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         vif->rx_event = true;
 104         xenvif_kick_thread(vif);
 105
 106         return IRQ_HANDLED;
 107 }
 108
 109 static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 110 {
 111         xenvif_tx_interrupt(irq, dev_id);
 112         xenvif_rx_interrupt(irq, dev_id);
 113
 114         return IRQ_HANDLED;
 115 }
 116
 117 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 118 {
 119         struct xenvif *vif = netdev_priv(dev);
 120         int min_slots_needed;
 121
 122         BUG_ON(skb->dev != dev);
 123
 124         /* Drop the packet if vif is not ready */
 125         if (vif->task == NULL || !xenvif_schedulable(vif))
 126                 goto drop;
 127
 128         /* At best we'll need one slot for the header and one for each
 129          * frag.
 130          */
 131         min_slots_needed = 1 + skb_shinfo(skb)->nr_frags;
 132
 133         /* If the skb is GSO then we'll also need an extra slot for the
 134          * metadata.
 135          */
 136         if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
 137             skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 138                 min_slots_needed++;
 139
 140         /* If the skb can't possibly fit in the remaining slots
 141          * then turn off the queue to give the ring a chance to
 142          * drain.
 143          */
 144         if (!xenvif_rx_ring_slots_available(vif, min_slots_needed))
 145                 xenvif_stop_queue(vif);
 146
 147         skb_queue_tail(&vif->rx_queue, skb);
 148         xenvif_kick_thread(vif);
 149
 150         return NETDEV_TX_OK;
 151
 152  drop:
 153         vif->dev->stats.tx_dropped++;
 154         dev_kfree_skb(skb);
 155         return NETDEV_TX_OK;
 156 }
 157
 158 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 159 {
 160         struct xenvif *vif = netdev_priv(dev);
 161         return &vif->dev->stats;
 162 }
 163
 164 static void xenvif_up(struct xenvif *vif)
 165 {
 166         napi_enable(&vif->napi);
 167         enable_irq(vif->tx_irq);
 168         if (vif->tx_irq != vif->rx_irq)
 169                 enable_irq(vif->rx_irq);
 170         xenvif_check_rx_xenvif(vif);
 171 }
 172
 173 static void xenvif_down(struct xenvif *vif)
 174 {
 175         napi_disable(&vif->napi);
 176         disable_irq(vif->tx_irq);
 177         if (vif->tx_irq != vif->rx_irq)
 178                 disable_irq(vif->rx_irq);
 179         del_timer_sync(&vif->credit_timeout);
 180 }
 181
 182 static int xenvif_open(struct net_device *dev)
 183 {
 184         struct xenvif *vif = netdev_priv(dev);
 185         if (netif_carrier_ok(dev))
 186                 xenvif_up(vif);
 187         netif_start_queue(dev);
 188         return 0;
 189 }
 190
 191 static int xenvif_close(struct net_device *dev)
 192 {
 193         struct xenvif *vif = netdev_priv(dev);
 194         if (netif_carrier_ok(dev))
 195                 xenvif_down(vif);
 196         netif_stop_queue(dev);
 197         return 0;
 198 }
 199
 200 static int xenvif_change_mtu(struct net_device *dev, int mtu)
 201 {
 202         struct xenvif *vif = netdev_priv(dev);
 203         int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
 204
 205         if (mtu > max)
 206                 return -EINVAL;
 207         dev->mtu = mtu;
 208         return 0;
 209 }
 210
 211 static netdev_features_t xenvif_fix_features(struct net_device *dev,
 212         netdev_features_t features)
 213 {
 214         struct xenvif *vif = netdev_priv(dev);
 215
 216         if (!vif->can_sg)
 217                 features &= ~NETIF_F_SG;
 218         if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV4))
 219                 features &= ~NETIF_F_TSO;
 220         if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV6))
 221                 features &= ~NETIF_F_TSO6;
 222         if (!vif->ip_csum)
 223                 features &= ~NETIF_F_IP_CSUM;
 224         if (!vif->ipv6_csum)
 225                 features &= ~NETIF_F_IPV6_CSUM;
 226
 227         return features;
 228 }
 229
 230 static const struct xenvif_stat {
 231         char name[ETH_GSTRING_LEN];
 232         u16 offset;
 233 } xenvif_stats[] = {
 234         {
 235                 "rx_gso_checksum_fixup",
 236                 offsetof(struct xenvif, rx_gso_checksum_fixup)
