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1/*
2 * Virtual network driver for conversing with remote driver backends.
3 *
4 * Copyright (c) 2002-2005, K A Fraser
5 * Copyright (c) 2005, XenSource Ltd
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version 2
9 * as published by the Free Software Foundation; or, when distributed
10 * separately from the Linux kernel or incorporated into other
11 * software packages, subject to the following license:
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this source file (the "Software"), to deal in the Software without
15 * restriction, including without limitation the rights to use, copy, modify,
16 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
17 * and to permit persons to whom the Software is furnished to do so, subject to
18 * the following conditions:
19 *
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
29 * IN THE SOFTWARE.
30 */
31
32#include <linux/module.h>
33#include <linux/kernel.h>
34#include <linux/netdevice.h>
35#include <linux/etherdevice.h>
36#include <linux/skbuff.h>
37#include <linux/ethtool.h>
38#include <linux/if_ether.h>
39#include <linux/tcp.h>
40#include <linux/udp.h>
41#include <linux/moduleparam.h>
42#include <linux/mm.h>
43#include <linux/slab.h>
44#include <net/ip.h>
45
46#include <xen/xen.h>
47#include <xen/xenbus.h>
48#include <xen/events.h>
49#include <xen/page.h>
50#include <xen/grant_table.h>
51
52#include <xen/interface/io/netif.h>
53#include <xen/interface/memory.h>
54#include <xen/interface/grant_table.h>
55
56static const struct ethtool_ops xennet_ethtool_ops;
57
58struct netfront_cb {
59 struct page *page;
60 unsigned offset;
61};
62
63#define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb))
64
65#define RX_COPY_THRESHOLD 256
66
67#define GRANT_INVALID_REF 0
68
69#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
70#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
71#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
72
73struct netfront_stats {
74 u64 rx_packets;
75 u64 tx_packets;
76 u64 rx_bytes;
77 u64 tx_bytes;
78 struct u64_stats_sync syncp;
79};
80
81struct netfront_info {
82 struct list_head list;
83 struct net_device *netdev;
84
85 struct napi_struct napi;
86
87 unsigned int evtchn;
88 struct xenbus_device *xbdev;
89
90 spinlock_t tx_lock;
91 struct xen_netif_tx_front_ring tx;
92 int tx_ring_ref;
93
94 /*
95 * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
96 * are linked from tx_skb_freelist through skb_entry.link.
97 *
98 * NB. Freelist index entries are always going to be less than
99 * PAGE_OFFSET, whereas pointers to skbs will always be equal or
100 * greater than PAGE_OFFSET: we use this property to distinguish
101 * them.
102 */
103 union skb_entry {
104 struct sk_buff *skb;
105 unsigned long link;
106 } tx_skbs[NET_TX_RING_SIZE];
107 grant_ref_t gref_tx_head;
108 grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
109 unsigned tx_skb_freelist;
110
111 spinlock_t rx_lock ____cacheline_aligned_in_smp;
112 struct xen_netif_rx_front_ring rx;
113 int rx_ring_ref;
114
115 /* Receive-ring batched refills. */
116#define RX_MIN_TARGET 8
117#define RX_DFL_MIN_TARGET 64
118#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
119 unsigned rx_min_target, rx_max_target, rx_target;
120 struct sk_buff_head rx_batch;
121
122 struct timer_list rx_refill_timer;
123
124 struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
125 grant_ref_t gref_rx_head;
126 grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
127
128 unsigned long rx_pfn_array[NET_RX_RING_SIZE];
129 struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
130 struct mmu_update rx_mmu[NET_RX_RING_SIZE];
131
132 /* Statistics */
133 struct netfront_stats __percpu *stats;
134
135 unsigned long rx_gso_checksum_fixup;
136};
137
138struct netfront_rx_info {
139 struct xen_netif_rx_response rx;
140 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
141};
142
143static void skb_entry_set_link(union skb_entry *list, unsigned short id)
144{
145 list->link = id;
146}
147
148static int skb_entry_is_link(const union skb_entry *list)
149{
150 BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
151 return (unsigned long)list->skb < PAGE_OFFSET;
152}
153
154/*
155 * Access macros for acquiring freeing slots in tx_skbs[].
156 */
157
158static void add_id_to_freelist(unsigned *head, union skb_entry *list,
159 unsigned short id)
160{
161 skb_entry_set_link(&list[id], *head);
162 *head = id;
163}
164
165static unsigned short get_id_from_freelist(unsigned *head,
166 union skb_entry *list)
167{
168 unsigned int id = *head;
169 *head = list[id].link;
170 return id;
171}
172
173static int xennet_rxidx(RING_IDX idx)
174{
175 return idx & (NET_RX_RING_SIZE - 1);
176}
177
178static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
179 RING_IDX ri)
180{
181 int i = xennet_rxidx(ri);
182 struct sk_buff *skb = np->rx_skbs[i];
183 np->rx_skbs[i] = NULL;
184 return skb;
185}
186
187static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
188 RING_IDX ri)
189{
190 int i = xennet_rxidx(ri);
191 grant_ref_t ref = np->grant_rx_ref[i];
192 np->grant_rx_ref[i] = GRANT_INVALID_REF;
193 return ref;
194}
195
196#ifdef CONFIG_SYSFS
197static int xennet_sysfs_addif(struct net_device *netdev);
198static void xennet_sysfs_delif(struct net_device *netdev);
199#else /* !CONFIG_SYSFS */
200#define xennet_sysfs_addif(dev) (0)
201#define xennet_sysfs_delif(dev) do { } while (0)
202#endif
203
204static int xennet_can_sg(struct net_device *dev)
205{
206 return dev->features & NETIF_F_SG;
207}
208
209
210static void rx_refill_timeout(unsigned long data)
211{
212 struct net_device *dev = (struct net_device *)data;
213 struct netfront_info *np = netdev_priv(dev);
214 napi_schedule(&np->napi);
215}
216
217static int netfront_tx_slot_available(struct netfront_info *np)
218{
219 return (np->tx.req_prod_pvt - np->tx.rsp_cons) <
220 (TX_MAX_TARGET - MAX_SKB_FRAGS - 2);
221}
222
223static void xennet_maybe_wake_tx(struct net_device *dev)
224{
225 struct netfront_info *np = netdev_priv(dev);
226
227 if (unlikely(netif_queue_stopped(dev)) &&
228 netfront_tx_slot_available(np) &&
229 likely(netif_running(dev)))
230 netif_wake_queue(dev);
231}
232
233static void xennet_alloc_rx_buffers(struct net_device *dev)
234{
235 unsigned short id;
236 struct netfront_info *np = netdev_priv(dev);
237 struct sk_buff *skb;
238 struct page *page;
239 int i, batch_target, notify;
240 RING_IDX req_prod = np->rx.req_prod_pvt;
241 grant_ref_t ref;
242 unsigned long pfn;
243 void *vaddr;
244 struct xen_netif_rx_request *req;
245
246 if (unlikely(!netif_carrier_ok(dev)))
247 return;
248
249 /*
250 * Allocate skbuffs greedily, even though we batch updates to the
251 * receive ring. This creates a less bursty demand on the memory
252 * allocator, so should reduce the chance of failed allocation requests
253 * both for ourself and for other kernel subsystems.
254 */
255 batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
256 for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
257 skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN,
258 GFP_ATOMIC | __GFP_NOWARN);
259 if (unlikely(!skb))
260 goto no_skb;
261
262 /* Align ip header to a 16 bytes boundary */
263 skb_reserve(skb, NET_IP_ALIGN);
264
265 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
266 if (!page) {
267 kfree_skb(skb);
268no_skb:
269 /* Any skbuffs queued for refill? Force them out. */
270 if (i != 0)
271 goto refill;
272 /* Could not allocate any skbuffs. Try again later. */
273 mod_timer(&np->rx_refill_timer,
274 jiffies + (HZ/10));
275 break;
276 }
277
278 skb_shinfo(skb)->frags[0].page = page;
279 skb_shinfo(skb)->nr_frags = 1;
280 __skb_queue_tail(&np->rx_batch, skb);
281 }
282
283 /* Is the batch large enough to be worthwhile? */
284 if (i < (np->rx_target/2)) {
285 if (req_prod > np->rx.sring->req_prod)
286 goto push;
287 return;
288 }
289
290 /* Adjust our fill target if we risked running out of buffers. */
291 if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
292 ((np->rx_target *= 2) > np->rx_max_target))
293 np->rx_target = np->rx_max_target;
294
295 refill:
296 for (i = 0; ; i++) {
297 skb = __skb_dequeue(&np->rx_batch);
298 if (skb == NULL)
299 break;
300
301 skb->dev = dev;
302
303 id = xennet_rxidx(req_prod + i);
304
305 BUG_ON(np->rx_skbs[id]);
306 np->rx_skbs[id] = skb;
307
308 ref = gnttab_claim_grant_reference(&np->gref_rx_head);
309 BUG_ON((signed short)ref < 0);
310 np->grant_rx_ref[id] = ref;
311
312 pfn = page_to_pfn(skb_shinfo(skb)->frags[0].page);
313 vaddr = page_address(skb_shinfo(skb)->frags[0].page);
314
315 req = RING_GET_REQUEST(&np->rx, req_prod + i);
316 gnttab_grant_foreign_access_ref(ref,
317 np->xbdev->otherend_id,
318 pfn_to_mfn(pfn),
319 0);
320
321 req->id = id;
322 req->gref = ref;
323 }
324
325 wmb(); /* barrier so backend seens requests */
326
327 /* Above is a suitable barrier to ensure backend will see requests. */
328 np->rx.req_prod_pvt = req_prod + i;
329 push:
330 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
331 if (notify)
332 notify_remote_via_irq(np->netdev->irq);
333}
334
335static int xennet_open(struct net_device *dev)
336{
337 struct netfront_info *np = netdev_priv(dev);
338
339 napi_enable(&np->napi);
340
341 spin_lock_bh(&np->rx_lock);
342 if (netif_carrier_ok(dev)) {
343 xennet_alloc_rx_buffers(dev);
344 np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
345 if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
346 napi_schedule(&np->napi);
347 }
348 spin_unlock_bh(&np->rx_lock);
349
350 netif_start_queue(dev);
351
352 return 0;
353}
354
355static void xennet_tx_buf_gc(struct net_device *dev)
356{
357 RING_IDX cons, prod;
358 unsigned short id;
359 struct netfront_info *np = netdev_priv(dev);
360 struct sk_buff *skb;
361
362 BUG_ON(!netif_carrier_ok(dev));
363
364 do {
365 prod = np->tx.sring->rsp_prod;
366 rmb(); /* Ensure we see responses up to 'rp'. */
367
368 for (cons = np->tx.rsp_cons; cons != prod; cons++) {
369 struct xen_netif_tx_response *txrsp;
370
371 txrsp = RING_GET_RESPONSE(&np->tx, cons);
372 if (txrsp->status == XEN_NETIF_RSP_NULL)
373 continue;
374
375 id = txrsp->id;
376 skb = np->tx_skbs[id].skb;
377 if (unlikely(gnttab_query_foreign_access(
378 np->grant_tx_ref[id]) != 0)) {
379 printk(KERN_ALERT "xennet_tx_buf_gc: warning "
380 "-- grant still in use by backend "
381 "domain.\n");
382 BUG();
383 }
384 gnttab_end_foreign_access_ref(
385 np->grant_tx_ref[id], GNTMAP_readonly);
386 gnttab_release_grant_reference(
387 &np->gref_tx_head, np->grant_tx_ref[id]);
388 np->grant_tx_ref[id] = GRANT_INVALID_REF;
389 add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
390 dev_kfree_skb_irq(skb);
391 }
392
393 np->tx.rsp_cons = prod;
394
395 /*
396 * Set a new event, then check for race with update of tx_cons.
397 * Note that it is essential to schedule a callback, no matter
398 * how few buffers are pending. Even if there is space in the
399 * transmit ring, higher layers may be blocked because too much
400 * data is outstanding: in such cases notification from Xen is
401 * likely to be the only kick that we'll get.
402 */
403 np->tx.sring->rsp_event =
404 prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
405 mb(); /* update shared area */
406 } while ((cons == prod) && (prod != np->tx.sring->rsp_prod));
407
408 xennet_maybe_wake_tx(dev);
409}
410
411static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
412 struct xen_netif_tx_request *tx)
413{
414 struct netfront_info *np = netdev_priv(dev);
415 char *data = skb->data;
416 unsigned long mfn;
417 RING_IDX prod = np->tx.req_prod_pvt;
418 int frags = skb_shinfo(skb)->nr_frags;
419 unsigned int offset = offset_in_page(data);
420 unsigned int len = skb_headlen(skb);
421 unsigned int id;
422 grant_ref_t ref;
423 int i;
424
425 /* While the header overlaps a page boundary (including being
426 larger than a page), split it it into page-sized chunks. */
427 while (len > PAGE_SIZE - offset) {
428 tx->size = PAGE_SIZE - offset;
429 tx->flags |= XEN_NETTXF_more_data;
430 len -= tx->size;
431 data += tx->size;
432 offset = 0;
433
434 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
435 np->tx_skbs[id].skb = skb_get(skb);
436 tx = RING_GET_REQUEST(&np->tx, prod++);
437 tx->id = id;
438 ref = gnttab_claim_grant_reference(&np->gref_tx_head);
439 BUG_ON((signed short)ref < 0);
440
441 mfn = virt_to_mfn(data);
442 gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
443 mfn, GNTMAP_readonly);
444
445 tx->gref = np->grant_tx_ref[id] = ref;
446 tx->offset = offset;
447 tx->size = len;
448 tx->flags = 0;
449 }
450
451 /* Grant backend access to each skb fragment page. */
452 for (i = 0; i < frags; i++) {
453 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
454
455 tx->flags |= XEN_NETTXF_more_data;
456
457 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
458 np->tx_skbs[id].skb = skb_get(skb);
459 tx = RING_GET_REQUEST(&np->tx, prod++);
460 tx->id = id;
461 ref = gnttab_claim_grant_reference(&np->gref_tx_head);
462 BUG_ON((signed short)ref < 0);
463
464 mfn = pfn_to_mfn(page_to_pfn(frag->page));
465 gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
466 mfn, GNTMAP_readonly);
467
468 tx->gref = np->grant_tx_ref[id] = ref;
469 tx->offset = frag->page_offset;
470 tx->size = frag->size;
471 tx->flags = 0;
472 }
473
474 np->tx.req_prod_pvt = prod;
475}
476
477static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
478{
479 unsigned short id;
480 struct netfront_info *np = netdev_priv(dev);
481 struct netfront_stats *stats = this_cpu_ptr(np->stats);
482 struct xen_netif_tx_request *tx;
483 struct xen_netif_extra_info *extra;
484 char *data = skb->data;
485 RING_IDX i;
486 grant_ref_t ref;
487 unsigned long mfn;
488 int notify;
489 int frags = skb_shinfo(skb)->nr_frags;
490 unsigned int offset = offset_in_page(data);
491 unsigned int len = skb_headlen(skb);
492
493 frags += DIV_ROUND_UP(offset + len, PAGE_SIZE);
494 if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
495 printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
496 frags);
497 dump_stack();
498 goto drop;
499 }
500
501 spin_lock_irq(&np->tx_lock);
502
503 if (unlikely(!netif_carrier_ok(dev) ||
504 (frags > 1 && !xennet_can_sg(dev)) ||
505 netif_needs_gso(skb, netif_skb_features(skb)))) {
506 spin_unlock_irq(&np->tx_lock);
507 goto drop;
508 }
509
510 i = np->tx.req_prod_pvt;
511
512 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
513 np->tx_skbs[id].skb = skb;
514
515 tx = RING_GET_REQUEST(&np->tx, i);
516
517 tx->id = id;
518 ref = gnttab_claim_grant_reference(&np->gref_tx_head);
519 BUG_ON((signed short)ref < 0);
520 mfn = virt_to_mfn(data);
521 gnttab_grant_foreign_access_ref(
522 ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
523 tx->gref = np->grant_tx_ref[id] = ref;
524 tx->offset = offset;
525 tx->size = len;
526 extra = NULL;
527
528 tx->flags = 0;
529 if (skb->ip_summed == CHECKSUM_PARTIAL)
530 /* local packet? */
531 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
532 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
533 /* remote but checksummed. */
534 tx->flags |= XEN_NETTXF_data_validated;
535
536 if (skb_shinfo(skb)->gso_size) {
537 struct xen_netif_extra_info *gso;
538
539 gso = (struct xen_netif_extra_info *)
540 RING_GET_REQUEST(&np->tx, ++i);
541
542 if (extra)
543 extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
544 else
545 tx->flags |= XEN_NETTXF_extra_info;
546
547 gso->u.gso.size = skb_shinfo(skb)->gso_size;
548 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
549 gso->u.gso.pad = 0;
550 gso->u.gso.features = 0;
551
552 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
553 gso->flags = 0;
554 extra = gso;
555 }
556
557 np->tx.req_prod_pvt = i + 1;
558
559 xennet_make_frags(skb, dev, tx);
560 tx->size = skb->len;
561
562 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
563 if (notify)
564 notify_remote_via_irq(np->netdev->irq);
565
566 u64_stats_update_begin(&stats->syncp);
567 stats->tx_bytes += skb->len;
568 stats->tx_packets++;
569 u64_stats_update_end(&stats->syncp);
570
571 /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
572 xennet_tx_buf_gc(dev);
573
574 if (!netfront_tx_slot_available(np))
575 netif_stop_queue(dev);
576
577 spin_unlock_irq(&np->tx_lock);
578
579 return NETDEV_TX_OK;
580
581 drop:
582 dev->stats.tx_dropped++;
583 dev_kfree_skb(skb);
584 return NETDEV_TX_OK;
585}
586
587static int xennet_close(struct net_device *dev)
588{
589 struct netfront_info *np = netdev_priv(dev);
590 netif_stop_queue(np->netdev);
591 napi_disable(&np->napi);
592 return 0;
593}
594
595static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
596 grant_ref_t ref)
597{
598 int new = xennet_rxidx(np->rx.req_prod_pvt);
599
600 BUG_ON(np->rx_skbs[new]);
601 np->rx_skbs[new] = skb;
602 np->grant_rx_ref[new] = ref;
603 RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
604 RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
605 np->rx.req_prod_pvt++;
606}
607
608static int xennet_get_extras(struct netfront_info *np,
609 struct xen_netif_extra_info *extras,
610 RING_IDX rp)
611
612{
613 struct xen_netif_extra_info *extra;
614 struct device *dev = &np->netdev->dev;
615 RING_IDX cons = np->rx.rsp_cons;
616 int err = 0;
617
618 do {
619 struct sk_buff *skb;
620 grant_ref_t ref;
621
622 if (unlikely(cons + 1 == rp)) {
623 if (net_ratelimit())
624 dev_warn(dev, "Missing extra info\n");
625 err = -EBADR;
626 break;
627 }
628
629 extra = (struct xen_netif_extra_info *)
630 RING_GET_RESPONSE(&np->rx, ++cons);
631
632 if (unlikely(!extra->type ||
633 extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
634 if (net_ratelimit())
635 dev_warn(dev, "Invalid extra type: %d\n",
636 extra->type);
637 err = -EINVAL;
638 } else {
639 memcpy(&extras[extra->type - 1], extra,
640 sizeof(*extra));
641 }
642
643 skb = xennet_get_rx_skb(np, cons);
644 ref = xennet_get_rx_ref(np, cons);
645 xennet_move_rx_slot(np, skb, ref);
646 } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
647
648 np->rx.rsp_cons = cons;
649 return err;
650}
651
652static int xennet_get_responses(struct netfront_info *np,
653 struct netfront_rx_info *rinfo, RING_IDX rp,
654 struct sk_buff_head *list)
655{
656 struct xen_netif_rx_response *rx = &rinfo->rx;
657 struct xen_netif_extra_info *extras = rinfo->extras;
658 struct device *dev = &np->netdev->dev;
659 RING_IDX cons = np->rx.rsp_cons;
660 struct sk_buff *skb = xennet_get_rx_skb(np, cons);
661 grant_ref_t ref = xennet_get_rx_ref(np, cons);
662 int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
663 int frags = 1;
664 int err = 0;
665 unsigned long ret;
666
667 if (rx->flags & XEN_NETRXF_extra_info) {
668 err = xennet_get_extras(np, extras, rp);
669 cons = np->rx.rsp_cons;
670 }
671
672 for (;;) {
673 if (unlikely(rx->status < 0 ||
674 rx->offset + rx->status > PAGE_SIZE)) {
675 if (net_ratelimit())
676 dev_warn(dev, "rx->offset: %x, size: %u\n",
677 rx->offset, rx->status);
678 xennet_move_rx_slot(np, skb, ref);
679 err = -EINVAL;
680 goto next;
681 }
682
683 /*
684 * This definitely indicates a bug, either in this driver or in
685 * the backend driver. In future this should flag the bad
686 * situation to the system controller to reboot the backed.
