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xen/balloon: pre-allocate p2m entries for ballooned pages
[linux-2.6-block.git] / drivers / net / xen-netback / netback.c
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1/*
2 * Back-end of the driver for virtual network devices. This portion of the
3 * driver exports a 'unified' network-device interface that can be accessed
4 * by any operating system that implements a compatible front end. A
5 * reference front-end implementation can be found in:
6 * drivers/net/xen-netfront.c
7 *
8 * Copyright (c) 2002-2005, K A Fraser
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35#include "common.h"
36
37#include <linux/kthread.h>
38#include <linux/if_vlan.h>
39#include <linux/udp.h>
40#include <linux/highmem.h>
41
42#include <net/tcp.h>
43
44#include <xen/xen.h>
45#include <xen/events.h>
46#include <xen/interface/memory.h>
47#include <xen/page.h>
48
49#include <asm/xen/hypercall.h>
50
51/* Provide an option to disable split event channels at load time as
52 * event channels are limited resource. Split event channels are
53 * enabled by default.
54 */
55bool separate_tx_rx_irq = true;
56module_param(separate_tx_rx_irq, bool, 0644);
57
58/* The time that packets can stay on the guest Rx internal queue
59 * before they are dropped.
60 */
61unsigned int rx_drain_timeout_msecs = 10000;
62module_param(rx_drain_timeout_msecs, uint, 0444);
63
64/* The length of time before the frontend is considered unresponsive
65 * because it isn't providing Rx slots.
66 */
67unsigned int rx_stall_timeout_msecs = 60000;
68module_param(rx_stall_timeout_msecs, uint, 0444);
69
70unsigned int xenvif_max_queues;
71module_param_named(max_queues, xenvif_max_queues, uint, 0644);
72MODULE_PARM_DESC(max_queues,
73 "Maximum number of queues per virtual interface");
74
75/*
76 * This is the maximum slots a skb can have. If a guest sends a skb
77 * which exceeds this limit it is considered malicious.
78 */
79#define FATAL_SKB_SLOTS_DEFAULT 20
80static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
81module_param(fatal_skb_slots, uint, 0444);
82
83/* The amount to copy out of the first guest Tx slot into the skb's
84 * linear area. If the first slot has more data, it will be mapped
85 * and put into the first frag.
86 *
87 * This is sized to avoid pulling headers from the frags for most
88 * TCP/IP packets.
89 */
90#define XEN_NETBACK_TX_COPY_LEN 128
91
92
93static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
94 u8 status);
95
96static void make_tx_response(struct xenvif_queue *queue,
97 struct xen_netif_tx_request *txp,
98 s8 st);
99static void push_tx_responses(struct xenvif_queue *queue);
100
101static inline int tx_work_todo(struct xenvif_queue *queue);
102
103static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
104 u16 id,
105 s8 st,
106 u16 offset,
107 u16 size,
108 u16 flags);
109
110static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
111 u16 idx)
112{
113 return page_to_pfn(queue->mmap_pages[idx]);
114}
115
116static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
117 u16 idx)
118{
119 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
120}
121
122#define callback_param(vif, pending_idx) \
123 (vif->pending_tx_info[pending_idx].callback_struct)
124
125/* Find the containing VIF's structure from a pointer in pending_tx_info array
126 */
127static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
128{
129 u16 pending_idx = ubuf->desc;
130 struct pending_tx_info *temp =
131 container_of(ubuf, struct pending_tx_info, callback_struct);
132 return container_of(temp - pending_idx,
133 struct xenvif_queue,
134 pending_tx_info[0]);
135}
136
137static u16 frag_get_pending_idx(skb_frag_t *frag)
138{
139 return (u16)frag->page_offset;
140}
141
142static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
143{
144 frag->page_offset = pending_idx;
145}
146
147static inline pending_ring_idx_t pending_index(unsigned i)
148{
149 return i & (MAX_PENDING_REQS-1);
150}
151
152static int xenvif_rx_ring_slots_needed(struct xenvif *vif)
153{
154 if (vif->gso_mask)
155 return DIV_ROUND_UP(vif->dev->gso_max_size, PAGE_SIZE) + 1;
156 else
157 return DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
158}
159
160static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
161{
162 RING_IDX prod, cons;
163 int needed;
164
165 needed = xenvif_rx_ring_slots_needed(queue->vif);
166
167 do {
168 prod = queue->rx.sring->req_prod;
169 cons = queue->rx.req_cons;
170
171 if (prod - cons >= needed)
172 return true;
173
174 queue->rx.sring->req_event = prod + 1;
175
176 /* Make sure event is visible before we check prod
177 * again.
178 */
179 mb();
180 } while (queue->rx.sring->req_prod != prod);
181
182 return false;
183}
184
185void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
186{
187 unsigned long flags;
188
189 spin_lock_irqsave(&queue->rx_queue.lock, flags);
190
191 __skb_queue_tail(&queue->rx_queue, skb);
192
193 queue->rx_queue_len += skb->len;
194 if (queue->rx_queue_len > queue->rx_queue_max)
195 netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
196
197 spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
198}
199
200static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
201{
202 struct sk_buff *skb;
203
204 spin_lock_irq(&queue->rx_queue.lock);
205
206 skb = __skb_dequeue(&queue->rx_queue);
207 if (skb)
208 queue->rx_queue_len -= skb->len;
209
210 spin_unlock_irq(&queue->rx_queue.lock);
211
212 return skb;
213}
214
215static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue)
216{
217 spin_lock_irq(&queue->rx_queue.lock);
218
219 if (queue->rx_queue_len < queue->rx_queue_max)
220 netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
221
222 spin_unlock_irq(&queue->rx_queue.lock);
223}
224
225
226static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
227{
228 struct sk_buff *skb;
229 while ((skb = xenvif_rx_dequeue(queue)) != NULL)
230 kfree_skb(skb);
231}
232
233static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
234{
235 struct sk_buff *skb;
236
237 for(;;) {
238 skb = skb_peek(&queue->rx_queue);
239 if (!skb)
240 break;
241 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
242 break;
243 xenvif_rx_dequeue(queue);
244 kfree_skb(skb);
245 }
246}
247
248struct netrx_pending_operations {
249 unsigned copy_prod, copy_cons;
250 unsigned meta_prod, meta_cons;
251 struct gnttab_copy *copy;
252 struct xenvif_rx_meta *meta;
253 int copy_off;
254 grant_ref_t copy_gref;
255};
256
257static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue,
258 struct netrx_pending_operations *npo)
259{
260 struct xenvif_rx_meta *meta;
261 struct xen_netif_rx_request *req;
262
263 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
264
265 meta = npo->meta + npo->meta_prod++;
266 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
267 meta->gso_size = 0;
268 meta->size = 0;
269 meta->id = req->id;
270
271 npo->copy_off = 0;
272 npo->copy_gref = req->gref;
273
274 return meta;
275}
276
277/*
278 * Set up the grant operations for this fragment. If it's a flipping
279 * interface, we also set up the unmap request from here.
