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1/*
2 * Copyright (c) 2016 Citrix Systems Inc.
3 * Copyright (c) 2002-2005, K A Fraser
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License version 2
7 * as published by the Free Software Foundation; or, when distributed
8 * separately from the Linux kernel or incorporated into other
9 * software packages, subject to the following license:
10 *
11 * Permission is hereby granted, free of charge, to any person obtaining a copy
12 * of this source file (the "Software"), to deal in the Software without
13 * restriction, including without limitation the rights to use, copy, modify,
14 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
15 * and to permit persons to whom the Software is furnished to do so, subject to
16 * the following conditions:
17 *
18 * The above copyright notice and this permission notice shall be included in
19 * all copies or substantial portions of the Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
27 * IN THE SOFTWARE.
28 */
29#include "common.h"
30
31#include <linux/kthread.h>
32
33#include <xen/xen.h>
34#include <xen/events.h>
35
36static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
37{
38 RING_IDX prod, cons;
39 struct sk_buff *skb;
40 int needed;
41
42 skb = skb_peek(&queue->rx_queue);
43 if (!skb)
44 return false;
45
46 needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
47 if (skb_is_gso(skb))
48 needed++;
49 if (skb->sw_hash)
50 needed++;
51
52 do {
53 prod = queue->rx.sring->req_prod;
54 cons = queue->rx.req_cons;
55
56 if (prod - cons >= needed)
57 return true;
58
59 queue->rx.sring->req_event = prod + 1;
60
61 /* Make sure event is visible before we check prod
62 * again.
63 */
64 mb();
65 } while (queue->rx.sring->req_prod != prod);
66
67 return false;
68}
69
70void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
71{
72 unsigned long flags;
73
74 spin_lock_irqsave(&queue->rx_queue.lock, flags);
75
76 __skb_queue_tail(&queue->rx_queue, skb);
77
78 queue->rx_queue_len += skb->len;
79 if (queue->rx_queue_len > queue->rx_queue_max) {
80 struct net_device *dev = queue->vif->dev;
81
82 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
83 }
84
85 spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
86}
87
88static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
89{
90 struct sk_buff *skb;
91
92 spin_lock_irq(&queue->rx_queue.lock);
93
94 skb = __skb_dequeue(&queue->rx_queue);
95 if (skb) {
96 queue->rx_queue_len -= skb->len;
97 if (queue->rx_queue_len < queue->rx_queue_max) {
98 struct netdev_queue *txq;
99
100 txq = netdev_get_tx_queue(queue->vif->dev, queue->id);
101 netif_tx_wake_queue(txq);
102 }
103 }
104
105 spin_unlock_irq(&queue->rx_queue.lock);
106
107 return skb;
108}
109
110static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
111{
112 struct sk_buff *skb;
113
114 while ((skb = xenvif_rx_dequeue(queue)) != NULL)
115 kfree_skb(skb);
116}
117
118static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
119{
120 struct sk_buff *skb;
121
122 for (;;) {
123 skb = skb_peek(&queue->rx_queue);
124 if (!skb)
125 break;
126 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
127 break;
128 xenvif_rx_dequeue(queue);
129 kfree_skb(skb);
130 }
131}
132
133static void xenvif_rx_copy_flush(struct xenvif_queue *queue)
134{
135 unsigned int i;
136 int notify;
137
138 gnttab_batch_copy(queue->rx_copy.op, queue->rx_copy.num);
139
140 for (i = 0; i < queue->rx_copy.num; i++) {
141 struct gnttab_copy *op;
142
143 op = &queue->rx_copy.op[i];
144
145 /* If the copy failed, overwrite the status field in
146 * the corresponding response.