687 */
688 if (ref == GRANT_INVALID_REF) {
689 if (net_ratelimit())
690 dev_warn(dev, "Bad rx response id %d.\n",
691 rx->id);
692 err = -EINVAL;
693 goto next;
694 }
695
696 ret = gnttab_end_foreign_access_ref(ref, 0);
697 BUG_ON(!ret);
698
699 gnttab_release_grant_reference(&np->gref_rx_head, ref);
700
701 __skb_queue_tail(list, skb);
702
703next:
704 if (!(rx->flags & XEN_NETRXF_more_data))
705 break;
706
707 if (cons + frags == rp) {
708 if (net_ratelimit())
709 dev_warn(dev, "Need more frags\n");
710 err = -ENOENT;
711 break;
712 }
713
714 rx = RING_GET_RESPONSE(&np->rx, cons + frags);
715 skb = xennet_get_rx_skb(np, cons + frags);
716 ref = xennet_get_rx_ref(np, cons + frags);
717 frags++;
718 }
719
720 if (unlikely(frags > max)) {
721 if (net_ratelimit())
722 dev_warn(dev, "Too many frags\n");
723 err = -E2BIG;
724 }
725
726 if (unlikely(err))
727 np->rx.rsp_cons = cons + frags;
728
729 return err;
730}
731
732static int xennet_set_skb_gso(struct sk_buff *skb,
733 struct xen_netif_extra_info *gso)
734{
735 if (!gso->u.gso.size) {
736 if (net_ratelimit())
737 printk(KERN_WARNING "GSO size must not be zero.\n");
738 return -EINVAL;
739 }
740
741 /* Currently only TCPv4 S.O. is supported. */
742 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
743 if (net_ratelimit())
744 printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type);
745 return -EINVAL;
746 }
747
748 skb_shinfo(skb)->gso_size = gso->u.gso.size;
749 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
750
751 /* Header must be checked, and gso_segs computed. */
752 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
753 skb_shinfo(skb)->gso_segs = 0;
754
755 return 0;
756}
757
758static RING_IDX xennet_fill_frags(struct netfront_info *np,
759 struct sk_buff *skb,
760 struct sk_buff_head *list)
761{
762 struct skb_shared_info *shinfo = skb_shinfo(skb);
763 int nr_frags = shinfo->nr_frags;
764 RING_IDX cons = np->rx.rsp_cons;
765 skb_frag_t *frag = shinfo->frags + nr_frags;
766 struct sk_buff *nskb;
767
768 while ((nskb = __skb_dequeue(list))) {
769 struct xen_netif_rx_response *rx =
770 RING_GET_RESPONSE(&np->rx, ++cons);
771
772 frag->page = skb_shinfo(nskb)->frags[0].page;
773 frag->page_offset = rx->offset;
774 frag->size = rx->status;
775
776 skb->data_len += rx->status;
777
778 skb_shinfo(nskb)->nr_frags = 0;
779 kfree_skb(nskb);
780
781 frag++;
782 nr_frags++;
783 }
784
785 shinfo->nr_frags = nr_frags;
786 return cons;
787}
788
789static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
790{
791 struct iphdr *iph;
792 unsigned char *th;
793 int err = -EPROTO;
794 int recalculate_partial_csum = 0;
795
796 /*
797 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
798 * peers can fail to set NETRXF_csum_blank when sending a GSO
799 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
800 * recalculate the partial checksum.
801 */
802 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
803 struct netfront_info *np = netdev_priv(dev);
804 np->rx_gso_checksum_fixup++;
805 skb->ip_summed = CHECKSUM_PARTIAL;
806 recalculate_partial_csum = 1;
807 }
808
809 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
810 if (skb->ip_summed != CHECKSUM_PARTIAL)
811 return 0;
812
813 if (skb->protocol != htons(ETH_P_IP))
814 goto out;
815
816 iph = (void *)skb->data;
817 th = skb->data + 4 * iph->ihl;
818 if (th >= skb_tail_pointer(skb))
819 goto out;
820
821 skb->csum_start = th - skb->head;
822 switch (iph->protocol) {
823 case IPPROTO_TCP:
824 skb->csum_offset = offsetof(struct tcphdr, check);
825
826 if (recalculate_partial_csum) {
827 struct tcphdr *tcph = (struct tcphdr *)th;
828 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
829 skb->len - iph->ihl*4,
830 IPPROTO_TCP, 0);
831 }
832 break;
833 case IPPROTO_UDP:
834 skb->csum_offset = offsetof(struct udphdr, check);
835
836 if (recalculate_partial_csum) {
837 struct udphdr *udph = (struct udphdr *)th;
838 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
839 skb->len - iph->ihl*4,
840 IPPROTO_UDP, 0);
841 }
842 break;
843 default:
844 if (net_ratelimit())
845 printk(KERN_ERR "Attempting to checksum a non-"
846 "TCP/UDP packet, dropping a protocol"
847 " %d packet", iph->protocol);
848 goto out;
849 }
850
851 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
852 goto out;
853
854 err = 0;
855
856out:
857 return err;
858}
859
860static int handle_incoming_queue(struct net_device *dev,
861 struct sk_buff_head *rxq)
862{
863 struct netfront_info *np = netdev_priv(dev);
864 struct netfront_stats *stats = this_cpu_ptr(np->stats);
865 int packets_dropped = 0;
866 struct sk_buff *skb;
867
868 while ((skb = __skb_dequeue(rxq)) != NULL) {
869 struct page *page = NETFRONT_SKB_CB(skb)->page;
870 void *vaddr = page_address(page);
871 unsigned offset = NETFRONT_SKB_CB(skb)->offset;
872
873 memcpy(skb->data, vaddr + offset,
874 skb_headlen(skb));
875
876 if (page != skb_shinfo(skb)->frags[0].page)
877 __free_page(page);
878
879 /* Ethernet work: Delayed to here as it peeks the header. */
880 skb->protocol = eth_type_trans(skb, dev);
881
882 if (checksum_setup(dev, skb)) {
883 kfree_skb(skb);
884 packets_dropped++;
885 dev->stats.rx_errors++;
886 continue;
887 }
888
889 u64_stats_update_begin(&stats->syncp);
890 stats->rx_packets++;
891 stats->rx_bytes += skb->len;
892 u64_stats_update_end(&stats->syncp);
893
894 /* Pass it up. */
895 netif_receive_skb(skb);
896 }
897
898 return packets_dropped;
899}
900
901static int xennet_poll(struct napi_struct *napi, int budget)
902{
903 struct netfront_info *np = container_of(napi, struct netfront_info, napi);
904 struct net_device *dev = np->netdev;
905 struct sk_buff *skb;
906 struct netfront_rx_info rinfo;
907 struct xen_netif_rx_response *rx = &rinfo.rx;
908 struct xen_netif_extra_info *extras = rinfo.extras;
909 RING_IDX i, rp;
910 int work_done;
911 struct sk_buff_head rxq;
912 struct sk_buff_head errq;
913 struct sk_buff_head tmpq;
914 unsigned long flags;
915 unsigned int len;
916 int err;
917
918 spin_lock(&np->rx_lock);
919
920 skb_queue_head_init(&rxq);
921 skb_queue_head_init(&errq);
922 skb_queue_head_init(&tmpq);
923
924 rp = np->rx.sring->rsp_prod;
925 rmb(); /* Ensure we see queued responses up to 'rp'. */
926
927 i = np->rx.rsp_cons;
928 work_done = 0;
929 while ((i != rp) && (work_done < budget)) {
930 memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
931 memset(extras, 0, sizeof(rinfo.extras));
932
933 err = xennet_get_responses(np, &rinfo, rp, &tmpq);
934
935 if (unlikely(err)) {
936err:
937 while ((skb = __skb_dequeue(&tmpq)))
938 __skb_queue_tail(&errq, skb);
939 dev->stats.rx_errors++;
940 i = np->rx.rsp_cons;
941 continue;
942 }
943
944 skb = __skb_dequeue(&tmpq);
945
946 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
947 struct xen_netif_extra_info *gso;
948 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
949
950 if (unlikely(xennet_set_skb_gso(skb, gso))) {
951 __skb_queue_head(&tmpq, skb);
952 np->rx.rsp_cons += skb_queue_len(&tmpq);
953 goto err;
954 }
955 }
956
957 NETFRONT_SKB_CB(skb)->page = skb_shinfo(skb)->frags[0].page;
958 NETFRONT_SKB_CB(skb)->offset = rx->offset;
959
960 len = rx->status;
961 if (len > RX_COPY_THRESHOLD)
962 len = RX_COPY_THRESHOLD;
963 skb_put(skb, len);
964
965 if (rx->status > len) {
966 skb_shinfo(skb)->frags[0].page_offset =
967 rx->offset + len;
968 skb_shinfo(skb)->frags[0].size = rx->status - len;
969 skb->data_len = rx->status - len;
970 } else {
971 skb_shinfo(skb)->frags[0].page = NULL;
972 skb_shinfo(skb)->nr_frags = 0;
973 }
974
975 i = xennet_fill_frags(np, skb, &tmpq);
976
977 /*
978 * Truesize approximates the size of true data plus
979 * any supervisor overheads. Adding hypervisor
980 * overheads has been shown to significantly reduce
981 * achievable bandwidth with the default receive
982 * buffer size. It is therefore not wise to account
983 * for it here.
984 *
985 * After alloc_skb(RX_COPY_THRESHOLD), truesize is set
986 * to RX_COPY_THRESHOLD + the supervisor
987 * overheads. Here, we add the size of the data pulled
988 * in xennet_fill_frags().
989 *
990 * We also adjust for any unused space in the main
991 * data area by subtracting (RX_COPY_THRESHOLD -
992 * len). This is especially important with drivers
993 * which split incoming packets into header and data,
994 * using only 66 bytes of the main data area (see the
995 * e1000 driver for example.) On such systems,
996 * without this last adjustement, our achievable
997 * receive throughout using the standard receive
998 * buffer size was cut by 25%(!!!).
