw->vtnet_hdr_size;
 201         start_dp[idx].flags =  VRING_DESC_F_WRITE;
 202         idx = start_dp[idx].next;
 203         vq->vq_desc_head_idx = idx;
 204         if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
 205                 vq->vq_desc_tail_idx = idx;
 206         vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
 207         vq_update_avail_ring(vq, head_idx);
 208
 209         return 0;
 210 }
 211
 212 /* When doing TSO, the IP length is not included in the pseudo header
 213  * checksum of the packet given to the PMD, but for virtio it is
 214  * expected.
 215  */
 216 static void
 217 virtio_tso_fix_cksum(struct rte_mbuf *m)
 218 {
 219         /* common case: header is not fragmented */
 220         if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
 221                         m->l4_len)) {
 222                 struct ipv4_hdr *iph;
 223                 struct ipv6_hdr *ip6h;
 224                 struct tcp_hdr *th;
 225                 uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
 226                 uint32_t tmp;
 227
 228                 iph = rte_pktmbuf_mtod_offset(m, struct ipv4_hdr *, m->l2_len);
 229                 th = RTE_PTR_ADD(iph, m->l3_len);
 230                 if ((iph->version_ihl >> 4) == 4) {
 231                         iph->hdr_checksum = 0;
 232                         iph->hdr_checksum = rte_ipv4_cksum(iph);
 233                         ip_len = iph->total_length;
 234                         ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
 235                                 m->l3_len);
 236                 } else {
 237                         ip6h = (struct ipv6_hdr *)iph;
 238                         ip_paylen = ip6h->payload_len;
 239                 }
 240
 241                 /* calculate the new phdr checksum not including ip_paylen */
 242                 prev_cksum = th->cksum;
 243                 tmp = prev_cksum;
 244                 tmp += ip_paylen;
 245                 tmp = (tmp & 0xffff) + (tmp >> 16);
 246                 new_cksum = tmp;
 247
 248                 /* replace it in the packet */
 249                 th->cksum = new_cksum;
 250         }
 251 }
 252
 253 static inline int
 254 tx_offload_enabled(struct virtio_hw *hw)
 255 {
 256         return vtpci_with_feature(hw, VIRTIO_NET_F_CSUM) ||
 257                 vtpci_with_feature(hw, VIRTIO_NET_F_HOST_TSO4) ||
 258                 vtpci_with_feature(hw, VIRTIO_NET_F_HOST_TSO6);
 259 }
 260
 261 static inline void
 262 virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 263                        uint16_t needed, int use_indirect, int can_push)
 264 {
 265         struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
 266         struct vq_desc_extra *dxp;
 267         struct virtqueue *vq = txvq->vq;
 268         struct vring_desc *start_dp;
 269         uint16_t seg_num = cookie->nb_segs;
 270         uint16_t head_idx, idx;
 271         uint16_t head_size = vq->hw->vtnet_hdr_size;
 272         struct virtio_net_hdr *hdr;
 273         int offload;
 274
 275         offload = tx_offload_enabled(vq->hw);
 276         head_idx = vq->vq_desc_head_idx;
 277         idx = head_idx;
 278         dxp = &vq->vq_descx[idx];
 279         dxp->cookie = (void *)cookie;
 280         dxp->ndescs = needed;
 281
 282         start_dp = vq->vq_ring.desc;
 283
 284         if (can_push) {
 285                 /* prepend cannot fail, checked by caller */
 286                 hdr = (struct virtio_net_hdr *)
 287                         rte_pktmbuf_prepend(cookie, head_size);
 288                 /* if offload disabled, it is not zeroed below, do it now */
 289                 if (offload == 0)
 290                         memset(hdr, 0, head_size);
 291         } else if (use_indirect) {
 292                 /* setup tx ring slot to point to indirect
 293                  * descriptor list stored in reserved region.
 294                  *
 295                  * the first slot in indirect ring is already preset
 296                  * to point to the header in reserved region
 297                  */
 298                 start_dp[idx].addr  = txvq->virtio_net_hdr_mem +
 299                         RTE_PTR_DIFF(&txr[idx].tx_indir, txr);
 300                 start_dp[idx].len   = (seg_num + 1) * sizeof(struct vring_desc);
 301                 start_dp[idx].flags = VRING_DESC_F_INDIRECT;
 302                 hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;
 303
 304                 /* loop below will fill in rest of the indirect elements */
 305                 start_dp = txr[idx].tx_indir;
 306                 idx = 1;
 307         } else {
 308                 /* setup first tx ring slot to point to header
 309                  * stored in reserved region.