280 */
281static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb,
282 struct netrx_pending_operations *npo,
283 struct page *page, unsigned long size,
284 unsigned long offset, int *head)
285{
286 struct gnttab_copy *copy_gop;
287 struct xenvif_rx_meta *meta;
288 unsigned long bytes;
289 int gso_type = XEN_NETIF_GSO_TYPE_NONE;
290
291 /* Data must not cross a page boundary. */
292 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
293
294 meta = npo->meta + npo->meta_prod - 1;
295
296 /* Skip unused frames from start of page */
297 page += offset >> PAGE_SHIFT;
298 offset &= ~PAGE_MASK;
299
300 while (size > 0) {
301 struct xen_page_foreign *foreign;
302
303 BUG_ON(offset >= PAGE_SIZE);
304 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
305
306 if (npo->copy_off == MAX_BUFFER_OFFSET)
307 meta = get_next_rx_buffer(queue, npo);
308
309 bytes = PAGE_SIZE - offset;
310 if (bytes > size)
311 bytes = size;
312
313 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
314 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
315
316 copy_gop = npo->copy + npo->copy_prod++;
317 copy_gop->flags = GNTCOPY_dest_gref;
318 copy_gop->len = bytes;
319
320 foreign = xen_page_foreign(page);
321 if (foreign) {
322 copy_gop->source.domid = foreign->domid;
323 copy_gop->source.u.ref = foreign->gref;
324 copy_gop->flags |= GNTCOPY_source_gref;
325 } else {
326 copy_gop->source.domid = DOMID_SELF;
327 copy_gop->source.u.gmfn =
328 virt_to_gfn(page_address(page));
329 }
330 copy_gop->source.offset = offset;
331
332 copy_gop->dest.domid = queue->vif->domid;
333 copy_gop->dest.offset = npo->copy_off;
334 copy_gop->dest.u.ref = npo->copy_gref;
335
336 npo->copy_off += bytes;
337 meta->size += bytes;
338
339 offset += bytes;
340 size -= bytes;
341
342 /* Next frame */
343 if (offset == PAGE_SIZE && size) {
344 BUG_ON(!PageCompound(page));
345 page++;
346 offset = 0;
347 }
348
349 /* Leave a gap for the GSO descriptor. */
350 if (skb_is_gso(skb)) {
351 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
352 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
353 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
354 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
355 }
356
357 if (*head && ((1 << gso_type) & queue->vif->gso_mask))
358 queue->rx.req_cons++;
359
360 *head = 0; /* There must be something in this buffer now. */
361
362 }
363}
364
365/*
366 * Prepare an SKB to be transmitted to the frontend.
367 *
368 * This function is responsible for allocating grant operations, meta
369 * structures, etc.
370 *
371 * It returns the number of meta structures consumed. The number of
372 * ring slots used is always equal to the number of meta slots used
373 * plus the number of GSO descriptors used. Currently, we use either
374 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
375 * frontend-side LRO).
376 */
377static int xenvif_gop_skb(struct sk_buff *skb,
378 struct netrx_pending_operations *npo,
379 struct xenvif_queue *queue)
380{
381 struct xenvif *vif = netdev_priv(skb->dev);
382 int nr_frags = skb_shinfo(skb)->nr_frags;
383 int i;
384 struct xen_netif_rx_request *req;
385 struct xenvif_rx_meta *meta;
386 unsigned char *data;
387 int head = 1;
388 int old_meta_prod;
389 int gso_type;
390
391 old_meta_prod = npo->meta_prod;
392
393 gso_type = XEN_NETIF_GSO_TYPE_NONE;
394 if (skb_is_gso(skb)) {
395 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
396 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
397 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
398 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
399 }
400
401 /* Set up a GSO prefix descriptor, if necessary */
402 if ((1 << gso_type) & vif->gso_prefix_mask) {
403 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
404 meta = npo->meta + npo->meta_prod++;
405 meta->gso_type = gso_type;
406 meta->gso_size = skb_shinfo(skb)->gso_size;
407 meta->size = 0;
408 meta->id = req->id;
409 }
410
411 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
412 meta = npo->meta + npo->meta_prod++;
413
414 if ((1 << gso_type) & vif->gso_mask) {
415 meta->gso_type = gso_type;
416 meta->gso_size = skb_shinfo(skb)->gso_size;
417 } else {
418 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
419 meta->gso_size = 0;
420 }
421
422 meta->size = 0;
423 meta->id = req->id;
424 npo->copy_off = 0;
425 npo->copy_gref = req->gref;
426
427 data = skb->data;
428 while (data < skb_tail_pointer(skb)) {
429 unsigned int offset = offset_in_page(data);
430 unsigned int len = PAGE_SIZE - offset;
431
432 if (data + len > skb_tail_pointer(skb))
433 len = skb_tail_pointer(skb) - data;
434
435 xenvif_gop_frag_copy(queue, skb, npo,
436 virt_to_page(data), len, offset, &head);
437 data += len;
438 }
439
440 for (i = 0; i < nr_frags; i++) {
441 xenvif_gop_frag_copy(queue, skb, npo,
442 skb_frag_page(&skb_shinfo(skb)->frags[i]),
443 skb_frag_size(&skb_shinfo(skb)->frags[i]),
444 skb_shinfo(skb)->frags[i].page_offset,
445 &head);
446 }
447
448 return npo->meta_prod - old_meta_prod;
449}
450
451/*
452 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
453 * used to set up the operations on the top of
454 * netrx_pending_operations, which have since been done. Check that
455 * they didn't give any errors and advance over them.
456 */
457static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
458 struct netrx_pending_operations *npo)
459{
460 struct gnttab_copy *copy_op;
461 int status = XEN_NETIF_RSP_OKAY;
462 int i;
463
464 for (i = 0; i < nr_meta_slots; i++) {
465 copy_op = npo->copy + npo->copy_cons++;
466 if (copy_op->status != GNTST_okay) {
467 netdev_dbg(vif->dev,
468 "Bad status %d from copy to DOM%d.\n",
469 copy_op->status, vif->domid);
470 status = XEN_NETIF_RSP_ERROR;
471 }
472 }
473
474 return status;
475}
476
477static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status,
478 struct xenvif_rx_meta *meta,
479 int nr_meta_slots)
480{
481 int i;
482 unsigned long offset;
483
484 /* No fragments used */
485 if (nr_meta_slots <= 1)
486 return;
487
488 nr_meta_slots--;
489
490 for (i = 0; i < nr_meta_slots; i++) {
491 int flags;
492 if (i == nr_meta_slots - 1)
493 flags = 0;
494 else
495 flags = XEN_NETRXF_more_data;
496
497 offset = 0;
498 make_rx_response(queue, meta[i].id, status, offset,
499 meta[i].size, flags);
500 }
501}
502
503void xenvif_kick_thread(struct xenvif_queue *queue)
504{
505 wake_up(&queue->wq);
506}
507
508static void xenvif_rx_action(struct xenvif_queue *queue)
509{
510 s8 status;
511 u16 flags;
512 struct xen_netif_rx_response *resp;
513 struct sk_buff_head rxq;
514 struct sk_buff *skb;
515 LIST_HEAD(notify);
516 int ret;
517 unsigned long offset;
518 bool need_to_notify = false;
519
520 struct netrx_pending_operations npo = {
521 .copy = queue->grant_copy_op,
522 .meta = queue->meta,
523 };
524
525 skb_queue_head_init(&rxq);
526
527 while (xenvif_rx_ring_slots_available(queue)
528 && (skb = xenvif_rx_dequeue(queue)) != NULL) {
529 queue->last_rx_time = jiffies;
530
531 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
532
533 __skb_queue_tail(&rxq, skb);
534 }
535
536 BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
537
538 if (!npo.copy_prod)
539 goto done;
540
541 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
542 gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
543
544 while ((skb = __skb_dequeue(&rxq)) != NULL) {
545
546 if ((1 << queue->meta[npo.meta_cons].gso_type) &
547 queue->vif->gso_prefix_mask) {
548 resp = RING_GET_RESPONSE(&queue->rx,
549 queue->rx.rsp_prod_pvt++);
550
551 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
552
553 resp->offset = queue->meta[npo.meta_cons].gso_size;
554 resp->id = queue->meta[npo.meta_cons].id;
555 resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
556
557 npo.meta_cons++;
558 XENVIF_RX_CB(skb)->meta_slots_used--;
559 }
560
561
562 queue->stats.tx_bytes += skb->len;
563 queue->stats.tx_packets++;
564
565 status = xenvif_check_gop(queue->vif,
566 XENVIF_RX_CB(skb)->meta_slots_used,
567 &npo);
568
569 if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
570 flags = 0;
571 else
572 flags = XEN_NETRXF_more_data;
573
574 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
575 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
576 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
577 /* remote but checksummed. */
578 flags |= XEN_NETRXF_data_validated;
579
580 offset = 0;
581 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
582 status, offset,
583 queue->meta[npo.meta_cons].size,
584 flags);
585
586 if ((1 << queue->meta[npo.meta_cons].gso_type) &
587 queue->vif->gso_mask) {
588 struct xen_netif_extra_info *gso =
589 (struct xen_netif_extra_info *)
590 RING_GET_RESPONSE(&queue->rx,
591 queue->rx.rsp_prod_pvt++);
592
593 resp->flags |= XEN_NETRXF_extra_info;
594
595 gso->u.gso.type = queue->meta[npo.meta_cons].gso_type;
596 gso->u.gso.size = queue->meta[npo.meta_cons].gso_size;
597 gso->u.gso.pad = 0;
598 gso->u.gso.features = 0;
599
600 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
601 gso->flags = 0;
602 }
603
604 xenvif_add_frag_responses(queue, status,
605 queue->meta + npo.meta_cons + 1,
606 XENVIF_RX_CB(skb)->meta_slots_used);
607
608 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
609
610 need_to_notify |= !!ret;
611
612 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
613 dev_kfree_skb(skb);
614 }
615
616done:
617 if (need_to_notify)
618 notify_remote_via_irq(queue->rx_irq);
619}
620
621void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
622{
623 int more_to_do;
624
625 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
626
627 if (more_to_do)
628 napi_schedule(&queue->napi);
629}
630
631static void tx_add_credit(struct xenvif_queue *queue)
632{
633 unsigned long max_burst, max_credit;
634
635 /*
636 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
637 * Otherwise the interface can seize up due to insufficient credit.
