LXR dpdk/examples/vhost/virtio

   1/* SPDX-License-Identifier: BSD-3-Clause
   2 * Copyright(c) 2010-2017 Intel Corporation
   3 */
   4
   5#include <stdint.h>
   6#include <stdbool.h>
   7#include <linux/virtio_net.h>
   8
   9#include <rte_mbuf.h>
  10#include <rte_memcpy.h>
  11#include <rte_vhost.h>
  12
  13#include "main.h"
  14
  15/*
  16 * A very simple vhost-user net driver implementation, without
  17 * any extra features being enabled, such as TSO and mrg-Rx.
  18 */
  19
  20void
  21vs_vhost_net_setup(struct vhost_dev *dev)
  22{
  23        uint16_t i;
  24        int vid = dev->vid;
  25        struct vhost_queue *queue;
  26        int ret;
  27
  28        RTE_LOG(INFO, VHOST_CONFIG,
  29                "setting builtin vhost-user net driver\n");
  30
  31        rte_vhost_get_negotiated_features(vid, &dev->features);
  32        if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
  33                dev->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
  34        else
  35                dev->hdr_len = sizeof(struct virtio_net_hdr);
  36
  37        ret = rte_vhost_get_mem_table(vid, &dev->mem);
  38        if (ret < 0) {
  39                RTE_LOG(ERR, VHOST_CONFIG, "Failed to get "
  40                        "VM memory layout for device(%d)\n", vid);
  41                return;
  42        }
  43
  44        dev->nr_vrings = rte_vhost_get_vring_num(vid);
  45        for (i = 0; i < dev->nr_vrings; i++) {
  46                queue = &dev->queues[i];
  47
  48                queue->last_used_idx  = 0;
  49                queue->last_avail_idx = 0;
  50                rte_vhost_get_vhost_vring(vid, i, &queue->vr);
  51        }
  52}
  53
  54void
  55vs_vhost_net_remove(struct vhost_dev *dev)
  56{
  57        free(dev->mem);
  58}
  59
  60static __rte_always_inline int
  61enqueue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
  62            struct rte_mbuf *m, uint16_t desc_idx)
  63{
  64        uint32_t desc_avail, desc_offset;
  65        uint64_t desc_chunck_len;
  66        uint32_t mbuf_avail, mbuf_offset;
  67        uint32_t cpy_len;
  68        struct vring_desc *desc;
  69        uint64_t desc_addr, desc_gaddr;
  70        struct virtio_net_hdr virtio_hdr = {0, 0, 0, 0, 0, 0};
  71        /* A counter to avoid desc dead loop chain */
  72        uint16_t nr_desc = 1;
  73
  74        desc = &vr->desc[desc_idx];
  75        desc_chunck_len = desc->len;
  76        desc_gaddr = desc->addr;
  77        desc_addr = rte_vhost_va_from_guest_pa(
  78                        dev->mem, desc_gaddr, &desc_chunck_len);
  79        /*
  80         * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
  81         * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
  82         * otherwise stores offset on the stack instead of in a register.