 237         },
 238 };
 239
 240 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
 241 {
 242         switch (string_set) {
 243         case ETH_SS_STATS:
 244                 return ARRAY_SIZE(xenvif_stats);
 245         default:
 246                 return -EINVAL;
 247         }
 248 }
 249
 250 static void xenvif_get_ethtool_stats(struct net_device *dev,
 251                                      struct ethtool_stats *stats, u64 * data)
 252 {
 253         void *vif = netdev_priv(dev);
 254         int i;
 255
 256         for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 257                 data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
 258 }
 259
 260 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
 261 {
 262         int i;
 263
 264         switch (stringset) {
 265         case ETH_SS_STATS:
 266                 for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 267                         memcpy(data + i * ETH_GSTRING_LEN,
 268                                xenvif_stats[i].name, ETH_GSTRING_LEN);
 269                 break;
 270         }
 271 }
 272
 273 static const struct ethtool_ops xenvif_ethtool_ops = {
 274         .get_link       = ethtool_op_get_link,
 275
 276         .get_sset_count = xenvif_get_sset_count,
 277         .get_ethtool_stats = xenvif_get_ethtool_stats,
 278         .get_strings = xenvif_get_strings,
 279 };
 280
 281 static const struct net_device_ops xenvif_netdev_ops = {
 282         .ndo_start_xmit = xenvif_start_xmit,
 283         .ndo_get_stats  = xenvif_get_stats,
 284         .ndo_open       = xenvif_open,
 285         .ndo_stop       = xenvif_close,
 286         .ndo_change_mtu = xenvif_change_mtu,
 287         .ndo_fix_features = xenvif_fix_features,
 288         .ndo_set_mac_address = eth_mac_addr,
 289         .ndo_validate_addr   = eth_validate_addr,
 290 };
 291
 292 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 293                             unsigned int handle)
 294 {
 295         int err;
 296         struct net_device *dev;
 297         struct xenvif *vif;
 298         char name[IFNAMSIZ] = {};
 299         int i;
 300
 301         snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
 302         dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
 303         if (dev == NULL) {
 304                 pr_warn("Could not allocate netdev for %s\n", name);
 305                 return ERR_PTR(-ENOMEM);
 306         }
 307
 308         SET_NETDEV_DEV(dev, parent);
 309
 310         vif = netdev_priv(dev);
 311
 312         vif->grant_copy_op = vmalloc(sizeof(struct gnttab_copy) *
 313                                      MAX_GRANT_COPY_OPS);
 314         if (vif->grant_copy_op == NULL) {
 315                 pr_warn("Could not allocate grant copy space for %s\n", name);
 316                 free_netdev(dev);
 317                 return ERR_PTR(-ENOMEM);
 318         }
 319
 320         vif->domid  = domid;
 321         vif->handle = handle;
 322         vif->can_sg = 1;
 323         vif->ip_csum = 1;
 324         vif->dev = dev;
 325
 326         vif->credit_bytes = vif->remaining_credit = ~0UL;
 327         vif->credit_usec  = 0UL;
 328         init_timer(&vif->credit_timeout);
 329         vif->credit_window_start = get_jiffies_64();
 330
 331         dev->netdev_ops = &xenvif_netdev_ops;
 332         dev->hw_features = NETIF_F_SG |
 333                 NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
 334                 NETIF_F_TSO | NETIF_F_TSO6;
 335         dev->features = dev->hw_features | NETIF_F_RXCSUM;
 336         SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
 337
 338         dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 339
 340         skb_queue_head_init(&vif->rx_queue);
 341         skb_queue_head_init(&vif->tx_queue);
 342
 343         vif->pending_cons = 0;
 344         vif->pending_prod = MAX_PENDING_REQS;
 345         for (i = 0; i < MAX_PENDING_REQS; i++)
 346                 vif->pending_ring[i] = i;
 347         for (i = 0; i < MAX_PENDING_REQS; i++)
 348                 vif->mmap_pages[i] = NULL;
 349
 350         /*
 351          * Initialise a dummy MAC address. We choose the numerically
 352          * largest non-broadcast address to prevent the address getting
 353          * stolen by an Ethernet bridge for STP purposes.