638 */
639 max_burst = RING_GET_REQUEST(&queue->tx, queue->tx.req_cons)->size;
640 max_burst = min(max_burst, 131072UL);
641 max_burst = max(max_burst, queue->credit_bytes);
642
643 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
644 max_credit = queue->remaining_credit + queue->credit_bytes;
645 if (max_credit < queue->remaining_credit)
646 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
647
648 queue->remaining_credit = min(max_credit, max_burst);
649}
650
651void xenvif_tx_credit_callback(unsigned long data)
652{
653 struct xenvif_queue *queue = (struct xenvif_queue *)data;
654 tx_add_credit(queue);
655 xenvif_napi_schedule_or_enable_events(queue);
656}
657
658static void xenvif_tx_err(struct xenvif_queue *queue,
659 struct xen_netif_tx_request *txp, RING_IDX end)
660{
661 RING_IDX cons = queue->tx.req_cons;
662 unsigned long flags;
663
664 do {
665 spin_lock_irqsave(&queue->response_lock, flags);
666 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
667 push_tx_responses(queue);
668 spin_unlock_irqrestore(&queue->response_lock, flags);
669 if (cons == end)
670 break;
671 txp = RING_GET_REQUEST(&queue->tx, cons++);
672 } while (1);
673 queue->tx.req_cons = cons;
674}
675
676static void xenvif_fatal_tx_err(struct xenvif *vif)
677{
678 netdev_err(vif->dev, "fatal error; disabling device\n");
679 vif->disabled = true;
680 /* Disable the vif from queue 0's kthread */
681 if (vif->queues)
682 xenvif_kick_thread(&vif->queues[0]);
683}
684
685static int xenvif_count_requests(struct xenvif_queue *queue,
686 struct xen_netif_tx_request *first,
687 struct xen_netif_tx_request *txp,
688 int work_to_do)
689{
690 RING_IDX cons = queue->tx.req_cons;
691 int slots = 0;
692 int drop_err = 0;
693 int more_data;
694
695 if (!(first->flags & XEN_NETTXF_more_data))
696 return 0;
697
698 do {
699 struct xen_netif_tx_request dropped_tx = { 0 };
700
701 if (slots >= work_to_do) {
702 netdev_err(queue->vif->dev,
703 "Asked for %d slots but exceeds this limit\n",
704 work_to_do);
705 xenvif_fatal_tx_err(queue->vif);
706 return -ENODATA;
707 }
708
709 /* This guest is really using too many slots and
710 * considered malicious.
711 */
712 if (unlikely(slots >= fatal_skb_slots)) {
713 netdev_err(queue->vif->dev,
714 "Malicious frontend using %d slots, threshold %u\n",
715 slots, fatal_skb_slots);
716 xenvif_fatal_tx_err(queue->vif);
717 return -E2BIG;
718 }
719
720 /* Xen network protocol had implicit dependency on
721 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
722 * the historical MAX_SKB_FRAGS value 18 to honor the
723 * same behavior as before. Any packet using more than
724 * 18 slots but less than fatal_skb_slots slots is
725 * dropped
726 */
727 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
728 if (net_ratelimit())
729 netdev_dbg(queue->vif->dev,
730 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
731 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
732 drop_err = -E2BIG;
733 }
734
735 if (drop_err)
736 txp = &dropped_tx;
737
738 memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots),
739 sizeof(*txp));
740
741 /* If the guest submitted a frame >= 64 KiB then
742 * first->size overflowed and following slots will
743 * appear to be larger than the frame.
744 *
745 * This cannot be fatal error as there are buggy
746 * frontends that do this.
747 *
748 * Consume all slots and drop the packet.
749 */
750 if (!drop_err && txp->size > first->size) {
751 if (net_ratelimit())
752 netdev_dbg(queue->vif->dev,
753 "Invalid tx request, slot size %u > remaining size %u\n",
754 txp->size, first->size);
755 drop_err = -EIO;
756 }
757
758 first->size -= txp->size;
759 slots++;
760
761 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
762 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
763 txp->offset, txp->size);
764 xenvif_fatal_tx_err(queue->vif);
765 return -EINVAL;
766 }
767
768 more_data = txp->flags & XEN_NETTXF_more_data;
769
770 if (!drop_err)
771 txp++;
772
773 } while (more_data);
774
775 if (drop_err) {
776 xenvif_tx_err(queue, first, cons + slots);
777 return drop_err;
778 }
779
780 return slots;
781}
782
783
784struct xenvif_tx_cb {
785 u16 pending_idx;
786};
787
788#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
789
790static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
791 u16 pending_idx,
792 struct xen_netif_tx_request *txp,
793 struct gnttab_map_grant_ref *mop)
794{
795 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
796 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
797 GNTMAP_host_map | GNTMAP_readonly,
798 txp->gref, queue->vif->domid);
799
800 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
801 sizeof(*txp));
802}
803
804static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
805{
806 struct sk_buff *skb =
807 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
808 GFP_ATOMIC | __GFP_NOWARN);
809 if (unlikely(skb == NULL))
810 return NULL;
811
812 /* Packets passed to netif_rx() must have some headroom. */
813 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
814
815 /* Initialize it here to avoid later surprises */
816 skb_shinfo(skb)->destructor_arg = NULL;
817
818 return skb;
819}
820
821static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
822 struct sk_buff *skb,
823 struct xen_netif_tx_request *txp,
824 struct gnttab_map_grant_ref *gop,
825 unsigned int frag_overflow,
826 struct sk_buff *nskb)
827{
828 struct skb_shared_info *shinfo = skb_shinfo(skb);
829 skb_frag_t *frags = shinfo->frags;
830 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
831 int start;
832 pending_ring_idx_t index;
833 unsigned int nr_slots;
834
835 nr_slots = shinfo->nr_frags;
836
837 /* Skip first skb fragment if it is on same page as header fragment. */
838 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
839
840 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
841 shinfo->nr_frags++, txp++, gop++) {
842 index = pending_index(queue->pending_cons++);
843 pending_idx = queue->pending_ring[index];
844 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
845 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
846 }
847
848 if (frag_overflow) {
849
850 shinfo = skb_shinfo(nskb);
851 frags = shinfo->frags;
852
853 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
854 shinfo->nr_frags++, txp++, gop++) {
855 index = pending_index(queue->pending_cons++);
856 pending_idx = queue->pending_ring[index];
857 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
858 frag_set_pending_idx(&frags[shinfo->nr_frags],
859 pending_idx);
860 }
861
862 skb_shinfo(skb)->frag_list = nskb;
863 }
864
865 return gop;
866}
867
868static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
869 u16 pending_idx,
870 grant_handle_t handle)
871{
872 if (unlikely(queue->grant_tx_handle[pending_idx] !=
873 NETBACK_INVALID_HANDLE)) {
874 netdev_err(queue->vif->dev,
875 "Trying to overwrite active handle! pending_idx: 0x%x\n",
876 pending_idx);
877 BUG();
878 }
879 queue->grant_tx_handle[pending_idx] = handle;
880}
881
882static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
883 u16 pending_idx)
884{
885 if (unlikely(queue->grant_tx_handle[pending_idx] ==
886 NETBACK_INVALID_HANDLE)) {
887 netdev_err(queue->vif->dev,