  83         */
  84        if (unlikely(desc->len < dev->hdr_len) || !desc_addr)
  85                return -1;
  86
  87        rte_prefetch0((void *)(uintptr_t)desc_addr);
  88
  89        /* write virtio-net header */
  90        if (likely(desc_chunck_len >= dev->hdr_len)) {
  91                *(struct virtio_net_hdr *)(uintptr_t)desc_addr = virtio_hdr;
  92                desc_offset = dev->hdr_len;
  93        } else {
  94                uint64_t len;
  95                uint64_t remain = dev->hdr_len;
  96                uint64_t src = (uint64_t)(uintptr_t)&virtio_hdr, dst;
  97                uint64_t guest_addr = desc_gaddr;
  98
  99                while (remain) {
 100                        len = remain;
 101                        dst = rte_vhost_va_from_guest_pa(dev->mem,
 102                                        guest_addr, &len);
 103                        if (unlikely(!dst || !len))
 104                                return -1;
 105
 106                        rte_memcpy((void *)(uintptr_t)dst,
 107                                        (void *)(uintptr_t)src,
 108                                        len);
 109
 110                        remain -= len;
 111                        guest_addr += len;
 112                        src += len;
 113                }
 114
 115                desc_chunck_len = desc->len - dev->hdr_len;
 116                desc_gaddr += dev->hdr_len;
 117                desc_addr = rte_vhost_va_from_guest_pa(
 118                                dev->mem, desc_gaddr,
 119                                &desc_chunck_len);
 120                if (unlikely(!desc_addr))
 121                        return -1;
 122
 123                desc_offset = 0;
 124        }
 125
 126        desc_avail  = desc->len - dev->hdr_len;
 127
 128        mbuf_avail  = rte_pktmbuf_data_len(m);
 129        mbuf_offset = 0;
 130        while (mbuf_avail != 0 || m->next != NULL) {
 131                /* done with current mbuf, fetch next */
 132                if (mbuf_avail == 0) {
 133                        m = m->next;
 134
 135                        mbuf_offset = 0;
 136                        mbuf_avail  = rte_pktmbuf_data_len(m);
 137                }
 138
 139                /* done with current desc buf, fetch next */
 140                if (desc_avail == 0) {
 141                        if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
 142                                /* Room in vring buffer is not enough */
 143                                return -1;
 144                        }
 145                        if (unlikely(desc->next >= vr->size ||
 146                                     ++nr_desc > vr->size))
 147                                return -1;
 148
 149                        desc = &vr->desc[desc->next];
 150                        desc_chunck_len = desc->len;
 151                        desc_gaddr = desc->addr;
 152                        desc_addr = rte_vhost_va_from_guest_pa(
 153                                        dev->mem, desc_gaddr, &desc_chunck_len);
 154                        if (unlikely(!desc_addr))
 155                                return -1;
 156
 157                        desc_offset = 0;
 158                        desc_avail  = desc->len;
 159                } else if (unlikely(desc_chunck_len == 0)) {
 160                        desc_chunck_len = desc_avail;
 161                        desc_gaddr += desc_offset;
 162                        desc_addr = rte_vhost_va_from_guest_pa(dev->mem,
 163                                        desc_gaddr,
 164                                        &desc_chunck_len);
 165                        if (unlikely(!desc_addr))
 166                                return -1;
 167
 168                        desc_offset = 0;
 169                }
 170
 171                cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail);
 172                rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
 173                        rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 174                        cpy_len);
 175
 176                mbuf_avail  -= cpy_len;
 177                mbuf_offset += cpy_len;
 178                desc_avail  -= cpy_len;
 179                desc_offset += cpy_len;
 180                desc_chunck_len -= cpy_len;
 181        }
 182
 183        return 0;
 184}
 185
 186uint16_t
 187vs_enqueue_pkts(struct vhost_dev *dev, uint16_t queue_id,
 188                struct rte_mbuf **pkts, uint32_t count)
 189{
 190        struct vhost_queue *queue;
 191        struct rte_vhost_vring *vr;
 192        uint16_t avail_idx, free_entries, start_idx;
 193        uint16_t desc_indexes[MAX_PKT_BURST];
 194        uint16_t used_idx;
 195        uint32_t i;
 196
 197        queue = &dev->queues[queue_id];
 198        vr    = &queue->vr;
 199
 200        avail_idx = __atomic_load_n(&vr->avail->idx, __ATOMIC_ACQUIRE);
 201        start_idx = queue->last_used_idx;
 202        free_entries = avail_idx - start_idx;
 203        count = RTE_MIN(count, free_entries);
 204        count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
 205        if (count == 0)
 206                return 0;
 207
 208        /* Retrieve all of the desc indexes first to avoid caching issues. */
 209        rte_prefetch0(&vr->avail->ring[start_idx & (vr->size - 1)]);
 210        for (i = 0; i < count; i++) {
 211                used_idx = (start_idx + i) & (vr->size - 1);