147 */
148 if (unlikely(op->status != GNTST_okay)) {
149 struct xen_netif_rx_response *rsp;
150
151 rsp = RING_GET_RESPONSE(&queue->rx,
152 queue->rx_copy.idx[i]);
153 rsp->status = op->status;
154 }
155 }
156
157 queue->rx_copy.num = 0;
158
159 /* Push responses for all completed packets. */
160 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, notify);
161 if (notify)
162 notify_remote_via_irq(queue->rx_irq);
163
164 __skb_queue_purge(queue->rx_copy.completed);
165}
166
167static void xenvif_rx_copy_add(struct xenvif_queue *queue,
168 struct xen_netif_rx_request *req,
169 unsigned int offset, void *data, size_t len)
170{
171 struct gnttab_copy *op;
172 struct page *page;
173 struct xen_page_foreign *foreign;
174
175 if (queue->rx_copy.num == COPY_BATCH_SIZE)
176 xenvif_rx_copy_flush(queue);
177
178 op = &queue->rx_copy.op[queue->rx_copy.num];
179
180 page = virt_to_page(data);
181
182 op->flags = GNTCOPY_dest_gref;
183
184 foreign = xen_page_foreign(page);
185 if (foreign) {
186 op->source.domid = foreign->domid;
187 op->source.u.ref = foreign->gref;
188 op->flags |= GNTCOPY_source_gref;
189 } else {
190 op->source.u.gmfn = virt_to_gfn(data);
191 op->source.domid = DOMID_SELF;
192 }
193
194 op->source.offset = xen_offset_in_page(data);
195 op->dest.u.ref = req->gref;
196 op->dest.domid = queue->vif->domid;
197 op->dest.offset = offset;
198 op->len = len;
199
200 queue->rx_copy.idx[queue->rx_copy.num] = queue->rx.req_cons;
201 queue->rx_copy.num++;
202}
203
204static unsigned int xenvif_gso_type(struct sk_buff *skb)
205{
206 if (skb_is_gso(skb)) {
207 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
208 return XEN_NETIF_GSO_TYPE_TCPV4;
209 else
210 return XEN_NETIF_GSO_TYPE_TCPV6;
211 }
212 return XEN_NETIF_GSO_TYPE_NONE;
213}
214
215struct xenvif_pkt_state {
216 struct sk_buff *skb;
217 size_t remaining_len;
218 struct sk_buff *frag_iter;
219 int frag; /* frag == -1 => frag_iter->head */
220 unsigned int frag_offset;
221 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
222 unsigned int extra_count;
223 unsigned int slot;
224};
225
226static void xenvif_rx_next_skb(struct xenvif_queue *queue,
227 struct xenvif_pkt_state *pkt)
228{
229 struct sk_buff *skb;
230 unsigned int gso_type;
231
232 skb = xenvif_rx_dequeue(queue);
233
234 queue->stats.tx_bytes += skb->len;
235 queue->stats.tx_packets++;
236
237 /* Reset packet state. */
238 memset(pkt, 0, sizeof(struct xenvif_pkt_state));
239
240 pkt->skb = skb;
241 pkt->frag_iter = skb;
242 pkt->remaining_len = skb->len;
243 pkt->frag = -1;
244
245 gso_type = xenvif_gso_type(skb);
246 if ((1 << gso_type) & queue->vif->gso_mask) {
247 struct xen_netif_extra_info *extra;
248
249 extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
250
251 extra->u.gso.type = gso_type;
252 extra->u.gso.size = skb_shinfo(skb)->gso_size;
253 extra->u.gso.pad = 0;
254 extra->u.gso.features = 0;
255 extra->type = XEN_NETIF_EXTRA_TYPE_GSO;
256 extra->flags = 0;
257
258 pkt->extra_count++;
259 }
260
261 if (skb->sw_hash) {
262 struct xen_netif_extra_info *extra;
263
264 extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
265
266 extra->u.hash.algorithm =
267 XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ;
268
269 if (skb->l4_hash)
270 extra->u.hash.type =
271 skb->protocol == htons(ETH_P_IP) ?
272 _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP :
273 _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
274 else
275 extra->u.hash.type =
276 skb->protocol == htons(ETH_P_IP) ?
277 _XEN_NETIF_CTRL_HASH_TYPE_IPV4 :
278 _XEN_NETIF_CTRL_HASH_TYPE_IPV6;
279
280 *(uint32_t *)extra->u.hash.value = skb_get_hash_raw(skb);
281
282 extra->type = XEN_NETIF_EXTRA_TYPE_HASH;
283 extra->flags = 0;
284
285 pkt->extra_count++;
286 }
287}
288
289static void xenvif_rx_complete(struct xenvif_queue *queue,
290 struct xenvif_pkt_state *pkt)
291{
292 /* All responses are ready to be pushed. */
293 queue->rx.rsp_prod_pvt = queue->rx.req_cons;
294
295 __skb_queue_tail(queue->rx_copy.completed, pkt->skb);
296}
297
298static void xenvif_rx_next_frag(struct xenvif_pkt_state *pkt)
299{
300 struct sk_buff *frag_iter = pkt->frag_iter;
301 unsigned int nr_frags = skb_shinfo(frag_iter)->nr_frags;
302
303 pkt->frag++;
