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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 (queue->vif->xdp_headroom) {
262 struct xen_netif_extra_info *extra;
263
264 extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
265
266 memset(extra, 0, sizeof(struct xen_netif_extra_info));
267 extra->u.xdp.headroom = queue->vif->xdp_headroom;
268 extra->type = XEN_NETIF_EXTRA_TYPE_XDP;
269 extra->flags = 0;
270
271 pkt->extra_count++;
272 }
273
274 if (skb->sw_hash) {
275 struct xen_netif_extra_info *extra;
276
277 extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
278
279 extra->u.hash.algorithm =
280 XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ;
281
282 if (skb->l4_hash)
283 extra->u.hash.type =
284 skb->protocol == htons(ETH_P_IP) ?
285 _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP :
286 _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
287 else
288 extra->u.hash.type =
289 skb->protocol == htons(ETH_P_IP) ?
290 _XEN_NETIF_CTRL_HASH_TYPE_IPV4 :
291 _XEN_NETIF_CTRL_HASH_TYPE_IPV6;
292
293 *(uint32_t *)extra->u.hash.value = skb_get_hash_raw(skb);
294
295 extra->type = XEN_NETIF_EXTRA_TYPE_HASH;
296 extra->flags = 0;
297
298 pkt->extra_count++;
299 }
300}
301
302static void xenvif_rx_complete(struct xenvif_queue *queue,
303 struct xenvif_pkt_state *pkt)
304{
305 /* All responses are ready to be pushed. */
306 queue->rx.rsp_prod_pvt = queue->rx.req_cons;
307
308 __skb_queue_tail(queue->rx_copy.completed, pkt->skb);
309}
310
311static void xenvif_rx_next_frag(struct xenvif_pkt_state *pkt)
312{
313 struct sk_buff *frag_iter = pkt->frag_iter;
314 unsigned int nr_frags = skb_shinfo(frag_iter)->nr_frags;
315
316 pkt->frag++;
317 pkt->frag_offset = 0;
318
319 if (pkt->frag >= nr_frags) {
320 if (frag_iter == pkt->skb)
321 pkt->frag_iter = skb_shinfo(frag_iter)->frag_list;
322 else
323 pkt->frag_iter = frag_iter->next;
324
325 pkt->frag = -1;
326 }
327}
328
329static void xenvif_rx_next_chunk(struct xenvif_queue *queue,
330 struct xenvif_pkt_state *pkt,
331 unsigned int offset, void **data,
332 size_t *len)
333{
334 struct sk_buff *frag_iter = pkt->frag_iter;
335 void *frag_data;
336 size_t frag_len, chunk_len;
337
338 BUG_ON(!frag_iter);
339
340 if (pkt->frag == -1) {
341 frag_data = frag_iter->data;
342 frag_len = skb_headlen(frag_iter);
343 } else {
344 skb_frag_t *frag = &skb_shinfo(frag_iter)->frags[pkt->frag];
345
346 frag_data = skb_frag_address(frag);
347 frag_len = skb_frag_size(frag);
348 }
349
350 frag_data += pkt->frag_offset;
351 frag_len -= pkt->frag_offset;
352
353 chunk_len = min_t(size_t, frag_len, XEN_PAGE_SIZE - offset);
354 chunk_len = min_t(size_t, chunk_len, XEN_PAGE_SIZE -
355 xen_offset_in_page(frag_data));
356
357 pkt->frag_offset += chunk_len;
358
359 /* Advance to next frag? */
360 if (frag_len == chunk_len)
361 xenvif_rx_next_frag(pkt);
362
363 *data = frag_data;
364 *len = chunk_len;
365}
366
367static void xenvif_rx_data_slot(struct xenvif_queue *queue,
368 struct xenvif_pkt_state *pkt,
369 struct xen_netif_rx_request *req,
370 struct xen_netif_rx_response *rsp)
371{
372 unsigned int offset = queue->vif->xdp_headroom;
373 unsigned int flags;
374
375 do {
376 size_t len;
377 void *data;
378
379 xenvif_rx_next_chunk(queue, pkt, offset, &data, &len);
380 xenvif_rx_copy_add(queue, req, offset, data, len);
381
382 offset += len;
383 pkt->remaining_len -= len;
384
385 } while (offset < XEN_PAGE_SIZE && pkt->remaining_len > 0);
386