 212                desc_indexes[i] = vr->avail->ring[used_idx];
 213                vr->used->ring[used_idx].id = desc_indexes[i];
 214                vr->used->ring[used_idx].len = pkts[i]->pkt_len +
 215                                               dev->hdr_len;
 216        }
 217
 218        rte_prefetch0(&vr->desc[desc_indexes[0]]);
 219        for (i = 0; i < count; i++) {
 220                uint16_t desc_idx = desc_indexes[i];
 221                int err;
 222
 223                err = enqueue_pkt(dev, vr, pkts[i], desc_idx);
 224                if (unlikely(err)) {
 225                        used_idx = (start_idx + i) & (vr->size - 1);
 226                        vr->used->ring[used_idx].len = dev->hdr_len;
 227                }
 228
 229                if (i + 1 < count)
 230                        rte_prefetch0(&vr->desc[desc_indexes[i+1]]);
 231        }
 232
 233        __atomic_add_fetch(&vr->used->idx, count, __ATOMIC_RELEASE);
 234        queue->last_used_idx += count;
 235
 236        rte_vhost_vring_call(dev->vid, queue_id);
 237
 238        return count;
 239}
 240
 241static __rte_always_inline int
 242dequeue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
 243            struct rte_mbuf *m, uint16_t desc_idx,
 244            struct rte_mempool *mbuf_pool)
 245{
 246        struct vring_desc *desc;
 247        uint64_t desc_addr, desc_gaddr;
 248        uint32_t desc_avail, desc_offset;
 249        uint64_t desc_chunck_len;
 250        uint32_t mbuf_avail, mbuf_offset;
 251        uint32_t cpy_len;
 252        struct rte_mbuf *cur = m, *prev = m;
 253        /* A counter to avoid desc dead loop chain */
 254        uint32_t nr_desc = 1;
 255
 256        desc = &vr->desc[desc_idx];
 257        if (unlikely((desc->len < dev->hdr_len)) ||
 258                        (desc->flags & VRING_DESC_F_INDIRECT))
 259                return -1;
 260
 261        desc_chunck_len = desc->len;
 262        desc_gaddr = desc->addr;
 263        desc_addr = rte_vhost_va_from_guest_pa(
 264                        dev->mem, desc_gaddr, &desc_chunck_len);
 265        if (unlikely(!desc_addr))
 266                return -1;
 267
 268        /*
 269         * We don't support ANY_LAYOUT, neither VERSION_1, meaning
 270         * a Tx packet from guest must have 2 desc buffers at least:
 271         * the first for storing the header and the others for
 272         * storing the data.
 273         *
 274         * And since we don't support TSO, we could simply skip the
 275         * header.
 276         */
 277        desc = &vr->desc[desc->next];
 278        desc_chunck_len = desc->len;
 279        desc_gaddr = desc->addr;
 280        desc_addr = rte_vhost_va_from_guest_pa(
 281                        dev->mem, desc_gaddr, &desc_chunck_len);
 282        if (unlikely(!desc_addr))
 283                return -1;
 284        rte_prefetch0((void *)(uintptr_t)desc_addr);
 285
 286        desc_offset = 0;
 287        desc_avail  = desc->len;
 288        nr_desc    += 1;
 289
 290        mbuf_offset = 0;
 291        mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
 292        while (1) {
 293                cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail);
 294                rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
 295                                                   mbuf_offset),
 296                        (void *)((uintptr_t)(desc_addr + desc_offset)),
 297                        cpy_len);
 298
 299                mbuf_avail  -= cpy_len;
 300                mbuf_offset += cpy_len;
 301                desc_avail  -= cpy_len;
 302                desc_offset += cpy_len;
 303                desc_chunck_len -= cpy_len;
 304
 305                /* This desc reaches to its end, get the next one */
 306                if (desc_avail == 0) {
 307                        if ((desc->flags & VRING_DESC_F_NEXT) == 0)
 308                                break;
 309
 310                        if (unlikely(desc->next >= vr->size ||
 311                                     ++nr_desc > vr->size))
 312                                return -1;
 313                        desc = &vr->desc[desc->next];
 314
 315                        desc_chunck_len = desc->len;
 316                        desc_gaddr = desc->addr;
 317                        desc_addr = rte_vhost_va_from_guest_pa(
 318                                        dev->mem, desc_gaddr, &desc_chunck_len);
 319                        if (unlikely(!desc_addr))
 320                                return -1;
 321                        rte_prefetch0((void *)(uintptr_t)desc_addr);
 322
 323                        desc_offset = 0;
 324                        desc_avail  = desc->len;
 325                } else if (unlikely(desc_chunck_len == 0)) {
 326                        desc_chunck_len = desc_avail;
 327                        desc_gaddr += desc_offset;
 328                        desc_addr = rte_vhost_va_from_guest_pa(dev->mem,
 329                                        desc_gaddr,
 330                                        &desc_chunck_len);
 331                        if (unlikely(!desc_addr))
 332                                return -1;
 333
 334                        desc_offset = 0;
 335                }
 336
 337                /*
 338                 * This mbuf reaches to its end, get a new one
 339                 * to hold more data.
