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 #include <linux/vmalloc.h>
  38
  39 #include <xen/events.h>
  40 #include <asm/xen/hypercall.h>
  41
  42 #define XENVIF_QUEUE_LENGTH 32
  43 #define XENVIF_NAPI_WEIGHT  64
  44
  45 int xenvif_schedulable(struct xenvif *vif)
  46 {
  47         return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
  48 }
  49
  50 static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
  51 {
  52         struct xenvif *vif = dev_id;
  53
  54         if (RING_HAS_UNCONSUMED_REQUESTS(&vif->tx))
  55                 napi_schedule(&vif->napi);
  56
  57         return IRQ_HANDLED;
  58 }
  59
  60 static int xenvif_poll(struct napi_struct *napi, int budget)
  61 {
  62         struct xenvif *vif = container_of(napi, struct xenvif, napi);
  63         int work_done;
  64
  65         work_done = xenvif_tx_action(vif, budget);
  66
  67         if (work_done < budget) {
  68                 int more_to_do = 0;
  69                 unsigned long flags;
  70
  71                 /* It is necessary to disable IRQ before calling
  72                  * RING_HAS_UNCONSUMED_REQUESTS. Otherwise we might
  73                  * lose event from the frontend.
  74                  *
  75                  * Consider:
  76                  *   RING_HAS_UNCONSUMED_REQUESTS
  77                  *   <frontend generates event to trigger napi_schedule>
  78                  *   __napi_complete
  79                  *
  80                  * This handler is still in scheduled state so the
  81                  * event has no effect at all. After __napi_complete
  82                  * this handler is descheduled and cannot get
  83                  * scheduled again. We lose event in this case and the ring
  84                  * will be completely stalled.
  85                  */
  86
  87                 local_irq_save(flags);
  88
  89                 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
  90                 if (!more_to_do)
  91                         __napi_complete(napi);
  92
  93                 local_irq_restore(flags);
  94         }
  95
  96         return work_done;
  97 }
  98
  99 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
 100 {
 101         struct xenvif *vif = dev_id;
 102
 103         xenvif_kick_thread(vif);
 104
 105         return IRQ_HANDLED;
 106 }
 107
 108 static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 109 {
 110         xenvif_tx_interrupt(irq, dev_id);
 111         xenvif_rx_interrupt(irq, dev_id);
 112
 113         return IRQ_HANDLED;
 114 }
 115
 116 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 117 {
 118         struct xenvif *vif = netdev_priv(dev);
 119         int min_slots_needed;
 120
 121         BUG_ON(skb->dev != dev);
 122
 123         /* Drop the packet if vif is not ready */
 124         if (vif->task == NULL || !xenvif_schedulable(vif))
 125                 goto drop;
 126
 127         /* At best we'll need one slot for the header and one for each
 128          * frag.
 129          */
 130         min_slots_needed = 1 + skb_shinfo(skb)->nr_frags;
 131
 132         /* If the skb is GSO then we'll also need an extra slot for the
 133          * metadata.
 134          */
 135         if (skb_is_gso(skb))
 136                 min_slots_needed++;
 137
 138         /* If the skb can't possibly fit in the remaining slots
 139          * then turn off the queue to give the ring a chance to
 140          * drain.