888 "Trying to unmap invalid handle! pending_idx: 0x%x\n",
889 pending_idx);
890 BUG();
891 }
892 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
893}
894
895static int xenvif_tx_check_gop(struct xenvif_queue *queue,
896 struct sk_buff *skb,
897 struct gnttab_map_grant_ref **gopp_map,
898 struct gnttab_copy **gopp_copy)
899{
900 struct gnttab_map_grant_ref *gop_map = *gopp_map;
901 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
902 /* This always points to the shinfo of the skb being checked, which
903 * could be either the first or the one on the frag_list
904 */
905 struct skb_shared_info *shinfo = skb_shinfo(skb);
906 /* If this is non-NULL, we are currently checking the frag_list skb, and
907 * this points to the shinfo of the first one
908 */
909 struct skb_shared_info *first_shinfo = NULL;
910 int nr_frags = shinfo->nr_frags;
911 const bool sharedslot = nr_frags &&
912 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
913 int i, err;
914
915 /* Check status of header. */
916 err = (*gopp_copy)->status;
917 if (unlikely(err)) {
918 if (net_ratelimit())
919 netdev_dbg(queue->vif->dev,
920 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
921 (*gopp_copy)->status,
922 pending_idx,
923 (*gopp_copy)->source.u.ref);
924 /* The first frag might still have this slot mapped */
925 if (!sharedslot)
926 xenvif_idx_release(queue, pending_idx,
927 XEN_NETIF_RSP_ERROR);
928 }
929 (*gopp_copy)++;
930
931check_frags:
932 for (i = 0; i < nr_frags; i++, gop_map++) {
933 int j, newerr;
934
935 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
936
937 /* Check error status: if okay then remember grant handle. */
938 newerr = gop_map->status;
939
940 if (likely(!newerr)) {
941 xenvif_grant_handle_set(queue,
942 pending_idx,
943 gop_map->handle);
944 /* Had a previous error? Invalidate this fragment. */
945 if (unlikely(err)) {
946 xenvif_idx_unmap(queue, pending_idx);
947 /* If the mapping of the first frag was OK, but
948 * the header's copy failed, and they are
949 * sharing a slot, send an error
950 */
951 if (i == 0 && sharedslot)
952 xenvif_idx_release(queue, pending_idx,
953 XEN_NETIF_RSP_ERROR);
954 else
955 xenvif_idx_release(queue, pending_idx,
956 XEN_NETIF_RSP_OKAY);
957 }
958 continue;
959 }
960
961 /* Error on this fragment: respond to client with an error. */
962 if (net_ratelimit())
963 netdev_dbg(queue->vif->dev,
964 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
965 i,
966 gop_map->status,
967 pending_idx,
968 gop_map->ref);
969
970 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
971
972 /* Not the first error? Preceding frags already invalidated. */
973 if (err)
974 continue;
975
976 /* First error: if the header haven't shared a slot with the
977 * first frag, release it as well.
978 */
979 if (!sharedslot)
980 xenvif_idx_release(queue,
981 XENVIF_TX_CB(skb)->pending_idx,
982 XEN_NETIF_RSP_OKAY);
983
984 /* Invalidate preceding fragments of this skb. */
985 for (j = 0; j < i; j++) {
986 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
987 xenvif_idx_unmap(queue, pending_idx);
988 xenvif_idx_release(queue, pending_idx,
989 XEN_NETIF_RSP_OKAY);
990 }
991
992 /* And if we found the error while checking the frag_list, unmap
993 * the first skb's frags
994 */
995 if (first_shinfo) {
996 for (j = 0; j < first_shinfo->nr_frags; j++) {
997 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
998 xenvif_idx_unmap(queue, pending_idx);
999 xenvif_idx_release(queue, pending_idx,
1000 XEN_NETIF_RSP_OKAY);
1001 }
1002 }
1003
1004 /* Remember the error: invalidate all subsequent fragments. */
1005 err = newerr;
1006 }
1007
1008 if (skb_has_frag_list(skb) && !first_shinfo) {
1009 first_shinfo = skb_shinfo(skb);
1010 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
1011 nr_frags = shinfo->nr_frags;
1012
1013 goto check_frags;
1014 }
1015
1016 *gopp_map = gop_map;
1017 return err;
1018}
1019
1020static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
1021{
1022 struct skb_shared_info *shinfo = skb_shinfo(skb);
1023 int nr_frags = shinfo->nr_frags;
1024 int i;
1025 u16 prev_pending_idx = INVALID_PENDING_IDX;
1026
1027 for (i = 0; i < nr_frags; i++) {
1028 skb_frag_t *frag = shinfo->frags + i;
1029 struct xen_netif_tx_request *txp;
1030 struct page *page;
1031 u16 pending_idx;
1032
1033 pending_idx = frag_get_pending_idx(frag);
1034
1035 /* If this is not the first frag, chain it to the previous*/
1036 if (prev_pending_idx == INVALID_PENDING_IDX)
1037 skb_shinfo(skb)->destructor_arg =
1038 &callback_param(queue, pending_idx);
1039 else
1040 callback_param(queue, prev_pending_idx).ctx =
1041 &callback_param(queue, pending_idx);
1042
1043 callback_param(queue, pending_idx).ctx = NULL;
1044 prev_pending_idx = pending_idx;
1045
1046 txp = &queue->pending_tx_info[pending_idx].req;
1047 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
1048 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1049 skb->len += txp->size;
1050 skb->data_len += txp->size;
1051 skb->truesize += txp->size;
1052
1053 /* Take an extra reference to offset network stack's put_page */
1054 get_page(queue->mmap_pages[pending_idx]);
1055 }
1056}
1057
1058static int xenvif_get_extras(struct xenvif_queue *queue,
1059 struct xen_netif_extra_info *extras,
1060 int work_to_do)
1061{
1062 struct xen_netif_extra_info extra;
1063 RING_IDX cons = queue->tx.req_cons;
1064
1065 do {
1066 if (unlikely(work_to_do-- <= 0)) {
1067 netdev_err(queue->vif->dev, "Missing extra info\n");
1068 xenvif_fatal_tx_err(queue->vif);
1069 return -EBADR;
1070 }
1071
1072 memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons),
1073 sizeof(extra));
1074 if (unlikely(!extra.type ||
1075 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1076 queue->tx.req_cons = ++cons;
1077 netdev_err(queue->vif->dev,
1078 "Invalid extra type: %d\n", extra.type);
1079 xenvif_fatal_tx_err(queue->vif);
1080 return -EINVAL;
1081 }
1082
1083 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1084 queue->tx.req_cons = ++cons;
1085 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1086
1087 return work_to_do;
1088}
1089
1090static int xenvif_set_skb_gso(struct xenvif *vif,
1091 struct sk_buff *skb,
1092 struct xen_netif_extra_info *gso)
1093{
1094 if (!gso->u.gso.size) {
1095 netdev_err(vif->dev, "GSO size must not be zero.\n");
1096 xenvif_fatal_tx_err(vif);
1097 return -EINVAL;
1098 }
1099
1100 switch (gso->u.gso.type) {
1101 case XEN_NETIF_GSO_TYPE_TCPV4:
1102 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1103 break;
1104 case XEN_NETIF_GSO_TYPE_TCPV6:
1105 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1106 break;
1107 default:
1108 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1109 xenvif_fatal_tx_err(vif);
1110 return -EINVAL;
1111 }
1112
1113 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1114 /* gso_segs will be calculated later */
1115
1116 return 0;
1117}
1118
1119static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
1120{
1121 bool recalculate_partial_csum = false;
1122
1123 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1124 * peers can fail to set NETRXF_csum_blank when sending a GSO
1125 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1126 * recalculate the partial checksum.
