drivers/net/xen-netback/interface.c

   1 /*
   2  * Network-device interface management.
   3  *
   4  * Copyright (c) 2004-2005, Keir Fraser
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License version 2
   8  * as published by the Free Software Foundation; or, when distributed
   9  * separately from the Linux kernel or incorporated into other
  10  * software packages, subject to the following license:
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a copy
  13  * of this source file (the "Software"), to deal in the Software without
  14  * restriction, including without limitation the rights to use, copy, modify,
  15  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  16  * and to permit persons to whom the Software is furnished to do so, subject to
  17  * the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included in
  20  * all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  28  * IN THE SOFTWARE.
  29  */
  30
  31 #include "common.h"
  32
  33 #include <linux/kthread.h>
  34 #include <linux/ethtool.h>
  35 #include <linux/rtnetlink.h>
  36 #include <linux/if_vlan.h>
  37
  38 #include <xen/events.h>
  39 #include <asm/xen/hypercall.h>
  40
  41 #define XENVIF_QUEUE_LENGTH 32
  42 #define XENVIF_NAPI_WEIGHT  64
  43
  44 int xenvif_schedulable(struct xenvif *vif)
  45 {
  46         return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
  47 }
  48
  49 static int xenvif_rx_schedulable(struct xenvif *vif)
  50 {
  51         return xenvif_schedulable(vif) && !xenvif_rx_ring_full(vif);
  52 }
  53
  54 static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
  55 {
  56         struct xenvif *vif = dev_id;
  57
  58         if (RING_HAS_UNCONSUMED_REQUESTS(&vif->tx))
  59                 napi_schedule(&vif->napi);
  60
  61         return IRQ_HANDLED;
  62 }
  63
  64 static int xenvif_poll(struct napi_struct *napi, int budget)
  65 {
  66         struct xenvif *vif = container_of(napi, struct xenvif, napi);
  67         int work_done;
  68
  69         /* This vif is rogue, we pretend we've there is nothing to do
  70          * for this vif to deschedule it from NAPI. But this interface
  71          * will be turned off in thread context later.
  72          */
  73         if (unlikely(vif->disabled)) {
  74                 napi_complete(napi);
  75                 return 0;
  76         }
  77
  78         work_done = xenvif_tx_action(vif, budget);
  79
  80         if (work_done < budget) {
  81                 int more_to_do = 0;
  82                 unsigned long flags;
  83
  84                 /* It is necessary to disable IRQ before calling
  85                  * RING_HAS_UNCONSUMED_REQUESTS. Otherwise we might
  86                  * lose event from the frontend.
  87                  *
  88                  * Consider:
  89                  *   RING_HAS_UNCONSUMED_REQUESTS
  90                  *   <frontend generates event to trigger napi_schedule>
  91                  *   __napi_complete
  92                  *
  93                  * This handler is still in scheduled state so the
  94                  * event has no effect at all. After __napi_complete
  95                  * this handler is descheduled and cannot get
  96                  * scheduled again. We lose event in this case and the ring
  97                  * will be completely stalled.