 310                  */
 311                 start_dp[idx].addr  = txvq->virtio_net_hdr_mem +
 312                         RTE_PTR_DIFF(&txr[idx].tx_hdr, txr);
 313                 start_dp[idx].len   = vq->hw->vtnet_hdr_size;
 314                 start_dp[idx].flags = VRING_DESC_F_NEXT;
 315                 hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;
 316
 317                 idx = start_dp[idx].next;
 318         }
 319
 320         /* Checksum Offload / TSO */
 321         if (offload) {
 322                 if (cookie->ol_flags & PKT_TX_TCP_SEG)
 323                         cookie->ol_flags |= PKT_TX_TCP_CKSUM;
 324
 325                 switch (cookie->ol_flags & PKT_TX_L4_MASK) {
 326                 case PKT_TX_UDP_CKSUM:
 327                         hdr->csum_start = cookie->l2_len + cookie->l3_len;
 328                         hdr->csum_offset = offsetof(struct udp_hdr,
 329                                 dgram_cksum);
 330                         hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 331                         break;
 332
 333                 case PKT_TX_TCP_CKSUM:
 334                         hdr->csum_start = cookie->l2_len + cookie->l3_len;
 335                         hdr->csum_offset = offsetof(struct tcp_hdr, cksum);
 336                         hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 337                         break;
 338
 339                 default:
 340                         hdr->csum_start = 0;
 341                         hdr->csum_offset = 0;
 342                         hdr->flags = 0;
 343                         break;
 344                 }
 345
 346                 /* TCP Segmentation Offload */
 347                 if (cookie->ol_flags & PKT_TX_TCP_SEG) {
 348                         virtio_tso_fix_cksum(cookie);
 349                         hdr->gso_type = (cookie->ol_flags & PKT_TX_IPV6) ?
 350                                 VIRTIO_NET_HDR_GSO_TCPV6 :
 351                                 VIRTIO_NET_HDR_GSO_TCPV4;
 352                         hdr->gso_size = cookie->tso_segsz;
 353                         hdr->hdr_len =
 354                                 cookie->l2_len +
 355                                 cookie->l3_len +
 356                                 cookie->l4_len;
 357                 } else {
 358                         hdr->gso_type = 0;
 359                         hdr->gso_size = 0;
 360                         hdr->hdr_len = 0;
 361                 }
 362         }
 363
 364         do {
 365                 start_dp[idx].addr  = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq);
 366                 start_dp[idx].len   = cookie->data_len;
 367                 start_dp[idx].flags = cookie->next ? VRING_DESC_F_NEXT : 0;
 368                 idx = start_dp[idx].next;
 369         } while ((cookie = cookie->next) != NULL);
 370
 371         if (use_indirect)
 372                 idx = vq->vq_ring.desc[head_idx].next;
 373
 374         vq->vq_desc_head_idx = idx;
 375         if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
 376                 vq->vq_desc_tail_idx = idx;
 377         vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
 378         vq_update_avail_ring(vq, head_idx);
 379 }
 380
 381 static void
 382 virtio_dev_vring_start(struct virtqueue *vq)
 383 {
 384         int size = vq->vq_nentries;
 385         struct vring *vr = &vq->vq_ring;
 386         uint8_t *ring_mem = vq->vq_ring_virt_mem;
 387
 388         PMD_INIT_FUNC_TRACE();
 389
 390         /*
 391          * Reinitialise since virtio port might have been stopped and restarted
 392          */
 393         memset(vq->vq_ring_virt_mem, 0, vq->vq_ring_size);
 394         vring_init(vr, size, ring_mem, VIRTIO_PCI_VRING_ALIGN);
 395         vq->vq_used_cons_idx = 0;
 396         vq->vq_desc_head_idx = 0;
 397         vq->vq_avail_idx = 0;
 398         vq->vq_desc_tail_idx = (uint16_t)(vq->vq_nentries - 1);
 399         vq->vq_free_cnt = vq->vq_nentries;
 400         memset(vq->vq_descx, 0, sizeof(struct vq_desc_extra) * vq->vq_nentries);
 401
 402         vring_desc_init(vr->desc, size);
 403
 404         /*
 405          * Disable device(host) interrupting guest
 406          */
 407         virtqueue_disable_intr(vq);
 408 }
 409
 410 void
 411 virtio_dev_cq_start(struct rte_eth_dev *dev)
 412 {
 413         struct virtio_hw *hw = dev->data->dev_private;
 414
 415         if (hw->cvq && hw->cvq->vq) {
 416                 virtio_dev_vring_start(hw->cvq->vq);
 417                 VIRTQUEUE_DUMP((struct virtqueue *)hw->cvq->vq);
 418         }
 419 }
 420
 421 void
 422 virtio_dev_rxtx_start(struct rte_eth_dev *dev)
 423 {
 424         /*
 425          * Start receive and transmit vrings
 426          * -    Setup vring structure for all queues
 427          * -    Initialize descriptor for the rx vring
 428          * -    Allocate blank mbufs for the each rx descriptor
 429          *
 430          */
 431         uint16_t i;
 432         uint16_t desc_idx;
 433         struct virtio_hw *hw = dev->data->dev_private;
 434
 435         PMD_INIT_FUNC_TRACE();
 436
 437         /* Start rx vring. */
 438         for (i = 0; i < dev->data->nb_rx_queues; i++) {
 439                 struct virtnet_rx *rxvq = dev->data->rx_queues[i];
 440                 struct virtqueue *vq = rxvq->vq;
 441                 int error, nbufs;
 442                 struct rte_mbuf *m;
 443
 444                 virtio_dev_vring_start(vq);