1127 */
1128 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1129 queue->stats.rx_gso_checksum_fixup++;
1130 skb->ip_summed = CHECKSUM_PARTIAL;
1131 recalculate_partial_csum = true;
1132 }
1133
1134 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1135 if (skb->ip_summed != CHECKSUM_PARTIAL)
1136 return 0;
1137
1138 return skb_checksum_setup(skb, recalculate_partial_csum);
1139}
1140
1141static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
1142{
1143 u64 now = get_jiffies_64();
1144 u64 next_credit = queue->credit_window_start +
1145 msecs_to_jiffies(queue->credit_usec / 1000);
1146
1147 /* Timer could already be pending in rare cases. */
1148 if (timer_pending(&queue->credit_timeout))
1149 return true;
1150
1151 /* Passed the point where we can replenish credit? */
1152 if (time_after_eq64(now, next_credit)) {
1153 queue->credit_window_start = now;
1154 tx_add_credit(queue);
1155 }
1156
1157 /* Still too big to send right now? Set a callback. */
1158 if (size > queue->remaining_credit) {
1159 queue->credit_timeout.data =
1160 (unsigned long)queue;
1161 mod_timer(&queue->credit_timeout,
1162 next_credit);
1163 queue->credit_window_start = next_credit;
1164
1165 return true;
1166 }
1167
1168 return false;
1169}
1170
1171/* No locking is required in xenvif_mcast_add/del() as they are
1172 * only ever invoked from NAPI poll. An RCU list is used because
1173 * xenvif_mcast_match() is called asynchronously, during start_xmit.
1174 */
1175
1176static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
1177{
1178 struct xenvif_mcast_addr *mcast;
1179
1180 if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
1181 if (net_ratelimit())
1182 netdev_err(vif->dev,
1183 "Too many multicast addresses\n");
1184 return -ENOSPC;
1185 }
1186
1187 mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
1188 if (!mcast)
1189 return -ENOMEM;
1190
1191 ether_addr_copy(mcast->addr, addr);
1192 list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
1193 vif->fe_mcast_count++;
1194
1195 return 0;
1196}
1197
1198static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
1199{
1200 struct xenvif_mcast_addr *mcast;
1201
1202 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
1203 if (ether_addr_equal(addr, mcast->addr)) {
1204 --vif->fe_mcast_count;
1205 list_del_rcu(&mcast->entry);
1206 kfree_rcu(mcast, rcu);
1207 break;
1208 }
1209 }
1210}
1211
1212bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
1213{
1214 struct xenvif_mcast_addr *mcast;
1215
1216 rcu_read_lock();
1217 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
1218 if (ether_addr_equal(addr, mcast->addr)) {
1219 rcu_read_unlock();
1220 return true;
1221 }
1222 }
1223 rcu_read_unlock();
1224
1225 return false;
1226}
1227
1228void xenvif_mcast_addr_list_free(struct xenvif *vif)
1229{
1230 /* No need for locking or RCU here. NAPI poll and TX queue
1231 * are stopped.
1232 */
1233 while (!list_empty(&vif->fe_mcast_addr)) {
1234 struct xenvif_mcast_addr *mcast;
1235
1236 mcast = list_first_entry(&vif->fe_mcast_addr,
1237 struct xenvif_mcast_addr,
1238 entry);
1239 --vif->fe_mcast_count;
1240 list_del(&mcast->entry);
1241 kfree(mcast);
1242 }
1243}
1244
1245static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1246 int budget,
1247 unsigned *copy_ops,
1248 unsigned *map_ops)
1249{
1250 struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
1251 struct sk_buff *skb, *nskb;
1252 int ret;
1253 unsigned int frag_overflow;
1254
1255 while (skb_queue_len(&queue->tx_queue) < budget) {
1256 struct xen_netif_tx_request txreq;
1257 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1258 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1259 u16 pending_idx;
1260 RING_IDX idx;
1261 int work_to_do;
1262 unsigned int data_len;
1263 pending_ring_idx_t index;
1264
1265 if (queue->tx.sring->req_prod - queue->tx.req_cons >
1266 XEN_NETIF_TX_RING_SIZE) {
1267 netdev_err(queue->vif->dev,
1268 "Impossible number of requests. "
1269 "req_prod %d, req_cons %d, size %ld\n",
1270 queue->tx.sring->req_prod, queue->tx.req_cons,
1271 XEN_NETIF_TX_RING_SIZE);
1272 xenvif_fatal_tx_err(queue->vif);
1273 break;
1274 }
1275
1276 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
1277 if (!work_to_do)
1278 break;
1279
1280 idx = queue->tx.req_cons;
1281 rmb(); /* Ensure that we see the request before we copy it. */
1282 memcpy(&txreq, RING_GET_REQUEST(&queue->tx, idx), sizeof(txreq));
1283
1284 /* Credit-based scheduling. */
1285 if (txreq.size > queue->remaining_credit &&
1286 tx_credit_exceeded(queue, txreq.size))
1287 break;
1288
1289 queue->remaining_credit -= txreq.size;
1290
1291 work_to_do--;
1292 queue->tx.req_cons = ++idx;
1293
1294 memset(extras, 0, sizeof(extras));
1295 if (txreq.flags & XEN_NETTXF_extra_info) {
1296 work_to_do = xenvif_get_extras(queue, extras,
1297 work_to_do);
1298 idx = queue->tx.req_cons;
1299 if (unlikely(work_to_do < 0))
1300 break;
1301 }
1302
1303 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
1304 struct xen_netif_extra_info *extra;
1305
1306 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
1307 ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
1308
1309 make_tx_response(queue, &txreq,
1310 (ret == 0) ?
