hw/virtio-net.c

   1 /*
   2  * Virtio Network Device
   3  *
   4  * Copyright IBM, Corp. 2007
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "virtio.h"
  15 #include "net.h"
  16 #include "qemu-timer.h"
  17 #include "virtio-net.h"
  18
  19 typedef struct VirtIONet
  20 {
  21     VirtIODevice vdev;
  22     uint8_t mac[6];
  23     VirtQueue *rx_vq;
  24     VirtQueue *tx_vq;
  25     VLANClientState *vc;
  26     QEMUTimer *tx_timer;
  27     int tx_timer_active;
  28     int mergeable_rx_bufs;
  29 } VirtIONet;
  30
  31 /* TODO
  32  * - we could suppress RX interrupt if we were so inclined.
  33  */
  34
  35 static VirtIONet *to_virtio_net(VirtIODevice *vdev)
  36 {
  37     return (VirtIONet *)vdev;
  38 }
  39
  40 static void virtio_net_update_config(VirtIODevice *vdev, uint8_t *config)
  41 {
  42     VirtIONet *n = to_virtio_net(vdev);
  43     struct virtio_net_config netcfg;
  44
  45     memcpy(netcfg.mac, n->mac, 6);
  46     memcpy(config, &netcfg, sizeof(netcfg));
  47 }
  48
  49 static uint32_t virtio_net_get_features(VirtIODevice *vdev)
  50 {
  51     uint32_t features = (1 << VIRTIO_NET_F_MAC);
  52
  53     return features;
  54 }
  55
  56 static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)
  57 {
  58     VirtIONet *n = to_virtio_net(vdev);
  59
  60     n->mergeable_rx_bufs = !!(features & (1 << VIRTIO_NET_F_MRG_RXBUF));
  61 }
  62
  63 /* RX */
  64
  65 static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)
  66 {
  67 }
  68
  69 static int do_virtio_net_can_receive(VirtIONet *n, int bufsize)
  70 {
  71     if (!virtio_queue_ready(n->rx_vq) ||
  72         !(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
  73         return 0;
  74
  75     if (virtio_queue_empty(n->rx_vq) ||
  76         (n->mergeable_rx_bufs &&
  77          !virtqueue_avail_bytes(n->rx_vq, bufsize, 0))) {
  78         virtio_queue_set_notification(n->rx_vq, 1);
  79         return 0;
  80     }
  81
  82     virtio_queue_set_notification(n->rx_vq, 0);
  83     return 1;
  84 }
  85
  86 static int virtio_net_can_receive(void *opaque)
  87 {
  88     VirtIONet *n = opaque;
  89
  90     return do_virtio_net_can_receive(n, VIRTIO_NET_MAX_BUFSIZE);
  91 }
  92
  93 static int iov_fill(struct iovec *iov, int iovcnt, const void *buf, int count)
  94 {
  95     int offset, i;
  96
  97     offset = i = 0;
  98     while (offset < count && i < iovcnt) {
  99         int len = MIN(iov[i].iov_len, count - offset);
 100         memcpy(iov[i].iov_base, buf + offset, len);
 101         offset += len;
 102         i++;
 103     }
 104
 105     return offset;
 106 }
 107
 108 static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,
 109                           const void *buf, int size, int hdr_len)
 110 {
 111     struct virtio_net_hdr *hdr = iov[0].iov_base;
 112     int offset = 0;
 113
 114     hdr->flags = 0;
 115     hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 116
 117     /* We only ever receive a struct virtio_net_hdr from the tapfd,
 118      * but we may be passing along a larger header to the guest.
 119      */
 120     iov[0].iov_base += hdr_len;
 121     iov[0].iov_len  -= hdr_len;
 122
 123     return offset;
 124 }
 125
 126 static void virtio_net_receive(void *opaque, const uint8_t *buf, int size)
 127 {
 128     VirtIONet *n = opaque;
 129     struct virtio_net_hdr_mrg_rxbuf *mhdr = NULL;
 130     int hdr_len, offset, i;
 131
 132     if (!do_virtio_net_can_receive(n, size))
 133         return;
 134
 135     /* hdr_len refers to the header we supply to the guest */
 136     hdr_len = n->mergeable_rx_bufs ?