 445                 if (rxvq->mpool == NULL) {
 446                         rte_exit(EXIT_FAILURE,
 447                                 "Cannot allocate mbufs for rx virtqueue");
 448                 }
 449
 450                 /* Allocate blank mbufs for the each rx descriptor */
 451                 nbufs = 0;
 452                 error = ENOSPC;
 453
 454                 if (hw->use_simple_rxtx) {
 455                         for (desc_idx = 0; desc_idx < vq->vq_nentries;
 456                              desc_idx++) {
 457                                 vq->vq_ring.avail->ring[desc_idx] = desc_idx;
 458                                 vq->vq_ring.desc[desc_idx].flags =
 459                                         VRING_DESC_F_WRITE;
 460                         }
 461                 }
 462
 463                 memset(&rxvq->fake_mbuf, 0, sizeof(rxvq->fake_mbuf));
 464                 for (desc_idx = 0; desc_idx < RTE_PMD_VIRTIO_RX_MAX_BURST;
 465                      desc_idx++) {
 466                         vq->sw_ring[vq->vq_nentries + desc_idx] =
 467                                 &rxvq->fake_mbuf;
 468                 }
 469
 470                 while (!virtqueue_full(vq)) {
 471                         m = rte_mbuf_raw_alloc(rxvq->mpool);
 472                         if (m == NULL)
 473                                 break;
 474
 475                         /******************************************
 476                         *         Enqueue allocated buffers        *
 477                         *******************************************/
 478                         if (hw->use_simple_rxtx)
 479                                 error = virtqueue_enqueue_recv_refill_simple(vq, m);
 480                         else
 481                                 error = virtqueue_enqueue_recv_refill(vq, m);
 482
 483                         if (error) {
 484                                 rte_pktmbuf_free(m);
 485                                 break;
 486                         }
 487                         nbufs++;
 488                 }
 489
 490                 vq_update_avail_idx(vq);
 491
 492                 PMD_INIT_LOG(DEBUG, "Allocated %d bufs", nbufs);
 493
 494                 VIRTQUEUE_DUMP(vq);
 495         }
 496
 497         /* Start tx vring. */
 498         for (i = 0; i < dev->data->nb_tx_queues; i++) {
 499                 struct virtnet_tx *txvq = dev->data->tx_queues[i];
 500                 struct virtqueue *vq = txvq->vq;
 501
 502                 virtio_dev_vring_start(vq);
 503                 if (hw->use_simple_rxtx) {
 504                         uint16_t mid_idx  = vq->vq_nentries >> 1;
 505
 506                         for (desc_idx = 0; desc_idx < mid_idx; desc_idx++) {
 507                                 vq->vq_ring.avail->ring[desc_idx] =
 508                                         desc_idx + mid_idx;
 509                                 vq->vq_ring.desc[desc_idx + mid_idx].next =
 510                                         desc_idx;
 511                                 vq->vq_ring.desc[desc_idx + mid_idx].addr =
 512                                         txvq->virtio_net_hdr_mem +
 513                                         offsetof(struct virtio_tx_region, tx_hdr);
 514                                 vq->vq_ring.desc[desc_idx + mid_idx].len =
 515                                         vq->hw->vtnet_hdr_size;
 516                                 vq->vq_ring.desc[desc_idx + mid_idx].flags =
 517                                         VRING_DESC_F_NEXT;
 518                                 vq->vq_ring.desc[desc_idx].flags = 0;
 519                         }
 520                         for (desc_idx = mid_idx; desc_idx < vq->vq_nentries;
 521                              desc_idx++)
 522                                 vq->vq_ring.avail->ring[desc_idx] = desc_idx;
 523                 }
 524
 525                 VIRTQUEUE_DUMP(vq);
 526         }
 527 }
 528
 529 int
 530 virtio_dev_rx_queue_setup(struct rte_eth_dev *dev,
 531                         uint16_t queue_idx,
 532                         uint16_t nb_desc,
 533                         unsigned int socket_id,
 534                         __rte_unused const struct rte_eth_rxconf *rx_conf,
 535                         struct rte_mempool *mp)
 536 {
 537         uint16_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_RQ_QUEUE_IDX;
 538         struct virtnet_rx *rxvq;
 539         int ret;
 540
 541         PMD_INIT_FUNC_TRACE();
 542         ret = virtio_dev_queue_setup(dev, VTNET_RQ, queue_idx, vtpci_queue_idx,
 543                         nb_desc, socket_id, (void **)&rxvq);
 544         if (ret < 0) {
 545                 PMD_INIT_LOG(ERR, "rvq initialization failed");
 546                 return ret;
 547         }
 548
 549         /* Create mempool for rx mbuf allocation */
 550         rxvq->mpool = mp;
 551
 552         dev->data->rx_queues[queue_idx] = rxvq;
 553
 554         virtio_rxq_vec_setup(rxvq);
 555
 556         return 0;
 557 }
 558
 559 void
 560 virtio_dev_rx_queue_release(void *rxq)
 561 {
 562         struct virtnet_rx *rxvq = rxq;
 563         struct virtqueue *vq;
 564         const struct rte_memzone *mz;
 565
 566         if (rxvq == NULL)
 567                 return;
 568
 569         /*
 570          * rxvq is freed when vq is freed, and as mz should be freed after the
 571          * del_queue, so we reserve the mz pointer first.