 141          */
 142         if (!xenvif_rx_ring_slots_available(vif, min_slots_needed))
 143                 xenvif_stop_queue(vif);
 144
 145         skb_queue_tail(&vif->rx_queue, skb);
 146         xenvif_kick_thread(vif);
 147
 148         return NETDEV_TX_OK;
 149
 150  drop:
 151         vif->dev->stats.tx_dropped++;
 152         dev_kfree_skb(skb);
 153         return NETDEV_TX_OK;
 154 }
 155
 156 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 157 {
 158         struct xenvif *vif = netdev_priv(dev);
 159         return &vif->dev->stats;
 160 }
 161
 162 static void xenvif_up(struct xenvif *vif)
 163 {
 164         napi_enable(&vif->napi);
 165         enable_irq(vif->tx_irq);
 166         if (vif->tx_irq != vif->rx_irq)
 167                 enable_irq(vif->rx_irq);
 168         xenvif_check_rx_xenvif(vif);
 169 }
 170
 171 static void xenvif_down(struct xenvif *vif)
 172 {
 173         napi_disable(&vif->napi);
 174         disable_irq(vif->tx_irq);
 175         if (vif->tx_irq != vif->rx_irq)
 176                 disable_irq(vif->rx_irq);
 177         del_timer_sync(&vif->credit_timeout);
 178 }
 179
 180 static int xenvif_open(struct net_device *dev)
 181 {
 182         struct xenvif *vif = netdev_priv(dev);
 183         if (netif_carrier_ok(dev))
 184                 xenvif_up(vif);
 185         netif_start_queue(dev);
 186         return 0;
 187 }
 188
 189 static int xenvif_close(struct net_device *dev)
 190 {
 191         struct xenvif *vif = netdev_priv(dev);
 192         if (netif_carrier_ok(dev))
 193                 xenvif_down(vif);
 194         netif_stop_queue(dev);
 195         return 0;
 196 }
 197
 198 static int xenvif_change_mtu(struct net_device *dev, int mtu)
 199 {
 200         struct xenvif *vif = netdev_priv(dev);
 201         int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
 202
 203         if (mtu > max)
 204                 return -EINVAL;
 205         dev->mtu = mtu;
 206         return 0;
 207 }
 208
 209 static netdev_features_t xenvif_fix_features(struct net_device *dev,
 210         netdev_features_t features)
 211 {
 212         struct xenvif *vif = netdev_priv(dev);
 213
 214         if (!vif->can_sg)
 215                 features &= ~NETIF_F_SG;
 216         if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV4))
 217                 features &= ~NETIF_F_TSO;
 218         if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV6))
 219                 features &= ~NETIF_F_TSO6;
 220         if (!vif->ip_csum)
 221                 features &= ~NETIF_F_IP_CSUM;
 222         if (!vif->ipv6_csum)
 223                 features &= ~NETIF_F_IPV6_CSUM;
 224
 225         return features;
 226 }
 227
 228 static const struct xenvif_stat {
 229         char name[ETH_GSTRING_LEN];
 230         u16 offset;
 231 } xenvif_stats[] = {
 232         {
 233                 "rx_gso_checksum_fixup",
 234                 offsetof(struct xenvif, rx_gso_checksum_fixup)
 235         },
 236 };
 237
 238 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
 239 {
 240         switch (string_set) {
 241         case ETH_SS_STATS:
 242                 return ARRAY_SIZE(xenvif_stats);
 243         default:
 244                 return -EINVAL;
 245         }
 246 }
 247
 248 static void xenvif_get_ethtool_stats(struct net_device *dev,
 249                                      struct ethtool_stats *stats, u64 * data)
 250 {
 251         void *vif = netdev_priv(dev);
 252         int i;
 253
 254         for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 255                 data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
 256 }
 257
 258 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
 259 {
 260         int i;
 261
 262         switch (stringset) {
 263         case ETH_SS_STATS:
 264                 for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 265                         memcpy(data + i * ETH_GSTRING_LEN,
 266                                xenvif_stats[i].name, ETH_GSTRING_LEN);
 267                 break;
 268         }
 269 }
 270
 271 static const struct ethtool_ops xenvif_ethtool_ops = {
 272         .get_link       = ethtool_op_get_link,
 273
