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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
70#define MAX_QUEUES_DEFAULT 8
71unsigned int xenvif_max_queues;
72module_param_named(max_queues, xenvif_max_queues, uint, 0644);
73MODULE_PARM_DESC(max_queues,
74 "Maximum number of queues per virtual interface");
75
76/*
77 * This is the maximum slots a skb can have. If a guest sends a skb
78 * which exceeds this limit it is considered malicious.
79 */
80#define FATAL_SKB_SLOTS_DEFAULT 20
81static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
82module_param(fatal_skb_slots, uint, 0444);
83
84/* The amount to copy out of the first guest Tx slot into the skb's
85 * linear area. If the first slot has more data, it will be mapped
86 * and put into the first frag.
87 *
88 * This is sized to avoid pulling headers from the frags for most
89 * TCP/IP packets.
90 */
91#define XEN_NETBACK_TX_COPY_LEN 128
92
93/* This is the maximum number of flows in the hash cache. */
94#define XENVIF_HASH_CACHE_SIZE_DEFAULT 64
95unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
96module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
97MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
98
99/* The module parameter tells that we have to put data
100 * for xen-netfront with the XDP_PACKET_HEADROOM offset
101 * needed for XDP processing
102 */
103bool provides_xdp_headroom = true;
104module_param(provides_xdp_headroom, bool, 0644);
105
106static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
107 u8 status);
108
109static void make_tx_response(struct xenvif_queue *queue,
110 struct xen_netif_tx_request *txp,
111 unsigned int extra_count,
112 s8 st);
113static void push_tx_responses(struct xenvif_queue *queue);
114
115static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
116
117static inline int tx_work_todo(struct xenvif_queue *queue);
118
119static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
120 u16 idx)
121{
122 return page_to_pfn(queue->mmap_pages[idx]);
123}
124
125static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
126 u16 idx)
127{
128 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
129}
130
131#define callback_param(vif, pending_idx) \
132 (vif->pending_tx_info[pending_idx].callback_struct)
133
134/* Find the containing VIF's structure from a pointer in pending_tx_info array
135 */
136static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info_msgzc *ubuf)
137{
138 u16 pending_idx = ubuf->desc;
139 struct pending_tx_info *temp =
140 container_of(ubuf, struct pending_tx_info, callback_struct);
141 return container_of(temp - pending_idx,
142 struct xenvif_queue,
143 pending_tx_info[0]);
144}
145
146static u16 frag_get_pending_idx(skb_frag_t *frag)
147{
148 return (u16)skb_frag_off(frag);
149}
150
151static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
152{
153 skb_frag_off_set(frag, pending_idx);
154}
155
156static inline pending_ring_idx_t pending_index(unsigned i)
157{
158 return i & (MAX_PENDING_REQS-1);
159}
160
161void xenvif_kick_thread(struct xenvif_queue *queue)
162{
163 wake_up(&queue->wq);
164}
165
166void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
167{
168 int more_to_do;
169
170 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
171
172 if (more_to_do)
173 napi_schedule(&queue->napi);
174 else if (atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
175 &queue->eoi_pending) &
176 (NETBK_TX_EOI | NETBK_COMMON_EOI))
177 xen_irq_lateeoi(queue->tx_irq, 0);
178}
179
180static void tx_add_credit(struct xenvif_queue *queue)
181{
182 unsigned long max_burst, max_credit;
183
184 /*
185 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
186 * Otherwise the interface can seize up due to insufficient credit.
187 */
188 max_burst = max(131072UL, queue->credit_bytes);
189
190 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
191 max_credit = queue->remaining_credit + queue->credit_bytes;
192 if (max_credit < queue->remaining_credit)
193 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
194
195 queue->remaining_credit = min(max_credit, max_burst);
196 queue->rate_limited = false;
197}
198
199void xenvif_tx_credit_callback(struct timer_list *t)
200{
201 struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
202 tx_add_credit(queue);
203 xenvif_napi_schedule_or_enable_events(queue);
204}
205
206static void xenvif_tx_err(struct xenvif_queue *queue,
207 struct xen_netif_tx_request *txp,
208 unsigned int extra_count, RING_IDX end)
209{
210 RING_IDX cons = queue->tx.req_cons;
211 unsigned long flags;
212
213 do {
214 spin_lock_irqsave(&queue->response_lock, flags);
215 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
216 push_tx_responses(queue);
217 spin_unlock_irqrestore(&queue->response_lock, flags);
218 if (cons == end)
219 break;
220 RING_COPY_REQUEST(&queue->tx, cons++, txp);
221 extra_count = 0; /* only the first frag can have extras */
222 } while (1);
223 queue->tx.req_cons = cons;
224}
225
226static void xenvif_fatal_tx_err(struct xenvif *vif)
227{
228 netdev_err(vif->dev, "fatal error; disabling device\n");
229 vif->disabled = true;
230 /* Disable the vif from queue 0's kthread */
231 if (vif->num_queues)
232 xenvif_kick_thread(&vif->queues[0]);
233}
234
235static int xenvif_count_requests(struct xenvif_queue *queue,
236 struct xen_netif_tx_request *first,
237 unsigned int extra_count,
238 struct xen_netif_tx_request *txp,
239 int work_to_do)
240{
241 RING_IDX cons = queue->tx.req_cons;
242 int slots = 0;
243 int drop_err = 0;
244 int more_data;
245
246 if (!(first->flags & XEN_NETTXF_more_data))
247 return 0;
248
249 do {
250 struct xen_netif_tx_request dropped_tx = { 0 };
251
252 if (slots >= work_to_do) {
253 netdev_err(queue->vif->dev,
254 "Asked for %d slots but exceeds this limit\n",
255 work_to_do);
256 xenvif_fatal_tx_err(queue->vif);
257 return -ENODATA;
258 }
259
260 /* This guest is really using too many slots and
261 * considered malicious.
262 */
263 if (unlikely(slots >= fatal_skb_slots)) {
264 netdev_err(queue->vif->dev,
265 "Malicious frontend using %d slots, threshold %u\n",
266 slots, fatal_skb_slots);
267 xenvif_fatal_tx_err(queue->vif);
268 return -E2BIG;
269 }
270
271 /* Xen network protocol had implicit dependency on
272 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
273 * the historical MAX_SKB_FRAGS value 18 to honor the
274 * same behavior as before. Any packet using more than
275 * 18 slots but less than fatal_skb_slots slots is
276 * dropped
277 */
278 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
279 if (net_ratelimit())
280 netdev_dbg(queue->vif->dev,
281 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
282 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
283 drop_err = -E2BIG;
284 }
285
286 if (drop_err)
287 txp = &dropped_tx;
288
289 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
290
291 /* If the guest submitted a frame >= 64 KiB then
292 * first->size overflowed and following slots will
293 * appear to be larger than the frame.
294 *
295 * This cannot be fatal error as there are buggy
296 * frontends that do this.
297 *
298 * Consume all slots and drop the packet.