1311 XEN_NETIF_RSP_OKAY :
1312 XEN_NETIF_RSP_ERROR);
1313 push_tx_responses(queue);
1314 continue;
1315 }
1316
1317 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
1318 struct xen_netif_extra_info *extra;
1319
1320 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
1321 xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
1322
1323 make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);
1324 push_tx_responses(queue);
1325 continue;
1326 }
1327
1328 ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
1329 if (unlikely(ret < 0))
1330 break;
1331
1332 idx += ret;
1333
1334 if (unlikely(txreq.size < ETH_HLEN)) {
1335 netdev_dbg(queue->vif->dev,
1336 "Bad packet size: %d\n", txreq.size);
1337 xenvif_tx_err(queue, &txreq, idx);
1338 break;
1339 }
1340
1341 /* No crossing a page as the payload mustn't fragment. */
1342 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1343 netdev_err(queue->vif->dev,
1344 "txreq.offset: %u, size: %u, end: %lu\n",
1345 txreq.offset, txreq.size,
1346 (unsigned long)(txreq.offset&~PAGE_MASK) + txreq.size);
1347 xenvif_fatal_tx_err(queue->vif);
1348 break;
1349 }
1350
1351 index = pending_index(queue->pending_cons);
1352 pending_idx = queue->pending_ring[index];
1353
1354 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
1355 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1356 XEN_NETBACK_TX_COPY_LEN : txreq.size;
1357
1358 skb = xenvif_alloc_skb(data_len);
1359 if (unlikely(skb == NULL)) {
1360 netdev_dbg(queue->vif->dev,
1361 "Can't allocate a skb in start_xmit.\n");
1362 xenvif_tx_err(queue, &txreq, idx);
1363 break;
1364 }
1365
1366 skb_shinfo(skb)->nr_frags = ret;
1367 if (data_len < txreq.size)
1368 skb_shinfo(skb)->nr_frags++;
1369 /* At this point shinfo->nr_frags is in fact the number of
1370 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
1371 */
1372 frag_overflow = 0;
1373 nskb = NULL;
1374 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
1375 frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
1376 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
1377 skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
1378 nskb = xenvif_alloc_skb(0);
1379 if (unlikely(nskb == NULL)) {
1380 kfree_skb(skb);
1381 xenvif_tx_err(queue, &txreq, idx);
1382 if (net_ratelimit())
1383 netdev_err(queue->vif->dev,
1384 "Can't allocate the frag_list skb.\n");
1385 break;
1386 }
1387 }
1388
1389 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1390 struct xen_netif_extra_info *gso;
1391 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1392
1393 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1394 /* Failure in xenvif_set_skb_gso is fatal. */
1395 kfree_skb(skb);
1396 kfree_skb(nskb);
1397 break;
1398 }
1399 }
1400
1401 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
1402
1403 __skb_put(skb, data_len);
1404 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1405 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
1406 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1407
1408 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
1409 virt_to_gfn(skb->data);
1410 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1411 queue->tx_copy_ops[*copy_ops].dest.offset =
1412 offset_in_page(skb->data);
1413
1414 queue->tx_copy_ops[*copy_ops].len = data_len;
1415 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1416
1417 (*copy_ops)++;
1418
1419 if (data_len < txreq.size) {
1420 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1421 pending_idx);
1422 xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
1423 gop++;
1424 } else {
1425 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1426 INVALID_PENDING_IDX);
1427 memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
1428 sizeof(txreq));
1429 }
1430
1431 queue->pending_cons++;
1432
1433 gop = xenvif_get_requests(queue, skb, txfrags, gop,
1434 frag_overflow, nskb);
1435
1436 __skb_queue_tail(&queue->tx_queue, skb);
1437
1438 queue->tx.req_cons = idx;
1439
1440 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1441 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1442 break;
1443 }
1444
1445 (*map_ops) = gop - queue->tx_map_ops;
1446 return;
1447}
1448
1449/* Consolidate skb with a frag_list into a brand new one with local pages on
1450 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1451 */
1452static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1453{
1454 unsigned int offset = skb_headlen(skb);
1455 skb_frag_t frags[MAX_SKB_FRAGS];
1456 int i, f;
1457 struct ubuf_info *uarg;
1458 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1459
1460 queue->stats.tx_zerocopy_sent += 2;
1461 queue->stats.tx_frag_overflow++;
1462
1463 xenvif_fill_frags(queue, nskb);
1464 /* Subtract frags size, we will correct it later */
1465 skb->truesize -= skb->data_len;
1466 skb->len += nskb->len;
1467 skb->data_len += nskb->len;
1468
1469 /* create a brand new frags array and coalesce there */
1470 for (i = 0; offset < skb->len; i++) {
1471 struct page *page;
1472 unsigned int len;
1473
1474 BUG_ON(i >= MAX_SKB_FRAGS);
1475 page = alloc_page(GFP_ATOMIC);
1476 if (!page) {
1477 int j;
1478 skb->truesize += skb->data_len;
1479 for (j = 0; j < i; j++)
1480 put_page(frags[j].page.p);
1481 return -ENOMEM;
1482 }
1483
1484 if (offset + PAGE_SIZE < skb->len)
1485 len = PAGE_SIZE;
1486 else
1487 len = skb->len - offset;
1488 if (skb_copy_bits(skb, offset, page_address(page), len))
1489 BUG();
1490
1491 offset += len;
1492 frags[i].page.p = page;
1493 frags[i].page_offset = 0;
1494 skb_frag_size_set(&frags[i], len);
1495 }
1496
1497 /* Copied all the bits from the frag list -- free it. */
1498 skb_frag_list_init(skb);
1499 xenvif_skb_zerocopy_prepare(queue, nskb);
1500 kfree_skb(nskb);
1501
1502 /* Release all the original (foreign) frags. */
1503 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1504 skb_frag_unref(skb, f);
1505 uarg = skb_shinfo(skb)->destructor_arg;
1506 /* increase inflight counter to offset decrement in callback */
1507 atomic_inc(&queue->inflight_packets);
1508 uarg->callback(uarg, true);
1509 skb_shinfo(skb)->destructor_arg = NULL;
1510
1511 /* Fill the skb with the new (local) frags. */
1512 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1513 skb_shinfo(skb)->nr_frags = i;
1514 skb->truesize += i * PAGE_SIZE;
1515
1516 return 0;
1517}
1518
1519static int xenvif_tx_submit(struct xenvif_queue *queue)
1520{
1521 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1522 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1523 struct sk_buff *skb;
1524 int work_done = 0;
1525
1526 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1527 struct xen_netif_tx_request *txp;
1528 u16 pending_idx;
1529 unsigned data_len;
1530
1531 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1532 txp = &queue->pending_tx_info[pending_idx].req;
1533
1534 /* Check the remap error code. */
1535 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1536 /* If there was an error, xenvif_tx_check_gop is
1537 * expected to release all the frags which were mapped,
1538 * so kfree_skb shouldn't do it again
1539 */
1540 skb_shinfo(skb)->nr_frags = 0;
1541 if (skb_has_frag_list(skb)) {
1542 struct sk_buff *nskb =
1543 skb_shinfo(skb)->frag_list;
1544 skb_shinfo(nskb)->nr_frags = 0;
1545 }
1546 kfree_skb(skb);
1547 continue;
1548 }
1549
1550 data_len = skb->len;
1551 callback_param(queue, pending_idx).ctx = NULL;
1552 if (data_len < txp->size) {
1553 /* Append the packet payload as a fragment. */
1554 txp->offset += data_len;
1555 txp->size -= data_len;
1556 } else {
1557 /* Schedule a response immediately. */
1558 xenvif_idx_release(queue, pending_idx,
1559 XEN_NETIF_RSP_OKAY);
1560 }
1561
1562 if (txp->flags & XEN_NETTXF_csum_blank)
1563 skb->ip_summed = CHECKSUM_PARTIAL;
1564 else if (txp->flags & XEN_NETTXF_data_validated)
1565 skb->ip_summed = CHECKSUM_UNNECESSARY;
1566
1567 xenvif_fill_frags(queue, skb);
1568
1569 if (unlikely(skb_has_frag_list(skb))) {
1570 if (xenvif_handle_frag_list(queue, skb)) {
1571 if (net_ratelimit())
1572 netdev_err(queue->vif->dev,
1573 "Not enough memory to consolidate frag_list!\n");
1574 xenvif_skb_zerocopy_prepare(queue, skb);
1575 kfree_skb(skb);
1576 continue;
1577 }
1578 }
1579
1580 skb->dev = queue->vif->dev;
1581 skb->protocol = eth_type_trans(skb, skb->dev);
1582 skb_reset_network_header(skb);
1583
1584 if (checksum_setup(queue, skb)) {
1585 netdev_dbg(queue->vif->dev,
1586 "Can't setup checksum in net_tx_action\n");
1587 /* We have to set this flag to trigger the callback */
1588 if (skb_shinfo(skb)->destructor_arg)
1589 xenvif_skb_zerocopy_prepare(queue, skb);
1590 kfree_skb(skb);
1591 continue;
1592 }
1593
1594 skb_probe_transport_header(skb, 0);
1595
1596 /* If the packet is GSO then we will have just set up the
1597 * transport header offset in checksum_setup so it's now
1598 * straightforward to calculate gso_segs.
1599 */
1600 if (skb_is_gso(skb)) {
1601 int mss = skb_shinfo(skb)->gso_size;
1602 int hdrlen = skb_transport_header(skb) -
1603 skb_mac_header(skb) +
1604 tcp_hdrlen(skb);
1605
1606 skb_shinfo(skb)->gso_segs =
1607 DIV_ROUND_UP(skb->len - hdrlen, mss);
1608 }
1609
1610 queue->stats.rx_bytes += skb->len;
1611 queue->stats.rx_packets++;
1612
1613 work_done++;
1614
1615 /* Set this flag right before netif_receive_skb, otherwise
1616 * someone might think this packet already left netback, and
1617 * do a skb_copy_ubufs while we are still in control of the
1618 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1619 */
1620 if (skb_shinfo(skb)->destructor_arg) {
1621 xenvif_skb_zerocopy_prepare(queue, skb);
1622 queue->stats.tx_zerocopy_sent++;
1623 }
1624
1625 netif_receive_skb(skb);
1626 }
1627
1628 return work_done;
1629}
1630
1631void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1632{
1633 unsigned long flags;
1634 pending_ring_idx_t index;
1635 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1636
1637 /* This is the only place where we grab this lock, to protect callbacks
1638 * from each other.