 572          */
 573         vq = rxvq->vq;
 574         mz = rxvq->mz;
 575
 576         virtio_dev_queue_release(vq);
 577         rte_memzone_free(mz);
 578 }
 579
 580 static void
 581 virtio_update_rxtx_handler(struct rte_eth_dev *dev,
 582                            const struct rte_eth_txconf *tx_conf)
 583 {
 584         uint8_t use_simple_rxtx = 0;
 585         struct virtio_hw *hw = dev->data->dev_private;
 586
 587 #if defined RTE_ARCH_X86
 588         if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE3))
 589                 use_simple_rxtx = 1;
 590 #elif defined RTE_ARCH_ARM64 || defined CONFIG_RTE_ARCH_ARM
 591         if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_NEON))
 592                 use_simple_rxtx = 1;
 593 #endif
 594         /* Use simple rx/tx func if single segment and no offloads */
 595         if (use_simple_rxtx &&
 596             (tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
 597             !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
 598                 PMD_INIT_LOG(INFO, "Using simple rx/tx path");
 599                 dev->tx_pkt_burst = virtio_xmit_pkts_simple;
 600                 dev->rx_pkt_burst = virtio_recv_pkts_vec;
 601                 hw->use_simple_rxtx = use_simple_rxtx;
 602         }
 603 }
 604
 605 /*
 606  * struct rte_eth_dev *dev: Used to update dev
 607  * uint16_t nb_desc: Defaults to values read from config space
 608  * unsigned int socket_id: Used to allocate memzone
 609  * const struct rte_eth_txconf *tx_conf: Used to setup tx engine
 610  * uint16_t queue_idx: Just used as an index in dev txq list
 611  */
 612 int
 613 virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
 614                         uint16_t queue_idx,
 615                         uint16_t nb_desc,
 616                         unsigned int socket_id,
 617                         const struct rte_eth_txconf *tx_conf)
 618 {
 619         uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
 620         struct virtnet_tx *txvq;
 621         struct virtqueue *vq;
 622         uint16_t tx_free_thresh;
 623         int ret;
 624
 625         PMD_INIT_FUNC_TRACE();
 626
 627
 628         virtio_update_rxtx_handler(dev, tx_conf);
 629
 630         ret = virtio_dev_queue_setup(dev, VTNET_TQ, queue_idx, vtpci_queue_idx,
 631                         nb_desc, socket_id, (void **)&txvq);
 632         if (ret < 0) {
 633                 PMD_INIT_LOG(ERR, "tvq initialization failed");
 634                 return ret;
 635         }
 636         vq = txvq->vq;
 637
 638         tx_free_thresh = tx_conf->tx_free_thresh;
 639         if (tx_free_thresh == 0)
 640                 tx_free_thresh =
 641                         RTE_MIN(vq->vq_nentries / 4, DEFAULT_TX_FREE_THRESH);
 642
 643         if (tx_free_thresh >= (vq->vq_nentries - 3)) {
 644                 RTE_LOG(ERR, PMD, "tx_free_thresh must be less than the "
 645                         "number of TX entries minus 3 (%u)."
 646                         " (tx_free_thresh=%u port=%u queue=%u)\n",
 647                         vq->vq_nentries - 3,
 648                         tx_free_thresh, dev->data->port_id, queue_idx);
 649                 return -EINVAL;
 650         }
 651
 652         vq->vq_free_thresh = tx_free_thresh;
 653
 654         dev->data->tx_queues[queue_idx] = txvq;
 655         return 0;
 656 }
 657
 658 void
 659 virtio_dev_tx_queue_release(void *txq)
 660 {
 661         struct virtnet_tx *txvq = txq;
 662         struct virtqueue *vq;
 663         const struct rte_memzone *mz;
 664         const struct rte_memzone *hdr_mz;
 665
 666         if (txvq == NULL)
 667                 return;
 668
 669         /*
 670          * txvq is freed when vq is freed, and as mz should be freed after the
 671          * del_queue, so we reserve the mz pointer first.
 672          */
 673         vq = txvq->vq;
 674         mz = txvq->mz;
 675         hdr_mz = txvq->virtio_net_hdr_mz;
 676
 677         virtio_dev_queue_release(vq);
 678         rte_memzone_free(mz);
 679         rte_memzone_free(hdr_mz);
 680 }
 681
 682 static void
 683 virtio_discard_rxbuf(struct virtqueue *vq, struct rte_mbuf *m)
 684 {
 685         int error;
 686         /*
 687          * Requeue the discarded mbuf. This should always be
 688          * successful since it was just dequeued.