  98                  */
  99
 100                 local_irq_save(flags);
 101
 102                 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
 103                 if (!more_to_do)
 104                         __napi_complete(napi);
 105
 106                 local_irq_restore(flags);
 107         }
 108
 109         return work_done;
 110 }
 111
 112 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
 113 {
 114         struct xenvif *vif = dev_id;
 115
 116         if (xenvif_rx_schedulable(vif))
 117                 netif_wake_queue(vif->dev);
 118
 119         return IRQ_HANDLED;
 120 }
 121
 122 static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 123 {
 124         xenvif_tx_interrupt(irq, dev_id);
 125         xenvif_rx_interrupt(irq, dev_id);
 126
 127         return IRQ_HANDLED;
 128 }
 129
 130 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 131 {
 132         struct xenvif *vif = netdev_priv(dev);
 133
 134         BUG_ON(skb->dev != dev);
 135
 136         /* Drop the packet if vif is not ready */
 137         if (vif->task == NULL)
 138                 goto drop;
 139
 140         /* Drop the packet if the target domain has no receive buffers. */
 141         if (!xenvif_rx_schedulable(vif))
 142                 goto drop;
 143
 144         /* Reserve ring slots for the worst-case number of fragments. */
 145         vif->rx_req_cons_peek += xenvif_count_skb_slots(vif, skb);
 146
 147         if (vif->can_queue && xenvif_must_stop_queue(vif))
 148                 netif_stop_queue(dev);
 149
 150         xenvif_queue_tx_skb(vif, skb);
 151
 152         return NETDEV_TX_OK;
 153
 154  drop:
 155         vif->dev->stats.tx_dropped++;
 156         dev_kfree_skb(skb);
 157         return NETDEV_TX_OK;
 158 }
 159
 160 void xenvif_notify_tx_completion(struct xenvif *vif)
 161 {
 162         if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
 163                 netif_wake_queue(vif->dev);
 164 }
 165
 166 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 167 {
 168         struct xenvif *vif = netdev_priv(dev);
 169         return &vif->dev->stats;
 170 }
 171
 172 static void xenvif_up(struct xenvif *vif)
 173 {
 174         napi_enable(&vif->napi);
 175         enable_irq(vif->tx_irq);
 176         if (vif->tx_irq != vif->rx_irq)
 177                 enable_irq(vif->rx_irq);
 178         xenvif_check_rx_xenvif(vif);
 179 }
 180
 181 static void xenvif_down(struct xenvif *vif)
 182 {
 183         napi_disable(&vif->napi);
 184         disable_irq(vif->tx_irq);
 185         if (vif->tx_irq != vif->rx_irq)
 186                 disable_irq(vif->rx_irq);
 187         del_timer_sync(&vif->credit_timeout);
 188 }
 189
 190 static int xenvif_open(struct net_device *dev)
 191 {
 192         struct xenvif *vif = netdev_priv(dev);
 193         if (netif_carrier_ok(dev))
 194                 xenvif_up(vif);
 195         netif_start_queue(dev);
 196         return 0;
 197 }
 198
 199 static int xenvif_close(struct net_device *dev)
 200 {
 201         struct xenvif *vif = netdev_priv(dev);
 202         if (netif_carrier_ok(dev))
 203                 xenvif_down(vif);
 204         netif_stop_queue(dev);
 205         return 0;
 206 }
 207
 208 static int xenvif_change_mtu(struct net_device *dev, int mtu)
 209 {
 210         struct xenvif *vif = netdev_priv(dev);
 211         int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
 212
 213         if (mtu > max)
 214                 return -EINVAL;
 215         dev->mtu = mtu;
 216         return 0;
 217 }
 218
 219 static netdev_features_t xenvif_fix_features(struct net_device *dev,
 220         netdev_features_t features)
 221 {
 222         struct xenvif *vif = netdev_priv(dev);
 223
 224         if (!vif->can_sg)
 225                 features &= ~NETIF_F_SG;
 226         if (!vif->gso && !vif->gso_prefix)
 227                 features &= ~NETIF_F_TSO;
 228         if (!vif->csum)
 229                 features &= ~NETIF_F_IP_CSUM;
 230
 231         return features;
 232 }
 233
 234 static const struct xenvif_stat {
 235         char name[ETH_GSTRING_LEN];