299 */
300 if (!drop_err && txp->size > first->size) {
301 if (net_ratelimit())
302 netdev_dbg(queue->vif->dev,
303 "Invalid tx request, slot size %u > remaining size %u\n",
304 txp->size, first->size);
305 drop_err = -EIO;
306 }
307
308 first->size -= txp->size;
309 slots++;
310
311 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
312 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
313 txp->offset, txp->size);
314 xenvif_fatal_tx_err(queue->vif);
315 return -EINVAL;
316 }
317
318 more_data = txp->flags & XEN_NETTXF_more_data;
319
320 if (!drop_err)
321 txp++;
322
323 } while (more_data);
324
325 if (drop_err) {
326 xenvif_tx_err(queue, first, extra_count, cons + slots);
327 return drop_err;
328 }
329
330 return slots;
331}
332
333
334struct xenvif_tx_cb {
335 u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1];
336 u8 copy_count;
337};
338
339#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
340#define copy_pending_idx(skb, i) (XENVIF_TX_CB(skb)->copy_pending_idx[i])
341#define copy_count(skb) (XENVIF_TX_CB(skb)->copy_count)
342
343static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
344 u16 pending_idx,
345 struct xen_netif_tx_request *txp,
346 unsigned int extra_count,
347 struct gnttab_map_grant_ref *mop)
348{
349 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
350 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
351 GNTMAP_host_map | GNTMAP_readonly,
352 txp->gref, queue->vif->domid);
353
354 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
355 sizeof(*txp));
356 queue->pending_tx_info[pending_idx].extra_count = extra_count;
357}
358
359static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
360{
361 struct sk_buff *skb =
362 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
363 GFP_ATOMIC | __GFP_NOWARN);
364 if (unlikely(skb == NULL))
365 return NULL;
366
367 /* Packets passed to netif_rx() must have some headroom. */
368 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
369
370 /* Initialize it here to avoid later surprises */
371 skb_shinfo(skb)->destructor_arg = NULL;
372
373 return skb;
374}
375
376static void xenvif_get_requests(struct xenvif_queue *queue,
377 struct sk_buff *skb,
378 struct xen_netif_tx_request *first,
379 struct xen_netif_tx_request *txfrags,
380 unsigned *copy_ops,
381 unsigned *map_ops,
382 unsigned int frag_overflow,
383 struct sk_buff *nskb,
384 unsigned int extra_count,
385 unsigned int data_len)
386{
387 struct skb_shared_info *shinfo = skb_shinfo(skb);
388 skb_frag_t *frags = shinfo->frags;
389 u16 pending_idx;
390 pending_ring_idx_t index;
391 unsigned int nr_slots;
392 struct gnttab_copy *cop = queue->tx_copy_ops + *copy_ops;
393 struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
394 struct xen_netif_tx_request *txp = first;
395
396 nr_slots = shinfo->nr_frags + 1;
397
398 copy_count(skb) = 0;
399
400 /* Create copy ops for exactly data_len bytes into the skb head. */
401 __skb_put(skb, data_len);
402 while (data_len > 0) {
403 int amount = data_len > txp->size ? txp->size : data_len;
404
405 cop->source.u.ref = txp->gref;
406 cop->source.domid = queue->vif->domid;
407 cop->source.offset = txp->offset;
408
409 cop->dest.domid = DOMID_SELF;
410 cop->dest.offset = (offset_in_page(skb->data +
411 skb_headlen(skb) -
412 data_len)) & ~XEN_PAGE_MASK;
413 cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb)
414 - data_len);
415
416 cop->len = amount;
417 cop->flags = GNTCOPY_source_gref;
418
419 index = pending_index(queue->pending_cons);
420 pending_idx = queue->pending_ring[index];
421 callback_param(queue, pending_idx).ctx = NULL;
422 copy_pending_idx(skb, copy_count(skb)) = pending_idx;
423 copy_count(skb)++;
424
425 cop++;
426 data_len -= amount;
427
428 if (amount == txp->size) {
429 /* The copy op covered the full tx_request */
430
431 memcpy(&queue->pending_tx_info[pending_idx].req,
432 txp, sizeof(*txp));
433 queue->pending_tx_info[pending_idx].extra_count =
434 (txp == first) ? extra_count : 0;
435
436 if (txp == first)
437 txp = txfrags;
438 else
439 txp++;
440 queue->pending_cons++;
441 nr_slots--;
442 } else {
443 /* The copy op partially covered the tx_request.
444 * The remainder will be mapped.
445 */
446 txp->offset += amount;
447 txp->size -= amount;
448 }
449 }
450
451 for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
452 shinfo->nr_frags++, gop++) {
453 index = pending_index(queue->pending_cons++);
454 pending_idx = queue->pending_ring[index];
455 xenvif_tx_create_map_op(queue, pending_idx, txp,
456 txp == first ? extra_count : 0, gop);
457 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
458
459 if (txp == first)
460 txp = txfrags;
461 else
462 txp++;
463 }
464
465 if (frag_overflow) {
466
467 shinfo = skb_shinfo(nskb);
468 frags = shinfo->frags;
469
470 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
471 shinfo->nr_frags++, txp++, gop++) {
472 index = pending_index(queue->pending_cons++);
473 pending_idx = queue->pending_ring[index];
474 xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
475 gop);
476 frag_set_pending_idx(&frags[shinfo->nr_frags],
477 pending_idx);
478 }
479
480 skb_shinfo(skb)->frag_list = nskb;
481 }
482
483 (*copy_ops) = cop - queue->tx_copy_ops;
484 (*map_ops) = gop - queue->tx_map_ops;
485}
486
487static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
488 u16 pending_idx,
489 grant_handle_t handle)
490{
491 if (unlikely(queue->grant_tx_handle[pending_idx] !=
492 NETBACK_INVALID_HANDLE)) {
493 netdev_err(queue->vif->dev,
494 "Trying to overwrite active handle! pending_idx: 0x%x\n",
495 pending_idx);
496 BUG();
497 }
498 queue->grant_tx_handle[pending_idx] = handle;
499}
500
501static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
502 u16 pending_idx)
503{
504 if (unlikely(queue->grant_tx_handle[pending_idx] ==
505 NETBACK_INVALID_HANDLE)) {
506 netdev_err(queue->vif->dev,
507 "Trying to unmap invalid handle! pending_idx: 0x%x\n",
508 pending_idx);
509 BUG();
510 }
511 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
512}
513
514static int xenvif_tx_check_gop(struct xenvif_queue *queue,
515 struct sk_buff *skb,
516 struct gnttab_map_grant_ref **gopp_map,
517 struct gnttab_copy **gopp_copy)
518{
519 struct gnttab_map_grant_ref *gop_map = *gopp_map;
520 u16 pending_idx;
521 /* This always points to the shinfo of the skb being checked, which
522 * could be either the first or the one on the frag_list
523 */
524 struct skb_shared_info *shinfo = skb_shinfo(skb);
525 /* If this is non-NULL, we are currently checking the frag_list skb, and
526 * this points to the shinfo of the first one
527 */
528 struct skb_shared_info *first_shinfo = NULL;
529 int nr_frags = shinfo->nr_frags;
530 const bool sharedslot = nr_frags &&
531 frag_get_pending_idx(&shinfo->frags[0]) ==
532 copy_pending_idx(skb, copy_count(skb) - 1);
533 int i, err = 0;
534
535 for (i = 0; i < copy_count(skb); i++) {
536 int newerr;
537
538 /* Check status of header. */
539 pending_idx = copy_pending_idx(skb, i);
540
541 newerr = (*gopp_copy)->status;
542 if (likely(!newerr)) {
543 /* The first frag might still have this slot mapped */
544 if (i < copy_count(skb) - 1 || !sharedslot)
545 xenvif_idx_release(queue, pending_idx,
546 XEN_NETIF_RSP_OKAY);
547 } else {
548 err = newerr;
549 if (net_ratelimit())
550 netdev_dbg(queue->vif->dev,
551 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
552 (*gopp_copy)->status,
553 pending_idx,
554 (*gopp_copy)->source.u.ref);
555 /* The first frag might still have this slot mapped */
556 if (i < copy_count(skb) - 1 || !sharedslot)
557 xenvif_idx_release(queue, pending_idx,
558 XEN_NETIF_RSP_ERROR);
559 }
560 (*gopp_copy)++;
561 }
562
563check_frags:
564 for (i = 0; i < nr_frags; i++, gop_map++) {
565 int j, newerr;
566
567 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
568
569 /* Check error status: if okay then remember grant handle. */
570 newerr = gop_map->status;
571
572 if (likely(!newerr)) {
573 xenvif_grant_handle_set(queue,
574 pending_idx,
575 gop_map->handle);
576 /* Had a previous error? Invalidate this fragment. */
577 if (unlikely(err)) {
578 xenvif_idx_unmap(queue, pending_idx);
579 /* If the mapping of the first frag was OK, but
580 * the header's copy failed, and they are
581 * sharing a slot, send an error
582 */
583 if (i == 0 && !first_shinfo && sharedslot)
584 xenvif_idx_release(queue, pending_idx,
585 XEN_NETIF_RSP_ERROR);
586 else
587 xenvif_idx_release(queue, pending_idx,
588 XEN_NETIF_RSP_OKAY);
589 }
590 continue;
591 }
592
593 /* Error on this fragment: respond to client with an error. */
594 if (net_ratelimit())
595 netdev_dbg(queue->vif->dev,
596 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
597 i,
598 gop_map->status,
599 pending_idx,
600 gop_map->ref);
601
602 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
603
604 /* Not the first error? Preceding frags already invalidated. */
605 if (err)
606 continue;
607
608 /* Invalidate preceding fragments of this skb. */
609 for (j = 0; j < i; j++) {
610 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
611 xenvif_idx_unmap(queue, pending_idx);