999 */
1000 skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len);
1001 skb->len += skb->data_len;
1002
1003 if (rx->flags & XEN_NETRXF_csum_blank)
1004 skb->ip_summed = CHECKSUM_PARTIAL;
1005 else if (rx->flags & XEN_NETRXF_data_validated)
1006 skb->ip_summed = CHECKSUM_UNNECESSARY;
1007
1008 __skb_queue_tail(&rxq, skb);
1009
1010 np->rx.rsp_cons = ++i;
1011 work_done++;
1012 }
1013
1014 __skb_queue_purge(&errq);
1015
1016 work_done -= handle_incoming_queue(dev, &rxq);
1017
1018 /* If we get a callback with very few responses, reduce fill target. */
1019 /* NB. Note exponential increase, linear decrease. */
1020 if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
1021 ((3*np->rx_target) / 4)) &&
1022 (--np->rx_target < np->rx_min_target))
1023 np->rx_target = np->rx_min_target;
1024
1025 xennet_alloc_rx_buffers(dev);
1026
1027 if (work_done < budget) {
1028 int more_to_do = 0;
1029
1030 local_irq_save(flags);
1031
1032 RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
1033 if (!more_to_do)
1034 __napi_complete(napi);
1035
1036 local_irq_restore(flags);
1037 }
1038
1039 spin_unlock(&np->rx_lock);
1040
1041 return work_done;
1042}
1043
1044static int xennet_change_mtu(struct net_device *dev, int mtu)
1045{
1046 int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;
1047
1048 if (mtu > max)
1049 return -EINVAL;
1050 dev->mtu = mtu;
1051 return 0;
1052}
1053
1054static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev,
1055 struct rtnl_link_stats64 *tot)
1056{
1057 struct netfront_info *np = netdev_priv(dev);
1058 int cpu;
1059
1060 for_each_possible_cpu(cpu) {
1061 struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu);
1062 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1063 unsigned int start;
1064
1065 do {
1066 start = u64_stats_fetch_begin_bh(&stats->syncp);
1067
1068 rx_packets = stats->rx_packets;
1069 tx_packets = stats->tx_packets;
1070 rx_bytes = stats->rx_bytes;
1071 tx_bytes = stats->tx_bytes;
1072 } while (u64_stats_fetch_retry_bh(&stats->syncp, start));
1073
1074 tot->rx_packets += rx_packets;
1075 tot->tx_packets += tx_packets;
1076 tot->rx_bytes += rx_bytes;
1077 tot->tx_bytes += tx_bytes;
1078 }
1079
1080 tot->rx_errors = dev->stats.rx_errors;
1081 tot->tx_dropped = dev->stats.tx_dropped;
1082
1083 return tot;
1084}
1085
1086static void xennet_release_tx_bufs(struct netfront_info *np)
1087{
1088 struct sk_buff *skb;
1089 int i;
1090
1091 for (i = 0; i < NET_TX_RING_SIZE; i++) {
1092 /* Skip over entries which are actually freelist references */
1093 if (skb_entry_is_link(&np->tx_skbs[i]))
1094 continue;
1095
1096 skb = np->tx_skbs[i].skb;
1097 gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
1098 GNTMAP_readonly);
1099 gnttab_release_grant_reference(&np->gref_tx_head,
1100 np->grant_tx_ref[i]);
1101 np->grant_tx_ref[i] = GRANT_INVALID_REF;
1102 add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
1103 dev_kfree_skb_irq(skb);
1104 }
1105}
1106
1107static void xennet_release_rx_bufs(struct netfront_info *np)
1108{
1109 struct mmu_update *mmu = np->rx_mmu;
1110 struct multicall_entry *mcl = np->rx_mcl;
1111 struct sk_buff_head free_list;
1112 struct sk_buff *skb;
1113 unsigned long mfn;
1114 int xfer = 0, noxfer = 0, unused = 0;
1115 int id, ref;
1116
1117 dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
1118 __func__);
1119 return;
1120
1121 skb_queue_head_init(&free_list);
1122
1123 spin_lock_bh(&np->rx_lock);
1124
1125 for (id = 0; id < NET_RX_RING_SIZE; id++) {
1126 ref = np->grant_rx_ref[id];
1127 if (ref == GRANT_INVALID_REF) {
1128 unused++;
1129 continue;
1130 }
1131
1132 skb = np->rx_skbs[id];
1133 mfn = gnttab_end_foreign_transfer_ref(ref);
1134 gnttab_release_grant_reference(&np->gref_rx_head, ref);
1135 np->grant_rx_ref[id] = GRANT_INVALID_REF;
1136
1137 if (0 == mfn) {
1138 skb_shinfo(skb)->nr_frags = 0;
1139 dev_kfree_skb(skb);
1140 noxfer++;
1141 continue;
1142 }
1143
1144 if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1145 /* Remap the page. */
1146 struct page *page = skb_shinfo(skb)->frags[0].page;
1147 unsigned long pfn = page_to_pfn(page);
1148 void *vaddr = page_address(page);
1149
1150 MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
1151 mfn_pte(mfn, PAGE_KERNEL),
1152 0);
1153 mcl++;
1154 mmu->ptr = ((u64)mfn << PAGE_SHIFT)
1155 | MMU_MACHPHYS_UPDATE;
1156 mmu->val = pfn;
1157 mmu++;
1158
1159 set_phys_to_machine(pfn, mfn);
1160 }
1161 __skb_queue_tail(&free_list, skb);
1162 xfer++;
1163 }
1164
1165 dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
1166 __func__, xfer, noxfer, unused);
1167
1168 if (xfer) {
1169 if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1170 /* Do all the remapping work and M2P updates. */
1171 MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
1172 NULL, DOMID_SELF);
1173 mcl++;
1174 HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
1175 }
1176 }
1177
1178 __skb_queue_purge(&free_list);
1179
1180 spin_unlock_bh(&np->rx_lock);
1181}
1182
1183static void xennet_uninit(struct net_device *dev)
1184{
1185 struct netfront_info *np = netdev_priv(dev);
1186 xennet_release_tx_bufs(np);
1187 xennet_release_rx_bufs(np);
1188 gnttab_free_grant_references(np->gref_tx_head);
1189 gnttab_free_grant_references(np->gref_rx_head);
1190}
1191
1192static u32 xennet_fix_features(struct net_device *dev, u32 features)
1193{
1194 struct netfront_info *np = netdev_priv(dev);
1195 int val;
1196
1197 if (features & NETIF_F_SG) {
1198 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
1199 "%d", &val) < 0)
1200 val = 0;
1201
1202 if (!val)
1203 features &= ~NETIF_F_SG;
1204 }
1205
1206 if (features & NETIF_F_TSO) {
1207 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1208 "feature-gso-tcpv4", "%d", &val) < 0)
1209 val = 0;
1210
1211 if (!val)
1212 features &= ~NETIF_F_TSO;
1213 }
1214
1215 return features;
1216}
1217
1218static int xennet_set_features(struct net_device *dev, u32 features)
1219{
1220 if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1221 netdev_info(dev, "Reducing MTU because no SG offload");
1222 dev->mtu = ETH_DATA_LEN;
1223 }
1224
1225 return 0;
1226}
1227
1228static const struct net_device_ops xennet_netdev_ops = {
1229 .ndo_open = xennet_open,
1230 .ndo_uninit = xennet_uninit,
1231 .ndo_stop = xennet_close,
1232 .ndo_start_xmit = xennet_start_xmit,
1233 .ndo_change_mtu = xennet_change_mtu,
1234 .ndo_get_stats64 = xennet_get_stats64,
1235 .ndo_set_mac_address = eth_mac_addr,
1236 .ndo_validate_addr = eth_validate_addr,
1237 .ndo_fix_features = xennet_fix_features,
1238 .ndo_set_features = xennet_set_features,
1239};
1240
1241static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
1242{
1243 int i, err;
1244 struct net_device *netdev;
1245 struct netfront_info *np;
1246
1247 netdev = alloc_etherdev(sizeof(struct netfront_info));
1248 if (!netdev) {
1249 printk(KERN_WARNING "%s> alloc_etherdev failed.\n",
1250 __func__);
1251 return ERR_PTR(-ENOMEM);
1252 }
1253
1254 np = netdev_priv(netdev);
1255 np->xbdev = dev;
1256
1257 spin_lock_init(&np->tx_lock);
1258 spin_lock_init(&np->rx_lock);
1259
1260 skb_queue_head_init(&np->rx_batch);
1261 np->rx_target = RX_DFL_MIN_TARGET;
1262 np->rx_min_target = RX_DFL_MIN_TARGET;
1263 np->rx_max_target = RX_MAX_TARGET;
1264
1265 init_timer(&np->rx_refill_timer);
1266 np->rx_refill_timer.data = (unsigned long)netdev;
1267 np->rx_refill_timer.function = rx_refill_timeout;
1268
1269 err = -ENOMEM;
1270 np->stats = alloc_percpu(struct netfront_stats);
1271 if (np->stats == NULL)
1272 goto exit;
1273
1274 /* Initialise tx_skbs as a free chain containing every entry. */
1275 np->tx_skb_freelist = 0;
1276 for (i = 0; i < NET_TX_RING_SIZE; i++) {
1277 skb_entry_set_link(&np->tx_skbs[i], i+1);
1278 np->grant_tx_ref[i] = GRANT_INVALID_REF;
1279 }
1280
1281 /* Clear out rx_skbs */
1282 for (i = 0; i < NET_RX_RING_SIZE; i++) {
1283 np->rx_skbs[i] = NULL;
1284 np->grant_rx_ref[i] = GRANT_INVALID_REF;
1285 }
1286
1287 /* A grant for every tx ring slot */
1288 if (gnttab_alloc_grant_references(TX_MAX_TARGET,
1289 &np->gref_tx_head) < 0) {
1290 printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
1291 err = -ENOMEM;
1292 goto exit_free_stats;
1293 }
1294 /* A grant for every rx ring slot */
1295 if (gnttab_alloc_grant_references(RX_MAX_TARGET,
1296 &np->gref_rx_head) < 0) {
1297 printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n");
1298 err = -ENOMEM;
1299 goto exit_free_tx;
1300 }
1301
1302 netdev->netdev_ops = &xennet_netdev_ops;
1303
1304 netif_napi_add(netdev, &np->napi, xennet_poll, 64);
1305 netdev->features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1306 NETIF_F_GSO_ROBUST;
1307 netdev->hw_features = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO;
1308
1309 /*
1310 * Assume that all hw features are available for now. This set
1311 * will be adjusted by the call to netdev_update_features() in
1312 * xennet_connect() which is the earliest point where we can
1313 * negotiate with the backend regarding supported features.
1314 */
1315 netdev->features |= netdev->hw_features;
1316
1317 SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops);
1318 SET_NETDEV_DEV(netdev, &dev->dev);
1319
1320 np->netdev = netdev;
1321
1322 netif_carrier_off(netdev);
1323
1324 return netdev;
1325
1326 exit_free_tx:
1327 gnttab_free_grant_references(np->gref_tx_head);
1328 exit_free_stats:
1329 free_percpu(np->stats);
1330 exit:
1331 free_netdev(netdev);
1332 return ERR_PTR(err);
1333}
1334
1335/**
1336 * Entry point to this code when a new device is created. Allocate the basic
1337 * structures and the ring buffers for communication with the backend, and
1338 * inform the backend of the appropriate details for those.
1339 */
1340static int __devinit netfront_probe(struct xenbus_device *dev,
1341 const struct xenbus_device_id *id)
1342{
1343 int err;
1344 struct net_device *netdev;
1345 struct netfront_info *info;
1346
1347 netdev = xennet_create_dev(dev);
1348 if (IS_ERR(netdev)) {
1349 err = PTR_ERR(netdev);
1350 xenbus_dev_fatal(dev, err, "creating netdev");
1351 return err;
1352 }
1353
1354 info = netdev_priv(netdev);
1355 dev_set_drvdata(&dev->dev, info);
1356
1357 err = register_netdev(info->netdev);
1358 if (err) {
1359 printk(KERN_WARNING "%s: register_netdev err=%d\n",
1360 __func__, err);
1361 goto fail;
1362 }
1363
1364 err = xennet_sysfs_addif(info->netdev);
1365 if (err) {
1366 unregister_netdev(info->netdev);
1367 printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
1368 __func__, err);
1369 goto fail;
1370 }
1371
1372 return 0;
1373
1374 fail:
1375 free_netdev(netdev);
1376 dev_set_drvdata(&dev->dev, NULL);
1377 return err;
1378}
1379
1380static void xennet_end_access(int ref, void *page)
1381{
1382 /* This frees the page as a side-effect */
1383 if (ref != GRANT_INVALID_REF)
1384 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1385}
1386
1387static void xennet_disconnect_backend(struct netfront_info *info)
1388{
1389 /* Stop old i/f to prevent errors whilst we rebuild the state. */
1390 spin_lock_bh(&info->rx_lock);
1391 spin_lock_irq(&info->tx_lock);
1392 netif_carrier_off(info->netdev);
1393 spin_unlock_irq(&info->tx_lock);
1394 spin_unlock_bh(&info->rx_lock);
1395
1396 if (info->netdev->irq)
1397 unbind_from_irqhandler(info->netdev->irq, info->netdev);
1398 info->evtchn = info->netdev->irq = 0;
1399
1400 /* End access and free the pages */
1401 xennet_end_access(info->tx_ring_ref, info->tx.sring);
1402 xennet_end_access(info->rx_ring_ref, info->rx.sring);
1403
1404 info->tx_ring_ref = GRANT_INVALID_REF;
1405 info->rx_ring_ref = GRANT_INVALID_REF;
1406 info->tx.sring = NULL;
1407 info->rx.sring = NULL;
1408}
1409
1410/**
1411 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1412 * driver restart. We tear down our netif structure and recreate it, but
1413 * leave the device-layer structures intact so that this is transparent to the
1414 * rest of the kernel.
1415 */
1416static int netfront_resume(struct xenbus_device *dev)
1417{
1418 struct netfront_info *info = dev_get_drvdata(&dev->dev);
1419
1420 dev_dbg(&dev->dev, "%s\n", dev->nodename);
1421
1422 xennet_disconnect_backend(info);
1423 return 0;
1424}
1425
1426static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1427{
1428 char *s, *e, *macstr;
1429 int i;
1430
1431 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1432 if (IS_ERR(macstr))
1433 return PTR_ERR(macstr);
1434
1435 for (i = 0; i < ETH_ALEN; i++) {
1436 mac[i] = simple_strtoul(s, &e, 16);
1437 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1438 kfree(macstr);
1439 return -ENOENT;
1440 }
1441 s = e+1;
1442 }
1443
1444 kfree(macstr);
1445 return 0;
1446}
1447
1448static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1449{
1450 struct net_device *dev = dev_id;
1451 struct netfront_info *np = netdev_priv(dev);
1452 unsigned long flags;
1453
1454 spin_lock_irqsave(&np->tx_lock, flags);
1455
1456 if (likely(netif_carrier_ok(dev))) {
1457 xennet_tx_buf_gc(dev);
1458 /* Under tx_lock: protects access to rx shared-ring indexes. */
1459 if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
1460 napi_schedule(&np->napi);
1461 }
1462
1463 spin_unlock_irqrestore(&np->tx_lock, flags);
1464
1465 return IRQ_HANDLED;
1466}
1467
1468static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
1469{
1470 struct xen_netif_tx_sring *txs;
1471 struct xen_netif_rx_sring *rxs;
1472 int err;
1473 struct net_device *netdev = info->netdev;
1474
1475 info->tx_ring_ref = GRANT_INVALID_REF;
1476 info->rx_ring_ref = GRANT_INVALID_REF;
1477 info->rx.sring = NULL;
1478 info->tx.sring = NULL;
1479 netdev->irq = 0;
1480
1481 err = xen_net_read_mac(dev, netdev->dev_addr);
1482 if (err) {
1483 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1484 goto fail;
1485 }
1486
1487 txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1488 if (!txs) {
1489 err = -ENOMEM;
1490 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1491 goto fail;
1492 }
1493 SHARED_RING_INIT(txs);
1494 FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
1495
1496 err = xenbus_grant_ring(dev, virt_to_mfn(txs));
1497 if (err < 0) {
1498 free_page((unsigned long)txs);
1499 goto fail;
1500 }
1501
1502 info->tx_ring_ref = err;
1503 rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1504 if (!rxs) {
1505 err = -ENOMEM;
1506 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1507 goto fail;
1508 }
1509 SHARED_RING_INIT(rxs);
1510 FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
1511
1512 err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
1513 if (err < 0) {
1514 free_page((unsigned long)rxs);
1515 goto fail;
1516 }
1517 info->rx_ring_ref = err;
1518
1519 err = xenbus_alloc_evtchn(dev, &info->evtchn);
1520 if (err)
1521 goto fail;
1522
1523 err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
1524 0, netdev->name, netdev);
1525 if (err < 0)
1526 goto fail;
1527 netdev->irq = err;
1528 return 0;
1529
1530 fail:
1531 return err;
1532}
1533
1534/* Common code used when first setting up, and when resuming. */
1535static int talk_to_netback(struct xenbus_device *dev,
1536 struct netfront_info *info)
1537{
1538 const char *message;
1539 struct xenbus_transaction xbt;
1540 int err;
1541
1542 /* Create shared ring, alloc event channel. */
1543 err = setup_netfront(dev, info);
1544 if (err)
1545 goto out;
1546
1547again:
1548 err = xenbus_transaction_start(&xbt);
1549 if (err) {
1550 xenbus_dev_fatal(dev, err, "starting transaction");
1551 goto destroy_ring;
1552 }
1553
1554 err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
1555 info->tx_ring_ref);
1556 if (err) {
1557 message = "writing tx ring-ref";
1558 goto abort_transaction;
1559 }
1560 err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
1561 info->rx_ring_ref);
1562 if (err) {
1563 message = "writing rx ring-ref";
1564 goto abort_transaction;
1565 }
1566 err = xenbus_printf(xbt, dev->nodename,
1567 "event-channel", "%u", info->evtchn);
1568 if (err) {
1569 message = "writing event-channel";
1570 goto abort_transaction;
1571 }
1572
1573 err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1574 1);
1575 if (err) {
1576 message = "writing request-rx-copy";
1577 goto abort_transaction;
1578 }
1579
1580 err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1581 if (err) {
1582 message = "writing feature-rx-notify";
1583 goto abort_transaction;
1584 }
1585
1586 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1587 if (err) {
1588 message = "writing feature-sg";
1589 goto abort_transaction;
1590 }
1591
1592 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1593 if (err) {
1594 message = "writing feature-gso-tcpv4";
1595 goto abort_transaction;
1596 }
1597
1598 err = xenbus_transaction_end(xbt, 0);
1599 if (err) {
1600 if (err == -EAGAIN)
1601 goto again;
1602 xenbus_dev_fatal(dev, err, "completing transaction");
1603 goto destroy_ring;
1604 }
1605
1606 return 0;
1607
1608 abort_transaction:
1609 xenbus_transaction_end(xbt, 1);
1610 xenbus_dev_fatal(dev, err, "%s", message);
1611 destroy_ring:
1612 xennet_disconnect_backend(info);
1613 out:
1614 return err;
1615}
1616
1617static int xennet_connect(struct net_device *dev)
1618{
1619 struct netfront_info *np = netdev_priv(dev);
1620 int i, requeue_idx, err;
1621 struct sk_buff *skb;
1622 grant_ref_t ref;
1623 struct xen_netif_rx_request *req;
1624 unsigned int feature_rx_copy;
1625
1626 err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1627 "feature-rx-copy", "%u", &feature_rx_copy);
1628 if (err != 1)
1629 feature_rx_copy = 0;
1630
1631 if (!feature_rx_copy) {
1632 dev_info(&dev->dev,
1633 "backend does not support copying receive path\n");
1634 return -ENODEV;
1635 }
1636
1637 err = talk_to_netback(np->xbdev, np);
1638 if (err)
1639 return err;
1640
1641 rtnl_lock();
1642 netdev_update_features(dev);
1643 rtnl_unlock();
1644
1645 spin_lock_bh(&np->rx_lock);
1646 spin_lock_irq(&np->tx_lock);
1647
1648 /* Step 1: Discard all pending TX packet fragments. */
1649 xennet_release_tx_bufs(np);
1650
1651 /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
1652 for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
1653 if (!np->rx_skbs[i])
1654 continue;
1655
1656 skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
1657 ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
1658 req = RING_GET_REQUEST(&np->rx, requeue_idx);
1659
1660 gnttab_grant_foreign_access_ref(
1661 ref, np->xbdev->otherend_id,
1662 pfn_to_mfn(page_to_pfn(skb_shinfo(skb)->
1663 frags->page)),
1664 0);
1665 req->gref = ref;
1666 req->id = requeue_idx;
1667
1668 requeue_idx++;
1669 }
1670
1671 np->rx.req_prod_pvt = requeue_idx;
1672
1673 /*
1674 * Step 3: All public and private state should now be sane. Get
1675 * ready to start sending and receiving packets and give the driver
1676 * domain a kick because we've probably just requeued some
1677 * packets.