 137         sizeof(struct virtio_net_hdr_mrg_rxbuf) : sizeof(struct virtio_net_hdr);
 138
 139     offset = i = 0;
 140
 141     while (offset < size) {
 142         VirtQueueElement elem;
 143         int len, total;
 144         struct iovec sg[VIRTQUEUE_MAX_SIZE];
 145
 146         len = total = 0;
 147
 148         if ((i != 0 && !n->mergeable_rx_bufs) ||
 149             virtqueue_pop(n->rx_vq, &elem) == 0) {
 150             if (i == 0)
 151                 return;
 152             fprintf(stderr, "virtio-net truncating packet\n");
 153             exit(1);
 154         }
 155
 156         if (elem.in_num < 1) {
 157             fprintf(stderr, "virtio-net receive queue contains no in buffers\n");
 158             exit(1);
 159         }
 160
 161         if (!n->mergeable_rx_bufs && elem.in_sg[0].iov_len != hdr_len) {
 162             fprintf(stderr, "virtio-net header not in first element\n");
 163             exit(1);
 164         }
 165
 166         memcpy(&sg, &elem.in_sg[0], sizeof(sg[0]) * elem.in_num);
 167
 168         if (i == 0) {
 169             if (n->mergeable_rx_bufs)
 170                 mhdr = (struct virtio_net_hdr_mrg_rxbuf *)sg[0].iov_base;
 171
 172             offset += receive_header(n, sg, elem.in_num,
 173                                      buf + offset, size - offset, hdr_len);
 174             total += hdr_len;
 175         }
 176
 177         /* copy in packet.  ugh */
 178         len = iov_fill(sg, elem.in_num,
 179                        buf + offset, size - offset);
 180         total += len;
 181
 182         /* signal other side */
 183         virtqueue_fill(n->rx_vq, &elem, total, i++);
 184
 185         offset += len;
 186     }
 187
 188     if (mhdr)
 189         mhdr->num_buffers = i;
 190
 191     virtqueue_flush(n->rx_vq, i);
 192     virtio_notify(&n->vdev, n->rx_vq);
 193 }
 194
 195 /* TX */
 196 static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)
 197 {
 198     VirtQueueElement elem;
 199     int has_vnet_hdr = 0;
 200
 201     if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
 202         return;
 203
 204     while (virtqueue_pop(vq, &elem)) {
 205         ssize_t len = 0;
 206         unsigned int out_num = elem.out_num;
 207         struct iovec *out_sg = &elem.out_sg[0];
 208         unsigned hdr_len;
 209
 210         /* hdr_len refers to the header received from the guest */
 211         hdr_len = n->mergeable_rx_bufs ?
 212             sizeof(struct virtio_net_hdr_mrg_rxbuf) :
 213             sizeof(struct virtio_net_hdr);
 214
 215         if (out_num < 1 || out_sg->iov_len != hdr_len) {
 216             fprintf(stderr, "virtio-net header not in first element\n");
 217             exit(1);
 218         }
 219
 220         /* ignore the header if GSO is not supported */
 221         if (!has_vnet_hdr) {
 222             out_num--;
 223             out_sg++;
 224             len += hdr_len;
 225         } else if (n->mergeable_rx_bufs) {
 226             /* tapfd expects a struct virtio_net_hdr */
 227             hdr_len -= sizeof(struct virtio_net_hdr);
 228             out_sg->iov_len -= hdr_len;
 229             len += hdr_len;
 230         }
 231
 232         len += qemu_sendv_packet(n->vc, out_sg, out_num);
 233
 234         virtqueue_push(vq, &elem, len);
 235         virtio_notify(&n->vdev, vq);
 236     }
 237 }
 238
 239 static void virtio_net_handle_tx(VirtIODevice *vdev, VirtQueue *vq)
 240 {
 241     VirtIONet *n = to_virtio_net(vdev);
 242
 243     if (n->tx_timer_active) {
 244         virtio_queue_set_notification(vq, 1);
 245         qemu_del_timer(n->tx_timer);
 246         n->tx_timer_active = 0;
 247         virtio_net_flush_tx(n, vq);
 248     } else {
 249         qemu_mod_timer(n->tx_timer,
 250                        qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
 251         n->tx_timer_active = 1;
 252         virtio_queue_set_notification(vq, 0);
 253     }
 254 }
 255
 256 static void virtio_net_tx_timer(void *opaque)
 257 {
 258     VirtIONet *n = opaque;
 259
 260     n->tx_timer_active = 0;
 261
 262     /* Just in case the driver is not ready on more */
 263     if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
 264         return;
 265
 266     virtio_queue_set_notification(n->tx_vq, 1);
 267     virtio_net_flush_tx(n, n->tx_vq);
 268 }
 269
 270 static void virtio_net_save(QEMUFile *f, void *opaque)
 271 {
 272     VirtIONet *n = opaque;
 273
 274     virtio_save(&n->vdev, f);
 275
 276     qemu_put_buffer(f, n->mac, 6);
 277     qemu_put_be32(f, n->tx_timer_active);
 278 }
 279
 280 static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
 281 {
 282     VirtIONet *n = opaque;
 283
 284     if (version_id != 1)
 285         return -EINVAL;
 286
 287     virtio_load(&n->vdev, f);
 288
 289     qemu_get_buffer(f, n->mac, 6);
 290     n->tx_timer_active = qemu_get_be32(f);
 291
 292     if (n->tx_timer_active) {
 293         qemu_mod_timer(n->tx_timer,
 294                        qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
 295     }
 296
 297     return 0;
 298 }
 299
 300 PCIDevice *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
 301 {
 302     VirtIONet *n;
 303     static int virtio_net_id;
 304
 305     n = (VirtIONet *)virtio_init_pci(bus, "virtio-net", 6900, 0x1000,
 306                                      0, VIRTIO_ID_NET,
 307                                      0x02, 0x00, 0x00,
 308                                      6, sizeof(VirtIONet));
 309     if (!n)
 310         return NULL;
 311
 312     n->vdev.get_config = virtio_net_update_config;
 313     n->vdev.get_features = virtio_net_get_features;
 314     n->vdev.set_features = virtio_net_set_features;
 315     n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);
 316     n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx);
 317     memcpy(n->mac, nd->macaddr, 6);
 318     n->vc = qemu_new_vlan_client(nd->vlan, virtio_net_receive,
 319                                  virtio_net_can_receive, n);
 320
 321     n->tx_timer = qemu_new_timer(vm_clock, virtio_net_tx_timer, n);
 322     n->tx_timer_active = 0;
 323     n->mergeable_rx_bufs = 0;
 324
 325     register_savevm("virtio-net", virtio_net_id++, 1,
 326                     virtio_net_save, virtio_net_load, n);
 327
 328     return (PCIDevice *)n;
 329 }