612 xenvif_idx_release(queue, pending_idx,
613 XEN_NETIF_RSP_OKAY);
614 }
615
616 /* And if we found the error while checking the frag_list, unmap
617 * the first skb's frags
618 */
619 if (first_shinfo) {
620 for (j = 0; j < first_shinfo->nr_frags; j++) {
621 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
622 xenvif_idx_unmap(queue, pending_idx);
623 xenvif_idx_release(queue, pending_idx,
624 XEN_NETIF_RSP_OKAY);
625 }
626 }
627
628 /* Remember the error: invalidate all subsequent fragments. */
629 err = newerr;
630 }
631
632 if (skb_has_frag_list(skb) && !first_shinfo) {
633 first_shinfo = shinfo;
634 shinfo = skb_shinfo(shinfo->frag_list);
635 nr_frags = shinfo->nr_frags;
636
637 goto check_frags;
638 }
639
640 *gopp_map = gop_map;
641 return err;
642}
643
644static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
645{
646 struct skb_shared_info *shinfo = skb_shinfo(skb);
647 int nr_frags = shinfo->nr_frags;
648 int i;
649 u16 prev_pending_idx = INVALID_PENDING_IDX;
650
651 for (i = 0; i < nr_frags; i++) {
652 skb_frag_t *frag = shinfo->frags + i;
653 struct xen_netif_tx_request *txp;
654 struct page *page;
655 u16 pending_idx;
656
657 pending_idx = frag_get_pending_idx(frag);
658
659 /* If this is not the first frag, chain it to the previous*/
660 if (prev_pending_idx == INVALID_PENDING_IDX)
661 skb_shinfo(skb)->destructor_arg =
662 &callback_param(queue, pending_idx);
663 else
664 callback_param(queue, prev_pending_idx).ctx =
665 &callback_param(queue, pending_idx);
666
667 callback_param(queue, pending_idx).ctx = NULL;
668 prev_pending_idx = pending_idx;
669
670 txp = &queue->pending_tx_info[pending_idx].req;
671 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
672 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
673 skb->len += txp->size;
674 skb->data_len += txp->size;
675 skb->truesize += txp->size;
676
677 /* Take an extra reference to offset network stack's put_page */
678 get_page(queue->mmap_pages[pending_idx]);
679 }
680}
681
682static int xenvif_get_extras(struct xenvif_queue *queue,
683 struct xen_netif_extra_info *extras,
684 unsigned int *extra_count,
685 int work_to_do)
686{
687 struct xen_netif_extra_info extra;
688 RING_IDX cons = queue->tx.req_cons;
689
690 do {
691 if (unlikely(work_to_do-- <= 0)) {
692 netdev_err(queue->vif->dev, "Missing extra info\n");
693 xenvif_fatal_tx_err(queue->vif);
694 return -EBADR;
695 }
696
697 RING_COPY_REQUEST(&queue->tx, cons, &extra);
698
699 queue->tx.req_cons = ++cons;
700 (*extra_count)++;
701
702 if (unlikely(!extra.type ||
703 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
704 netdev_err(queue->vif->dev,
705 "Invalid extra type: %d\n", extra.type);
706 xenvif_fatal_tx_err(queue->vif);
707 return -EINVAL;
708 }
709
710 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
711 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
712
713 return work_to_do;
714}
715
716static int xenvif_set_skb_gso(struct xenvif *vif,
717 struct sk_buff *skb,
718 struct xen_netif_extra_info *gso)
719{
720 if (!gso->u.gso.size) {
721 netdev_err(vif->dev, "GSO size must not be zero.\n");
722 xenvif_fatal_tx_err(vif);
723 return -EINVAL;
724 }
725
726 switch (gso->u.gso.type) {
727 case XEN_NETIF_GSO_TYPE_TCPV4:
728 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
729 break;
730 case XEN_NETIF_GSO_TYPE_TCPV6:
731 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
732 break;
733 default:
734 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
735 xenvif_fatal_tx_err(vif);
736 return -EINVAL;
737 }
738
739 skb_shinfo(skb)->gso_size = gso->u.gso.size;
740 /* gso_segs will be calculated later */
741
742 return 0;
743}
744
745static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
746{
747 bool recalculate_partial_csum = false;
748
749 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
750 * peers can fail to set NETRXF_csum_blank when sending a GSO
751 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
752 * recalculate the partial checksum.
753 */
754 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
755 queue->stats.rx_gso_checksum_fixup++;
756 skb->ip_summed = CHECKSUM_PARTIAL;
757 recalculate_partial_csum = true;
758 }
759
760 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
761 if (skb->ip_summed != CHECKSUM_PARTIAL)
762 return 0;
763
764 return skb_checksum_setup(skb, recalculate_partial_csum);
765}
766
767static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
768{
769 u64 now = get_jiffies_64();
770 u64 next_credit = queue->credit_window_start +
771 msecs_to_jiffies(queue->credit_usec / 1000);
772
773 /* Timer could already be pending in rare cases. */
774 if (timer_pending(&queue->credit_timeout)) {
775 queue->rate_limited = true;
776 return true;
777 }
778
779 /* Passed the point where we can replenish credit? */
780 if (time_after_eq64(now, next_credit)) {
781 queue->credit_window_start = now;
782 tx_add_credit(queue);
783 }
784
785 /* Still too big to send right now? Set a callback. */
786 if (size > queue->remaining_credit) {
787 mod_timer(&queue->credit_timeout,
788 next_credit);
789 queue->credit_window_start = next_credit;
790 queue->rate_limited = true;
791
792 return true;
793 }
794
795 return false;
796}
797
798/* No locking is required in xenvif_mcast_add/del() as they are
799 * only ever invoked from NAPI poll. An RCU list is used because
800 * xenvif_mcast_match() is called asynchronously, during start_xmit.
801 */
802
803static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
804{
805 struct xenvif_mcast_addr *mcast;
806
807 if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
808 if (net_ratelimit())
809 netdev_err(vif->dev,
810 "Too many multicast addresses\n");
811 return -ENOSPC;
812 }
813
814 mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
815 if (!mcast)
816 return -ENOMEM;
817
818 ether_addr_copy(mcast->addr, addr);
819 list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
820 vif->fe_mcast_count++;
821
822 return 0;
823}
824
825static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
826{
827 struct xenvif_mcast_addr *mcast;
828
829 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
830 if (ether_addr_equal(addr, mcast->addr)) {
831 --vif->fe_mcast_count;
832 list_del_rcu(&mcast->entry);
833 kfree_rcu(mcast, rcu);
834 break;
835 }
836 }
837}
838
839bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
840{
841 struct xenvif_mcast_addr *mcast;
842
843 rcu_read_lock();
844 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
845 if (ether_addr_equal(addr, mcast->addr)) {
846 rcu_read_unlock();
847 return true;
848 }
849 }
850 rcu_read_unlock();
851
852 return false;
853}
854
855void xenvif_mcast_addr_list_free(struct xenvif *vif)
856{
857 /* No need for locking or RCU here. NAPI poll and TX queue
858 * are stopped.
859 */
860 while (!list_empty(&vif->fe_mcast_addr)) {
861 struct xenvif_mcast_addr *mcast;
862
863 mcast = list_first_entry(&vif->fe_mcast_addr,
864 struct xenvif_mcast_addr,
865 entry);
866 --vif->fe_mcast_count;
867 list_del(&mcast->entry);
868 kfree(mcast);
869 }
870}
871
872static void xenvif_tx_build_gops(struct xenvif_queue *queue,
873 int budget,
874 unsigned *copy_ops,
875 unsigned *map_ops)
876{
877 struct sk_buff *skb, *nskb;
878 int ret;
879 unsigned int frag_overflow;
880
881 while (skb_queue_len(&queue->tx_queue) < budget) {
882 struct xen_netif_tx_request txreq;
883 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
884 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
885 unsigned int extra_count;
886 u16 pending_idx;
887 RING_IDX idx;
888 int work_to_do;
889 unsigned int data_len;
890 pending_ring_idx_t index;
891
892 if (queue->tx.sring->req_prod - queue->tx.req_cons >
893 XEN_NETIF_TX_RING_SIZE) {
894 netdev_err(queue->vif->dev,
895 "Impossible number of requests. "
896 "req_prod %d, req_cons %d, size %ld\n",
897 queue->tx.sring->req_prod, queue->tx.req_cons,
898 XEN_NETIF_TX_RING_SIZE);
899 xenvif_fatal_tx_err(queue->vif);
900 break;
901 }
902
903 work_to_do = XEN_RING_NR_UNCONSUMED_REQUESTS(&queue->tx);
904 if (!work_to_do)
905 break;
906
907 idx = queue->tx.req_cons;
908 rmb(); /* Ensure that we see the request before we copy it. */
909 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
910
911 /* Credit-based scheduling. */
912 if (txreq.size > queue->remaining_credit &&
913 tx_credit_exceeded(queue, txreq.size))
914 break;
915
916 queue->remaining_credit -= txreq.size;
917
918 work_to_do--;
919 queue->tx.req_cons = ++idx;
920
921 memset(extras, 0, sizeof(extras));
922 extra_count = 0;
923 if (txreq.flags & XEN_NETTXF_extra_info) {
924 work_to_do = xenvif_get_extras(queue, extras,
925 &extra_count,
926 work_to_do);
927 idx = queue->tx.req_cons;
928 if (unlikely(work_to_do < 0))
929 break;
930 }
931
932 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
933 struct xen_netif_extra_info *extra;
934
935 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
936 ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
937
938 make_tx_response(queue, &txreq, extra_count,
939 (ret == 0) ?