1678 */
1679 netif_carrier_on(np->netdev);
1680 notify_remote_via_irq(np->netdev->irq);
1681 xennet_tx_buf_gc(dev);
1682 xennet_alloc_rx_buffers(dev);
1683
1684 spin_unlock_irq(&np->tx_lock);
1685 spin_unlock_bh(&np->rx_lock);
1686
1687 return 0;
1688}
1689
1690/**
1691 * Callback received when the backend's state changes.
1692 */
1693static void netback_changed(struct xenbus_device *dev,
1694 enum xenbus_state backend_state)
1695{
1696 struct netfront_info *np = dev_get_drvdata(&dev->dev);
1697 struct net_device *netdev = np->netdev;
1698
1699 dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
1700
1701 switch (backend_state) {
1702 case XenbusStateInitialising:
1703 case XenbusStateInitialised:
1704 case XenbusStateReconfiguring:
1705 case XenbusStateReconfigured:
1706 case XenbusStateConnected:
1707 case XenbusStateUnknown:
1708 case XenbusStateClosed:
1709 break;
1710
1711 case XenbusStateInitWait:
1712 if (dev->state != XenbusStateInitialising)
1713 break;
1714 if (xennet_connect(netdev) != 0)
1715 break;
1716 xenbus_switch_state(dev, XenbusStateConnected);
1717 netif_notify_peers(netdev);
1718 break;
1719
1720 case XenbusStateClosing:
1721 xenbus_frontend_closed(dev);
1722 break;
1723 }
1724}
1725
1726static const struct xennet_stat {
1727 char name[ETH_GSTRING_LEN];
1728 u16 offset;
1729} xennet_stats[] = {
1730 {
1731 "rx_gso_checksum_fixup",
1732 offsetof(struct netfront_info, rx_gso_checksum_fixup)
1733 },
1734};
1735
1736static int xennet_get_sset_count(struct net_device *dev, int string_set)
1737{
1738 switch (string_set) {
1739 case ETH_SS_STATS:
1740 return ARRAY_SIZE(xennet_stats);
1741 default:
1742 return -EINVAL;
1743 }
1744}
1745
1746static void xennet_get_ethtool_stats(struct net_device *dev,
1747 struct ethtool_stats *stats, u64 * data)
1748{
1749 void *np = netdev_priv(dev);
1750 int i;
1751
1752 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1753 data[i] = *(unsigned long *)(np + xennet_stats[i].offset);
1754}
1755
1756static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
1757{
1758 int i;
1759
1760 switch (stringset) {
1761 case ETH_SS_STATS:
1762 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1763 memcpy(data + i * ETH_GSTRING_LEN,
1764 xennet_stats[i].name, ETH_GSTRING_LEN);
1765 break;
1766 }
1767}
1768
1769static const struct ethtool_ops xennet_ethtool_ops =
1770{
1771 .get_link = ethtool_op_get_link,
1772
1773 .get_sset_count = xennet_get_sset_count,
1774 .get_ethtool_stats = xennet_get_ethtool_stats,
1775 .get_strings = xennet_get_strings,
1776};
1777
1778#ifdef CONFIG_SYSFS
1779static ssize_t show_rxbuf_min(struct device *dev,
1780 struct device_attribute *attr, char *buf)
1781{
1782 struct net_device *netdev = to_net_dev(dev);
1783 struct netfront_info *info = netdev_priv(netdev);
1784
1785 return sprintf(buf, "%u\n", info->rx_min_target);
1786}
1787
1788static ssize_t store_rxbuf_min(struct device *dev,
1789 struct device_attribute *attr,
1790 const char *buf, size_t len)
1791{
1792 struct net_device *netdev = to_net_dev(dev);
1793 struct netfront_info *np = netdev_priv(netdev);
1794 char *endp;
1795 unsigned long target;
1796
1797 if (!capable(CAP_NET_ADMIN))
1798 return -EPERM;
1799
1800 target = simple_strtoul(buf, &endp, 0);
1801 if (endp == buf)
1802 return -EBADMSG;
1803
1804 if (target < RX_MIN_TARGET)
1805 target = RX_MIN_TARGET;
1806 if (target > RX_MAX_TARGET)
1807 target = RX_MAX_TARGET;
1808
1809 spin_lock_bh(&np->rx_lock);
1810 if (target > np->rx_max_target)
1811 np->rx_max_target = target;
1812 np->rx_min_target = target;
1813 if (target > np->rx_target)
1814 np->rx_target = target;
1815
1816 xennet_alloc_rx_buffers(netdev);
1817
1818 spin_unlock_bh(&np->rx_lock);
1819 return len;
1820}
1821
1822static ssize_t show_rxbuf_max(struct device *dev,
1823 struct device_attribute *attr, char *buf)
1824{
1825 struct net_device *netdev = to_net_dev(dev);
1826 struct netfront_info *info = netdev_priv(netdev);
1827
1828 return sprintf(buf, "%u\n", info->rx_max_target);
1829}
1830
1831static ssize_t store_rxbuf_max(struct device *dev,
1832 struct device_attribute *attr,
1833 const char *buf, size_t len)
1834{
1835 struct net_device *netdev = to_net_dev(dev);
1836 struct netfront_info *np = netdev_priv(netdev);
1837 char *endp;
1838 unsigned long target;
1839
1840 if (!capable(CAP_NET_ADMIN))
1841 return -EPERM;
1842
1843 target = simple_strtoul(buf, &endp, 0);
1844 if (endp == buf)
1845 return -EBADMSG;
1846
1847 if (target < RX_MIN_TARGET)
1848 target = RX_MIN_TARGET;
1849 if (target > RX_MAX_TARGET)
1850 target = RX_MAX_TARGET;
1851
1852 spin_lock_bh(&np->rx_lock);
1853 if (target < np->rx_min_target)
1854 np->rx_min_target = target;
1855 np->rx_max_target = target;
1856 if (target < np->rx_target)
1857 np->rx_target = target;
1858
1859 xennet_alloc_rx_buffers(netdev);
1860
1861 spin_unlock_bh(&np->rx_lock);
1862 return len;
1863}
1864
1865static ssize_t show_rxbuf_cur(struct device *dev,
1866 struct device_attribute *attr, char *buf)
1867{
1868 struct net_device *netdev = to_net_dev(dev);
1869 struct netfront_info *info = netdev_priv(netdev);
1870
1871 return sprintf(buf, "%u\n", info->rx_target);
1872}
1873
1874static struct device_attribute xennet_attrs[] = {
1875 __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
1876 __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
1877 __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
1878};
1879
1880static int xennet_sysfs_addif(struct net_device *netdev)
1881{
1882 int i;
1883 int err;
1884
1885 for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
1886 err = device_create_file(&netdev->dev,
1887 &xennet_attrs[i]);
1888 if (err)
1889 goto fail;
1890 }
1891 return 0;
1892
1893 fail:
1894 while (--i >= 0)
1895 device_remove_file(&netdev->dev, &xennet_attrs[i]);
1896 return err;
1897}
1898
1899static void xennet_sysfs_delif(struct net_device *netdev)
1900{
1901 int i;
1902
1903 for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
1904 device_remove_file(&netdev->dev, &xennet_attrs[i]);
1905}
1906
1907#endif /* CONFIG_SYSFS */
1908
1909static struct xenbus_device_id netfront_ids[] = {
1910 { "vif" },
1911 { "" }
1912};
1913
1914
1915static int __devexit xennet_remove(struct xenbus_device *dev)
1916{
1917 struct netfront_info *info = dev_get_drvdata(&dev->dev);
1918
1919 dev_dbg(&dev->dev, "%s\n", dev->nodename);
1920
1921 unregister_netdev(info->netdev);
1922
1923 xennet_disconnect_backend(info);
1924
1925 del_timer_sync(&info->rx_refill_timer);
1926
1927 xennet_sysfs_delif(info->netdev);
1928
1929 free_percpu(info->stats);
1930
1931 free_netdev(info->netdev);
1932
1933 return 0;
1934}
1935
1936static struct xenbus_driver netfront_driver = {
1937 .name = "vif",
1938 .owner = THIS_MODULE,
1939 .ids = netfront_ids,
1940 .probe = netfront_probe,
1941 .remove = __devexit_p(xennet_remove),
1942 .resume = netfront_resume,
1943 .otherend_changed = netback_changed,
1944};
1945
1946static int __init netif_init(void)
1947{
1948 if (!xen_domain())
1949 return -ENODEV;
1950
1951 if (xen_initial_domain())
1952 return 0;
1953
1954 printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n");
1955
1956 return xenbus_register_frontend(&netfront_driver);
1957}
1958module_init(netif_init);
1959
1960
1961static void __exit netif_exit(void)
1962{
1963 if (xen_initial_domain())
1964 return;
1965
1966 xenbus_unregister_driver(&netfront_driver);
1967}
1968module_exit(netif_exit);
1969
1970MODULE_DESCRIPTION("Xen virtual network device frontend");
1971MODULE_LICENSE("GPL");
1972MODULE_ALIAS("xen:vif");
1973MODULE_ALIAS("xennet");
1/*
2 * Virtual network driver for conversing with remote driver backends.
3 *
4 * Copyright (c) 2002-2005, K A Fraser
5 * Copyright (c) 2005, XenSource Ltd
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version 2
9 * as published by the Free Software Foundation; or, when distributed
10 * separately from the Linux kernel or incorporated into other
11 * software packages, subject to the following license:
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this source file (the "Software"), to deal in the Software without
15 * restriction, including without limitation the rights to use, copy, modify,
16 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
17 * and to permit persons to whom the Software is furnished to do so, subject to
18 * the following conditions:
19 *
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
29 * IN THE SOFTWARE.
30 */
31
32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34#include <linux/module.h>
35#include <linux/kernel.h>
36#include <linux/netdevice.h>
37#include <linux/etherdevice.h>
38#include <linux/skbuff.h>
39#include <linux/ethtool.h>
40#include <linux/if_ether.h>
41#include <net/tcp.h>
42#include <linux/udp.h>
43#include <linux/moduleparam.h>
44#include <linux/mm.h>
45#include <linux/slab.h>
46#include <net/ip.h>
47#include <linux/bpf.h>
48#include <net/page_pool.h>
49#include <linux/bpf_trace.h>
50
51#include <xen/xen.h>
52#include <xen/xenbus.h>
53#include <xen/events.h>
54#include <xen/page.h>
55#include <xen/platform_pci.h>
56#include <xen/grant_table.h>
57
58#include <xen/interface/io/netif.h>
59#include <xen/interface/memory.h>
60#include <xen/interface/grant_table.h>
61
62/* Module parameters */
63#define MAX_QUEUES_DEFAULT 8
64static unsigned int xennet_max_queues;
65module_param_named(max_queues, xennet_max_queues, uint, 0644);
66MODULE_PARM_DESC(max_queues,
67 "Maximum number of queues per virtual interface");
68
69#define XENNET_TIMEOUT (5 * HZ)
70
71static const struct ethtool_ops xennet_ethtool_ops;
72
73struct netfront_cb {
74 int pull_to;
75};
76
77#define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb))
78
79#define RX_COPY_THRESHOLD 256
80
81#define GRANT_INVALID_REF 0
82
83#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
84#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
85
86/* Minimum number of Rx slots (includes slot for GSO metadata). */
87#define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
88
89/* Queue name is interface name with "-qNNN" appended */
90#define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
91
92/* IRQ name is queue name with "-tx" or "-rx" appended */
93#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
94
95static DECLARE_WAIT_QUEUE_HEAD(module_wq);
96
97struct netfront_stats {
98 u64 packets;
99 u64 bytes;
100 struct u64_stats_sync syncp;
101};
102
103struct netfront_info;
104
105struct netfront_queue {
106 unsigned int id; /* Queue ID, 0-based */
107 char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
108 struct netfront_info *info;
109
110 struct bpf_prog __rcu *xdp_prog;
111
112 struct napi_struct napi;
113
114 /* Split event channels support, tx_* == rx_* when using
115 * single event channel.
116 */
117 unsigned int tx_evtchn, rx_evtchn;
118 unsigned int tx_irq, rx_irq;
119 /* Only used when split event channels support is enabled */
120 char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
121 char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
122
123 spinlock_t tx_lock;
124 struct xen_netif_tx_front_ring tx;
125 int tx_ring_ref;
126
127 /*
128 * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
129 * are linked from tx_skb_freelist through skb_entry.link.
130 *
131 * NB. Freelist index entries are always going to be less than
132 * PAGE_OFFSET, whereas pointers to skbs will always be equal or
133 * greater than PAGE_OFFSET: we use this property to distinguish
134 * them.
135 */
136 union skb_entry {
137 struct sk_buff *skb;
138 unsigned long link;
139 } tx_skbs[NET_TX_RING_SIZE];
140 grant_ref_t gref_tx_head;
141 grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
142 struct page *grant_tx_page[NET_TX_RING_SIZE];
143 unsigned tx_skb_freelist;
144
145 spinlock_t rx_lock ____cacheline_aligned_in_smp;
146 struct xen_netif_rx_front_ring rx;
147 int rx_ring_ref;
148
149 struct timer_list rx_refill_timer;
150
151 struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
152 grant_ref_t gref_rx_head;
153 grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
154
155 struct page_pool *page_pool;
156 struct xdp_rxq_info xdp_rxq;
157};
158
159struct netfront_info {
160 struct list_head list;
161 struct net_device *netdev;
162
163 struct xenbus_device *xbdev;
164
165 /* Multi-queue support */
166 struct netfront_queue *queues;
167
168 /* Statistics */
169 struct netfront_stats __percpu *rx_stats;
170 struct netfront_stats __percpu *tx_stats;
171
172 /* XDP state */
173 bool netback_has_xdp_headroom;
174 bool netfront_xdp_enabled;
175
176 atomic_t rx_gso_checksum_fixup;
177};
178
179struct netfront_rx_info {
180 struct xen_netif_rx_response rx;
181 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
182};
183
184static void skb_entry_set_link(union skb_entry *list, unsigned short id)
185{
186 list->link = id;
187}
188
189static int skb_entry_is_link(const union skb_entry *list)
190{
191 BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
192 return (unsigned long)list->skb < PAGE_OFFSET;
193}
194
195/*
196 * Access macros for acquiring freeing slots in tx_skbs[].
197 */
198
199static void add_id_to_freelist(unsigned *head, union skb_entry *list,
200 unsigned short id)
201{
202 skb_entry_set_link(&list[id], *head);
203 *head = id;
204}
205
206static unsigned short get_id_from_freelist(unsigned *head,
207 union skb_entry *list)
208{
209 unsigned int id = *head;
210 *head = list[id].link;
211 return id;
212}
213
214static int xennet_rxidx(RING_IDX idx)
215{
216 return idx & (NET_RX_RING_SIZE - 1);
217}
218
219static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
220 RING_IDX ri)
221{
222 int i = xennet_rxidx(ri);
223 struct sk_buff *skb = queue->rx_skbs[i];
224 queue->rx_skbs[i] = NULL;
225 return skb;
226}
227
228static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
229 RING_IDX ri)
230{
231 int i = xennet_rxidx(ri);
232 grant_ref_t ref = queue->grant_rx_ref[i];
233 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
234 return ref;
235}
236
237#ifdef CONFIG_SYSFS
238static const struct attribute_group xennet_dev_group;
239#endif
240
241static bool xennet_can_sg(struct net_device *dev)
242{
243 return dev->features & NETIF_F_SG;
244}
245
246
247static void rx_refill_timeout(struct timer_list *t)
248{
249 struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer);
250 napi_schedule(&queue->napi);
251}
252
253static int netfront_tx_slot_available(struct netfront_queue *queue)
254{
255 return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
256 (NET_TX_RING_SIZE - XEN_NETIF_NR_SLOTS_MIN - 1);
257}
258
259static void xennet_maybe_wake_tx(struct netfront_queue *queue)
260{
261 struct net_device *dev = queue->info->netdev;
262 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
263
264 if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
265 netfront_tx_slot_available(queue) &&
266 likely(netif_running(dev)))
267 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
268}
269
270
271static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
272{
273 struct sk_buff *skb;
274 struct page *page;
275
276 skb = __netdev_alloc_skb(queue->info->netdev,
277 RX_COPY_THRESHOLD + NET_IP_ALIGN,
278 GFP_ATOMIC | __GFP_NOWARN);
279 if (unlikely(!skb))
280 return NULL;
281
282 page = page_pool_dev_alloc_pages(queue->page_pool);
283 if (unlikely(!page)) {
284 kfree_skb(skb);
285 return NULL;
286 }
287 skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
288
289 /* Align ip header to a 16 bytes boundary */
290 skb_reserve(skb, NET_IP_ALIGN);
291 skb->dev = queue->info->netdev;
292
293 return skb;
294}
295
296
297static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
298{
299 RING_IDX req_prod = queue->rx.req_prod_pvt;
300 int notify;
301 int err = 0;
302
303 if (unlikely(!netif_carrier_ok(queue->info->netdev)))
304 return;
305
306 for (req_prod = queue->rx.req_prod_pvt;
307 req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
308 req_prod++) {
309 struct sk_buff *skb;
310 unsigned short id;
311 grant_ref_t ref;
312 struct page *page;
313 struct xen_netif_rx_request *req;
314
315 skb = xennet_alloc_one_rx_buffer(queue);
316 if (!skb) {
317 err = -ENOMEM;
318 break;
319 }
320
321 id = xennet_rxidx(req_prod);
322
323 BUG_ON(queue->rx_skbs[id]);
324 queue->rx_skbs[id] = skb;
325
326 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
327 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
328 queue->grant_rx_ref[id] = ref;
329
330 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
331
332 req = RING_GET_REQUEST(&queue->rx, req_prod);
333 gnttab_page_grant_foreign_access_ref_one(ref,
334 queue->info->xbdev->otherend_id,
335 page,
336 0);
337 req->id = id;
338 req->gref = ref;
339 }
340
341 queue->rx.req_prod_pvt = req_prod;
342
343 /* Try again later if there are not enough requests or skb allocation
344 * failed.
