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         work_done = xenvif_tx_action(vif, budget);
  70
  71         if (work_done < budget) {
  72                 int more_to_do = 0;
  73                 unsigned long flags;
  74
  75                 /* It is necessary to disable IRQ before calling
  76                  * RING_HAS_UNCONSUMED_REQUESTS. Otherwise we might
  77                  * lose event from the frontend.
  78                  *
  79                  * Consider:
  80                  *   RING_HAS_UNCONSUMED_REQUESTS
  81                  *   <frontend generates event to trigger napi_schedule>
  82                  *   __napi_complete
  83                  *
  84                  * This handler is still in scheduled state so the
  85                  * event has no effect at all. After __napi_complete
  86                  * this handler is descheduled and cannot get
  87                  * scheduled again. We lose event in this case and the ring
  88                  * will be completely stalled.
  89                  */
  90
  91                 local_irq_save(flags);
  92
  93                 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
  94                 if (!more_to_do)
  95                         __napi_complete(napi);
  96
  97                 local_irq_restore(flags);
  98         }
  99
 100         return work_done;
 101 }
 102
 103 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
 104 {
 105         struct xenvif *vif = dev_id;
 106
 107         if (xenvif_rx_schedulable(vif))
 108                 netif_wake_queue(vif->dev);
 109
 110         return IRQ_HANDLED;
 111 }
 112
 113 static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 114 {
 115         xenvif_tx_interrupt(irq, dev_id);
 116         xenvif_rx_interrupt(irq, dev_id);
 117
 118         return IRQ_HANDLED;
 119 }
 120
 121 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 122 {
 123         struct xenvif *vif = netdev_priv(dev);
 124
 125         BUG_ON(skb->dev != dev);
 126
 127         /* Drop the packet if vif is not ready */
 128         if (vif->task == NULL)
 129                 goto drop;
 130
 131         /* Drop the packet if the target domain has no receive buffers. */
 132         if (!xenvif_rx_schedulable(vif))
 133                 goto drop;
 134
 135         /* Reserve ring slots for the worst-case number of fragments. */
 136         vif->rx_req_cons_peek += xenvif_count_skb_slots(vif, skb);
 137
 138         if (vif->can_queue && xenvif_must_stop_queue(vif))
 139                 netif_stop_queue(dev);
 140
 141         xenvif_queue_tx_skb(vif, skb);
 142
 143         return NETDEV_TX_OK;
 144
 145  drop:
 146         vif->dev->stats.tx_dropped++;
 147         dev_kfree_skb(skb);
 148         return NETDEV_TX_OK;
 149 }
 150
 151 void xenvif_notify_tx_completion(struct xenvif *vif)
 152 {
 153         if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
 154                 netif_wake_queue(vif->dev);
 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         vif->domid  = domid;
 311         vif->handle = handle;
 312         vif->can_sg = 1;
 313         vif->ip_csum = 1;
 314         vif->dev = dev;
 315
 316         vif->credit_bytes = vif->remaining_credit = ~0UL;
 317         vif->credit_usec  = 0UL;
 318         init_timer(&vif->credit_timeout);
 319         vif->credit_window_start = get_jiffies_64();
 320
 321         dev->netdev_ops = &xenvif_netdev_ops;
 322         dev->hw_features = NETIF_F_SG |
 323                 NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
 324                 NETIF_F_TSO | NETIF_F_TSO6;
 325         dev->features = dev->hw_features | NETIF_F_RXCSUM;
 326         SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
 327
 328         dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 329
 330         skb_queue_head_init(&vif->rx_queue);
 331         skb_queue_head_init(&vif->tx_queue);
 332
 333         vif->pending_cons = 0;
 334         vif->pending_prod = MAX_PENDING_REQS;
 335         for (i = 0; i < MAX_PENDING_REQS; i++)
 336                 vif->pending_ring[i] = i;
 337         for (i = 0; i < MAX_PENDING_REQS; i++)
 338                 vif->mmap_pages[i] = NULL;
 339
 340         /*
 341          * Initialise a dummy MAC address. We choose the numerically
 342          * largest non-broadcast address to prevent the address getting
 343          * stolen by an Ethernet bridge for STP purposes.