1639 */
1640 spin_lock_irqsave(&queue->callback_lock, flags);
1641 do {
1642 u16 pending_idx = ubuf->desc;
1643 ubuf = (struct ubuf_info *) ubuf->ctx;
1644 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1645 MAX_PENDING_REQS);
1646 index = pending_index(queue->dealloc_prod);
1647 queue->dealloc_ring[index] = pending_idx;
1648 /* Sync with xenvif_tx_dealloc_action:
1649 * insert idx then incr producer.
1650 */
1651 smp_wmb();
1652 queue->dealloc_prod++;
1653 } while (ubuf);
1654 spin_unlock_irqrestore(&queue->callback_lock, flags);
1655
1656 if (likely(zerocopy_success))
1657 queue->stats.tx_zerocopy_success++;
1658 else
1659 queue->stats.tx_zerocopy_fail++;
1660 xenvif_skb_zerocopy_complete(queue);
1661}
1662
1663static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1664{
1665 struct gnttab_unmap_grant_ref *gop;
1666 pending_ring_idx_t dc, dp;
1667 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1668 unsigned int i = 0;
1669
1670 dc = queue->dealloc_cons;
1671 gop = queue->tx_unmap_ops;
1672
1673 /* Free up any grants we have finished using */
1674 do {
1675 dp = queue->dealloc_prod;
1676
1677 /* Ensure we see all indices enqueued by all
1678 * xenvif_zerocopy_callback().
1679 */
1680 smp_rmb();
1681
1682 while (dc != dp) {
1683 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1684 pending_idx =
1685 queue->dealloc_ring[pending_index(dc++)];
1686
1687 pending_idx_release[gop - queue->tx_unmap_ops] =
1688 pending_idx;
1689 queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1690 queue->mmap_pages[pending_idx];
1691 gnttab_set_unmap_op(gop,
1692 idx_to_kaddr(queue, pending_idx),
1693 GNTMAP_host_map,
1694 queue->grant_tx_handle[pending_idx]);
1695 xenvif_grant_handle_reset(queue, pending_idx);
1696 ++gop;
1697 }
1698
1699 } while (dp != queue->dealloc_prod);
1700
1701 queue->dealloc_cons = dc;
1702
1703 if (gop - queue->tx_unmap_ops > 0) {
1704 int ret;
1705 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1706 NULL,
1707 queue->pages_to_unmap,
1708 gop - queue->tx_unmap_ops);
1709 if (ret) {
1710 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1711 gop - queue->tx_unmap_ops, ret);
1712 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1713 if (gop[i].status != GNTST_okay)
1714 netdev_err(queue->vif->dev,
1715 " host_addr: 0x%llx handle: 0x%x status: %d\n",
1716 gop[i].host_addr,
1717 gop[i].handle,
1718 gop[i].status);
1719 }
1720 BUG();
1721 }
1722 }
1723
1724 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1725 xenvif_idx_release(queue, pending_idx_release[i],
1726 XEN_NETIF_RSP_OKAY);
1727}
1728
1729
1730/* Called after netfront has transmitted */
1731int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1732{
1733 unsigned nr_mops, nr_cops = 0;
1734 int work_done, ret;
1735
1736 if (unlikely(!tx_work_todo(queue)))
1737 return 0;
1738
1739 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1740
1741 if (nr_cops == 0)
1742 return 0;
1743
1744 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1745 if (nr_mops != 0) {
1746 ret = gnttab_map_refs(queue->tx_map_ops,
1747 NULL,
1748 queue->pages_to_map,
1749 nr_mops);
1750 BUG_ON(ret);
1751 }
1752
1753 work_done = xenvif_tx_submit(queue);
1754
1755 return work_done;
1756}
1757
1758static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1759 u8 status)
1760{
1761 struct pending_tx_info *pending_tx_info;
1762 pending_ring_idx_t index;
1763 unsigned long flags;
1764
1765 pending_tx_info = &queue->pending_tx_info[pending_idx];
1766
1767 spin_lock_irqsave(&queue->response_lock, flags);
1768
1769 make_tx_response(queue, &pending_tx_info->req, status);
1770
1771 /* Release the pending index before pusing the Tx response so
1772 * its available before a new Tx request is pushed by the
1773 * frontend.
1774 */
1775 index = pending_index(queue->pending_prod++);
1776 queue->pending_ring[index] = pending_idx;
1777
1778 push_tx_responses(queue);
1779
1780 spin_unlock_irqrestore(&queue->response_lock, flags);
1781}
1782
1783
1784static void make_tx_response(struct xenvif_queue *queue,
1785 struct xen_netif_tx_request *txp,
1786 s8 st)
1787{
1788 RING_IDX i = queue->tx.rsp_prod_pvt;
1789 struct xen_netif_tx_response *resp;
1790
1791 resp = RING_GET_RESPONSE(&queue->tx, i);
1792 resp->id = txp->id;
1793 resp->status = st;
1794
1795 if (txp->flags & XEN_NETTXF_extra_info)
1796 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1797
1798 queue->tx.rsp_prod_pvt = ++i;
1799}
1800
1801static void push_tx_responses(struct xenvif_queue *queue)
1802{
1803 int notify;
1804
1805 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1806 if (notify)
1807 notify_remote_via_irq(queue->tx_irq);
1808}
1809
1810static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
1811 u16 id,
1812 s8 st,
1813 u16 offset,
1814 u16 size,
1815 u16 flags)
1816{
1817 RING_IDX i = queue->rx.rsp_prod_pvt;
1818 struct xen_netif_rx_response *resp;
1819
1820 resp = RING_GET_RESPONSE(&queue->rx, i);
1821 resp->offset = offset;
1822 resp->flags = flags;
1823 resp->id = id;
1824 resp->status = (s16)size;
1825 if (st < 0)
1826 resp->status = (s16)st;
1827
1828 queue->rx.rsp_prod_pvt = ++i;
1829
1830 return resp;
1831}
1832
1833void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1834{
1835 int ret;
1836 struct gnttab_unmap_grant_ref tx_unmap_op;
1837
1838 gnttab_set_unmap_op(&tx_unmap_op,
1839 idx_to_kaddr(queue, pending_idx),
1840 GNTMAP_host_map,
1841 queue->grant_tx_handle[pending_idx]);
1842 xenvif_grant_handle_reset(queue, pending_idx);
1843
1844 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1845 &queue->mmap_pages[pending_idx], 1);
1846 if (ret) {
1847 netdev_err(queue->vif->dev,
1848 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1849 ret,
1850 pending_idx,
1851 tx_unmap_op.host_addr,
1852 tx_unmap_op.handle,
1853 tx_unmap_op.status);
1854 BUG();
1855 }
1856}
1857
1858static inline int tx_work_todo(struct xenvif_queue *queue)
1859{
1860 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1861 return 1;
1862
1863 return 0;
1864}
1865
1866static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1867{
1868 return queue->dealloc_cons != queue->dealloc_prod;
1869}
1870
1871void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
1872{
1873 if (queue->tx.sring)
1874 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1875 queue->tx.sring);
1876 if (queue->rx.sring)
1877 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1878 queue->rx.sring);
1879}
1880
1881int xenvif_map_frontend_rings(struct xenvif_queue *queue,
1882 grant_ref_t tx_ring_ref,
1883 grant_ref_t rx_ring_ref)
1884{
1885 void *addr;
1886 struct xen_netif_tx_sring *txs;
1887 struct xen_netif_rx_sring *rxs;
1888
1889 int err = -ENOMEM;
1890
1891 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1892 &tx_ring_ref, 1, &addr);
1893 if (err)
1894 goto err;
1895
1896 txs = (struct xen_netif_tx_sring *)addr;
1897 BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);
1898
1899 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1900 &rx_ring_ref, 1, &addr);