940 XEN_NETIF_RSP_OKAY :
941 XEN_NETIF_RSP_ERROR);
942 push_tx_responses(queue);
943 continue;
944 }
945
946 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
947 struct xen_netif_extra_info *extra;
948
949 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
950 xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
951
952 make_tx_response(queue, &txreq, extra_count,
953 XEN_NETIF_RSP_OKAY);
954 push_tx_responses(queue);
955 continue;
956 }
957
958 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN) ?
959 XEN_NETBACK_TX_COPY_LEN : txreq.size;
960
961 ret = xenvif_count_requests(queue, &txreq, extra_count,
962 txfrags, work_to_do);
963
964 if (unlikely(ret < 0))
965 break;
966
967 idx += ret;
968
969 if (unlikely(txreq.size < ETH_HLEN)) {
970 netdev_dbg(queue->vif->dev,
971 "Bad packet size: %d\n", txreq.size);
972 xenvif_tx_err(queue, &txreq, extra_count, idx);
973 break;
974 }
975
976 /* No crossing a page as the payload mustn't fragment. */
977 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
978 netdev_err(queue->vif->dev,
979 "txreq.offset: %u, size: %u, end: %lu\n",
980 txreq.offset, txreq.size,
981 (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
982 xenvif_fatal_tx_err(queue->vif);
983 break;
984 }
985
986 index = pending_index(queue->pending_cons);
987 pending_idx = queue->pending_ring[index];
988
989 if (ret >= XEN_NETBK_LEGACY_SLOTS_MAX - 1 && data_len < txreq.size)
990 data_len = txreq.size;
991
992 skb = xenvif_alloc_skb(data_len);
993 if (unlikely(skb == NULL)) {
994 netdev_dbg(queue->vif->dev,
995 "Can't allocate a skb in start_xmit.\n");
996 xenvif_tx_err(queue, &txreq, extra_count, idx);
997 break;
998 }
999
1000 skb_shinfo(skb)->nr_frags = ret;
1001 /* At this point shinfo->nr_frags is in fact the number of
1002 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
1003 */
1004 frag_overflow = 0;
1005 nskb = NULL;
1006 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
1007 frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
1008 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
1009 skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
1010 nskb = xenvif_alloc_skb(0);
1011 if (unlikely(nskb == NULL)) {
1012 skb_shinfo(skb)->nr_frags = 0;
1013 kfree_skb(skb);
1014 xenvif_tx_err(queue, &txreq, extra_count, idx);
1015 if (net_ratelimit())
1016 netdev_err(queue->vif->dev,
1017 "Can't allocate the frag_list skb.\n");
1018 break;
1019 }
1020 }
1021
1022 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1023 struct xen_netif_extra_info *gso;
1024 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1025
1026 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1027 /* Failure in xenvif_set_skb_gso is fatal. */
1028 skb_shinfo(skb)->nr_frags = 0;
1029 kfree_skb(skb);
1030 kfree_skb(nskb);
1031 break;
1032 }
1033 }
1034
1035 if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
1036 struct xen_netif_extra_info *extra;
1037 enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
1038
1039 extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
1040
1041 switch (extra->u.hash.type) {
1042 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
1043 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
1044 type = PKT_HASH_TYPE_L3;
1045 break;
1046
1047 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
1048 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
1049 type = PKT_HASH_TYPE_L4;
1050 break;
1051
1052 default:
1053 break;
1054 }
1055
1056 if (type != PKT_HASH_TYPE_NONE)
1057 skb_set_hash(skb,
1058 *(u32 *)extra->u.hash.value,
1059 type);
1060 }
1061
1062 xenvif_get_requests(queue, skb, &txreq, txfrags, copy_ops,
1063 map_ops, frag_overflow, nskb, extra_count,
1064 data_len);
1065
1066 __skb_queue_tail(&queue->tx_queue, skb);
1067
1068 queue->tx.req_cons = idx;
1069
1070 if ((*map_ops >= ARRAY_SIZE(queue->tx_map_ops)) ||
1071 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1072 break;
1073 }
1074
1075 return;
1076}
1077
1078/* Consolidate skb with a frag_list into a brand new one with local pages on
1079 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1080 */
1081static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1082{
1083 unsigned int offset = skb_headlen(skb);
1084 skb_frag_t frags[MAX_SKB_FRAGS];
1085 int i, f;
1086 struct ubuf_info *uarg;
1087 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1088
1089 queue->stats.tx_zerocopy_sent += 2;
1090 queue->stats.tx_frag_overflow++;
1091
1092 xenvif_fill_frags(queue, nskb);
1093 /* Subtract frags size, we will correct it later */
1094 skb->truesize -= skb->data_len;
1095 skb->len += nskb->len;
1096 skb->data_len += nskb->len;
1097
1098 /* create a brand new frags array and coalesce there */
1099 for (i = 0; offset < skb->len; i++) {
1100 struct page *page;
1101 unsigned int len;
1102
1103 BUG_ON(i >= MAX_SKB_FRAGS);
1104 page = alloc_page(GFP_ATOMIC);
1105 if (!page) {
1106 int j;
1107 skb->truesize += skb->data_len;
1108 for (j = 0; j < i; j++)
1109 put_page(skb_frag_page(&frags[j]));
1110 return -ENOMEM;
1111 }
1112
1113 if (offset + PAGE_SIZE < skb->len)
1114 len = PAGE_SIZE;
1115 else
1116 len = skb->len - offset;
1117 if (skb_copy_bits(skb, offset, page_address(page), len))
1118 BUG();
1119
1120 offset += len;
1121 __skb_frag_set_page(&frags[i], page);
1122 skb_frag_off_set(&frags[i], 0);
1123 skb_frag_size_set(&frags[i], len);
1124 }
1125
1126 /* Release all the original (foreign) frags. */
1127 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1128 skb_frag_unref(skb, f);
1129 uarg = skb_shinfo(skb)->destructor_arg;
1130 /* increase inflight counter to offset decrement in callback */
1131 atomic_inc(&queue->inflight_packets);
1132 uarg->callback(NULL, uarg, true);
1133 skb_shinfo(skb)->destructor_arg = NULL;
1134
1135 /* Fill the skb with the new (local) frags. */
1136 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1137 skb_shinfo(skb)->nr_frags = i;
1138 skb->truesize += i * PAGE_SIZE;
1139
1140 return 0;
1141}
1142
1143static int xenvif_tx_submit(struct xenvif_queue *queue)
1144{
1145 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1146 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1147 struct sk_buff *skb;
1148 int work_done = 0;
1149
1150 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1151 struct xen_netif_tx_request *txp;
1152 u16 pending_idx;
1153
1154 pending_idx = copy_pending_idx(skb, 0);
1155 txp = &queue->pending_tx_info[pending_idx].req;
1156
1157 /* Check the remap error code. */
1158 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1159 /* If there was an error, xenvif_tx_check_gop is
1160 * expected to release all the frags which were mapped,
1161 * so kfree_skb shouldn't do it again
1162 */
1163 skb_shinfo(skb)->nr_frags = 0;
1164 if (skb_has_frag_list(skb)) {
1165 struct sk_buff *nskb =
1166 skb_shinfo(skb)->frag_list;
1167 skb_shinfo(nskb)->nr_frags = 0;
1168 }
1169 kfree_skb(skb);
1170 continue;
1171 }
1172
1173 if (txp->flags & XEN_NETTXF_csum_blank)
1174 skb->ip_summed = CHECKSUM_PARTIAL;
1175 else if (txp->flags & XEN_NETTXF_data_validated)
1176 skb->ip_summed = CHECKSUM_UNNECESSARY;
1177
1178 xenvif_fill_frags(queue, skb);
1179
1180 if (unlikely(skb_has_frag_list(skb))) {
1181 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1182 xenvif_skb_zerocopy_prepare(queue, nskb);
1183 if (xenvif_handle_frag_list(queue, skb)) {
1184 if (net_ratelimit())
1185 netdev_err(queue->vif->dev,
1186 "Not enough memory to consolidate frag_list!\n");
1187 xenvif_skb_zerocopy_prepare(queue, skb);
1188 kfree_skb(skb);
1189 continue;
1190 }
1191 /* Copied all the bits from the frag list -- free it. */
1192 skb_frag_list_init(skb);
1193 kfree_skb(nskb);
1194 }
1195
1196 skb->dev = queue->vif->dev;
1197 skb->protocol = eth_type_trans(skb, skb->dev);
1198 skb_reset_network_header(skb);
1199
1200 if (checksum_setup(queue, skb)) {
1201 netdev_dbg(queue->vif->dev,
1202 "Can't setup checksum in net_tx_action\n");
1203 /* We have to set this flag to trigger the callback */
1204 if (skb_shinfo(skb)->destructor_arg)
1205 xenvif_skb_zerocopy_prepare(queue, skb);
1206 kfree_skb(skb);
1207 continue;
1208 }
1209
1210 skb_probe_transport_header(skb);
1211
1212 /* If the packet is GSO then we will have just set up the
1213 * transport header offset in checksum_setup so it's now
1214 * straightforward to calculate gso_segs.