345 * Enough requests is quantified as the sum of newly created slots and
346 * the unconsumed slots at the backend.
347 */
348 if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
349 unlikely(err)) {
350 mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
351 return;
352 }
353
354 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
355 if (notify)
356 notify_remote_via_irq(queue->rx_irq);
357}
358
359static int xennet_open(struct net_device *dev)
360{
361 struct netfront_info *np = netdev_priv(dev);
362 unsigned int num_queues = dev->real_num_tx_queues;
363 unsigned int i = 0;
364 struct netfront_queue *queue = NULL;
365
366 if (!np->queues)
367 return -ENODEV;
368
369 for (i = 0; i < num_queues; ++i) {
370 queue = &np->queues[i];
371 napi_enable(&queue->napi);
372
373 spin_lock_bh(&queue->rx_lock);
374 if (netif_carrier_ok(dev)) {
375 xennet_alloc_rx_buffers(queue);
376 queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
377 if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
378 napi_schedule(&queue->napi);
379 }
380 spin_unlock_bh(&queue->rx_lock);
381 }
382
383 netif_tx_start_all_queues(dev);
384
385 return 0;
386}
387
388static void xennet_tx_buf_gc(struct netfront_queue *queue)
389{
390 RING_IDX cons, prod;
391 unsigned short id;
392 struct sk_buff *skb;
393 bool more_to_do;
394
395 BUG_ON(!netif_carrier_ok(queue->info->netdev));
396
397 do {
398 prod = queue->tx.sring->rsp_prod;
399 rmb(); /* Ensure we see responses up to 'rp'. */
400
401 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
402 struct xen_netif_tx_response *txrsp;
403
404 txrsp = RING_GET_RESPONSE(&queue->tx, cons);
405 if (txrsp->status == XEN_NETIF_RSP_NULL)
406 continue;
407
408 id = txrsp->id;
409 skb = queue->tx_skbs[id].skb;
410 if (unlikely(gnttab_query_foreign_access(
411 queue->grant_tx_ref[id]) != 0)) {
412 pr_alert("%s: warning -- grant still in use by backend domain\n",
413 __func__);
414 BUG();
415 }
416 gnttab_end_foreign_access_ref(
417 queue->grant_tx_ref[id], GNTMAP_readonly);
418 gnttab_release_grant_reference(
419 &queue->gref_tx_head, queue->grant_tx_ref[id]);
420 queue->grant_tx_ref[id] = GRANT_INVALID_REF;
421 queue->grant_tx_page[id] = NULL;
422 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
423 dev_kfree_skb_irq(skb);
424 }
425
426 queue->tx.rsp_cons = prod;
427
428 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
429 } while (more_to_do);
430
431 xennet_maybe_wake_tx(queue);
432}
433
434struct xennet_gnttab_make_txreq {
435 struct netfront_queue *queue;
436 struct sk_buff *skb;
437 struct page *page;
438 struct xen_netif_tx_request *tx; /* Last request */
439 unsigned int size;
440};
441
442static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
443 unsigned int len, void *data)
444{
445 struct xennet_gnttab_make_txreq *info = data;
446 unsigned int id;
447 struct xen_netif_tx_request *tx;
448 grant_ref_t ref;
449 /* convenient aliases */
450 struct page *page = info->page;
451 struct netfront_queue *queue = info->queue;
452 struct sk_buff *skb = info->skb;
453
454 id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
455 tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
456 ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
457 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
458
459 gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
460 gfn, GNTMAP_readonly);
461
462 queue->tx_skbs[id].skb = skb;
463 queue->grant_tx_page[id] = page;
464 queue->grant_tx_ref[id] = ref;
465
466 tx->id = id;
467 tx->gref = ref;
468 tx->offset = offset;
469 tx->size = len;
470 tx->flags = 0;
471
472 info->tx = tx;
473 info->size += tx->size;
474}
475
476static struct xen_netif_tx_request *xennet_make_first_txreq(
477 struct netfront_queue *queue, struct sk_buff *skb,
478 struct page *page, unsigned int offset, unsigned int len)
479{
480 struct xennet_gnttab_make_txreq info = {
481 .queue = queue,
482 .skb = skb,
483 .page = page,
484 .size = 0,
485 };
486
487 gnttab_for_one_grant(page, offset, len, xennet_tx_setup_grant, &info);
488
489 return info.tx;
490}
491
492static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
493 unsigned int len, void *data)
494{
495 struct xennet_gnttab_make_txreq *info = data;
496
497 info->tx->flags |= XEN_NETTXF_more_data;
498 skb_get(info->skb);
499 xennet_tx_setup_grant(gfn, offset, len, data);
500}
501
502static struct xen_netif_tx_request *xennet_make_txreqs(
503 struct netfront_queue *queue, struct xen_netif_tx_request *tx,
504 struct sk_buff *skb, struct page *page,
505 unsigned int offset, unsigned int len)
506{
507 struct xennet_gnttab_make_txreq info = {
508 .queue = queue,
509 .skb = skb,
510 .tx = tx,
511 };
512
513 /* Skip unused frames from start of page */
514 page += offset >> PAGE_SHIFT;
515 offset &= ~PAGE_MASK;
516
517 while (len) {
518 info.page = page;
519 info.size = 0;
520
521 gnttab_foreach_grant_in_range(page, offset, len,
522 xennet_make_one_txreq,
523 &info);
524
525 page++;
526 offset = 0;
527 len -= info.size;
528 }
529
530 return info.tx;
531}
532
533/*
534 * Count how many ring slots are required to send this skb. Each frag
535 * might be a compound page.
536 */
537static int xennet_count_skb_slots(struct sk_buff *skb)
538{
539 int i, frags = skb_shinfo(skb)->nr_frags;
540 int slots;
541
542 slots = gnttab_count_grant(offset_in_page(skb->data),
543 skb_headlen(skb));
544
545 for (i = 0; i < frags; i++) {
546 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
547 unsigned long size = skb_frag_size(frag);
548 unsigned long offset = skb_frag_off(frag);
549
550 /* Skip unused frames from start of page */
551 offset &= ~PAGE_MASK;
552
553 slots += gnttab_count_grant(offset, size);
554 }
555
556 return slots;
557}
558
559static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
560 struct net_device *sb_dev)
561{
562 unsigned int num_queues = dev->real_num_tx_queues;
563 u32 hash;
564 u16 queue_idx;
565
566 /* First, check if there is only one queue */
567 if (num_queues == 1) {
568 queue_idx = 0;
569 } else {
570 hash = skb_get_hash(skb);
571 queue_idx = hash % num_queues;
572 }
573
574 return queue_idx;
575}
576
577static int xennet_xdp_xmit_one(struct net_device *dev,
578 struct netfront_queue *queue,
579 struct xdp_frame *xdpf)
580{
581 struct netfront_info *np = netdev_priv(dev);
582 struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
583 int notify;
584
585 xennet_make_first_txreq(queue, NULL,
586 virt_to_page(xdpf->data),
587 offset_in_page(xdpf->data),
588 xdpf->len);
589
590 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
591 if (notify)
592 notify_remote_via_irq(queue->tx_irq);
593
594 u64_stats_update_begin(&tx_stats->syncp);
595 tx_stats->bytes += xdpf->len;
596 tx_stats->packets++;
597 u64_stats_update_end(&tx_stats->syncp);
598
599 xennet_tx_buf_gc(queue);
600
601 return 0;
602}
603
604static int xennet_xdp_xmit(struct net_device *dev, int n,
605 struct xdp_frame **frames, u32 flags)
606{
607 unsigned int num_queues = dev->real_num_tx_queues;
608 struct netfront_info *np = netdev_priv(dev);
609 struct netfront_queue *queue = NULL;
610 unsigned long irq_flags;
611 int nxmit = 0;
612 int i;
613
614 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
615 return -EINVAL;
616
617 queue = &np->queues[smp_processor_id() % num_queues];
618
619 spin_lock_irqsave(&queue->tx_lock, irq_flags);
620 for (i = 0; i < n; i++) {
621 struct xdp_frame *xdpf = frames[i];
622
623 if (!xdpf)
624 continue;
625 if (xennet_xdp_xmit_one(dev, queue, xdpf))
626 break;
627 nxmit++;
628 }
629 spin_unlock_irqrestore(&queue->tx_lock, irq_flags);
630
631 return nxmit;
632}
633
634
635#define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
636
637static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
638{
639 struct netfront_info *np = netdev_priv(dev);
640 struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
641 struct xen_netif_tx_request *tx, *first_tx;
642 unsigned int i;
643 int notify;
644 int slots;
645 struct page *page;
646 unsigned int offset;
647 unsigned int len;
648 unsigned long flags;
649 struct netfront_queue *queue = NULL;
650 unsigned int num_queues = dev->real_num_tx_queues;
651 u16 queue_index;
652 struct sk_buff *nskb;
653
654 /* Drop the packet if no queues are set up */
655 if (num_queues < 1)
656 goto drop;
657 /* Determine which queue to transmit this SKB on */
658 queue_index = skb_get_queue_mapping(skb);
659 queue = &np->queues[queue_index];
660
661 /* If skb->len is too big for wire format, drop skb and alert
662 * user about misconfiguration.
663 */
664 if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
665 net_alert_ratelimited(
666 "xennet: skb->len = %u, too big for wire format\n",
667 skb->len);
668 goto drop;
669 }
670
671 slots = xennet_count_skb_slots(skb);
672 if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
673 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
674 slots, skb->len);
675 if (skb_linearize(skb))
676 goto drop;
677 }
678
679 page = virt_to_page(skb->data);
680 offset = offset_in_page(skb->data);
681
682 /* The first req should be at least ETH_HLEN size or the packet will be
683 * dropped by netback.
684 */
685 if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
686 nskb = skb_copy(skb, GFP_ATOMIC);
687 if (!nskb)
688 goto drop;
689 dev_consume_skb_any(skb);
690 skb = nskb;
691 page = virt_to_page(skb->data);
692 offset = offset_in_page(skb->data);
693 }
694
695 len = skb_headlen(skb);
696
697 spin_lock_irqsave(&queue->tx_lock, flags);
698
699 if (unlikely(!netif_carrier_ok(dev) ||
700 (slots > 1 && !xennet_can_sg(dev)) ||
701 netif_needs_gso(skb, netif_skb_features(skb)))) {
702 spin_unlock_irqrestore(&queue->tx_lock, flags);
703 goto drop;
704 }
705
706 /* First request for the linear area. */
707 first_tx = tx = xennet_make_first_txreq(queue, skb,
708 page, offset, len);
709 offset += tx->size;
710 if (offset == PAGE_SIZE) {
711 page++;
712 offset = 0;
713 }
714 len -= tx->size;
715
716 if (skb->ip_summed == CHECKSUM_PARTIAL)
717 /* local packet? */
718 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
719 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
720 /* remote but checksummed. */
721 tx->flags |= XEN_NETTXF_data_validated;
722
723 /* Optional extra info after the first request. */
724 if (skb_shinfo(skb)->gso_size) {
725 struct xen_netif_extra_info *gso;
726
727 gso = (struct xen_netif_extra_info *)
728 RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
729
730 tx->flags |= XEN_NETTXF_extra_info;
731
732 gso->u.gso.size = skb_shinfo(skb)->gso_size;
733 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
734 XEN_NETIF_GSO_TYPE_TCPV6 :
735 XEN_NETIF_GSO_TYPE_TCPV4;
736 gso->u.gso.pad = 0;
737 gso->u.gso.features = 0;
738
739 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
740 gso->flags = 0;
741 }
742
743 /* Requests for the rest of the linear area. */
744 tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
745
746 /* Requests for all the frags. */
747 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
748 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
749 tx = xennet_make_txreqs(queue, tx, skb, skb_frag_page(frag),
750 skb_frag_off(frag),
751 skb_frag_size(frag));
752 }
753
754 /* First request has the packet length. */
755 first_tx->size = skb->len;
756
757 /* timestamp packet in software */
758 skb_tx_timestamp(skb);
759
760 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
761 if (notify)
762 notify_remote_via_irq(queue->tx_irq);
763
764 u64_stats_update_begin(&tx_stats->syncp);
765 tx_stats->bytes += skb->len;
766 tx_stats->packets++;
767 u64_stats_update_end(&tx_stats->syncp);
768
769 /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
770 xennet_tx_buf_gc(queue);
771
772 if (!netfront_tx_slot_available(queue))
773 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
774
775 spin_unlock_irqrestore(&queue->tx_lock, flags);
776
777 return NETDEV_TX_OK;
778
779 drop:
780 dev->stats.tx_dropped++;
781 dev_kfree_skb_any(skb);
782 return NETDEV_TX_OK;
783}
784
785static int xennet_close(struct net_device *dev)
786{
787 struct netfront_info *np = netdev_priv(dev);
788 unsigned int num_queues = dev->real_num_tx_queues;
789 unsigned int i;
790 struct netfront_queue *queue;
791 netif_tx_stop_all_queues(np->netdev);
792 for (i = 0; i < num_queues; ++i) {
793 queue = &np->queues[i];
794 napi_disable(&queue->napi);
795 }
796 return 0;
797}
798
799static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
800 grant_ref_t ref)
801{
802 int new = xennet_rxidx(queue->rx.req_prod_pvt);
803
804 BUG_ON(queue->rx_skbs[new]);
805 queue->rx_skbs[new] = skb;
806 queue->grant_rx_ref[new] = ref;
807 RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
808 RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
809 queue->rx.req_prod_pvt++;
810}
811
812static int xennet_get_extras(struct netfront_queue *queue,
813 struct xen_netif_extra_info *extras,
814 RING_IDX rp)
815
816{
817 struct xen_netif_extra_info *extra;
818 struct device *dev = &queue->info->netdev->dev;
819 RING_IDX cons = queue->rx.rsp_cons;
820 int err = 0;
821
822 do {
823 struct sk_buff *skb;
824 grant_ref_t ref;
825
826 if (unlikely(cons + 1 == rp)) {
827 if (net_ratelimit())
828 dev_warn(dev, "Missing extra info\n");
829 err = -EBADR;
830 break;
831 }
832
833 extra = (struct xen_netif_extra_info *)
834 RING_GET_RESPONSE(&queue->rx, ++cons);
835
836 if (unlikely(!extra->type ||
837 extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
838 if (net_ratelimit())
839 dev_warn(dev, "Invalid extra type: %d\n",
840 extra->type);
841 err = -EINVAL;
842 } else {
843 memcpy(&extras[extra->type - 1], extra,
844 sizeof(*extra));
845 }
846
847 skb = xennet_get_rx_skb(queue, cons);
848 ref = xennet_get_rx_ref(queue, cons);
849 xennet_move_rx_slot(queue, skb, ref);
850 } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
851
852 queue->rx.rsp_cons = cons;
853 return err;
854}
855
856static u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata,
857 struct xen_netif_rx_response *rx, struct bpf_prog *prog,
858 struct xdp_buff *xdp, bool *need_xdp_flush)
859{
860 struct xdp_frame *xdpf;
861 u32 len = rx->status;
862 u32 act;
863 int err;
864
865 xdp_init_buff(xdp, XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
866 &queue->xdp_rxq);
867 xdp_prepare_buff(xdp, page_address(pdata), XDP_PACKET_HEADROOM,
868 len, false);
869
870 act = bpf_prog_run_xdp(prog, xdp);
871 switch (act) {
872 case XDP_TX:
873 get_page(pdata);
874 xdpf = xdp_convert_buff_to_frame(xdp);
875 err = xennet_xdp_xmit(queue->info->netdev, 1, &xdpf, 0);
876 if (unlikely(!err))
877 xdp_return_frame_rx_napi(xdpf);
878 else if (unlikely(err < 0))
879 trace_xdp_exception(queue->info->netdev, prog, act);
880 break;
881 case XDP_REDIRECT:
882 get_page(pdata);
883 err = xdp_do_redirect(queue->info->netdev, xdp, prog);
884 *need_xdp_flush = true;
885 if (unlikely(err))
886 trace_xdp_exception(queue->info->netdev, prog, act);
887 break;
888 case XDP_PASS:
889 case XDP_DROP:
890 break;
891
892 case XDP_ABORTED:
893 trace_xdp_exception(queue->info->netdev, prog, act);
894 break;
895
896 default:
897 bpf_warn_invalid_xdp_action(act);
898 }
899
900 return act;
901}
902
903static int xennet_get_responses(struct netfront_queue *queue,
904 struct netfront_rx_info *rinfo, RING_IDX rp,
905 struct sk_buff_head *list,
906 bool *need_xdp_flush)
907{
908 struct xen_netif_rx_response *rx = &rinfo->rx;
909 int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
910 RING_IDX cons = queue->rx.rsp_cons;
911 struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
912 struct xen_netif_extra_info *extras = rinfo->extras;
913 grant_ref_t ref = xennet_get_rx_ref(queue, cons);
914 struct device *dev = &queue->info->netdev->dev;
915 struct bpf_prog *xdp_prog;
916 struct xdp_buff xdp;
917 unsigned long ret;
918 int slots = 1;
919 int err = 0;
920 u32 verdict;
921
922 if (rx->flags & XEN_NETRXF_extra_info) {
923 err = xennet_get_extras(queue, extras, rp);
924 if (!err) {
925 if (extras[XEN_NETIF_EXTRA_TYPE_XDP - 1].type) {
926 struct xen_netif_extra_info *xdp;
927
928 xdp = &extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
929 rx->offset = xdp->u.xdp.headroom;
930 }
931 }
932 cons = queue->rx.rsp_cons;
933 }
934
935 for (;;) {
936 if (unlikely(rx->status < 0 ||
937 rx->offset + rx->status > XEN_PAGE_SIZE)) {
938 if (net_ratelimit())
939 dev_warn(dev, "rx->offset: %u, size: %d\n",
940 rx->offset, rx->status);
941 xennet_move_rx_slot(queue, skb, ref);
942 err = -EINVAL;
943 goto next;
944 }
945
946 /*
947 * This definitely indicates a bug, either in this driver or in
948 * the backend driver. In future this should flag the bad
949 * situation to the system controller to reboot the backend.
