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