304 pkt->frag_offset = 0;
305
306 if (pkt->frag >= nr_frags) {
307 if (frag_iter == pkt->skb)
308 pkt->frag_iter = skb_shinfo(frag_iter)->frag_list;
309 else
310 pkt->frag_iter = frag_iter->next;
311
312 pkt->frag = -1;
313 }
314}
315
316static void xenvif_rx_next_chunk(struct xenvif_queue *queue,
317 struct xenvif_pkt_state *pkt,
318 unsigned int offset, void **data,
319 size_t *len)
320{
321 struct sk_buff *frag_iter = pkt->frag_iter;
322 void *frag_data;
323 size_t frag_len, chunk_len;
324
325 BUG_ON(!frag_iter);
326
327 if (pkt->frag == -1) {
328 frag_data = frag_iter->data;
329 frag_len = skb_headlen(frag_iter);
330 } else {
331 skb_frag_t *frag = &skb_shinfo(frag_iter)->frags[pkt->frag];
332
333 frag_data = skb_frag_address(frag);
334 frag_len = skb_frag_size(frag);
335 }
336
337 frag_data += pkt->frag_offset;
338 frag_len -= pkt->frag_offset;
339
340 chunk_len = min_t(size_t, frag_len, XEN_PAGE_SIZE - offset);
341 chunk_len = min_t(size_t, chunk_len, XEN_PAGE_SIZE -
342 xen_offset_in_page(frag_data));
343
344 pkt->frag_offset += chunk_len;
345
346 /* Advance to next frag? */
347 if (frag_len == chunk_len)
348 xenvif_rx_next_frag(pkt);
349
350 *data = frag_data;
351 *len = chunk_len;
352}
353
354static void xenvif_rx_data_slot(struct xenvif_queue *queue,
355 struct xenvif_pkt_state *pkt,
356 struct xen_netif_rx_request *req,
357 struct xen_netif_rx_response *rsp)
358{
359 unsigned int offset = 0;
360 unsigned int flags;
361
362 do {
363 size_t len;
364 void *data;
365
366 xenvif_rx_next_chunk(queue, pkt, offset, &data, &len);
367 xenvif_rx_copy_add(queue, req, offset, data, len);
368
369 offset += len;
370 pkt->remaining_len -= len;
371
372 } while (offset < XEN_PAGE_SIZE && pkt->remaining_len > 0);
373
374 if (pkt->remaining_len > 0)
375 flags = XEN_NETRXF_more_data;
376 else
377 flags = 0;
378
379 if (pkt->slot == 0) {
380 struct sk_buff *skb = pkt->skb;
381
382 if (skb->ip_summed == CHECKSUM_PARTIAL)
383 flags |= XEN_NETRXF_csum_blank |
384 XEN_NETRXF_data_validated;
385 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
386 flags |= XEN_NETRXF_data_validated;
387
388 if (pkt->extra_count != 0)
389 flags |= XEN_NETRXF_extra_info;
390 }
391
392 rsp->offset = 0;
393 rsp->flags = flags;
394 rsp->id = req->id;
395 rsp->status = (s16)offset;
396}
397
398static void xenvif_rx_extra_slot(struct xenvif_queue *queue,
399 struct xenvif_pkt_state *pkt,
400 struct xen_netif_rx_request *req,
401 struct xen_netif_rx_response *rsp)
402{
403 struct xen_netif_extra_info *extra = (void *)rsp;
404 unsigned int i;
405
406 pkt->extra_count--;
407
408 for (i = 0; i < ARRAY_SIZE(pkt->extras); i++) {
409 if (pkt->extras[i].type) {
410 *extra = pkt->extras[i];
411
412 if (pkt->extra_count != 0)
413 extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
414
415 pkt->extras[i].type = 0;
416 return;
417 }
418 }
419 BUG();
420}
421
422static void xenvif_rx_skb(struct xenvif_queue *queue)
423{
424 struct xenvif_pkt_state pkt;
425
426 xenvif_rx_next_skb(queue, &pkt);
427
428 queue->last_rx_time = jiffies;
429
430 do {
431 struct xen_netif_rx_request *req;
432 struct xen_netif_rx_response *rsp;
433
434 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons);
435 rsp = RING_GET_RESPONSE(&queue->rx, queue->rx.req_cons);
436
437 /* Extras must go after the first data slot */
438 if (pkt.slot != 0 && pkt.extra_count != 0)
439 xenvif_rx_extra_slot(queue, &pkt, req, rsp);
440 else
441 xenvif_rx_data_slot(queue, &pkt, req, rsp);
442
443 queue->rx.req_cons++;
444 pkt.slot++;
445 } while (pkt.remaining_len > 0 || pkt.extra_count != 0);
446
447 xenvif_rx_complete(queue, &pkt);
448}
449
450#define RX_BATCH_SIZE 64
451
452void xenvif_rx_action(struct xenvif_queue *queue)
453{
454 struct sk_buff_head completed_skbs;
455 unsigned int work_done = 0;
456
457 __skb_queue_head_init(&completed_skbs);
458 queue->rx_copy.completed = &completed_skbs;
459
460 while (xenvif_rx_ring_slots_available(queue) &&
461 work_done < RX_BATCH_SIZE) {
462 xenvif_rx_skb(queue);
463 work_done++;
464 }
465
466 /* Flush any pending copies and complete all skbs. */
467 xenvif_rx_copy_flush(queue);
468}
469
470static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
471{
472 RING_IDX prod, cons;