950 */
951 if (ref == GRANT_INVALID_REF) {
952 if (net_ratelimit())
953 dev_warn(dev, "Bad rx response id %d.\n",
954 rx->id);
955 err = -EINVAL;
956 goto next;
957 }
958
959 ret = gnttab_end_foreign_access_ref(ref, 0);
960 BUG_ON(!ret);
961
962 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
963
964 rcu_read_lock();
965 xdp_prog = rcu_dereference(queue->xdp_prog);
966 if (xdp_prog) {
967 if (!(rx->flags & XEN_NETRXF_more_data)) {
968 /* currently only a single page contains data */
969 verdict = xennet_run_xdp(queue,
970 skb_frag_page(&skb_shinfo(skb)->frags[0]),
971 rx, xdp_prog, &xdp, need_xdp_flush);
972 if (verdict != XDP_PASS)
973 err = -EINVAL;
974 } else {
975 /* drop the frame */
976 err = -EINVAL;
977 }
978 }
979 rcu_read_unlock();
980next:
981 __skb_queue_tail(list, skb);
982 if (!(rx->flags & XEN_NETRXF_more_data))
983 break;
984
985 if (cons + slots == rp) {
986 if (net_ratelimit())
987 dev_warn(dev, "Need more slots\n");
988 err = -ENOENT;
989 break;
990 }
991
992 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
993 skb = xennet_get_rx_skb(queue, cons + slots);
994 ref = xennet_get_rx_ref(queue, cons + slots);
995 slots++;
996 }
997
998 if (unlikely(slots > max)) {
999 if (net_ratelimit())
1000 dev_warn(dev, "Too many slots\n");
1001 err = -E2BIG;
1002 }
1003
1004 if (unlikely(err))
1005 queue->rx.rsp_cons = cons + slots;
1006
1007 return err;
1008}
1009
1010static int xennet_set_skb_gso(struct sk_buff *skb,
1011 struct xen_netif_extra_info *gso)
1012{
1013 if (!gso->u.gso.size) {
1014 if (net_ratelimit())
1015 pr_warn("GSO size must not be zero\n");
1016 return -EINVAL;
1017 }
1018
1019 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
1020 gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
1021 if (net_ratelimit())
1022 pr_warn("Bad GSO type %d\n", gso->u.gso.type);
1023 return -EINVAL;
1024 }
1025
1026 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1027 skb_shinfo(skb)->gso_type =
1028 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
1029 SKB_GSO_TCPV4 :
1030 SKB_GSO_TCPV6;
1031
1032 /* Header must be checked, and gso_segs computed. */
1033 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1034 skb_shinfo(skb)->gso_segs = 0;
1035
1036 return 0;
1037}
1038
1039static int xennet_fill_frags(struct netfront_queue *queue,
1040 struct sk_buff *skb,
1041 struct sk_buff_head *list)
1042{
1043 RING_IDX cons = queue->rx.rsp_cons;
1044 struct sk_buff *nskb;
1045
1046 while ((nskb = __skb_dequeue(list))) {
1047 struct xen_netif_rx_response *rx =
1048 RING_GET_RESPONSE(&queue->rx, ++cons);
1049 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
1050
1051 if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) {
1052 unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
1053
1054 BUG_ON(pull_to < skb_headlen(skb));
1055 __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
1056 }
1057 if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
1058 queue->rx.rsp_cons = ++cons + skb_queue_len(list);
1059 kfree_skb(nskb);
1060 return -ENOENT;
1061 }
1062
1063 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
1064 skb_frag_page(nfrag),
1065 rx->offset, rx->status, PAGE_SIZE);
1066
1067 skb_shinfo(nskb)->nr_frags = 0;
1068 kfree_skb(nskb);
1069 }
1070
1071 queue->rx.rsp_cons = cons;
1072
1073 return 0;
1074}
1075
1076static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
1077{
1078 bool recalculate_partial_csum = false;
1079
1080 /*
1081 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1082 * peers can fail to set NETRXF_csum_blank when sending a GSO
1083 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1084 * recalculate the partial checksum.
1085 */
1086 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1087 struct netfront_info *np = netdev_priv(dev);
1088 atomic_inc(&np->rx_gso_checksum_fixup);
1089 skb->ip_summed = CHECKSUM_PARTIAL;
1090 recalculate_partial_csum = true;
1091 }
1092
1093 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1094 if (skb->ip_summed != CHECKSUM_PARTIAL)
1095 return 0;
1096
1097 return skb_checksum_setup(skb, recalculate_partial_csum);
1098}
1099
1100static int handle_incoming_queue(struct netfront_queue *queue,
1101 struct sk_buff_head *rxq)
1102{
1103 struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
1104 int packets_dropped = 0;
1105 struct sk_buff *skb;
1106
1107 while ((skb = __skb_dequeue(rxq)) != NULL) {
1108 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
1109
1110 if (pull_to > skb_headlen(skb))
1111 __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
1112
1113 /* Ethernet work: Delayed to here as it peeks the header. */
1114 skb->protocol = eth_type_trans(skb, queue->info->netdev);
1115 skb_reset_network_header(skb);
1116
1117 if (checksum_setup(queue->info->netdev, skb)) {
1118 kfree_skb(skb);
1119 packets_dropped++;
1120 queue->info->netdev->stats.rx_errors++;
1121 continue;
1122 }
1123
1124 u64_stats_update_begin(&rx_stats->syncp);
1125 rx_stats->packets++;
1126 rx_stats->bytes += skb->len;
1127 u64_stats_update_end(&rx_stats->syncp);
1128
1129 /* Pass it up. */
1130 napi_gro_receive(&queue->napi, skb);
1131 }
1132
1133 return packets_dropped;
1134}
1135
1136static int xennet_poll(struct napi_struct *napi, int budget)
1137{
1138 struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
1139 struct net_device *dev = queue->info->netdev;
1140 struct sk_buff *skb;
1141 struct netfront_rx_info rinfo;
1142 struct xen_netif_rx_response *rx = &rinfo.rx;
1143 struct xen_netif_extra_info *extras = rinfo.extras;
1144 RING_IDX i, rp;
1145 int work_done;
1146 struct sk_buff_head rxq;
1147 struct sk_buff_head errq;
1148 struct sk_buff_head tmpq;
1149 int err;
1150 bool need_xdp_flush = false;
1151
1152 spin_lock(&queue->rx_lock);
1153
1154 skb_queue_head_init(&rxq);
1155 skb_queue_head_init(&errq);
1156 skb_queue_head_init(&tmpq);
1157
1158 rp = queue->rx.sring->rsp_prod;
1159 rmb(); /* Ensure we see queued responses up to 'rp'. */
1160
1161 i = queue->rx.rsp_cons;
1162 work_done = 0;
1163 while ((i != rp) && (work_done < budget)) {
1164 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1165 memset(extras, 0, sizeof(rinfo.extras));
1166
1167 err = xennet_get_responses(queue, &rinfo, rp, &tmpq,
1168 &need_xdp_flush);
1169
1170 if (unlikely(err)) {
1171err:
1172 while ((skb = __skb_dequeue(&tmpq)))
1173 __skb_queue_tail(&errq, skb);
1174 dev->stats.rx_errors++;
1175 i = queue->rx.rsp_cons;
1176 continue;
1177 }
1178
1179 skb = __skb_dequeue(&tmpq);
1180
1181 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1182 struct xen_netif_extra_info *gso;
1183 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1184
1185 if (unlikely(xennet_set_skb_gso(skb, gso))) {
1186 __skb_queue_head(&tmpq, skb);
1187 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1188 goto err;
1189 }
1190 }
1191
1192 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1193 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1194 NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1195
1196 skb_frag_off_set(&skb_shinfo(skb)->frags[0], rx->offset);
1197 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1198 skb->data_len = rx->status;
1199 skb->len += rx->status;
1200
1201 if (unlikely(xennet_fill_frags(queue, skb, &tmpq)))
1202 goto err;
1203
1204 if (rx->flags & XEN_NETRXF_csum_blank)
1205 skb->ip_summed = CHECKSUM_PARTIAL;
1206 else if (rx->flags & XEN_NETRXF_data_validated)
1207 skb->ip_summed = CHECKSUM_UNNECESSARY;
1208
1209 __skb_queue_tail(&rxq, skb);
1210
1211 i = ++queue->rx.rsp_cons;
1212 work_done++;
1213 }
1214 if (need_xdp_flush)
1215 xdp_do_flush();
1216
1217 __skb_queue_purge(&errq);
1218
1219 work_done -= handle_incoming_queue(queue, &rxq);
1220
1221 xennet_alloc_rx_buffers(queue);
1222
1223 if (work_done < budget) {
1224 int more_to_do = 0;
1225
1226 napi_complete_done(napi, work_done);
1227
1228 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1229 if (more_to_do)
1230 napi_schedule(napi);
1231 }
1232
1233 spin_unlock(&queue->rx_lock);
1234
1235 return work_done;
1236}
1237
1238static int xennet_change_mtu(struct net_device *dev, int mtu)
1239{
1240 int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1241
1242 if (mtu > max)
1243 return -EINVAL;
1244 dev->mtu = mtu;
1245 return 0;
1246}
1247
1248static void xennet_get_stats64(struct net_device *dev,
1249 struct rtnl_link_stats64 *tot)
1250{
1251 struct netfront_info *np = netdev_priv(dev);
1252 int cpu;
1253
1254 for_each_possible_cpu(cpu) {
1255 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1256 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1257 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1258 unsigned int start;
1259
1260 do {
1261 start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
1262 tx_packets = tx_stats->packets;
1263 tx_bytes = tx_stats->bytes;
1264 } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
1265
1266 do {
1267 start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
1268 rx_packets = rx_stats->packets;
1269 rx_bytes = rx_stats->bytes;
1270 } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
1271
1272 tot->rx_packets += rx_packets;
1273 tot->tx_packets += tx_packets;
1274 tot->rx_bytes += rx_bytes;
1275 tot->tx_bytes += tx_bytes;
1276 }
1277
1278 tot->rx_errors = dev->stats.rx_errors;
1279 tot->tx_dropped = dev->stats.tx_dropped;
1280}
1281
1282static void xennet_release_tx_bufs(struct netfront_queue *queue)
1283{
1284 struct sk_buff *skb;
1285 int i;
1286
1287 for (i = 0; i < NET_TX_RING_SIZE; i++) {
1288 /* Skip over entries which are actually freelist references */
1289 if (skb_entry_is_link(&queue->tx_skbs[i]))
1290 continue;
1291
1292 skb = queue->tx_skbs[i].skb;
1293 get_page(queue->grant_tx_page[i]);
1294 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1295 GNTMAP_readonly,
1296 (unsigned long)page_address(queue->grant_tx_page[i]));
1297 queue->grant_tx_page[i] = NULL;
1298 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1299 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1300 dev_kfree_skb_irq(skb);
1301 }
1302}
1303
1304static void xennet_release_rx_bufs(struct netfront_queue *queue)
1305{
1306 int id, ref;
1307
1308 spin_lock_bh(&queue->rx_lock);
1309
1310 for (id = 0; id < NET_RX_RING_SIZE; id++) {
1311 struct sk_buff *skb;
1312 struct page *page;
1313
1314 skb = queue->rx_skbs[id];
1315 if (!skb)
1316 continue;
1317
1318 ref = queue->grant_rx_ref[id];
1319 if (ref == GRANT_INVALID_REF)
1320 continue;
1321
1322 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1323
1324 /* gnttab_end_foreign_access() needs a page ref until
1325 * foreign access is ended (which may be deferred).