1215 */
1216 if (skb_is_gso(skb)) {
1217 int mss, hdrlen;
1218
1219 /* GSO implies having the L4 header. */
1220 WARN_ON_ONCE(!skb_transport_header_was_set(skb));
1221 if (unlikely(!skb_transport_header_was_set(skb))) {
1222 kfree_skb(skb);
1223 continue;
1224 }
1225
1226 mss = skb_shinfo(skb)->gso_size;
1227 hdrlen = skb_tcp_all_headers(skb);
1228
1229 skb_shinfo(skb)->gso_segs =
1230 DIV_ROUND_UP(skb->len - hdrlen, mss);
1231 }
1232
1233 queue->stats.rx_bytes += skb->len;
1234 queue->stats.rx_packets++;
1235
1236 work_done++;
1237
1238 /* Set this flag right before netif_receive_skb, otherwise
1239 * someone might think this packet already left netback, and
1240 * do a skb_copy_ubufs while we are still in control of the
1241 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1242 */
1243 if (skb_shinfo(skb)->destructor_arg) {
1244 xenvif_skb_zerocopy_prepare(queue, skb);
1245 queue->stats.tx_zerocopy_sent++;
1246 }
1247
1248 netif_receive_skb(skb);
1249 }
1250
1251 return work_done;
1252}
1253
1254void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf_base,
1255 bool zerocopy_success)
1256{
1257 unsigned long flags;
1258 pending_ring_idx_t index;
1259 struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base);
1260 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1261
1262 /* This is the only place where we grab this lock, to protect callbacks
1263 * from each other.
1264 */
1265 spin_lock_irqsave(&queue->callback_lock, flags);
1266 do {
1267 u16 pending_idx = ubuf->desc;
1268 ubuf = (struct ubuf_info_msgzc *) ubuf->ctx;
1269 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1270 MAX_PENDING_REQS);
1271 index = pending_index(queue->dealloc_prod);
1272 queue->dealloc_ring[index] = pending_idx;
1273 /* Sync with xenvif_tx_dealloc_action:
1274 * insert idx then incr producer.
1275 */
1276 smp_wmb();
1277 queue->dealloc_prod++;
1278 } while (ubuf);
1279 spin_unlock_irqrestore(&queue->callback_lock, flags);
1280
1281 if (likely(zerocopy_success))
1282 queue->stats.tx_zerocopy_success++;
1283 else
1284 queue->stats.tx_zerocopy_fail++;
1285 xenvif_skb_zerocopy_complete(queue);
1286}
1287
1288static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1289{
1290 struct gnttab_unmap_grant_ref *gop;
1291 pending_ring_idx_t dc, dp;
1292 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1293 unsigned int i = 0;
1294
1295 dc = queue->dealloc_cons;
1296 gop = queue->tx_unmap_ops;
1297
1298 /* Free up any grants we have finished using */
1299 do {
1300 dp = queue->dealloc_prod;
1301
1302 /* Ensure we see all indices enqueued by all
1303 * xenvif_zerocopy_callback().
1304 */
1305 smp_rmb();
1306
1307 while (dc != dp) {
1308 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1309 pending_idx =
1310 queue->dealloc_ring[pending_index(dc++)];
1311
1312 pending_idx_release[gop - queue->tx_unmap_ops] =
1313 pending_idx;
1314 queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1315 queue->mmap_pages[pending_idx];
1316 gnttab_set_unmap_op(gop,
1317 idx_to_kaddr(queue, pending_idx),
1318 GNTMAP_host_map,
1319 queue->grant_tx_handle[pending_idx]);
1320 xenvif_grant_handle_reset(queue, pending_idx);
1321 ++gop;
1322 }
1323
1324 } while (dp != queue->dealloc_prod);
1325
1326 queue->dealloc_cons = dc;
1327
1328 if (gop - queue->tx_unmap_ops > 0) {
1329 int ret;
1330 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1331 NULL,
1332 queue->pages_to_unmap,
1333 gop - queue->tx_unmap_ops);
1334 if (ret) {
1335 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1336 gop - queue->tx_unmap_ops, ret);
1337 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1338 if (gop[i].status != GNTST_okay)
1339 netdev_err(queue->vif->dev,
1340 " host_addr: 0x%llx handle: 0x%x status: %d\n",
1341 gop[i].host_addr,
1342 gop[i].handle,
1343 gop[i].status);
1344 }
1345 BUG();
1346 }
1347 }
1348
1349 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1350 xenvif_idx_release(queue, pending_idx_release[i],
1351 XEN_NETIF_RSP_OKAY);
1352}
1353
1354
1355/* Called after netfront has transmitted */
1356int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1357{
1358 unsigned nr_mops = 0, nr_cops = 0;
1359 int work_done, ret;
1360
1361 if (unlikely(!tx_work_todo(queue)))
1362 return 0;
1363
1364 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1365
1366 if (nr_cops == 0)
1367 return 0;
1368
1369 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1370 if (nr_mops != 0) {
1371 ret = gnttab_map_refs(queue->tx_map_ops,
1372 NULL,
1373 queue->pages_to_map,
1374 nr_mops);
1375 if (ret) {
1376 unsigned int i;
1377
1378 netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n",
1379 nr_mops, ret);
1380 for (i = 0; i < nr_mops; ++i)
1381 WARN_ON_ONCE(queue->tx_map_ops[i].status ==
1382 GNTST_okay);
1383 }
1384 }
1385
1386 work_done = xenvif_tx_submit(queue);
1387
1388 return work_done;
1389}
1390
1391static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1392 u8 status)
1393{
1394 struct pending_tx_info *pending_tx_info;
1395 pending_ring_idx_t index;
1396 unsigned long flags;
1397
1398 pending_tx_info = &queue->pending_tx_info[pending_idx];
1399
1400 spin_lock_irqsave(&queue->response_lock, flags);
1401
1402 make_tx_response(queue, &pending_tx_info->req,
1403 pending_tx_info->extra_count, status);
1404
1405 /* Release the pending index before pusing the Tx response so
1406 * its available before a new Tx request is pushed by the
1407 * frontend.