473
474 prod = queue->rx.sring->req_prod;
475 cons = queue->rx.req_cons;
476
477 return !queue->stalled &&
478 prod - cons < 1 &&
479 time_after(jiffies,
480 queue->last_rx_time + queue->vif->stall_timeout);
481}
482
483static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
484{
485 RING_IDX prod, cons;
486
487 prod = queue->rx.sring->req_prod;
488 cons = queue->rx.req_cons;
489
490 return queue->stalled && prod - cons >= 1;
491}
492
493static bool xenvif_have_rx_work(struct xenvif_queue *queue)
494{
495 return xenvif_rx_ring_slots_available(queue) ||
496 (queue->vif->stall_timeout &&
497 (xenvif_rx_queue_stalled(queue) ||
498 xenvif_rx_queue_ready(queue))) ||
499 kthread_should_stop() ||
500 queue->vif->disabled;
501}
502
503static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
504{
505 struct sk_buff *skb;
506 long timeout;
507
508 skb = skb_peek(&queue->rx_queue);
509 if (!skb)
510 return MAX_SCHEDULE_TIMEOUT;
511
512 timeout = XENVIF_RX_CB(skb)->expires - jiffies;
513 return timeout < 0 ? 0 : timeout;
514}
515
516/* Wait until the guest Rx thread has work.
517 *
518 * The timeout needs to be adjusted based on the current head of the
519 * queue (and not just the head at the beginning). In particular, if
520 * the queue is initially empty an infinite timeout is used and this
521 * needs to be reduced when a skb is queued.
522 *
523 * This cannot be done with wait_event_timeout() because it only
524 * calculates the timeout once.
525 */
526static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
527{
528 DEFINE_WAIT(wait);
529
530 if (xenvif_have_rx_work(queue))
531 return;
532
533 for (;;) {
534 long ret;
535
536 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
537 if (xenvif_have_rx_work(queue))
538 break;
539 ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
540 if (!ret)
541 break;
542 }
543 finish_wait(&queue->wq, &wait);
544}
545
546static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
547{
548 struct xenvif *vif = queue->vif;
549
550 queue->stalled = true;
551
552 /* At least one queue has stalled? Disable the carrier. */
553 spin_lock(&vif->lock);
554 if (vif->stalled_queues++ == 0) {
555 netdev_info(vif->dev, "Guest Rx stalled");
556 netif_carrier_off(vif->dev);
557 }
558 spin_unlock(&vif->lock);
559}
560
561static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
562{
563 struct xenvif *vif = queue->vif;
564
565 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
566 queue->stalled = false;
567
568 /* All queues are ready? Enable the carrier. */
569 spin_lock(&vif->lock);
570 if (--vif->stalled_queues == 0) {
571 netdev_info(vif->dev, "Guest Rx ready");
572 netif_carrier_on(vif->dev);
573 }
574 spin_unlock(&vif->lock);
575}
576
577int xenvif_kthread_guest_rx(void *data)
578{
579 struct xenvif_queue *queue = data;
580 struct xenvif *vif = queue->vif;
581
582 if (!vif->stall_timeout)
583 xenvif_queue_carrier_on(queue);
584
585 for (;;) {
586 xenvif_wait_for_rx_work(queue);
587
588 if (kthread_should_stop())
589 break;
590
591 /* This frontend is found to be rogue, disable it in
592 * kthread context. Currently this is only set when
593 * netback finds out frontend sends malformed packet,
594 * but we cannot disable the interface in softirq
595 * context so we defer it here, if this thread is
596 * associated with queue 0.
597 */
598 if (unlikely(vif->disabled && queue->id == 0)) {
599 xenvif_carrier_off(vif);
600 break;
601 }
602
603 if (!skb_queue_empty(&queue->rx_queue))
604 xenvif_rx_action(queue);
605
606 /* If the guest hasn't provided any Rx slots for a
607 * while it's probably not responsive, drop the
608 * carrier so packets are dropped earlier.
609 */
610 if (vif->stall_timeout) {
611 if (xenvif_rx_queue_stalled(queue))
612 xenvif_queue_carrier_off(queue);
613 else if (xenvif_rx_queue_ready(queue))
614 xenvif_queue_carrier_on(queue);
615 }
616
617 /* Queued packets may have foreign pages from other
618 * domains. These cannot be queued indefinitely as
619 * this would starve guests of grant refs and transmit
620 * slots.
621 */
622 xenvif_rx_queue_drop_expired(queue);
623
624 cond_resched();
625 }
626
627 /* Bin any remaining skbs */
628 xenvif_rx_queue_purge(queue);
629
630 return 0;
631}