 689          */
 690         error = virtqueue_enqueue_recv_refill(vq, m);
 691         if (unlikely(error)) {
 692                 RTE_LOG(ERR, PMD, "cannot requeue discarded mbuf");
 693                 rte_pktmbuf_free(m);
 694         }
 695 }
 696
 697 static void
 698 virtio_update_packet_stats(struct virtnet_stats *stats, struct rte_mbuf *mbuf)
 699 {
 700         uint32_t s = mbuf->pkt_len;
 701         struct ether_addr *ea;
 702
 703         if (s == 64) {
 704                 stats->size_bins[1]++;
 705         } else if (s > 64 && s < 1024) {
 706                 uint32_t bin;
 707
 708                 /* count zeros, and offset into correct bin */
 709                 bin = (sizeof(s) * 8) - __builtin_clz(s) - 5;
 710                 stats->size_bins[bin]++;
 711         } else {
 712                 if (s < 64)
 713                         stats->size_bins[0]++;
 714                 else if (s < 1519)
 715                         stats->size_bins[6]++;
 716                 else if (s >= 1519)
 717                         stats->size_bins[7]++;
 718         }
 719
 720         ea = rte_pktmbuf_mtod(mbuf, struct ether_addr *);
 721         if (is_multicast_ether_addr(ea)) {
 722                 if (is_broadcast_ether_addr(ea))
 723                         stats->broadcast++;
 724                 else
 725                         stats->multicast++;
 726         }
 727 }
 728
 729 /* Optionally fill offload information in structure */
 730 static int
 731 virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
 732 {
 733         struct rte_net_hdr_lens hdr_lens;
 734         uint32_t hdrlen, ptype;
 735         int l4_supported = 0;
 736
 737         /* nothing to do */
 738         if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
 739                 return 0;
 740
 741         m->ol_flags |= PKT_RX_IP_CKSUM_UNKNOWN;
 742
 743         ptype = rte_net_get_ptype(m, &hdr_lens, RTE_PTYPE_ALL_MASK);
 744         m->packet_type = ptype;
 745         if ((ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_TCP ||
 746             (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_UDP ||
 747             (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_SCTP)
 748                 l4_supported = 1;
 749
 750         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 751                 hdrlen = hdr_lens.l2_len + hdr_lens.l3_len + hdr_lens.l4_len;
 752                 if (hdr->csum_start <= hdrlen && l4_supported) {
 753                         m->ol_flags |= PKT_RX_L4_CKSUM_NONE;
 754                 } else {
 755                         /* Unknown proto or tunnel, do sw cksum. We can assume
 756                          * the cksum field is in the first segment since the
 757                          * buffers we provided to the host are large enough.
 758                          * In case of SCTP, this will be wrong since it's a CRC
 759                          * but there's nothing we can do.
 760                          */
 761                         uint16_t csum, off;
 762
 763                         rte_raw_cksum_mbuf(m, hdr->csum_start,
 764                                 rte_pktmbuf_pkt_len(m) - hdr->csum_start,
 765                                 &csum);
 766                         if (likely(csum != 0xffff))
 767                                 csum = ~csum;
 768                         off = hdr->csum_offset + hdr->csum_start;
 769                         if (rte_pktmbuf_data_len(m) >= off + 1)
 770                                 *rte_pktmbuf_mtod_offset(m, uint16_t *,
 771                                         off) = csum;
 772                 }
 773         } else if (hdr->flags & VIRTIO_NET_HDR_F_DATA_VALID && l4_supported) {
 774                 m->ol_flags |= PKT_RX_L4_CKSUM_GOOD;
 775         }
 776
 777         /* GSO request, save required information in mbuf */
 778         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 779                 /* Check unsupported modes */
 780                 if ((hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) ||
 781                     (hdr->gso_size == 0)) {
 782                         return -EINVAL;
 783                 }
 784
 785                 /* Update mss lengthes in mbuf */
 786                 m->tso_segsz = hdr->gso_size;
 787                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 788                         case VIRTIO_NET_HDR_GSO_TCPV4:
 789                         case VIRTIO_NET_HDR_GSO_TCPV6:
 790                                 m->ol_flags |= PKT_RX_LRO | \
 791                                         PKT_RX_L4_CKSUM_NONE;
 792                                 break;
 793                         default:
 794                                 return -EINVAL;
 795                 }
 796         }
 797
 798         return 0;
 799 }
 800
 801 static inline int
 802 rx_offload_enabled(struct virtio_hw *hw)
 803 {
 804         return vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_CSUM) ||