 274         .get_sset_count = xenvif_get_sset_count,
 275         .get_ethtool_stats = xenvif_get_ethtool_stats,
 276         .get_strings = xenvif_get_strings,
 277 };
 278
 279 static const struct net_device_ops xenvif_netdev_ops = {
 280         .ndo_start_xmit = xenvif_start_xmit,
 281         .ndo_get_stats  = xenvif_get_stats,
 282         .ndo_open       = xenvif_open,
 283         .ndo_stop       = xenvif_close,
 284         .ndo_change_mtu = xenvif_change_mtu,
 285         .ndo_fix_features = xenvif_fix_features,
 286         .ndo_set_mac_address = eth_mac_addr,
 287         .ndo_validate_addr   = eth_validate_addr,
 288 };
 289
 290 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 291                             unsigned int handle)
 292 {
 293         int err;
 294         struct net_device *dev;
 295         struct xenvif *vif;
 296         char name[IFNAMSIZ] = {};
 297         int i;
 298
 299         snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
 300         dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
 301         if (dev == NULL) {
 302                 pr_warn("Could not allocate netdev for %s\n", name);
 303                 return ERR_PTR(-ENOMEM);
 304         }
 305
 306         SET_NETDEV_DEV(dev, parent);
 307
 308         vif = netdev_priv(dev);
 309
 310         vif->grant_copy_op = vmalloc(sizeof(struct gnttab_copy) *
 311                                      MAX_GRANT_COPY_OPS);
 312         if (vif->grant_copy_op == NULL) {
 313                 pr_warn("Could not allocate grant copy space for %s\n", name);
 314                 free_netdev(dev);
 315                 return ERR_PTR(-ENOMEM);
 316         }
 317
 318         vif->domid  = domid;
 319         vif->handle = handle;
 320         vif->can_sg = 1;
 321         vif->ip_csum = 1;
 322         vif->dev = dev;
 323
 324         vif->credit_bytes = vif->remaining_credit = ~0UL;
 325         vif->credit_usec  = 0UL;
 326         init_timer(&vif->credit_timeout);
 327         vif->credit_window_start = get_jiffies_64();
 328
 329         dev->netdev_ops = &xenvif_netdev_ops;
 330         dev->hw_features = NETIF_F_SG |
 331                 NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
 332                 NETIF_F_TSO | NETIF_F_TSO6;
 333         dev->features = dev->hw_features | NETIF_F_RXCSUM;
 334         SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
 335
 336         dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 337
 338         skb_queue_head_init(&vif->rx_queue);
 339         skb_queue_head_init(&vif->tx_queue);
 340
 341         vif->pending_cons = 0;
 342         vif->pending_prod = MAX_PENDING_REQS;
 343         for (i = 0; i < MAX_PENDING_REQS; i++)
 344                 vif->pending_ring[i] = i;
 345         for (i = 0; i < MAX_PENDING_REQS; i++)
 346                 vif->mmap_pages[i] = NULL;
 347
 348         /*
 349          * Initialise a dummy MAC address. We choose the numerically
 350          * largest non-broadcast address to prevent the address getting
 351          * stolen by an Ethernet bridge for STP purposes.
 352          * (FE:FF:FF:FF:FF:FF)
 353          */
 354         memset(dev->dev_addr, 0xFF, ETH_ALEN);
 355         dev->dev_addr[0] &= ~0x01;
 356
 357         netif_napi_add(dev, &vif->napi, xenvif_poll, XENVIF_NAPI_WEIGHT);
 358
 359         netif_carrier_off(dev);
 360
 361         err = register_netdev(dev);
 362         if (err) {
 363                 netdev_warn(dev, "Could not register device: err=%d\n", err);
 364                 free_netdev(dev);
 365                 return ERR_PTR(err);
 366         }
 367
 368         netdev_dbg(dev, "Successfully created xenvif\n");
 369
 370         __module_get(THIS_MODULE);
 371
 372         return vif;
 373 }
 374
 375 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 376                    unsigned long rx_ring_ref, unsigned int tx_evtchn,
 377                    unsigned int rx_evtchn)
 378 {
 379         struct task_struct *task;
 380         int err = -ENOMEM;
 381
 382         BUG_ON(vif->tx_irq);
 383         BUG_ON(vif->task);
 384
 385         err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