1901 if (err)
1902 goto err;
1903
1904 rxs = (struct xen_netif_rx_sring *)addr;
1905 BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE);
1906
1907 return 0;
1908
1909err:
1910 xenvif_unmap_frontend_rings(queue);
1911 return err;
1912}
1913
1914static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
1915{
1916 struct xenvif *vif = queue->vif;
1917
1918 queue->stalled = true;
1919
1920 /* At least one queue has stalled? Disable the carrier. */
1921 spin_lock(&vif->lock);
1922 if (vif->stalled_queues++ == 0) {
1923 netdev_info(vif->dev, "Guest Rx stalled");
1924 netif_carrier_off(vif->dev);
1925 }
1926 spin_unlock(&vif->lock);
1927}
1928
1929static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
1930{
1931 struct xenvif *vif = queue->vif;
1932
1933 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
1934 queue->stalled = false;
1935
1936 /* All queues are ready? Enable the carrier. */
1937 spin_lock(&vif->lock);
1938 if (--vif->stalled_queues == 0) {
1939 netdev_info(vif->dev, "Guest Rx ready");
1940 netif_carrier_on(vif->dev);
1941 }
1942 spin_unlock(&vif->lock);
1943}
1944
1945static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
1946{
1947 RING_IDX prod, cons;
1948
1949 prod = queue->rx.sring->req_prod;
1950 cons = queue->rx.req_cons;
1951
1952 return !queue->stalled && prod - cons < 1
1953 && time_after(jiffies,
1954 queue->last_rx_time + queue->vif->stall_timeout);
1955}
1956
1957static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
1958{
1959 RING_IDX prod, cons;
1960
1961 prod = queue->rx.sring->req_prod;
1962 cons = queue->rx.req_cons;
1963
1964 return queue->stalled && prod - cons >= 1;
1965}
1966
1967static bool xenvif_have_rx_work(struct xenvif_queue *queue)
1968{
1969 return (!skb_queue_empty(&queue->rx_queue)
1970 && xenvif_rx_ring_slots_available(queue))
1971 || (queue->vif->stall_timeout &&
1972 (xenvif_rx_queue_stalled(queue)
1973 || xenvif_rx_queue_ready(queue)))
1974 || kthread_should_stop()
1975 || queue->vif->disabled;
1976}
1977
1978static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
1979{
1980 struct sk_buff *skb;
1981 long timeout;
1982
1983 skb = skb_peek(&queue->rx_queue);
1984 if (!skb)
1985 return MAX_SCHEDULE_TIMEOUT;
1986
1987 timeout = XENVIF_RX_CB(skb)->expires - jiffies;
1988 return timeout < 0 ? 0 : timeout;
1989}
1990
1991/* Wait until the guest Rx thread has work.
1992 *
1993 * The timeout needs to be adjusted based on the current head of the
1994 * queue (and not just the head at the beginning). In particular, if
1995 * the queue is initially empty an infinite timeout is used and this
1996 * needs to be reduced when a skb is queued.
1997 *
1998 * This cannot be done with wait_event_timeout() because it only
1999 * calculates the timeout once.
2000 */
2001static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
2002{
2003 DEFINE_WAIT(wait);
2004
2005 if (xenvif_have_rx_work(queue))
2006 return;
2007
2008 for (;;) {
2009 long ret;
2010
2011 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
2012 if (xenvif_have_rx_work(queue))
2013 break;
2014 ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
2015 if (!ret)
2016 break;
2017 }
2018 finish_wait(&queue->wq, &wait);
2019}
2020
2021int xenvif_kthread_guest_rx(void *data)
2022{
2023 struct xenvif_queue *queue = data;
2024 struct xenvif *vif = queue->vif;
2025
2026 if (!vif->stall_timeout)
2027 xenvif_queue_carrier_on(queue);
2028
2029 for (;;) {
2030 xenvif_wait_for_rx_work(queue);
2031
2032 if (kthread_should_stop())
2033 break;
2034
2035 /* This frontend is found to be rogue, disable it in
2036 * kthread context. Currently this is only set when
2037 * netback finds out frontend sends malformed packet,
2038 * but we cannot disable the interface in softirq
2039 * context so we defer it here, if this thread is
2040 * associated with queue 0.
2041 */
2042 if (unlikely(vif->disabled && queue->id == 0)) {
2043 xenvif_carrier_off(vif);
2044 break;
2045 }
2046
2047 if (!skb_queue_empty(&queue->rx_queue))
2048 xenvif_rx_action(queue);
2049
2050 /* If the guest hasn't provided any Rx slots for a
2051 * while it's probably not responsive, drop the
2052 * carrier so packets are dropped earlier.
2053 */
2054 if (vif->stall_timeout) {
2055 if (xenvif_rx_queue_stalled(queue))
2056 xenvif_queue_carrier_off(queue);
2057 else if (xenvif_rx_queue_ready(queue))
2058 xenvif_queue_carrier_on(queue);
2059 }
2060
2061 /* Queued packets may have foreign pages from other
2062 * domains. These cannot be queued indefinitely as
2063 * this would starve guests of grant refs and transmit
2064 * slots.
2065 */
2066 xenvif_rx_queue_drop_expired(queue);
2067
2068 xenvif_rx_queue_maybe_wake(queue);
2069
2070 cond_resched();
2071 }
2072
2073 /* Bin any remaining skbs */
2074 xenvif_rx_queue_purge(queue);
2075
2076 return 0;
2077}
2078
2079static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
2080{
2081 /* Dealloc thread must remain running until all inflight
2082 * packets complete.
2083 */
2084 return kthread_should_stop() &&
2085 !atomic_read(&queue->inflight_packets);
2086}
2087
2088int xenvif_dealloc_kthread(void *data)
2089{
2090 struct xenvif_queue *queue = data;
2091
2092 for (;;) {
2093 wait_event_interruptible(queue->dealloc_wq,
2094 tx_dealloc_work_todo(queue) ||
2095 xenvif_dealloc_kthread_should_stop(queue));
2096 if (xenvif_dealloc_kthread_should_stop(queue))
2097 break;
2098
2099 xenvif_tx_dealloc_action(queue);
2100 cond_resched();
2101 }
2102
2103 /* Unmap anything remaining*/
2104 if (tx_dealloc_work_todo(queue))
2105 xenvif_tx_dealloc_action(queue);
2106
2107 return 0;
2108}
2109
2110static int __init netback_init(void)
2111{
2112 int rc = 0;
2113
2114 if (!xen_domain())
2115 return -ENODEV;
2116
2117 /* Allow as many queues as there are CPUs if user has not
2118 * specified a value.
2119 */
2120 if (xenvif_max_queues == 0)
2121 xenvif_max_queues = num_online_cpus();
2122
2123 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
2124 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
2125 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
2126 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
2127 }
2128
2129 rc = xenvif_xenbus_init();
2130 if (rc)
2131 goto failed_init;
2132
2133#ifdef CONFIG_DEBUG_FS
2134 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
2135 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
2136 pr_warn("Init of debugfs returned %ld!\n",
2137 PTR_ERR(xen_netback_dbg_root));
2138#endif /* CONFIG_DEBUG_FS */
2139
2140 return 0;
2141
2142failed_init:
2143 return rc;
2144}
2145
2146module_init(netback_init);
2147
2148static void __exit netback_fini(void)
2149{
2150#ifdef CONFIG_DEBUG_FS
2151 if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
2152 debugfs_remove_recursive(xen_netback_dbg_root);
2153#endif /* CONFIG_DEBUG_FS */
2154 xenvif_xenbus_fini();
2155}
2156module_exit(netback_fini);
2157
2158MODULE_LICENSE("Dual BSD/GPL");
2159MODULE_ALIAS("xen-backend:vif");
Linux 6.x block layer and io_uring tree(s)