 805                 vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_TSO4) ||
 806                 vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_TSO6);
 807 }
 808
 809 #define VIRTIO_MBUF_BURST_SZ 64
 810 #define DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct vring_desc))
 811 uint16_t
 812 virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 813 {
 814         struct virtnet_rx *rxvq = rx_queue;
 815         struct virtqueue *vq = rxvq->vq;
 816         struct virtio_hw *hw;
 817         struct rte_mbuf *rxm, *new_mbuf;
 818         uint16_t nb_used, num, nb_rx;
 819         uint32_t len[VIRTIO_MBUF_BURST_SZ];
 820         struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
 821         int error;
 822         uint32_t i, nb_enqueued;
 823         uint32_t hdr_size;
 824         int offload;
 825         struct virtio_net_hdr *hdr;
 826
 827         nb_used = VIRTQUEUE_NUSED(vq);
 828
 829         virtio_rmb();
 830
 831         num = (uint16_t)(likely(nb_used <= nb_pkts) ? nb_used : nb_pkts);
 832         num = (uint16_t)(likely(num <= VIRTIO_MBUF_BURST_SZ) ? num : VIRTIO_MBUF_BURST_SZ);
 833         if (likely(num > DESC_PER_CACHELINE))
 834                 num = num - ((vq->vq_used_cons_idx + num) % DESC_PER_CACHELINE);
 835
 836         num = virtqueue_dequeue_burst_rx(vq, rcv_pkts, len, num);
 837         PMD_RX_LOG(DEBUG, "used:%d dequeue:%d", nb_used, num);
 838
 839         hw = vq->hw;
 840         nb_rx = 0;
 841         nb_enqueued = 0;
 842         hdr_size = hw->vtnet_hdr_size;
 843         offload = rx_offload_enabled(hw);
 844
 845         for (i = 0; i < num ; i++) {
 846                 rxm = rcv_pkts[i];
 847
 848                 PMD_RX_LOG(DEBUG, "packet len:%d", len[i]);
 849
 850                 if (unlikely(len[i] < hdr_size + ETHER_HDR_LEN)) {
 851                         PMD_RX_LOG(ERR, "Packet drop");
 852                         nb_enqueued++;
 853                         virtio_discard_rxbuf(vq, rxm);
 854                         rxvq->stats.errors++;
 855                         continue;
 856                 }
 857
 858                 rxm->port = rxvq->port_id;
 859                 rxm->data_off = RTE_PKTMBUF_HEADROOM;
 860                 rxm->ol_flags = 0;
 861                 rxm->vlan_tci = 0;
 862
 863                 rxm->nb_segs = 1;
 864                 rxm->next = NULL;
 865                 rxm->pkt_len = (uint32_t)(len[i] - hdr_size);
 866                 rxm->data_len = (uint16_t)(len[i] - hdr_size);
 867
 868                 hdr = (struct virtio_net_hdr *)((char *)rxm->buf_addr +
 869                         RTE_PKTMBUF_HEADROOM - hdr_size);
 870
 871                 if (hw->vlan_strip)
 872                         rte_vlan_strip(rxm);
 873
 874                 if (offload && virtio_rx_offload(rxm, hdr) < 0) {
 875                         virtio_discard_rxbuf(vq, rxm);
 876                         rxvq->stats.errors++;
 877                         continue;
 878                 }
 879
 880                 VIRTIO_DUMP_PACKET(rxm, rxm->data_len);
 881
 882                 rx_pkts[nb_rx++] = rxm;
 883
 884                 rxvq->stats.bytes += rx_pkts[nb_rx - 1]->pkt_len;
 885                 virtio_update_packet_stats(&rxvq->stats, rxm);
 886         }
 887
 888         rxvq->stats.packets += nb_rx;
 889
 890         /* Allocate new mbuf for the used descriptor */
 891         error = ENOSPC;
 892         while (likely(!virtqueue_full(vq))) {
 893                 new_mbuf = rte_mbuf_raw_alloc(rxvq->mpool);
 894                 if (unlikely(new_mbuf == NULL)) {
 895                         struct rte_eth_dev *dev
 896                                 = &rte_eth_devices[rxvq->port_id];
 897                         dev->data->rx_mbuf_alloc_failed++;
 898                         break;
 899                 }
 900                 error = virtqueue_enqueue_recv_refill(vq, new_mbuf);
 901                 if (unlikely(error)) {
 902                         rte_pktmbuf_free(new_mbuf);
 903                         break;
 904                 }
 905                 nb_enqueued++;
 906         }
 907
 908         if (likely(nb_enqueued)) {
 909                 vq_update_avail_idx(vq);
 910
 911                 if (unlikely(virtqueue_kick_prepare(vq))) {
 912                         virtqueue_notify(vq);
 913                         PMD_RX_LOG(DEBUG, "Notified");
 914                 }
 915         }
 916
 917         return nb_rx;
 918 }
 919
 920 uint16_t
 921 virtio_recv_mergeable_pkts(void *rx_queue,
 922                         struct rte_mbuf **rx_pkts,
 923                         uint16_t nb_pkts)
 924 {
 925         struct virtnet_rx *rxvq = rx_queue;
 926         struct virtqueue *vq = rxvq->vq;
 927         struct virtio_hw *hw;
 928         struct rte_mbuf *rxm, *new_mbuf;
 929         uint16_t nb_used, num, nb_rx;
 930         uint32_t len[VIRTIO_MBUF_BURST_SZ];
 931         struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
 932         struct rte_mbuf *prev;
 933         int error;