1408 */
1409 index = pending_index(queue->pending_prod++);
1410 queue->pending_ring[index] = pending_idx;
1411
1412 push_tx_responses(queue);
1413
1414 spin_unlock_irqrestore(&queue->response_lock, flags);
1415}
1416
1417
1418static void make_tx_response(struct xenvif_queue *queue,
1419 struct xen_netif_tx_request *txp,
1420 unsigned int extra_count,
1421 s8 st)
1422{
1423 RING_IDX i = queue->tx.rsp_prod_pvt;
1424 struct xen_netif_tx_response *resp;
1425
1426 resp = RING_GET_RESPONSE(&queue->tx, i);
1427 resp->id = txp->id;
1428 resp->status = st;
1429
1430 while (extra_count-- != 0)
1431 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1432
1433 queue->tx.rsp_prod_pvt = ++i;
1434}
1435
1436static void push_tx_responses(struct xenvif_queue *queue)
1437{
1438 int notify;
1439
1440 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1441 if (notify)
1442 notify_remote_via_irq(queue->tx_irq);
1443}
1444
1445static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1446{
1447 int ret;
1448 struct gnttab_unmap_grant_ref tx_unmap_op;
1449
1450 gnttab_set_unmap_op(&tx_unmap_op,
1451 idx_to_kaddr(queue, pending_idx),
1452 GNTMAP_host_map,
1453 queue->grant_tx_handle[pending_idx]);
1454 xenvif_grant_handle_reset(queue, pending_idx);
1455
1456 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1457 &queue->mmap_pages[pending_idx], 1);
1458 if (ret) {
1459 netdev_err(queue->vif->dev,
1460 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1461 ret,
1462 pending_idx,
1463 tx_unmap_op.host_addr,
1464 tx_unmap_op.handle,
1465 tx_unmap_op.status);
1466 BUG();
1467 }
1468}
1469
1470static inline int tx_work_todo(struct xenvif_queue *queue)
1471{
1472 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1473 return 1;
1474
1475 return 0;
1476}
1477
1478static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1479{
1480 return queue->dealloc_cons != queue->dealloc_prod;
1481}
1482
1483void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1484{
1485 if (queue->tx.sring)
1486 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1487 queue->tx.sring);
1488 if (queue->rx.sring)
1489 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1490 queue->rx.sring);
1491}
1492
1493int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1494 grant_ref_t tx_ring_ref,
1495 grant_ref_t rx_ring_ref)
1496{
1497 void *addr;
1498 struct xen_netif_tx_sring *txs;
1499 struct xen_netif_rx_sring *rxs;
1500 RING_IDX rsp_prod, req_prod;
1501 int err;
1502
1503 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1504 &tx_ring_ref, 1, &addr);
1505 if (err)
1506 goto err;
1507
1508 txs = (struct xen_netif_tx_sring *)addr;
1509 rsp_prod = READ_ONCE(txs->rsp_prod);
1510 req_prod = READ_ONCE(txs->req_prod);
1511
1512 BACK_RING_ATTACH(&queue->tx, txs, rsp_prod, XEN_PAGE_SIZE);
1513
1514 err = -EIO;
1515 if (req_prod - rsp_prod > RING_SIZE(&queue->tx))
1516 goto err;
1517
1518 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1519 &rx_ring_ref, 1, &addr);
1520 if (err)
1521 goto err;
1522
1523 rxs = (struct xen_netif_rx_sring *)addr;
1524 rsp_prod = READ_ONCE(rxs->rsp_prod);
1525 req_prod = READ_ONCE(rxs->req_prod);
1526
1527 BACK_RING_ATTACH(&queue->rx, rxs, rsp_prod, XEN_PAGE_SIZE);
1528
1529 err = -EIO;
1530 if (req_prod - rsp_prod > RING_SIZE(&queue->rx))
1531 goto err;
1532
1533 return 0;
1534
1535err:
1536 xenvif_unmap_frontend_data_rings(queue);
1537 return err;
1538}
1539
1540static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1541{
1542 /* Dealloc thread must remain running until all inflight
1543 * packets complete.
1544 */
1545 return kthread_should_stop() &&
1546 !atomic_read(&queue->inflight_packets);
1547}
1548
1549int xenvif_dealloc_kthread(void *data)
1550{
1551 struct xenvif_queue *queue = data;
1552
1553 for (;;) {
1554 wait_event_interruptible(queue->dealloc_wq,
1555 tx_dealloc_work_todo(queue) ||
1556 xenvif_dealloc_kthread_should_stop(queue));
1557 if (xenvif_dealloc_kthread_should_stop(queue))
1558 break;
1559
1560 xenvif_tx_dealloc_action(queue);
1561 cond_resched();
1562 }
1563
1564 /* Unmap anything remaining*/
1565 if (tx_dealloc_work_todo(queue))
1566 xenvif_tx_dealloc_action(queue);
1567
1568 return 0;
1569}
1570
1571static void make_ctrl_response(struct xenvif *vif,
1572 const struct xen_netif_ctrl_request *req,
1573 u32 status, u32 data)
1574{
1575 RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1576 struct xen_netif_ctrl_response rsp = {
1577 .id = req->id,
1578 .type = req->type,
1579 .status = status,
1580 .data = data,
1581 };
1582
1583 *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1584 vif->ctrl.rsp_prod_pvt = ++idx;
1585}
1586
1587static void push_ctrl_response(struct xenvif *vif)
1588{
1589 int notify;
1590
1591 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1592 if (notify)
1593 notify_remote_via_irq(vif->ctrl_irq);
1594}
1595
1596static void process_ctrl_request(struct xenvif *vif,
1597 const struct xen_netif_ctrl_request *req)
1598{
1599 u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1600 u32 data = 0;
1601
1602 switch (req->type) {
1603 case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1604 status = xenvif_set_hash_alg(vif, req->data[0]);
1605 break;
1606
1607 case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1608 status = xenvif_get_hash_flags(vif, &data);
1609 break;
1610
1611 case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1612 status = xenvif_set_hash_flags(vif, req->data[0]);
1613 break;
1614
1615 case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1616 status = xenvif_set_hash_key(vif, req->data[0],
1617 req->data[1]);
1618 break;
1619
1620 case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1621 status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1622 data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1623 break;
1624
1625 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1626 status = xenvif_set_hash_mapping_size(vif,
1627 req->data[0]);
1628 break;
1629
1630 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1631 status = xenvif_set_hash_mapping(vif, req->data[0],
1632 req->data[1],
1633 req->data[2]);
1634 break;
1635
1636 default:
1637 break;
1638 }
1639
1640 make_ctrl_response(vif, req, status, data);
1641 push_ctrl_response(vif);
1642}
1643
1644static void xenvif_ctrl_action(struct xenvif *vif)
1645{
1646 for (;;) {
1647 RING_IDX req_prod, req_cons;
1648
1649 req_prod = vif->ctrl.sring->req_prod;
1650 req_cons = vif->ctrl.req_cons;
1651
1652 /* Make sure we can see requests before we process them. */
1653 rmb();
1654
1655 if (req_cons == req_prod)
1656 break;
1657
1658 while (req_cons != req_prod) {
1659 struct xen_netif_ctrl_request req;
1660
1661 RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1662 req_cons++;
1663
1664 process_ctrl_request(vif, &req);
1665 }
1666
1667 vif->ctrl.req_cons = req_cons;
1668 vif->ctrl.sring->req_event = req_cons + 1;
1669 }
1670}
1671
1672static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1673{
1674 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1675 return true;
1676
1677 return false;
1678}
1679
1680irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1681{
1682 struct xenvif *vif = data;
1683 unsigned int eoi_flag = XEN_EOI_FLAG_SPURIOUS;
1684
1685 while (xenvif_ctrl_work_todo(vif)) {
1686 xenvif_ctrl_action(vif);
1687 eoi_flag = 0;
1688 }
1689
1690 xen_irq_lateeoi(irq, eoi_flag);
1691
1692 return IRQ_HANDLED;
1693}
1694
1695static int __init netback_init(void)
1696{
1697 int rc = 0;
1698
1699 if (!xen_domain())
1700 return -ENODEV;
1701
1702 /* Allow as many queues as there are CPUs but max. 8 if user has not
1703 * specified a value.
1704 */
1705 if (xenvif_max_queues == 0)
1706 xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1707 num_online_cpus());
1708
1709 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1710 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1711 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1712 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1713 }
1714
1715 rc = xenvif_xenbus_init();
1716 if (rc)
1717 goto failed_init;
1718
1719#ifdef CONFIG_DEBUG_FS
1720 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1721#endif /* CONFIG_DEBUG_FS */
1722
1723 return 0;
1724
1725failed_init:
1726 return rc;
1727}
1728
1729module_init(netback_init);
1730
1731static void __exit netback_fini(void)
1732{
1733#ifdef CONFIG_DEBUG_FS
1734 debugfs_remove_recursive(xen_netback_dbg_root);
1735#endif /* CONFIG_DEBUG_FS */
1736 xenvif_xenbus_fini();
1737}
1738module_exit(netback_fini);
1739
1740MODULE_LICENSE("Dual BSD/GPL");
1741MODULE_ALIAS("xen-backend:vif");
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
41#include <net/tcp.h>
42
43#include <xen/events.h>
44#include <xen/interface/memory.h>
45
46#include <asm/xen/hypercall.h>
47#include <asm/xen/page.h>
48
49struct pending_tx_info {
50 struct xen_netif_tx_request req;
51 struct xenvif *vif;
52};
53typedef unsigned int pending_ring_idx_t;
54
55struct netbk_rx_meta {
56 int id;
57 int size;
58 int gso_size;
59};
60
61#define MAX_PENDING_REQS 256
62
63#define MAX_BUFFER_OFFSET PAGE_SIZE
64
65/* extra field used in struct page */
66union page_ext {
67 struct {
68#if BITS_PER_LONG < 64
69#define IDX_WIDTH 8
70#define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH)
71 unsigned int group:GROUP_WIDTH;
72 unsigned int idx:IDX_WIDTH;
73#else
74 unsigned int group, idx;
75#endif
76 } e;
77 void *mapping;
78};
79
80struct xen_netbk {
81 wait_queue_head_t wq;
82 struct task_struct *task;
83
84 struct sk_buff_head rx_queue;
85 struct sk_buff_head tx_queue;
86
87 struct timer_list net_timer;
88
89 struct page *mmap_pages[MAX_PENDING_REQS];
90
91 pending_ring_idx_t pending_prod;
92 pending_ring_idx_t pending_cons;
93 struct list_head net_schedule_list;
94
95 /* Protect the net_schedule_list in netif. */
96 spinlock_t net_schedule_list_lock;
97
98 atomic_t netfront_count;
99
100 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
101 struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
102
103 u16 pending_ring[MAX_PENDING_REQS];
104
105 /*
106 * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
107 * head/fragment page uses 2 copy operations because it
108 * straddles two buffers in the frontend.