1326 */
1327 get_page(page);
1328 gnttab_end_foreign_access(ref, 0,
1329 (unsigned long)page_address(page));
1330 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1331
1332 kfree_skb(skb);
1333 }
1334
1335 spin_unlock_bh(&queue->rx_lock);
1336}
1337
1338static netdev_features_t xennet_fix_features(struct net_device *dev,
1339 netdev_features_t features)
1340{
1341 struct netfront_info *np = netdev_priv(dev);
1342
1343 if (features & NETIF_F_SG &&
1344 !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1345 features &= ~NETIF_F_SG;
1346
1347 if (features & NETIF_F_IPV6_CSUM &&
1348 !xenbus_read_unsigned(np->xbdev->otherend,
1349 "feature-ipv6-csum-offload", 0))
1350 features &= ~NETIF_F_IPV6_CSUM;
1351
1352 if (features & NETIF_F_TSO &&
1353 !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1354 features &= ~NETIF_F_TSO;
1355
1356 if (features & NETIF_F_TSO6 &&
1357 !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1358 features &= ~NETIF_F_TSO6;
1359
1360 return features;
1361}
1362
1363static int xennet_set_features(struct net_device *dev,
1364 netdev_features_t features)
1365{
1366 if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1367 netdev_info(dev, "Reducing MTU because no SG offload");
1368 dev->mtu = ETH_DATA_LEN;
1369 }
1370
1371 return 0;
1372}
1373
1374static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1375{
1376 struct netfront_queue *queue = dev_id;
1377 unsigned long flags;
1378
1379 spin_lock_irqsave(&queue->tx_lock, flags);
1380 xennet_tx_buf_gc(queue);
1381 spin_unlock_irqrestore(&queue->tx_lock, flags);
1382
1383 return IRQ_HANDLED;
1384}
1385
1386static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1387{
1388 struct netfront_queue *queue = dev_id;
1389 struct net_device *dev = queue->info->netdev;
1390
1391 if (likely(netif_carrier_ok(dev) &&
1392 RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1393 napi_schedule(&queue->napi);
1394
1395 return IRQ_HANDLED;
1396}
1397
1398static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1399{
1400 xennet_tx_interrupt(irq, dev_id);
1401 xennet_rx_interrupt(irq, dev_id);
1402 return IRQ_HANDLED;
1403}
1404
1405#ifdef CONFIG_NET_POLL_CONTROLLER
1406static void xennet_poll_controller(struct net_device *dev)
1407{
1408 /* Poll each queue */
1409 struct netfront_info *info = netdev_priv(dev);
1410 unsigned int num_queues = dev->real_num_tx_queues;
1411 unsigned int i;
1412 for (i = 0; i < num_queues; ++i)
1413 xennet_interrupt(0, &info->queues[i]);
1414}
1415#endif
1416
1417#define NETBACK_XDP_HEADROOM_DISABLE 0
1418#define NETBACK_XDP_HEADROOM_ENABLE 1
1419
1420static int talk_to_netback_xdp(struct netfront_info *np, int xdp)
1421{
1422 int err;
1423 unsigned short headroom;
1424
1425 headroom = xdp ? XDP_PACKET_HEADROOM : 0;
1426 err = xenbus_printf(XBT_NIL, np->xbdev->nodename,
1427 "xdp-headroom", "%hu",
1428 headroom);
1429 if (err)
1430 pr_warn("Error writing xdp-headroom\n");
1431
1432 return err;
1433}
1434
1435static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1436 struct netlink_ext_ack *extack)
1437{
1438 unsigned long max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
1439 struct netfront_info *np = netdev_priv(dev);
1440 struct bpf_prog *old_prog;
1441 unsigned int i, err;
1442
1443 if (dev->mtu > max_mtu) {
1444 netdev_warn(dev, "XDP requires MTU less than %lu\n", max_mtu);
1445 return -EINVAL;
1446 }
1447
1448 if (!np->netback_has_xdp_headroom)
1449 return 0;
1450
1451 xenbus_switch_state(np->xbdev, XenbusStateReconfiguring);
1452
1453 err = talk_to_netback_xdp(np, prog ? NETBACK_XDP_HEADROOM_ENABLE :
1454 NETBACK_XDP_HEADROOM_DISABLE);
1455 if (err)
1456 return err;
1457
1458 /* avoid the race with XDP headroom adjustment */
1459 wait_event(module_wq,
1460 xenbus_read_driver_state(np->xbdev->otherend) ==
1461 XenbusStateReconfigured);
1462 np->netfront_xdp_enabled = true;
1463
1464 old_prog = rtnl_dereference(np->queues[0].xdp_prog);
1465
1466 if (prog)
1467 bpf_prog_add(prog, dev->real_num_tx_queues);
1468
1469 for (i = 0; i < dev->real_num_tx_queues; ++i)
1470 rcu_assign_pointer(np->queues[i].xdp_prog, prog);
1471
1472 if (old_prog)
1473 for (i = 0; i < dev->real_num_tx_queues; ++i)
1474 bpf_prog_put(old_prog);
1475
1476 xenbus_switch_state(np->xbdev, XenbusStateConnected);
1477
1478 return 0;
1479}
1480
1481static int xennet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1482{
1483 switch (xdp->command) {
1484 case XDP_SETUP_PROG:
1485 return xennet_xdp_set(dev, xdp->prog, xdp->extack);
1486 default:
1487 return -EINVAL;
1488 }
1489}
1490
1491static const struct net_device_ops xennet_netdev_ops = {
1492 .ndo_open = xennet_open,
1493 .ndo_stop = xennet_close,
1494 .ndo_start_xmit = xennet_start_xmit,
1495 .ndo_change_mtu = xennet_change_mtu,
1496 .ndo_get_stats64 = xennet_get_stats64,
1497 .ndo_set_mac_address = eth_mac_addr,
1498 .ndo_validate_addr = eth_validate_addr,
1499 .ndo_fix_features = xennet_fix_features,
1500 .ndo_set_features = xennet_set_features,
1501 .ndo_select_queue = xennet_select_queue,
1502 .ndo_bpf = xennet_xdp,
1503 .ndo_xdp_xmit = xennet_xdp_xmit,
1504#ifdef CONFIG_NET_POLL_CONTROLLER
1505 .ndo_poll_controller = xennet_poll_controller,
1506#endif
1507};
1508
1509static void xennet_free_netdev(struct net_device *netdev)
1510{
1511 struct netfront_info *np = netdev_priv(netdev);
1512
1513 free_percpu(np->rx_stats);
1514 free_percpu(np->tx_stats);
1515 free_netdev(netdev);
1516}
1517
1518static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1519{
1520 int err;
1521 struct net_device *netdev;
1522 struct netfront_info *np;
1523
1524 netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1525 if (!netdev)
1526 return ERR_PTR(-ENOMEM);
1527
1528 np = netdev_priv(netdev);
1529 np->xbdev = dev;
1530
1531 np->queues = NULL;
1532
1533 err = -ENOMEM;
1534 np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1535 if (np->rx_stats == NULL)
1536 goto exit;
1537 np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1538 if (np->tx_stats == NULL)
1539 goto exit;
1540
1541 netdev->netdev_ops = &xennet_netdev_ops;
1542
1543 netdev->features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1544 NETIF_F_GSO_ROBUST;
1545 netdev->hw_features = NETIF_F_SG |
1546 NETIF_F_IPV6_CSUM |
1547 NETIF_F_TSO | NETIF_F_TSO6;
1548
1549 /*
1550 * Assume that all hw features are available for now. This set
1551 * will be adjusted by the call to netdev_update_features() in
1552 * xennet_connect() which is the earliest point where we can
1553 * negotiate with the backend regarding supported features.
1554 */
1555 netdev->features |= netdev->hw_features;
1556
1557 netdev->ethtool_ops = &xennet_ethtool_ops;
1558 netdev->min_mtu = ETH_MIN_MTU;
1559 netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1560 SET_NETDEV_DEV(netdev, &dev->dev);
1561
1562 np->netdev = netdev;
1563 np->netfront_xdp_enabled = false;
1564
1565 netif_carrier_off(netdev);
1566
1567 do {
1568 xenbus_switch_state(dev, XenbusStateInitialising);
1569 err = wait_event_timeout(module_wq,
1570 xenbus_read_driver_state(dev->otherend) !=
1571 XenbusStateClosed &&
1572 xenbus_read_driver_state(dev->otherend) !=
1573 XenbusStateUnknown, XENNET_TIMEOUT);
1574 } while (!err);
1575
1576 return netdev;
1577
1578 exit:
1579 xennet_free_netdev(netdev);
1580 return ERR_PTR(err);
1581}
1582
1583/*
1584 * Entry point to this code when a new device is created. Allocate the basic
1585 * structures and the ring buffers for communication with the backend, and
1586 * inform the backend of the appropriate details for those.
1587 */
1588static int netfront_probe(struct xenbus_device *dev,
1589 const struct xenbus_device_id *id)
1590{
1591 int err;
1592 struct net_device *netdev;
1593 struct netfront_info *info;
1594
1595 netdev = xennet_create_dev(dev);
1596 if (IS_ERR(netdev)) {
1597 err = PTR_ERR(netdev);
1598 xenbus_dev_fatal(dev, err, "creating netdev");
1599 return err;
1600 }
1601
1602 info = netdev_priv(netdev);
1603 dev_set_drvdata(&dev->dev, info);
1604#ifdef CONFIG_SYSFS
1605 info->netdev->sysfs_groups[0] = &xennet_dev_group;
1606#endif
1607
1608 return 0;
1609}
1610
1611static void xennet_end_access(int ref, void *page)
1612{
1613 /* This frees the page as a side-effect */
1614 if (ref != GRANT_INVALID_REF)
1615 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1616}
1617
1618static void xennet_disconnect_backend(struct netfront_info *info)
1619{
1620 unsigned int i = 0;
1621 unsigned int num_queues = info->netdev->real_num_tx_queues;
1622
1623 netif_carrier_off(info->netdev);
1624
1625 for (i = 0; i < num_queues && info->queues; ++i) {
1626 struct netfront_queue *queue = &info->queues[i];
1627
1628 del_timer_sync(&queue->rx_refill_timer);
1629
1630 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1631 unbind_from_irqhandler(queue->tx_irq, queue);
1632 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1633 unbind_from_irqhandler(queue->tx_irq, queue);
1634 unbind_from_irqhandler(queue->rx_irq, queue);
1635 }
1636 queue->tx_evtchn = queue->rx_evtchn = 0;
1637 queue->tx_irq = queue->rx_irq = 0;
1638
1639 if (netif_running(info->netdev))
1640 napi_synchronize(&queue->napi);
1641
1642 xennet_release_tx_bufs(queue);
1643 xennet_release_rx_bufs(queue);
1644 gnttab_free_grant_references(queue->gref_tx_head);
1645 gnttab_free_grant_references(queue->gref_rx_head);
1646
1647 /* End access and free the pages */
1648 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1649 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1650
1651 queue->tx_ring_ref = GRANT_INVALID_REF;
1652 queue->rx_ring_ref = GRANT_INVALID_REF;
1653 queue->tx.sring = NULL;
1654 queue->rx.sring = NULL;
1655
1656 page_pool_destroy(queue->page_pool);
1657 }
1658}
1659
1660/*
1661 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1662 * driver restart. We tear down our netif structure and recreate it, but
1663 * leave the device-layer structures intact so that this is transparent to the
1664 * rest of the kernel.
1665 */
1666static int netfront_resume(struct xenbus_device *dev)
1667{
1668 struct netfront_info *info = dev_get_drvdata(&dev->dev);
1669
1670 dev_dbg(&dev->dev, "%s\n", dev->nodename);
1671
1672 xennet_disconnect_backend(info);
1673 return 0;
1674}
1675
1676static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1677{
1678 char *s, *e, *macstr;
1679 int i;
1680
1681 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1682 if (IS_ERR(macstr))
1683 return PTR_ERR(macstr);
1684
1685 for (i = 0; i < ETH_ALEN; i++) {
1686 mac[i] = simple_strtoul(s, &e, 16);
1687 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1688 kfree(macstr);
1689 return -ENOENT;
1690 }
1691 s = e+1;
1692 }
1693
1694 kfree(macstr);
1695 return 0;
1696}
1697
1698static int setup_netfront_single(struct netfront_queue *queue)
1699{
1700 int err;
1701
1702 err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1703 if (err < 0)
1704 goto fail;
1705
1706 err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1707 xennet_interrupt,
1708 0, queue->info->netdev->name, queue);
1709 if (err < 0)
1710 goto bind_fail;
1711 queue->rx_evtchn = queue->tx_evtchn;
1712 queue->rx_irq = queue->tx_irq = err;
1713
1714 return 0;
1715
1716bind_fail:
1717 xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1718 queue->tx_evtchn = 0;
1719fail:
1720 return err;
1721}
1722
1723static int setup_netfront_split(struct netfront_queue *queue)
1724{
1725 int err;
1726
1727 err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1728 if (err < 0)
1729 goto fail;
1730 err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1731 if (err < 0)
1732 goto alloc_rx_evtchn_fail;
1733
1734 snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1735 "%s-tx", queue->name);
1736 err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1737 xennet_tx_interrupt,
1738 0, queue->tx_irq_name, queue);
1739 if (err < 0)
1740 goto bind_tx_fail;
1741 queue->tx_irq = err;
1742
1743 snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1744 "%s-rx", queue->name);
1745 err = bind_evtchn_to_irqhandler(queue->rx_evtchn,
1746 xennet_rx_interrupt,
1747 0, queue->rx_irq_name, queue);
1748 if (err < 0)
1749 goto bind_rx_fail;
1750 queue->rx_irq = err;
1751
1752 return 0;
1753
1754bind_rx_fail:
1755 unbind_from_irqhandler(queue->tx_irq, queue);
1756 queue->tx_irq = 0;
1757bind_tx_fail:
1758 xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1759 queue->rx_evtchn = 0;
1760alloc_rx_evtchn_fail:
1761 xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1762 queue->tx_evtchn = 0;
1763fail:
1764 return err;
1765}
1766
1767static int setup_netfront(struct xenbus_device *dev,
1768 struct netfront_queue *queue, unsigned int feature_split_evtchn)
1769{
1770 struct xen_netif_tx_sring *txs;
1771 struct xen_netif_rx_sring *rxs;
1772 grant_ref_t gref;
1773 int err;
1774
1775 queue->tx_ring_ref = GRANT_INVALID_REF;
1776 queue->rx_ring_ref = GRANT_INVALID_REF;
1777 queue->rx.sring = NULL;
1778 queue->tx.sring = NULL;
1779
1780 txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1781 if (!txs) {
1782 err = -ENOMEM;
1783 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1784 goto fail;
1785 }
1786 SHARED_RING_INIT(txs);
1787 FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1788
1789 err = xenbus_grant_ring(dev, txs, 1, &gref);
1790 if (err < 0)
1791 goto grant_tx_ring_fail;
1792 queue->tx_ring_ref = gref;
1793
1794 rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1795 if (!rxs) {
1796 err = -ENOMEM;
1797 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1798 goto alloc_rx_ring_fail;
1799 }
1800 SHARED_RING_INIT(rxs);
1801 FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1802
1803 err = xenbus_grant_ring(dev, rxs, 1, &gref);
1804 if (err < 0)
1805 goto grant_rx_ring_fail;
1806 queue->rx_ring_ref = gref;
1807
1808 if (feature_split_evtchn)
1809 err = setup_netfront_split(queue);
1810 /* setup single event channel if
1811 * a) feature-split-event-channels == 0
1812 * b) feature-split-event-channels == 1 but failed to setup
1813 */
1814 if (!feature_split_evtchn || err)
1815 err = setup_netfront_single(queue);
1816
1817 if (err)
1818 goto alloc_evtchn_fail;
1819
1820 return 0;
1821
1822 /* If we fail to setup netfront, it is safe to just revoke access to
1823 * granted pages because backend is not accessing it at this point.
1824 */
1825alloc_evtchn_fail:
1826 gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
1827grant_rx_ring_fail:
1828 free_page((unsigned long)rxs);
1829alloc_rx_ring_fail:
1830 gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
1831grant_tx_ring_fail:
1832 free_page((unsigned long)txs);
1833fail:
1834 return err;
1835}
1836
1837/* Queue-specific initialisation
1838 * This used to be done in xennet_create_dev() but must now
1839 * be run per-queue.
1840 */
1841static int xennet_init_queue(struct netfront_queue *queue)
1842{
1843 unsigned short i;
1844 int err = 0;
1845 char *devid;
1846
1847 spin_lock_init(&queue->tx_lock);
1848 spin_lock_init(&queue->rx_lock);
1849
1850 timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
1851
1852 devid = strrchr(queue->info->xbdev->nodename, '/') + 1;
1853 snprintf(queue->name, sizeof(queue->name), "vif%s-q%u",
1854 devid, queue->id);
1855
1856 /* Initialise tx_skbs as a free chain containing every entry. */
1857 queue->tx_skb_freelist = 0;
1858 for (i = 0; i < NET_TX_RING_SIZE; i++) {
1859 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1860 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1861 queue->grant_tx_page[i] = NULL;
1862 }
1863
1864 /* Clear out rx_skbs */
1865 for (i = 0; i < NET_RX_RING_SIZE; i++) {
1866 queue->rx_skbs[i] = NULL;
1867 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1868 }
1869
1870 /* A grant for every tx ring slot */
1871 if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
1872 &queue->gref_tx_head) < 0) {
1873 pr_alert("can't alloc tx grant refs\n");
1874 err = -ENOMEM;
1875 goto exit;
1876 }
1877
1878 /* A grant for every rx ring slot */
1879 if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
1880 &queue->gref_rx_head) < 0) {
1881 pr_alert("can't alloc rx grant refs\n");
1882 err = -ENOMEM;
1883 goto exit_free_tx;
1884 }
1885
1886 return 0;
1887
1888 exit_free_tx:
1889 gnttab_free_grant_references(queue->gref_tx_head);
1890 exit:
1891 return err;
1892}
1893
1894static int write_queue_xenstore_keys(struct netfront_queue *queue,
1895 struct xenbus_transaction *xbt, int write_hierarchical)
1896{
1897 /* Write the queue-specific keys into XenStore in the traditional
1898 * way for a single queue, or in a queue subkeys for multiple
1899 * queues.
1900 */
1901 struct xenbus_device *dev = queue->info->xbdev;
1902 int err;
1903 const char *message;
1904 char *path;
1905 size_t pathsize;
1906
1907 /* Choose the correct place to write the keys */
1908 if (write_hierarchical) {
1909 pathsize = strlen(dev->nodename) + 10;
1910 path = kzalloc(pathsize, GFP_KERNEL);
1911 if (!path) {
1912 err = -ENOMEM;
1913 message = "out of memory while writing ring references";
1914 goto error;
1915 }
1916 snprintf(path, pathsize, "%s/queue-%u",
1917 dev->nodename, queue->id);
1918 } else {
1919 path = (char *)dev->nodename;
1920 }
1921
1922 /* Write ring references */
1923 err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1924 queue->tx_ring_ref);
1925 if (err) {
1926 message = "writing tx-ring-ref";
1927 goto error;
1928 }
1929
1930 err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1931 queue->rx_ring_ref);
1932 if (err) {
1933 message = "writing rx-ring-ref";
1934 goto error;
1935 }
1936
1937 /* Write event channels; taking into account both shared
1938 * and split event channel scenarios.