 934         uint32_t i, nb_enqueued;
 935         uint32_t seg_num;
 936         uint16_t extra_idx;
 937         uint32_t seg_res;
 938         uint32_t hdr_size;
 939         int offload;
 940
 941         nb_used = VIRTQUEUE_NUSED(vq);
 942
 943         virtio_rmb();
 944
 945         PMD_RX_LOG(DEBUG, "used:%d", nb_used);
 946
 947         hw = vq->hw;
 948         nb_rx = 0;
 949         i = 0;
 950         nb_enqueued = 0;
 951         seg_num = 0;
 952         extra_idx = 0;
 953         seg_res = 0;
 954         hdr_size = hw->vtnet_hdr_size;
 955         offload = rx_offload_enabled(hw);
 956
 957         while (i < nb_used) {
 958                 struct virtio_net_hdr_mrg_rxbuf *header;
 959
 960                 if (nb_rx == nb_pkts)
 961                         break;
 962
 963                 num = virtqueue_dequeue_burst_rx(vq, rcv_pkts, len, 1);
 964                 if (num != 1)
 965                         continue;
 966
 967                 i++;
 968
 969                 PMD_RX_LOG(DEBUG, "dequeue:%d", num);
 970                 PMD_RX_LOG(DEBUG, "packet len:%d", len[0]);
 971
 972                 rxm = rcv_pkts[0];
 973
 974                 if (unlikely(len[0] < hdr_size + ETHER_HDR_LEN)) {
 975                         PMD_RX_LOG(ERR, "Packet drop");
 976                         nb_enqueued++;
 977                         virtio_discard_rxbuf(vq, rxm);
 978                         rxvq->stats.errors++;
 979                         continue;
 980                 }
 981
 982                 header = (struct virtio_net_hdr_mrg_rxbuf *)((char *)rxm->buf_addr +
 983                         RTE_PKTMBUF_HEADROOM - hdr_size);
 984                 seg_num = header->num_buffers;
 985
 986                 if (seg_num == 0)
 987                         seg_num = 1;
 988
 989                 rxm->data_off = RTE_PKTMBUF_HEADROOM;
 990                 rxm->nb_segs = seg_num;
 991                 rxm->next = NULL;
 992                 rxm->ol_flags = 0;
 993                 rxm->vlan_tci = 0;
 994                 rxm->pkt_len = (uint32_t)(len[0] - hdr_size);
 995                 rxm->data_len = (uint16_t)(len[0] - hdr_size);
 996
 997                 rxm->port = rxvq->port_id;
 998                 rx_pkts[nb_rx] = rxm;
 999                 prev = rxm;
1000
1001                 if (offload && virtio_rx_offload(rxm, &header->hdr) < 0) {
1002                         virtio_discard_rxbuf(vq, rxm);
1003                         rxvq->stats.errors++;
1004                         continue;
1005                 }
1006
1007                 seg_res = seg_num - 1;
1008
1009                 while (seg_res != 0) {
1010                         /*
1011                          * Get extra segments for current uncompleted packet.
1012                          */
1013                         uint16_t  rcv_cnt =
1014                                 RTE_MIN(seg_res, RTE_DIM(rcv_pkts));
1015                         if (likely(VIRTQUEUE_NUSED(vq) >= rcv_cnt)) {
1016                                 uint32_t rx_num =
1017                                         virtqueue_dequeue_burst_rx(vq,
1018                                         rcv_pkts, len, rcv_cnt);
1019                                 i += rx_num;
1020                                 rcv_cnt = rx_num;
1021                         } else {
1022                                 PMD_RX_LOG(ERR,
1023                                            "No enough segments for packet.");
1024                                 nb_enqueued++;
1025                                 virtio_discard_rxbuf(vq, rxm);
1026                                 rxvq->stats.errors++;
1027                                 break;
1028                         }
1029
1030                         extra_idx = 0;
1031
1032                         while (extra_idx < rcv_cnt) {
1033                                 rxm = rcv_pkts[extra_idx];
1034
1035                                 rxm->data_off = RTE_PKTMBUF_HEADROOM - hdr_size;
1036                                 rxm->next = NULL;
1037                                 rxm->pkt_len = (uint32_t)(len[extra_idx]);
1038                                 rxm->data_len = (uint16_t)(len[extra_idx]);
1039
1040                                 if (prev)
1041                                         prev->next = rxm;
1042
1043                                 prev = rxm;
1044                                 rx_pkts[nb_rx]->pkt_len += rxm->pkt_len;
1045                                 extra_idx++;
1046                         };
1047                         seg_res -= rcv_cnt;
1048                 }
1049
1050                 if (hw->vlan_strip)
1051                         rte_vlan_strip(rx_pkts[nb_rx]);
1052
1053                 VIRTIO_DUMP_PACKET(rx_pkts[nb_rx],
1054                         rx_pkts[nb_rx]->data_len);
1055
1056                 rxvq->stats.bytes += rx_pkts[nb_rx]->pkt_len;
1057                 virtio_update_packet_stats(&rxvq->stats, rx_pkts[nb_rx]);
1058                 nb_rx++;
1059         }
1060