 236         u16 offset;
 237 } xenvif_stats[] = {
 238         {
 239                 "rx_gso_checksum_fixup",
 240                 offsetof(struct xenvif, rx_gso_checksum_fixup)
 241         },
 242 };
 243
 244 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
 245 {
 246         switch (string_set) {
 247         case ETH_SS_STATS:
 248                 return ARRAY_SIZE(xenvif_stats);
 249         default:
 250                 return -EINVAL;
 251         }
 252 }
 253
 254 static void xenvif_get_ethtool_stats(struct net_device *dev,
 255                                      struct ethtool_stats *stats, u64 * data)
 256 {
 257         void *vif = netdev_priv(dev);
 258         int i;
 259
 260         for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 261                 data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
 262 }
 263
 264 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
 265 {
 266         int i;
 267
 268         switch (stringset) {
 269         case ETH_SS_STATS:
 270                 for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 271                         memcpy(data + i * ETH_GSTRING_LEN,
 272                                xenvif_stats[i].name, ETH_GSTRING_LEN);
 273                 break;
 274         }
 275 }
 276
 277 static const struct ethtool_ops xenvif_ethtool_ops = {
 278         .get_link       = ethtool_op_get_link,
 279
 280         .get_sset_count = xenvif_get_sset_count,
 281         .get_ethtool_stats = xenvif_get_ethtool_stats,
 282         .get_strings = xenvif_get_strings,
 283 };
 284
 285 static const struct net_device_ops xenvif_netdev_ops = {
 286         .ndo_start_xmit = xenvif_start_xmit,
 287         .ndo_get_stats  = xenvif_get_stats,
 288         .ndo_open       = xenvif_open,
 289         .ndo_stop       = xenvif_close,
 290         .ndo_change_mtu = xenvif_change_mtu,
 291         .ndo_fix_features = xenvif_fix_features,
 292         .ndo_set_mac_address = eth_mac_addr,
 293         .ndo_validate_addr   = eth_validate_addr,
 294 };
 295
 296 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 297                             unsigned int handle)
 298 {
 299         int err;
 300         struct net_device *dev;
 301         struct xenvif *vif;
 302         char name[IFNAMSIZ] = {};
 303         int i;
 304
 305         snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
 306         dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
 307         if (dev == NULL) {
 308                 pr_warn("Could not allocate netdev for %s\n", name);
 309                 return ERR_PTR(-ENOMEM);
 310         }
 311
 312         SET_NETDEV_DEV(dev, parent);
 313
 314         vif = netdev_priv(dev);
 315         vif->domid  = domid;
 316         vif->handle = handle;
 317         vif->can_sg = 1;
 318         vif->csum = 1;
 319         vif->dev = dev;
 320
 321         vif->disabled = false;
 322
 323         vif->credit_bytes = vif->remaining_credit = ~0UL;
 324         vif->credit_usec  = 0UL;
 325         init_timer(&vif->credit_timeout);
 326         vif->credit_window_start = get_jiffies_64();
 327
 328         dev->netdev_ops = &xenvif_netdev_ops;
 329         dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
 330         dev->features = dev->hw_features;
 331         SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
 332
 333         dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 334
 335         skb_queue_head_init(&vif->rx_queue);
 336         skb_queue_head_init(&vif->tx_queue);
 337
 338         vif->pending_cons = 0;
 339         vif->pending_prod = MAX_PENDING_REQS;
 340         for (i = 0; i < MAX_PENDING_REQS; i++)
 341                 vif->pending_ring[i] = i;
 342         for (i = 0; i < MAX_PENDING_REQS; i++)
 343                 vif->mmap_pages[i] = NULL;
 344
 345         /*
 346          * Initialise a dummy MAC address. We choose the numerically
 347          * largest non-broadcast address to prevent the address getting
 348          * stolen by an Ethernet bridge for STP purposes.