 354          * (FE:FF:FF:FF:FF:FF)
 355          */
 356         memset(dev->dev_addr, 0xFF, ETH_ALEN);
 357         dev->dev_addr[0] &= ~0x01;
 358
 359         netif_napi_add(dev, &vif->napi, xenvif_poll, XENVIF_NAPI_WEIGHT);
 360
 361         netif_carrier_off(dev);
 362
 363         err = register_netdev(dev);
 364         if (err) {
 365                 netdev_warn(dev, "Could not register device: err=%d\n", err);
 366                 free_netdev(dev);
 367                 return ERR_PTR(err);
 368         }
 369
 370         netdev_dbg(dev, "Successfully created xenvif\n");
 371
 372         __module_get(THIS_MODULE);
 373
 374         return vif;
 375 }
 376
 377 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 378                    unsigned long rx_ring_ref, unsigned int tx_evtchn,
 379                    unsigned int rx_evtchn)
 380 {
 381         struct task_struct *task;
 382         int err = -ENOMEM;
 383
 384         BUG_ON(vif->tx_irq);
 385         BUG_ON(vif->task);
 386
 387         err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
 388         if (err < 0)
 389                 goto err;
 390
 391         init_waitqueue_head(&vif->wq);
 392
 393         if (tx_evtchn == rx_evtchn) {
 394                 /* feature-split-event-channels == 0 */
 395                 err = bind_interdomain_evtchn_to_irqhandler(
 396                         vif->domid, tx_evtchn, xenvif_interrupt, 0,
 397                         vif->dev->name, vif);
 398                 if (err < 0)
 399                         goto err_unmap;
 400                 vif->tx_irq = vif->rx_irq = err;
 401                 disable_irq(vif->tx_irq);
 402         } else {
 403                 /* feature-split-event-channels == 1 */
 404                 snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name),
 405                          "%s-tx", vif->dev->name);
 406                 err = bind_interdomain_evtchn_to_irqhandler(
 407                         vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
 408                         vif->tx_irq_name, vif);
 409                 if (err < 0)
 410                         goto err_unmap;
 411                 vif->tx_irq = err;
 412                 disable_irq(vif->tx_irq);
 413
 414                 snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name),
 415                          "%s-rx", vif->dev->name);
 416                 err = bind_interdomain_evtchn_to_irqhandler(
 417                         vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
 418                         vif->rx_irq_name, vif);
 419                 if (err < 0)
 420                         goto err_tx_unbind;
 421                 vif->rx_irq = err;
 422                 disable_irq(vif->rx_irq);
 423         }
 424
 425         task = kthread_create(xenvif_kthread,
 426                               (void *)vif, "%s", vif->dev->name);
 427         if (IS_ERR(task)) {
 428                 pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
 429                 err = PTR_ERR(task);
 430                 goto err_rx_unbind;
 431         }
 432
 433         vif->task = task;
 434
 435         rtnl_lock();
 436         if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
 437                 dev_set_mtu(vif->dev, ETH_DATA_LEN);
 438         netdev_update_features(vif->dev);
 439         netif_carrier_on(vif->dev);
 440         if (netif_running(vif->dev))
 441                 xenvif_up(vif);
 442         rtnl_unlock();
 443
 444         wake_up_process(vif->task);
 445
 446         return 0;
 447
 448 err_rx_unbind:
 449         unbind_from_irqhandler(vif->rx_irq, vif);
 450         vif->rx_irq = 0;
 451 err_tx_unbind:
 452         unbind_from_irqhandler(vif->tx_irq, vif);
 453         vif->tx_irq = 0;
 454 err_unmap:
 455         xenvif_unmap_frontend_rings(vif);
 456 err:
 457         module_put(THIS_MODULE);
 458         return err;
 459 }
 460
 461 void xenvif_carrier_off(struct xenvif *vif)
 462 {
 463         struct net_device *dev = vif->dev;
 464
 465         rtnl_lock();
 466         netif_carrier_off(dev); /* discard queued packets */
 467         if (netif_running(dev))
 468                 xenvif_down(vif);
 469         rtnl_unlock();
 470 }
 471
 472 void xenvif_disconnect(struct xenvif *vif)
 473 {
 474         if (netif_carrier_ok(vif->dev))
 475                 xenvif_carrier_off(vif);
 476
 477         if (vif->task) {
 478                 kthread_stop(vif->task);
 479                 vif->task = NULL;
 480         }
 481
 482         if (vif->tx_irq) {
 483                 if (vif->tx_irq == vif->rx_irq)
 484                         unbind_from_irqhandler(vif->tx_irq, vif);
 485                 else {
 486                         unbind_from_irqhandler(vif->tx_irq, vif);
 487                         unbind_from_irqhandler(vif->rx_irq, vif);
 488                 }
 489                 vif->tx_irq = 0;
 490         }
 491
 492         xenvif_unmap_frontend_rings(vif);
 493 }
 494
 495 void xenvif_free(struct xenvif *vif)
 496 {
 497         netif_napi_del(&vif->napi);
 498
 499         unregister_netdev(vif->dev);
 500
 501         vfree(vif->grant_copy_op);
 502         free_netdev(vif->dev);
 503
 504         module_put(THIS_MODULE);
 505 }