1061         rxvq->stats.packets += nb_rx;
1062
1063         /* Allocate new mbuf for the used descriptor */
1064         error = ENOSPC;
1065         while (likely(!virtqueue_full(vq))) {
1066                 new_mbuf = rte_mbuf_raw_alloc(rxvq->mpool);
1067                 if (unlikely(new_mbuf == NULL)) {
1068                         struct rte_eth_dev *dev
1069                                 = &rte_eth_devices[rxvq->port_id];
1070                         dev->data->rx_mbuf_alloc_failed++;
1071                         break;
1072                 }
1073                 error = virtqueue_enqueue_recv_refill(vq, new_mbuf);
1074                 if (unlikely(error)) {
1075                         rte_pktmbuf_free(new_mbuf);
1076                         break;
1077                 }
1078                 nb_enqueued++;
1079         }
1080
1081         if (likely(nb_enqueued)) {
1082                 vq_update_avail_idx(vq);
1083
1084                 if (unlikely(virtqueue_kick_prepare(vq))) {
1085                         virtqueue_notify(vq);
1086                         PMD_RX_LOG(DEBUG, "Notified");
1087                 }
1088         }
1089
1090         return nb_rx;
1091 }
1092
1093 uint16_t
1094 virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
1095 {
1096         struct virtnet_tx *txvq = tx_queue;
1097         struct virtqueue *vq = txvq->vq;
1098         struct virtio_hw *hw = vq->hw;
1099         uint16_t hdr_size = hw->vtnet_hdr_size;
1100         uint16_t nb_used, nb_tx;
1101         int error;
1102
1103         if (unlikely(nb_pkts < 1))
1104                 return nb_pkts;
1105
1106         PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts);
1107         nb_used = VIRTQUEUE_NUSED(vq);
1108
1109         virtio_rmb();
1110         if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
1111                 virtio_xmit_cleanup(vq, nb_used);
1112
1113         for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
1114                 struct rte_mbuf *txm = tx_pkts[nb_tx];
1115                 int can_push = 0, use_indirect = 0, slots, need;
1116
1117                 /* Do VLAN tag insertion */
1118                 if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
1119                         error = rte_vlan_insert(&txm);
1120                         if (unlikely(error)) {
1121                                 rte_pktmbuf_free(txm);
1122                                 continue;
1123                         }
1124                 }
1125
1126                 /* optimize ring usage */
1127                 if (vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) &&
1128                     rte_mbuf_refcnt_read(txm) == 1 &&
1129                     RTE_MBUF_DIRECT(txm) &&
1130                     txm->nb_segs == 1 &&
1131                     rte_pktmbuf_headroom(txm) >= hdr_size &&
1132                     rte_is_aligned(rte_pktmbuf_mtod(txm, char *),
1133                                    __alignof__(struct virtio_net_hdr_mrg_rxbuf)))
1134                         can_push = 1;
1135                 else if (vtpci_with_feature(hw, VIRTIO_RING_F_INDIRECT_DESC) &&
1136                          txm->nb_segs < VIRTIO_MAX_TX_INDIRECT)
1137                         use_indirect = 1;
1138
1139                 /* How many main ring entries are needed to this Tx?
1140                  * any_layout => number of segments
1141                  * indirect   => 1
1142                  * default    => number of segments + 1
1143                  */
1144                 slots = use_indirect ? 1 : (txm->nb_segs + !can_push);
1145                 need = slots - vq->vq_free_cnt;
1146
1147                 /* Positive value indicates it need free vring descriptors */
1148                 if (unlikely(need > 0)) {
1149                         nb_used = VIRTQUEUE_NUSED(vq);
1150                         virtio_rmb();
1151                         need = RTE_MIN(need, (int)nb_used);
1152
1153                         virtio_xmit_cleanup(vq, need);
1154                         need = slots - vq->vq_free_cnt;
1155                         if (unlikely(need > 0)) {
1156                                 PMD_TX_LOG(ERR,
1157                                            "No free tx descriptors to transmit");
1158                                 break;
1159                         }
1160                 }
1161
1162                 /* Enqueue Packet buffers */
1163                 virtqueue_enqueue_xmit(txvq, txm, slots, use_indirect, can_push);
1164
1165                 txvq->stats.bytes += txm->pkt_len;
1166                 virtio_update_packet_stats(&txvq->stats, txm);
1167         }
1168
1169         txvq->stats.packets += nb_tx;
1170
1171         if (likely(nb_tx)) {
1172                 vq_update_avail_idx(vq);
1173
1174                 if (unlikely(virtqueue_kick_prepare(vq))) {
1175                         virtqueue_notify(vq);
1176                         PMD_TX_LOG(DEBUG, "Notified backend after xmit");
1177                 }
1178         }
1179
1180         return nb_tx;
1181 }