 344          * (FE:FF:FF:FF:FF:FF)
 345          */
 346         memset(dev->dev_addr, 0xFF, ETH_ALEN);
 347         dev->dev_addr[0] &= ~0x01;
 348
 349         netif_napi_add(dev, &vif->napi, xenvif_poll, XENVIF_NAPI_WEIGHT);
 350
 351         netif_carrier_off(dev);
 352
 353         err = register_netdev(dev);
 354         if (err) {
 355                 netdev_warn(dev, "Could not register device: err=%d\n", err);
 356                 free_netdev(dev);
 357                 return ERR_PTR(err);
 358         }
 359
 360         netdev_dbg(dev, "Successfully created xenvif\n");
 361
 362         __module_get(THIS_MODULE);
 363
 364         return vif;
 365 }
 366
 367 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 368                    unsigned long rx_ring_ref, unsigned int tx_evtchn,
 369                    unsigned int rx_evtchn)
 370 {
 371         struct task_struct *task;
 372         int err = -ENOMEM;
 373
 374         BUG_ON(vif->tx_irq);
 375         BUG_ON(vif->task);
 376
 377         err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
 378         if (err < 0)
 379                 goto err;
 380
 381         if (tx_evtchn == rx_evtchn) {
 382                 /* feature-split-event-channels == 0 */
 383                 err = bind_interdomain_evtchn_to_irqhandler(
 384                         vif->domid, tx_evtchn, xenvif_interrupt, 0,
 385                         vif->dev->name, vif);
 386                 if (err < 0)
 387                         goto err_unmap;
 388                 vif->tx_irq = vif->rx_irq = err;
 389                 disable_irq(vif->tx_irq);
 390         } else {
 391                 /* feature-split-event-channels == 1 */
 392                 snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name),
 393                          "%s-tx", vif->dev->name);
 394                 err = bind_interdomain_evtchn_to_irqhandler(
 395                         vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
 396                         vif->tx_irq_name, vif);
 397                 if (err < 0)
 398                         goto err_unmap;
 399                 vif->tx_irq = err;
 400                 disable_irq(vif->tx_irq);
 401
 402                 snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name),
 403                          "%s-rx", vif->dev->name);
 404                 err = bind_interdomain_evtchn_to_irqhandler(
 405                         vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
 406                         vif->rx_irq_name, vif);
 407                 if (err < 0)
 408                         goto err_tx_unbind;
 409                 vif->rx_irq = err;
 410                 disable_irq(vif->rx_irq);
 411         }
 412
 413         init_waitqueue_head(&vif->wq);
 414         task = kthread_create(xenvif_kthread,
 415                               (void *)vif, "%s", vif->dev->name);
 416         if (IS_ERR(task)) {
 417                 pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
 418                 err = PTR_ERR(task);
 419                 goto err_rx_unbind;
 420         }
 421
 422         vif->task = task;
 423
 424         rtnl_lock();
 425         if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
 426                 dev_set_mtu(vif->dev, ETH_DATA_LEN);
 427         netdev_update_features(vif->dev);
 428         netif_carrier_on(vif->dev);
 429         if (netif_running(vif->dev))
 430                 xenvif_up(vif);
 431         rtnl_unlock();
 432
 433         wake_up_process(vif->task);
 434
 435         return 0;
 436
 437 err_rx_unbind:
 438         unbind_from_irqhandler(vif->rx_irq, vif);
 439         vif->rx_irq = 0;
 440 err_tx_unbind:
 441         unbind_from_irqhandler(vif->tx_irq, vif);
 442         vif->tx_irq = 0;
 443 err_unmap:
 444         xenvif_unmap_frontend_rings(vif);
 445 err:
 446         module_put(THIS_MODULE);
 447         return err;
 448 }
 449
 450 void xenvif_carrier_off(struct xenvif *vif)
 451 {
 452         struct net_device *dev = vif->dev;
 453
 454         rtnl_lock();
 455         netif_carrier_off(dev); /* discard queued packets */
 456         if (netif_running(dev))
 457                 xenvif_down(vif);
 458         rtnl_unlock();
 459 }
 460
 461 void xenvif_disconnect(struct xenvif *vif)
 462 {
 463         if (netif_carrier_ok(vif->dev))
 464                 xenvif_carrier_off(vif);
 465
 466         if (vif->task) {
 467                 kthread_stop(vif->task);
 468                 vif->task = NULL;
 469         }
 470
 471         if (vif->tx_irq) {
 472                 if (vif->tx_irq == vif->rx_irq)
 473                         unbind_from_irqhandler(vif->tx_irq, vif);
 474                 else {
 475                         unbind_from_irqhandler(vif->tx_irq, vif);
 476                         unbind_from_irqhandler(vif->rx_irq, vif);
 477                 }
 478                 vif->tx_irq = 0;
 479         }
 480
 481         xenvif_unmap_frontend_rings(vif);
 482 }
 483
 484 void xenvif_free(struct xenvif *vif)
 485 {
 486         netif_napi_del(&vif->napi);
 487
 488         unregister_netdev(vif->dev);
 489
 490         free_netdev(vif->dev);
 491
 492         module_put(THIS_MODULE);
 493 }