387 if (pkt->remaining_len > 0)
388 flags = XEN_NETRXF_more_data;
389 else
390 flags = 0;
391
392 if (pkt->slot == 0) {
393 struct sk_buff *skb = pkt->skb;
394
395 if (skb->ip_summed == CHECKSUM_PARTIAL)
396 flags |= XEN_NETRXF_csum_blank |
397 XEN_NETRXF_data_validated;
398 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
399 flags |= XEN_NETRXF_data_validated;
400
401 if (pkt->extra_count != 0)
402 flags |= XEN_NETRXF_extra_info;
403 }
404
405 rsp->offset = 0;
406 rsp->flags = flags;
407 rsp->id = req->id;
408 rsp->status = (s16)offset;
409}
410
411static void xenvif_rx_extra_slot(struct xenvif_queue *queue,
412 struct xenvif_pkt_state *pkt,
413 struct xen_netif_rx_request *req,
414 struct xen_netif_rx_response *rsp)
415{
416 struct xen_netif_extra_info *extra = (void *)rsp;
417 unsigned int i;
418
419 pkt->extra_count--;
420
421 for (i = 0; i < ARRAY_SIZE(pkt->extras); i++) {
422 if (pkt->extras[i].type) {
423 *extra = pkt->extras[i];
424
425 if (pkt->extra_count != 0)
426 extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
427
428 pkt->extras[i].type = 0;
429 return;
430 }
431 }
432 BUG();
433}
434
435static void xenvif_rx_skb(struct xenvif_queue *queue)
436{
437 struct xenvif_pkt_state pkt;
438
439 xenvif_rx_next_skb(queue, &pkt);
440
441 queue->last_rx_time = jiffies;
442
443 do {
444 struct xen_netif_rx_request *req;
445 struct xen_netif_rx_response *rsp;
446
447 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons);
448 rsp = RING_GET_RESPONSE(&queue->rx, queue->rx.req_cons);
449
450 /* Extras must go after the first data slot */
451 if (pkt.slot != 0 && pkt.extra_count != 0)
452 xenvif_rx_extra_slot(queue, &pkt, req, rsp);
453 else
454 xenvif_rx_data_slot(queue, &pkt, req, rsp);
455
456 queue->rx.req_cons++;
457 pkt.slot++;
458 } while (pkt.remaining_len > 0 || pkt.extra_count != 0);
459
460 xenvif_rx_complete(queue, &pkt);
461}
462
463#define RX_BATCH_SIZE 64
464
465void xenvif_rx_action(struct xenvif_queue *queue)
466{
467 struct sk_buff_head completed_skbs;
468 unsigned int work_done = 0;
469
470 __skb_queue_head_init(&completed_skbs);
471 queue->rx_copy.completed = &completed_skbs;
472
473 while (xenvif_rx_ring_slots_available(queue) &&
474 work_done < RX_BATCH_SIZE) {
475 xenvif_rx_skb(queue);
476 work_done++;
477 }
478
479 /* Flush any pending copies and complete all skbs. */
480 xenvif_rx_copy_flush(queue);
481}
482
483static bool xenvif_rx_queue_stalled(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 &&
491 prod - cons < 1 &&
492 time_after(jiffies,
493 queue->last_rx_time + queue->vif->stall_timeout);
494}
495
496static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
497{
498 RING_IDX prod, cons;
499
500 prod = queue->rx.sring->req_prod;
501 cons = queue->rx.req_cons;
502
503 return queue->stalled && prod - cons >= 1;
504}
505
506static bool xenvif_have_rx_work(struct xenvif_queue *queue)
507{
508 return xenvif_rx_ring_slots_available(queue) ||
509 (queue->vif->stall_timeout &&
510 (xenvif_rx_queue_stalled(queue) ||
511 xenvif_rx_queue_ready(queue))) ||
512 kthread_should_stop() ||
513 queue->vif->disabled;
514}
515
516static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
517{
518 struct sk_buff *skb;
519 long timeout;
520
521 skb = skb_peek(&queue->rx_queue);
522 if (!skb)
523 return MAX_SCHEDULE_TIMEOUT;
524
525 timeout = XENVIF_RX_CB(skb)->expires - jiffies;
526 return timeout < 0 ? 0 : timeout;
527}
528
529/* Wait until the guest Rx thread has work.