109 */
110 struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
111 struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
112};
113
114static struct xen_netbk *xen_netbk;
115static int xen_netbk_group_nr;
116
117void xen_netbk_add_xenvif(struct xenvif *vif)
118{
119 int i;
120 int min_netfront_count;
121 int min_group = 0;
122 struct xen_netbk *netbk;
123
124 min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
125 for (i = 0; i < xen_netbk_group_nr; i++) {
126 int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
127 if (netfront_count < min_netfront_count) {
128 min_group = i;
129 min_netfront_count = netfront_count;
130 }
131 }
132
133 netbk = &xen_netbk[min_group];
134
135 vif->netbk = netbk;
136 atomic_inc(&netbk->netfront_count);
137}
138
139void xen_netbk_remove_xenvif(struct xenvif *vif)
140{
141 struct xen_netbk *netbk = vif->netbk;
142 vif->netbk = NULL;
143 atomic_dec(&netbk->netfront_count);
144}
145
146static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
147static void make_tx_response(struct xenvif *vif,
148 struct xen_netif_tx_request *txp,
149 s8 st);
150static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
151 u16 id,
152 s8 st,
153 u16 offset,
154 u16 size,
155 u16 flags);
156
157static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
158 unsigned int idx)
159{
160 return page_to_pfn(netbk->mmap_pages[idx]);
161}
162
163static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
164 unsigned int idx)
165{
166 return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
167}
168
169/* extra field used in struct page */
170static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk,
171 unsigned int idx)
172{
173 unsigned int group = netbk - xen_netbk;
174 union page_ext ext = { .e = { .group = group + 1, .idx = idx } };
175
176 BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping));
177 pg->mapping = ext.mapping;
178}
179
180static int get_page_ext(struct page *pg,
181 unsigned int *pgroup, unsigned int *pidx)
182{
183 union page_ext ext = { .mapping = pg->mapping };
184 struct xen_netbk *netbk;
185 unsigned int group, idx;
186
187 group = ext.e.group - 1;
188
189 if (group < 0 || group >= xen_netbk_group_nr)
190 return 0;
191
192 netbk = &xen_netbk[group];
193
194 idx = ext.e.idx;
195
196 if ((idx < 0) || (idx >= MAX_PENDING_REQS))
197 return 0;
198
199 if (netbk->mmap_pages[idx] != pg)
200 return 0;
201
202 *pgroup = group;
203 *pidx = idx;
204
205 return 1;
206}
207
208/*
209 * This is the amount of packet we copy rather than map, so that the
210 * guest can't fiddle with the contents of the headers while we do
211 * packet processing on them (netfilter, routing, etc).
212 */
213#define PKT_PROT_LEN (ETH_HLEN + \
214 VLAN_HLEN + \
215 sizeof(struct iphdr) + MAX_IPOPTLEN + \
216 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
217
218static inline pending_ring_idx_t pending_index(unsigned i)
219{
220 return i & (MAX_PENDING_REQS-1);
221}
222
223static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
224{
225 return MAX_PENDING_REQS -
226 netbk->pending_prod + netbk->pending_cons;
227}
228
229static void xen_netbk_kick_thread(struct xen_netbk *netbk)
230{
231 wake_up(&netbk->wq);
232}
233
234static int max_required_rx_slots(struct xenvif *vif)
235{
236 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
237
238 if (vif->can_sg || vif->gso || vif->gso_prefix)
239 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
240
241 return max;
242}
243
244int xen_netbk_rx_ring_full(struct xenvif *vif)
245{
246 RING_IDX peek = vif->rx_req_cons_peek;
247 RING_IDX needed = max_required_rx_slots(vif);
248
249 return ((vif->rx.sring->req_prod - peek) < needed) ||
250 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
251}
252
253int xen_netbk_must_stop_queue(struct xenvif *vif)
254{
255 if (!xen_netbk_rx_ring_full(vif))
256 return 0;
257
258 vif->rx.sring->req_event = vif->rx_req_cons_peek +
259 max_required_rx_slots(vif);
260 mb(); /* request notification /then/ check the queue */
261
262 return xen_netbk_rx_ring_full(vif);
263}
264
265/*
266 * Returns true if we should start a new receive buffer instead of
267 * adding 'size' bytes to a buffer which currently contains 'offset'
268 * bytes.
269 */
270static bool start_new_rx_buffer(int offset, unsigned long size, int head)
271{
272 /* simple case: we have completely filled the current buffer. */
273 if (offset == MAX_BUFFER_OFFSET)
274 return true;
275
276 /*
277 * complex case: start a fresh buffer if the current frag
278 * would overflow the current buffer but only if:
279 * (i) this frag would fit completely in the next buffer
280 * and (ii) there is already some data in the current buffer
281 * and (iii) this is not the head buffer.
282 *
283 * Where:
284 * - (i) stops us splitting a frag into two copies
285 * unless the frag is too large for a single buffer.
286 * - (ii) stops us from leaving a buffer pointlessly empty.
287 * - (iii) stops us leaving the first buffer
288 * empty. Strictly speaking this is already covered
289 * by (ii) but is explicitly checked because
290 * netfront relies on the first buffer being
291 * non-empty and can crash otherwise.
292 *
293 * This means we will effectively linearise small
294 * frags but do not needlessly split large buffers
295 * into multiple copies tend to give large frags their
296 * own buffers as before.
297 */
298 if ((offset + size > MAX_BUFFER_OFFSET) &&
299 (size <= MAX_BUFFER_OFFSET) && offset && !head)
300 return true;
301
302 return false;
303}
304
305/*
306 * Figure out how many ring slots we're going to need to send @skb to
307 * the guest. This function is essentially a dry run of
308 * netbk_gop_frag_copy.
309 */
310unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
311{
312 unsigned int count;
313 int i, copy_off;
314
315 count = DIV_ROUND_UP(
316 offset_in_page(skb->data)+skb_headlen(skb), PAGE_SIZE);
317
318 copy_off = skb_headlen(skb) % PAGE_SIZE;
319
320 if (skb_shinfo(skb)->gso_size)
321 count++;
322
323 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
324 unsigned long size = skb_shinfo(skb)->frags[i].size;
325 unsigned long bytes;
326 while (size > 0) {
327 BUG_ON(copy_off > MAX_BUFFER_OFFSET);
328
329 if (start_new_rx_buffer(copy_off, size, 0)) {
330 count++;
331 copy_off = 0;
332 }
333
334 bytes = size;
335 if (copy_off + bytes > MAX_BUFFER_OFFSET)
336 bytes = MAX_BUFFER_OFFSET - copy_off;
337
338 copy_off += bytes;
339 size -= bytes;
340 }
341 }
342 return count;
343}
344
345struct netrx_pending_operations {
346 unsigned copy_prod, copy_cons;
347 unsigned meta_prod, meta_cons;
348 struct gnttab_copy *copy;
349 struct netbk_rx_meta *meta;
350 int copy_off;
351 grant_ref_t copy_gref;
352};
353
354static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
355 struct netrx_pending_operations *npo)
356{
357 struct netbk_rx_meta *meta;
358 struct xen_netif_rx_request *req;
359
360 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
361
362 meta = npo->meta + npo->meta_prod++;
363 meta->gso_size = 0;
364 meta->size = 0;
365 meta->id = req->id;
366
367 npo->copy_off = 0;
368 npo->copy_gref = req->gref;
369
370 return meta;
371}
372
373/*
374 * Set up the grant operations for this fragment. If it's a flipping
375 * interface, we also set up the unmap request from here.
376 */
377static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
378 struct netrx_pending_operations *npo,
379 struct page *page, unsigned long size,
380 unsigned long offset, int *head)
381{
382 struct gnttab_copy *copy_gop;
383 struct netbk_rx_meta *meta;
384 /*
385 * These variables a used iff get_page_ext returns true,
386 * in which case they are guaranteed to be initialized.
387 */
388 unsigned int uninitialized_var(group), uninitialized_var(idx);
389 int foreign = get_page_ext(page, &group, &idx);
390 unsigned long bytes;
391
392 /* Data must not cross a page boundary. */
393 BUG_ON(size + offset > PAGE_SIZE);
394
395 meta = npo->meta + npo->meta_prod - 1;
396
397 while (size > 0) {
398 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
399
400 if (start_new_rx_buffer(npo->copy_off, size, *head)) {
401 /*
402 * Netfront requires there to be some data in the head
403 * buffer.