1939 */
1940 if (queue->tx_evtchn == queue->rx_evtchn) {
1941 /* Shared event channel */
1942 err = xenbus_printf(*xbt, path,
1943 "event-channel", "%u", queue->tx_evtchn);
1944 if (err) {
1945 message = "writing event-channel";
1946 goto error;
1947 }
1948 } else {
1949 /* Split event channels */
1950 err = xenbus_printf(*xbt, path,
1951 "event-channel-tx", "%u", queue->tx_evtchn);
1952 if (err) {
1953 message = "writing event-channel-tx";
1954 goto error;
1955 }
1956
1957 err = xenbus_printf(*xbt, path,
1958 "event-channel-rx", "%u", queue->rx_evtchn);
1959 if (err) {
1960 message = "writing event-channel-rx";
1961 goto error;
1962 }
1963 }
1964
1965 if (write_hierarchical)
1966 kfree(path);
1967 return 0;
1968
1969error:
1970 if (write_hierarchical)
1971 kfree(path);
1972 xenbus_dev_fatal(dev, err, "%s", message);
1973 return err;
1974}
1975
1976static void xennet_destroy_queues(struct netfront_info *info)
1977{
1978 unsigned int i;
1979
1980 for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
1981 struct netfront_queue *queue = &info->queues[i];
1982
1983 if (netif_running(info->netdev))
1984 napi_disable(&queue->napi);
1985 netif_napi_del(&queue->napi);
1986 }
1987
1988 kfree(info->queues);
1989 info->queues = NULL;
1990}
1991
1992
1993
1994static int xennet_create_page_pool(struct netfront_queue *queue)
1995{
1996 int err;
1997 struct page_pool_params pp_params = {
1998 .order = 0,
1999 .flags = 0,
2000 .pool_size = NET_RX_RING_SIZE,
2001 .nid = NUMA_NO_NODE,
2002 .dev = &queue->info->netdev->dev,
2003 .offset = XDP_PACKET_HEADROOM,
2004 .max_len = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
2005 };
2006
2007 queue->page_pool = page_pool_create(&pp_params);
2008 if (IS_ERR(queue->page_pool)) {
2009 err = PTR_ERR(queue->page_pool);
2010 queue->page_pool = NULL;
2011 return err;
2012 }
2013
2014 err = xdp_rxq_info_reg(&queue->xdp_rxq, queue->info->netdev,
2015 queue->id, 0);
2016 if (err) {
2017 netdev_err(queue->info->netdev, "xdp_rxq_info_reg failed\n");
2018 goto err_free_pp;
2019 }
2020
2021 err = xdp_rxq_info_reg_mem_model(&queue->xdp_rxq,
2022 MEM_TYPE_PAGE_POOL, queue->page_pool);
2023 if (err) {
2024 netdev_err(queue->info->netdev, "xdp_rxq_info_reg_mem_model failed\n");
2025 goto err_unregister_rxq;
2026 }
2027 return 0;
2028
2029err_unregister_rxq:
2030 xdp_rxq_info_unreg(&queue->xdp_rxq);
2031err_free_pp:
2032 page_pool_destroy(queue->page_pool);
2033 queue->page_pool = NULL;
2034 return err;
2035}
2036
2037static int xennet_create_queues(struct netfront_info *info,
2038 unsigned int *num_queues)
2039{
2040 unsigned int i;
2041 int ret;
2042
2043 info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
2044 GFP_KERNEL);
2045 if (!info->queues)
2046 return -ENOMEM;
2047
2048 for (i = 0; i < *num_queues; i++) {
2049 struct netfront_queue *queue = &info->queues[i];
2050
2051 queue->id = i;
2052 queue->info = info;
2053
2054 ret = xennet_init_queue(queue);
2055 if (ret < 0) {
2056 dev_warn(&info->xbdev->dev,
2057 "only created %d queues\n", i);
2058 *num_queues = i;
2059 break;
2060 }
2061
2062 /* use page pool recycling instead of buddy allocator */
2063 ret = xennet_create_page_pool(queue);
2064 if (ret < 0) {
2065 dev_err(&info->xbdev->dev, "can't allocate page pool\n");
2066 *num_queues = i;
2067 return ret;
2068 }
2069
2070 netif_napi_add(queue->info->netdev, &queue->napi,
2071 xennet_poll, 64);
2072 if (netif_running(info->netdev))
2073 napi_enable(&queue->napi);
2074 }
2075
2076 netif_set_real_num_tx_queues(info->netdev, *num_queues);
2077
2078 if (*num_queues == 0) {
2079 dev_err(&info->xbdev->dev, "no queues\n");
2080 return -EINVAL;
2081 }
2082 return 0;
2083}
2084
2085/* Common code used when first setting up, and when resuming. */
2086static int talk_to_netback(struct xenbus_device *dev,
2087 struct netfront_info *info)
2088{
2089 const char *message;
2090 struct xenbus_transaction xbt;
2091 int err;
2092 unsigned int feature_split_evtchn;
2093 unsigned int i = 0;
2094 unsigned int max_queues = 0;
2095 struct netfront_queue *queue = NULL;
2096 unsigned int num_queues = 1;
2097
2098 info->netdev->irq = 0;
2099
2100 /* Check if backend supports multiple queues */
2101 max_queues = xenbus_read_unsigned(info->xbdev->otherend,
2102 "multi-queue-max-queues", 1);
2103 num_queues = min(max_queues, xennet_max_queues);
2104
2105 /* Check feature-split-event-channels */
2106 feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
2107 "feature-split-event-channels", 0);
2108
2109 /* Read mac addr. */
2110 err = xen_net_read_mac(dev, info->netdev->dev_addr);
2111 if (err) {
2112 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
2113 goto out_unlocked;
2114 }
2115
2116 info->netback_has_xdp_headroom = xenbus_read_unsigned(info->xbdev->otherend,
2117 "feature-xdp-headroom", 0);
2118 if (info->netback_has_xdp_headroom) {
2119 /* set the current xen-netfront xdp state */
2120 err = talk_to_netback_xdp(info, info->netfront_xdp_enabled ?
2121 NETBACK_XDP_HEADROOM_ENABLE :
2122 NETBACK_XDP_HEADROOM_DISABLE);
2123 if (err)
2124 goto out_unlocked;
2125 }
2126
2127 rtnl_lock();
2128 if (info->queues)
2129 xennet_destroy_queues(info);
2130
2131 err = xennet_create_queues(info, &num_queues);
2132 if (err < 0) {
2133 xenbus_dev_fatal(dev, err, "creating queues");
2134 kfree(info->queues);
2135 info->queues = NULL;
2136 goto out;
2137 }
2138 rtnl_unlock();
2139
2140 /* Create shared ring, alloc event channel -- for each queue */
2141 for (i = 0; i < num_queues; ++i) {
2142 queue = &info->queues[i];
2143 err = setup_netfront(dev, queue, feature_split_evtchn);
2144 if (err)
2145 goto destroy_ring;
2146 }
2147
2148again:
2149 err = xenbus_transaction_start(&xbt);
2150 if (err) {
2151 xenbus_dev_fatal(dev, err, "starting transaction");
2152 goto destroy_ring;
2153 }
2154
2155 if (xenbus_exists(XBT_NIL,
2156 info->xbdev->otherend, "multi-queue-max-queues")) {
2157 /* Write the number of queues */
2158 err = xenbus_printf(xbt, dev->nodename,
2159 "multi-queue-num-queues", "%u", num_queues);
2160 if (err) {
2161 message = "writing multi-queue-num-queues";
2162 goto abort_transaction_no_dev_fatal;
2163 }
2164 }
2165
2166 if (num_queues == 1) {
2167 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
2168 if (err)
2169 goto abort_transaction_no_dev_fatal;
2170 } else {
2171 /* Write the keys for each queue */
2172 for (i = 0; i < num_queues; ++i) {
2173 queue = &info->queues[i];
2174 err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
2175 if (err)
2176 goto abort_transaction_no_dev_fatal;
2177 }
2178 }
2179
2180 /* The remaining keys are not queue-specific */
2181 err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
2182 1);
2183 if (err) {
2184 message = "writing request-rx-copy";
2185 goto abort_transaction;
2186 }
2187
2188 err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
2189 if (err) {
2190 message = "writing feature-rx-notify";
2191 goto abort_transaction;
2192 }
2193
2194 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
2195 if (err) {
2196 message = "writing feature-sg";
2197 goto abort_transaction;
2198 }
2199
2200 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
2201 if (err) {
2202 message = "writing feature-gso-tcpv4";
2203 goto abort_transaction;
2204 }
2205
2206 err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
2207 if (err) {
2208 message = "writing feature-gso-tcpv6";
2209 goto abort_transaction;
2210 }
2211
2212 err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
2213 "1");
2214 if (err) {
2215 message = "writing feature-ipv6-csum-offload";
2216 goto abort_transaction;
2217 }
2218
2219 err = xenbus_transaction_end(xbt, 0);
2220 if (err) {
2221 if (err == -EAGAIN)
2222 goto again;
2223 xenbus_dev_fatal(dev, err, "completing transaction");
2224 goto destroy_ring;
2225 }
2226
2227 return 0;
2228
2229 abort_transaction:
2230 xenbus_dev_fatal(dev, err, "%s", message);
2231abort_transaction_no_dev_fatal:
2232 xenbus_transaction_end(xbt, 1);
2233 destroy_ring:
2234 xennet_disconnect_backend(info);
2235 rtnl_lock();
2236 xennet_destroy_queues(info);
2237 out:
2238 rtnl_unlock();
2239out_unlocked:
2240 device_unregister(&dev->dev);
2241 return err;
2242}
2243
2244static int xennet_connect(struct net_device *dev)
2245{
2246 struct netfront_info *np = netdev_priv(dev);
2247 unsigned int num_queues = 0;
2248 int err;
2249 unsigned int j = 0;
2250 struct netfront_queue *queue = NULL;
2251
2252 if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
2253 dev_info(&dev->dev,
2254 "backend does not support copying receive path\n");
2255 return -ENODEV;
2256 }
2257
2258 err = talk_to_netback(np->xbdev, np);
2259 if (err)
2260 return err;
2261 if (np->netback_has_xdp_headroom)
2262 pr_info("backend supports XDP headroom\n");
2263
2264 /* talk_to_netback() sets the correct number of queues */
2265 num_queues = dev->real_num_tx_queues;
2266
2267 if (dev->reg_state == NETREG_UNINITIALIZED) {
2268 err = register_netdev(dev);
2269 if (err) {
2270 pr_warn("%s: register_netdev err=%d\n", __func__, err);
2271 device_unregister(&np->xbdev->dev);
2272 return err;
2273 }
2274 }
2275
2276 rtnl_lock();
2277 netdev_update_features(dev);
2278 rtnl_unlock();
2279
2280 /*
2281 * All public and private state should now be sane. Get
2282 * ready to start sending and receiving packets and give the driver
2283 * domain a kick because we've probably just requeued some
2284 * packets.
2285 */
2286 netif_carrier_on(np->netdev);
2287 for (j = 0; j < num_queues; ++j) {
2288 queue = &np->queues[j];
2289
2290 notify_remote_via_irq(queue->tx_irq);
2291 if (queue->tx_irq != queue->rx_irq)
2292 notify_remote_via_irq(queue->rx_irq);
2293
2294 spin_lock_irq(&queue->tx_lock);
2295 xennet_tx_buf_gc(queue);
2296 spin_unlock_irq(&queue->tx_lock);
2297
2298 spin_lock_bh(&queue->rx_lock);
2299 xennet_alloc_rx_buffers(queue);
2300 spin_unlock_bh(&queue->rx_lock);
2301 }
2302
2303 return 0;
2304}
2305
2306/*
2307 * Callback received when the backend's state changes.
2308 */
2309static void netback_changed(struct xenbus_device *dev,
2310 enum xenbus_state backend_state)
2311{
2312 struct netfront_info *np = dev_get_drvdata(&dev->dev);
2313 struct net_device *netdev = np->netdev;
2314
2315 dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2316
2317 wake_up_all(&module_wq);
2318
2319 switch (backend_state) {
2320 case XenbusStateInitialising:
2321 case XenbusStateInitialised:
2322 case XenbusStateReconfiguring:
2323 case XenbusStateReconfigured:
2324 case XenbusStateUnknown:
2325 break;
2326
2327 case XenbusStateInitWait:
2328 if (dev->state != XenbusStateInitialising)
2329 break;
2330 if (xennet_connect(netdev) != 0)
2331 break;
2332 xenbus_switch_state(dev, XenbusStateConnected);
2333 break;
2334
2335 case XenbusStateConnected:
2336 netdev_notify_peers(netdev);
2337 break;
2338
2339 case XenbusStateClosed:
2340 if (dev->state == XenbusStateClosed)
2341 break;
2342 fallthrough; /* Missed the backend's CLOSING state */
2343 case XenbusStateClosing:
2344 xenbus_frontend_closed(dev);
2345 break;
2346 }
2347}
2348
2349static const struct xennet_stat {
2350 char name[ETH_GSTRING_LEN];
2351 u16 offset;
2352} xennet_stats[] = {
2353 {
2354 "rx_gso_checksum_fixup",
2355 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2356 },
2357};
2358
2359static int xennet_get_sset_count(struct net_device *dev, int string_set)
2360{
2361 switch (string_set) {
2362 case ETH_SS_STATS:
2363 return ARRAY_SIZE(xennet_stats);
2364 default:
2365 return -EINVAL;
2366 }
2367}
2368
2369static void xennet_get_ethtool_stats(struct net_device *dev,
2370 struct ethtool_stats *stats, u64 * data)
2371{
2372 void *np = netdev_priv(dev);
2373 int i;
2374
2375 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2376 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2377}
2378
2379static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2380{
2381 int i;
2382
2383 switch (stringset) {
2384 case ETH_SS_STATS:
2385 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2386 memcpy(data + i * ETH_GSTRING_LEN,
2387 xennet_stats[i].name, ETH_GSTRING_LEN);
2388 break;
2389 }
2390}
2391
2392static const struct ethtool_ops xennet_ethtool_ops =
2393{
2394 .get_link = ethtool_op_get_link,
2395
2396 .get_sset_count = xennet_get_sset_count,
2397 .get_ethtool_stats = xennet_get_ethtool_stats,
2398 .get_strings = xennet_get_strings,
2399 .get_ts_info = ethtool_op_get_ts_info,
2400};
2401
2402#ifdef CONFIG_SYSFS
2403static ssize_t show_rxbuf(struct device *dev,
2404 struct device_attribute *attr, char *buf)
2405{
2406 return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2407}
2408
2409static ssize_t store_rxbuf(struct device *dev,
2410 struct device_attribute *attr,
2411 const char *buf, size_t len)
2412{
2413 char *endp;
2414
2415 if (!capable(CAP_NET_ADMIN))
2416 return -EPERM;
2417
2418 simple_strtoul(buf, &endp, 0);
2419 if (endp == buf)
2420 return -EBADMSG;
2421
2422 /* rxbuf_min and rxbuf_max are no longer configurable. */
2423
2424 return len;
2425}
2426
2427static DEVICE_ATTR(rxbuf_min, 0644, show_rxbuf, store_rxbuf);
2428static DEVICE_ATTR(rxbuf_max, 0644, show_rxbuf, store_rxbuf);
2429static DEVICE_ATTR(rxbuf_cur, 0444, show_rxbuf, NULL);
2430
2431static struct attribute *xennet_dev_attrs[] = {
2432 &dev_attr_rxbuf_min.attr,
2433 &dev_attr_rxbuf_max.attr,
2434 &dev_attr_rxbuf_cur.attr,
2435 NULL
2436};
2437
2438static const struct attribute_group xennet_dev_group = {
2439 .attrs = xennet_dev_attrs
2440};
2441#endif /* CONFIG_SYSFS */
2442
2443static void xennet_bus_close(struct xenbus_device *dev)
2444{
2445 int ret;
2446
2447 if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
2448 return;
2449 do {
2450 xenbus_switch_state(dev, XenbusStateClosing);
2451 ret = wait_event_timeout(module_wq,
2452 xenbus_read_driver_state(dev->otherend) ==
2453 XenbusStateClosing ||
2454 xenbus_read_driver_state(dev->otherend) ==
2455 XenbusStateClosed ||
2456 xenbus_read_driver_state(dev->otherend) ==
2457 XenbusStateUnknown,
2458 XENNET_TIMEOUT);
2459 } while (!ret);
2460
2461 if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
2462 return;
2463
2464 do {
2465 xenbus_switch_state(dev, XenbusStateClosed);
2466 ret = wait_event_timeout(module_wq,
2467 xenbus_read_driver_state(dev->otherend) ==
2468 XenbusStateClosed ||
2469 xenbus_read_driver_state(dev->otherend) ==
2470 XenbusStateUnknown,
2471 XENNET_TIMEOUT);
2472 } while (!ret);
2473}
2474
2475static int xennet_remove(struct xenbus_device *dev)
2476{
2477 struct netfront_info *info = dev_get_drvdata(&dev->dev);
2478
2479 xennet_bus_close(dev);
2480 xennet_disconnect_backend(info);
2481
2482 if (info->netdev->reg_state == NETREG_REGISTERED)
2483 unregister_netdev(info->netdev);
2484
2485 if (info->queues) {
2486 rtnl_lock();
2487 xennet_destroy_queues(info);
2488 rtnl_unlock();
2489 }
2490 xennet_free_netdev(info->netdev);
2491
2492 return 0;
2493}
2494
2495static const struct xenbus_device_id netfront_ids[] = {
2496 { "vif" },
2497 { "" }
2498};
2499
2500static struct xenbus_driver netfront_driver = {
2501 .ids = netfront_ids,
2502 .probe = netfront_probe,
2503 .remove = xennet_remove,
2504 .resume = netfront_resume,
2505 .otherend_changed = netback_changed,
2506};
2507
2508static int __init netif_init(void)
2509{
2510 if (!xen_domain())
2511 return -ENODEV;
2512
2513 if (!xen_has_pv_nic_devices())
2514 return -ENODEV;
2515
2516 pr_info("Initialising Xen virtual ethernet driver\n");
2517
2518 /* Allow as many queues as there are CPUs inut max. 8 if user has not
2519 * specified a value.
2520 */
2521 if (xennet_max_queues == 0)
2522 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2523 num_online_cpus());
2524
2525 return xenbus_register_frontend(&netfront_driver);
2526}
2527module_init(netif_init);
2528
2529
2530static void __exit netif_exit(void)
2531{
2532 xenbus_unregister_driver(&netfront_driver);
2533}
2534module_exit(netif_exit);
2535
2536MODULE_DESCRIPTION("Xen virtual network device frontend");
2537MODULE_LICENSE("GPL");
2538MODULE_ALIAS("xen:vif");
2539MODULE_ALIAS("xennet");