 349          * (FE:FF:FF:FF:FF:FF)
 350          */
 351         memset(dev->dev_addr, 0xFF, ETH_ALEN);
 352         dev->dev_addr[0] &= ~0x01;
 353
 354         netif_napi_add(dev, &vif->napi, xenvif_poll, XENVIF_NAPI_WEIGHT);
 355
 356         netif_carrier_off(dev);
 357
 358         err = register_netdev(dev);
 359         if (err) {
 360                 netdev_warn(dev, "Could not register device: err=%d\n", err);
 361                 free_netdev(dev);
 362                 return ERR_PTR(err);
 363         }
 364
 365         netdev_dbg(dev, "Successfully created xenvif\n");
 366
 367         __module_get(THIS_MODULE);
 368
 369         return vif;
 370 }
 371
 372 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 373                    unsigned long rx_ring_ref, unsigned int tx_evtchn,
 374                    unsigned int rx_evtchn)
 375 {
 376         int err = -ENOMEM;
 377
 378         /* Already connected through? */
 379         if (vif->tx_irq)
 380                 return 0;
 381
 382         err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
 383         if (err < 0)
 384                 goto err;
 385
 386         if (tx_evtchn == rx_evtchn) {
 387                 /* feature-split-event-channels == 0 */
 388                 err = bind_interdomain_evtchn_to_irqhandler(
 389                         vif->domid, tx_evtchn, xenvif_interrupt, 0,
 390                         vif->dev->name, vif);
 391                 if (err < 0)
 392                         goto err_unmap;
 393                 vif->tx_irq = vif->rx_irq = err;
 394                 disable_irq(vif->tx_irq);
 395         } else {
 396                 /* feature-split-event-channels == 1 */
 397                 snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name),
 398                          "%s-tx", vif->dev->name);
 399                 err = bind_interdomain_evtchn_to_irqhandler(
 400                         vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
 401                         vif->tx_irq_name, vif);
 402                 if (err < 0)
 403                         goto err_unmap;
 404                 vif->tx_irq = err;
 405                 disable_irq(vif->tx_irq);
 406
 407                 snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name),
 408                          "%s-rx", vif->dev->name);
 409                 err = bind_interdomain_evtchn_to_irqhandler(
 410                         vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
 411                         vif->rx_irq_name, vif);
 412                 if (err < 0)
 413                         goto err_tx_unbind;
 414                 vif->rx_irq = err;
 415                 disable_irq(vif->rx_irq);
 416         }
 417
 418         init_waitqueue_head(&vif->wq);
 419         vif->task = kthread_create(xenvif_kthread,
 420                                    (void *)vif, "%s", vif->dev->name);
 421         if (IS_ERR(vif->task)) {
 422                 pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
 423                 err = PTR_ERR(vif->task);
 424                 goto err_rx_unbind;
 425         }
 426
 427         rtnl_lock();
 428         if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
 429                 dev_set_mtu(vif->dev, ETH_DATA_LEN);
 430         netdev_update_features(vif->dev);
 431         netif_carrier_on(vif->dev);
 432         if (netif_running(vif->dev))
 433                 xenvif_up(vif);
 434         rtnl_unlock();
 435
 436         wake_up_process(vif->task);
 437
 438         return 0;
 439
 440 err_rx_unbind:
 441         unbind_from_irqhandler(vif->rx_irq, vif);
 442         vif->rx_irq = 0;
 443 err_tx_unbind:
 444         unbind_from_irqhandler(vif->tx_irq, vif);
 445         vif->tx_irq = 0;
 446 err_unmap:
 447         xenvif_unmap_frontend_rings(vif);
 448 err:
 449         module_put(THIS_MODULE);
 450         return err;
 451 }
 452
 453 void xenvif_carrier_off(struct xenvif *vif)
 454 {
 455         struct net_device *dev = vif->dev;
 456
 457         rtnl_lock();
 458         netif_carrier_off(dev); /* discard queued packets */
 459         if (netif_running(dev))
 460                 xenvif_down(vif);
 461         rtnl_unlock();
 462 }
 463
 464 void xenvif_disconnect(struct xenvif *vif)
 465 {
 466         if (netif_carrier_ok(vif->dev))
 467                 xenvif_carrier_off(vif);
 468
 469         if (vif->tx_irq) {
 470                 if (vif->tx_irq == vif->rx_irq)
 471                         unbind_from_irqhandler(vif->tx_irq, vif);
 472                 else {
 473                         unbind_from_irqhandler(vif->tx_irq, vif);
 474                         unbind_from_irqhandler(vif->rx_irq, vif);
 475                 }
 476                 vif->tx_irq = 0;
 477         }
 478
 479         if (vif->task)
 480                 kthread_stop(vif->task);
 481
 482         xenvif_unmap_frontend_rings(vif);
 483 }
 484
 485 void xenvif_free(struct xenvif *vif)
 486 {
 487         netif_napi_del(&vif->napi);
 488
 489         unregister_netdev(vif->dev);
 490
 491         free_netdev(vif->dev);
 492
 493         module_put(THIS_MODULE);
 494 }