530 *
531 * The timeout needs to be adjusted based on the current head of the
532 * queue (and not just the head at the beginning). In particular, if
533 * the queue is initially empty an infinite timeout is used and this
534 * needs to be reduced when a skb is queued.
535 *
536 * This cannot be done with wait_event_timeout() because it only
537 * calculates the timeout once.
538 */
539static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
540{
541 DEFINE_WAIT(wait);
542
543 if (xenvif_have_rx_work(queue))
544 return;
545
546 for (;;) {
547 long ret;
548
549 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
550 if (xenvif_have_rx_work(queue))
551 break;
552 ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
553 if (!ret)
554 break;
555 }
556 finish_wait(&queue->wq, &wait);
557}
558
559static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
560{
561 struct xenvif *vif = queue->vif;
562
563 queue->stalled = true;
564
565 /* At least one queue has stalled? Disable the carrier. */
566 spin_lock(&vif->lock);
567 if (vif->stalled_queues++ == 0) {
568 netdev_info(vif->dev, "Guest Rx stalled");
569 netif_carrier_off(vif->dev);
570 }
571 spin_unlock(&vif->lock);
572}
573
574static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
575{
576 struct xenvif *vif = queue->vif;
577
578 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
579 queue->stalled = false;
580
581 /* All queues are ready? Enable the carrier. */
582 spin_lock(&vif->lock);
583 if (--vif->stalled_queues == 0) {
584 netdev_info(vif->dev, "Guest Rx ready");
585 netif_carrier_on(vif->dev);
586 }
587 spin_unlock(&vif->lock);
588}
589
590int xenvif_kthread_guest_rx(void *data)
591{
592 struct xenvif_queue *queue = data;
593 struct xenvif *vif = queue->vif;
594
595 if (!vif->stall_timeout)
596 xenvif_queue_carrier_on(queue);
597
598 for (;;) {
599 xenvif_wait_for_rx_work(queue);
600
601 if (kthread_should_stop())
602 break;
603
604 /* This frontend is found to be rogue, disable it in
605 * kthread context. Currently this is only set when
606 * netback finds out frontend sends malformed packet,
607 * but we cannot disable the interface in softirq
608 * context so we defer it here, if this thread is
609 * associated with queue 0.
610 */
611 if (unlikely(vif->disabled && queue->id == 0)) {
612 xenvif_carrier_off(vif);
613 break;
614 }
615
616 if (!skb_queue_empty(&queue->rx_queue))
617 xenvif_rx_action(queue);
618
619 /* If the guest hasn't provided any Rx slots for a
620 * while it's probably not responsive, drop the
621 * carrier so packets are dropped earlier.
622 */
623 if (vif->stall_timeout) {
624 if (xenvif_rx_queue_stalled(queue))
625 xenvif_queue_carrier_off(queue);
626 else if (xenvif_rx_queue_ready(queue))
627 xenvif_queue_carrier_on(queue);
628 }
629
630 /* Queued packets may have foreign pages from other
631 * domains. These cannot be queued indefinitely as
632 * this would starve guests of grant refs and transmit
633 * slots.
634 */
635 xenvif_rx_queue_drop_expired(queue);
636
637 cond_resched();
638 }
639
640 /* Bin any remaining skbs */
641 xenvif_rx_queue_purge(queue);
642
643 return 0;
644}