 340                 */
 341                if (mbuf_avail == 0) {
 342                        cur = rte_pktmbuf_alloc(mbuf_pool);
 343                        if (unlikely(cur == NULL)) {
 344                                RTE_LOG(ERR, VHOST_DATA, "Failed to "
 345                                        "allocate memory for mbuf.\n");
 346                                return -1;
 347                        }
 348
 349                        prev->next = cur;
 350                        prev->data_len = mbuf_offset;
 351                        m->nb_segs += 1;
 352                        m->pkt_len += mbuf_offset;
 353                        prev = cur;
 354
 355                        mbuf_offset = 0;
 356                        mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
 357                }
 358        }
 359
 360        prev->data_len = mbuf_offset;
 361        m->pkt_len    += mbuf_offset;
 362
 363        return 0;
 364}
 365
 366uint16_t
 367vs_dequeue_pkts(struct vhost_dev *dev, uint16_t queue_id,
 368        struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
 369{
 370        struct vhost_queue *queue;
 371        struct rte_vhost_vring *vr;
 372        uint32_t desc_indexes[MAX_PKT_BURST];
 373        uint32_t used_idx;
 374        uint32_t i = 0;
 375        uint16_t free_entries;
 376        uint16_t avail_idx;
 377
 378        queue = &dev->queues[queue_id];
 379        vr    = &queue->vr;
 380
 381        free_entries = __atomic_load_n(&vr->avail->idx, __ATOMIC_ACQUIRE) -
 382                        queue->last_avail_idx;
 383        if (free_entries == 0)
 384                return 0;
 385
 386        /* Prefetch available and used ring */
 387        avail_idx = queue->last_avail_idx & (vr->size - 1);
 388        used_idx  = queue->last_used_idx  & (vr->size - 1);
 389        rte_prefetch0(&vr->avail->ring[avail_idx]);
 390        rte_prefetch0(&vr->used->ring[used_idx]);
 391
 392        count = RTE_MIN(count, MAX_PKT_BURST);
 393        count = RTE_MIN(count, free_entries);
 394
 395        if (unlikely(count == 0))
 396                return 0;
 397
 398        /*
 399         * Retrieve all of the head indexes first and pre-update used entries
 400         * to avoid caching issues.
 401         */
 402        for (i = 0; i < count; i++) {
 403                avail_idx = (queue->last_avail_idx + i) & (vr->size - 1);
 404                used_idx  = (queue->last_used_idx  + i) & (vr->size - 1);
 405                desc_indexes[i] = vr->avail->ring[avail_idx];
 406
 407                vr->used->ring[used_idx].id  = desc_indexes[i];
 408                vr->used->ring[used_idx].len = 0;
 409        }
 410
 411        /* Prefetch descriptor index. */
 412        rte_prefetch0(&vr->desc[desc_indexes[0]]);
 413        for (i = 0; i < count; i++) {
 414                int err;
 415
 416                if (likely(i + 1 < count))
 417                        rte_prefetch0(&vr->desc[desc_indexes[i + 1]]);
 418
 419                pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
 420                if (unlikely(pkts[i] == NULL)) {
 421                        RTE_LOG(ERR, VHOST_DATA,
 422                                "Failed to allocate memory for mbuf.\n");
 423                        break;
 424                }
 425
 426                err = dequeue_pkt(dev, vr, pkts[i], desc_indexes[i], mbuf_pool);
 427                if (unlikely(err)) {
 428                        rte_pktmbuf_free(pkts[i]);
 429                        break;
 430                }
 431
 432        }
 433
 434        queue->last_avail_idx += i;
 435        queue->last_used_idx += i;
 436
 437        __atomic_add_fetch(&vr->used->idx, i, __ATOMIC_ACQ_REL);
 438
 439        rte_vhost_vring_call(dev->vid, queue_id);
 440
 441        return i;
 442}
 443