 386         if (err < 0)
 387                 goto err;
 388
 389         init_waitqueue_head(&vif->wq);
 390
 391         if (tx_evtchn == rx_evtchn) {
 392                 /* feature-split-event-channels == 0 */
 393                 err = bind_interdomain_evtchn_to_irqhandler(
 394                         vif->domid, tx_evtchn, xenvif_interrupt, 0,
 395                         vif->dev->name, vif);
 396                 if (err < 0)
 397                         goto err_unmap;
 398                 vif->tx_irq = vif->rx_irq = err;
 399                 disable_irq(vif->tx_irq);
 400         } else {
 401                 /* feature-split-event-channels == 1 */
 402                 snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name),
 403                          "%s-tx", vif->dev->name);
 404                 err = bind_interdomain_evtchn_to_irqhandler(
 405                         vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
 406                         vif->tx_irq_name, vif);
 407                 if (err < 0)
 408                         goto err_unmap;
 409                 vif->tx_irq = err;
 410                 disable_irq(vif->tx_irq);
 411
 412                 snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name),
 413                          "%s-rx", vif->dev->name);
 414                 err = bind_interdomain_evtchn_to_irqhandler(
 415                         vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
 416                         vif->rx_irq_name, vif);
 417                 if (err < 0)
 418                         goto err_tx_unbind;
 419                 vif->rx_irq = err;
 420                 disable_irq(vif->rx_irq);
 421         }
 422
 423         task = kthread_create(xenvif_kthread,
 424                               (void *)vif, "%s", vif->dev->name);
 425         if (IS_ERR(task)) {
 426                 pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
 427                 err = PTR_ERR(task);
 428                 goto err_rx_unbind;
 429         }
 430
 431         vif->task = task;
 432
 433         rtnl_lock();
 434         if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
 435                 dev_set_mtu(vif->dev, ETH_DATA_LEN);
 436         netdev_update_features(vif->dev);
 437         netif_carrier_on(vif->dev);
 438         if (netif_running(vif->dev))
 439                 xenvif_up(vif);
 440         rtnl_unlock();
 441
 442         wake_up_process(vif->task);
 443
 444         return 0;
 445
 446 err_rx_unbind:
 447         unbind_from_irqhandler(vif->rx_irq, vif);
 448         vif->rx_irq = 0;
 449 err_tx_unbind:
 450         unbind_from_irqhandler(vif->tx_irq, vif);
 451         vif->tx_irq = 0;
 452 err_unmap:
 453         xenvif_unmap_frontend_rings(vif);
 454 err:
 455         module_put(THIS_MODULE);
 456         return err;
 457 }
 458
 459 void xenvif_carrier_off(struct xenvif *vif)
 460 {
 461         struct net_device *dev = vif->dev;
 462
 463         rtnl_lock();
 464         netif_carrier_off(dev); /* discard queued packets */
 465         if (netif_running(dev))
 466                 xenvif_down(vif);
 467         rtnl_unlock();
 468 }
 469
 470 void xenvif_disconnect(struct xenvif *vif)
 471 {
 472         if (netif_carrier_ok(vif->dev))
 473                 xenvif_carrier_off(vif);
 474
 475         if (vif->task) {
 476                 kthread_stop(vif->task);
 477                 vif->task = NULL;
 478         }
 479
 480         if (vif->tx_irq) {
 481                 if (vif->tx_irq == vif->rx_irq)
 482                         unbind_from_irqhandler(vif->tx_irq, vif);
 483                 else {
 484                         unbind_from_irqhandler(vif->tx_irq, vif);
 485                         unbind_from_irqhandler(vif->rx_irq, vif);
 486                 }
 487                 vif->tx_irq = 0;
 488         }
 489
 490         xenvif_unmap_frontend_rings(vif);
 491 }
 492
 493 void xenvif_free(struct xenvif *vif)
 494 {
 495         netif_napi_del(&vif->napi);
 496
 497         unregister_netdev(vif->dev);
 498
 499         vfree(vif->grant_copy_op);
 500         free_netdev(vif->dev);
 501
 502         module_put(THIS_MODULE);
 503 }