404 */
405 BUG_ON(*head);
406
407 meta = get_next_rx_buffer(vif, npo);
408 }
409
410 bytes = size;
411 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
412 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
413
414 copy_gop = npo->copy + npo->copy_prod++;
415 copy_gop->flags = GNTCOPY_dest_gref;
416 if (foreign) {
417 struct xen_netbk *netbk = &xen_netbk[group];
418 struct pending_tx_info *src_pend;
419
420 src_pend = &netbk->pending_tx_info[idx];
421
422 copy_gop->source.domid = src_pend->vif->domid;
423 copy_gop->source.u.ref = src_pend->req.gref;
424 copy_gop->flags |= GNTCOPY_source_gref;
425 } else {
426 void *vaddr = page_address(page);
427 copy_gop->source.domid = DOMID_SELF;
428 copy_gop->source.u.gmfn = virt_to_mfn(vaddr);
429 }
430 copy_gop->source.offset = offset;
431 copy_gop->dest.domid = vif->domid;
432
433 copy_gop->dest.offset = npo->copy_off;
434 copy_gop->dest.u.ref = npo->copy_gref;
435 copy_gop->len = bytes;
436
437 npo->copy_off += bytes;
438 meta->size += bytes;
439
440 offset += bytes;
441 size -= bytes;
442
443 /* Leave a gap for the GSO descriptor. */
444 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
445 vif->rx.req_cons++;
446
447 *head = 0; /* There must be something in this buffer now. */
448
449 }
450}
451
452/*
453 * Prepare an SKB to be transmitted to the frontend.
454 *
455 * This function is responsible for allocating grant operations, meta
456 * structures, etc.
457 *
458 * It returns the number of meta structures consumed. The number of
459 * ring slots used is always equal to the number of meta slots used
460 * plus the number of GSO descriptors used. Currently, we use either
461 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
462 * frontend-side LRO).
463 */
464static int netbk_gop_skb(struct sk_buff *skb,
465 struct netrx_pending_operations *npo)
466{
467 struct xenvif *vif = netdev_priv(skb->dev);
468 int nr_frags = skb_shinfo(skb)->nr_frags;
469 int i;
470 struct xen_netif_rx_request *req;
471 struct netbk_rx_meta *meta;
472 unsigned char *data;
473 int head = 1;
474 int old_meta_prod;
475
476 old_meta_prod = npo->meta_prod;
477
478 /* Set up a GSO prefix descriptor, if necessary */
479 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
480 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
481 meta = npo->meta + npo->meta_prod++;
482 meta->gso_size = skb_shinfo(skb)->gso_size;
483 meta->size = 0;
484 meta->id = req->id;
485 }
486
487 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
488 meta = npo->meta + npo->meta_prod++;
489
490 if (!vif->gso_prefix)
491 meta->gso_size = skb_shinfo(skb)->gso_size;
492 else
493 meta->gso_size = 0;
494
495 meta->size = 0;
496 meta->id = req->id;
497 npo->copy_off = 0;
498 npo->copy_gref = req->gref;
499
500 data = skb->data;
501 while (data < skb_tail_pointer(skb)) {
502 unsigned int offset = offset_in_page(data);
503 unsigned int len = PAGE_SIZE - offset;
504
505 if (data + len > skb_tail_pointer(skb))
506 len = skb_tail_pointer(skb) - data;
507
508 netbk_gop_frag_copy(vif, skb, npo,
509 virt_to_page(data), len, offset, &head);
510 data += len;
511 }
512
513 for (i = 0; i < nr_frags; i++) {
514 netbk_gop_frag_copy(vif, skb, npo,
515 skb_shinfo(skb)->frags[i].page,
516 skb_shinfo(skb)->frags[i].size,
517 skb_shinfo(skb)->frags[i].page_offset,
518 &head);
519 }
520
521 return npo->meta_prod - old_meta_prod;
522}
523
524/*
525 * This is a twin to netbk_gop_skb. Assume that netbk_gop_skb was
526 * used to set up the operations on the top of
527 * netrx_pending_operations, which have since been done. Check that
528 * they didn't give any errors and advance over them.
529 */
530static int netbk_check_gop(struct xenvif *vif, int nr_meta_slots,
531 struct netrx_pending_operations *npo)
532{
533 struct gnttab_copy *copy_op;
534 int status = XEN_NETIF_RSP_OKAY;
535 int i;
536
537 for (i = 0; i < nr_meta_slots; i++) {
538 copy_op = npo->copy + npo->copy_cons++;
539 if (copy_op->status != GNTST_okay) {
540 netdev_dbg(vif->dev,
541 "Bad status %d from copy to DOM%d.\n",
542 copy_op->status, vif->domid);
543 status = XEN_NETIF_RSP_ERROR;
544 }
545 }
546
547 return status;
548}
549
550static void netbk_add_frag_responses(struct xenvif *vif, int status,
551 struct netbk_rx_meta *meta,
552 int nr_meta_slots)
553{
554 int i;
555 unsigned long offset;
556
557 /* No fragments used */
558 if (nr_meta_slots <= 1)
559 return;
560
561 nr_meta_slots--;
562
563 for (i = 0; i < nr_meta_slots; i++) {
564 int flags;
565 if (i == nr_meta_slots - 1)
566 flags = 0;
567 else
568 flags = XEN_NETRXF_more_data;
569
570 offset = 0;
571 make_rx_response(vif, meta[i].id, status, offset,
572 meta[i].size, flags);
573 }
574}
575
576struct skb_cb_overlay {
577 int meta_slots_used;
578};
579
580static void xen_netbk_rx_action(struct xen_netbk *netbk)
581{
582 struct xenvif *vif = NULL, *tmp;
583 s8 status;
584 u16 irq, flags;
585 struct xen_netif_rx_response *resp;
586 struct sk_buff_head rxq;
587 struct sk_buff *skb;
588 LIST_HEAD(notify);
589 int ret;
590 int nr_frags;
591 int count;
592 unsigned long offset;
593 struct skb_cb_overlay *sco;
594
595 struct netrx_pending_operations npo = {
596 .copy = netbk->grant_copy_op,
597 .meta = netbk->meta,
598 };
599
600 skb_queue_head_init(&rxq);
601
602 count = 0;
603
604 while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
605 vif = netdev_priv(skb->dev);
606 nr_frags = skb_shinfo(skb)->nr_frags;
607
608 sco = (struct skb_cb_overlay *)skb->cb;
609 sco->meta_slots_used = netbk_gop_skb(skb, &npo);
610
611 count += nr_frags + 1;
612
613 __skb_queue_tail(&rxq, skb);
614
615 /* Filled the batch queue? */
616 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
617 break;
618 }
619
620 BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
621
622 if (!npo.copy_prod)
623 return;
624
625 BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
626 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, &netbk->grant_copy_op,
627 npo.copy_prod);
628 BUG_ON(ret != 0);
629
630 while ((skb = __skb_dequeue(&rxq)) != NULL) {
631 sco = (struct skb_cb_overlay *)skb->cb;
632
633 vif = netdev_priv(skb->dev);
634
635 if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
636 resp = RING_GET_RESPONSE(&vif->rx,
637 vif->rx.rsp_prod_pvt++);
638
639 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
640
641 resp->offset = netbk->meta[npo.meta_cons].gso_size;
642 resp->id = netbk->meta[npo.meta_cons].id;
643 resp->status = sco->meta_slots_used;
644
645 npo.meta_cons++;
646 sco->meta_slots_used--;
647 }
648
649
650 vif->dev->stats.tx_bytes += skb->len;
651 vif->dev->stats.tx_packets++;
652
653 status = netbk_check_gop(vif, sco->meta_slots_used, &npo);
654
655 if (sco->meta_slots_used == 1)
656 flags = 0;
657 else
658 flags = XEN_NETRXF_more_data;
659
660 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
661 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
662 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
663 /* remote but checksummed. */
664 flags |= XEN_NETRXF_data_validated;
665
666 offset = 0;
667 resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
668 status, offset,
669 netbk->meta[npo.meta_cons].size,
670 flags);
671
672 if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
673 struct xen_netif_extra_info *gso =
674 (struct xen_netif_extra_info *)
675 RING_GET_RESPONSE(&vif->rx,
676 vif->rx.rsp_prod_pvt++);
677
678 resp->flags |= XEN_NETRXF_extra_info;
679
680 gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
681 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
682 gso->u.gso.pad = 0;
683 gso->u.gso.features = 0;
684
685 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
686 gso->flags = 0;
687 }
688
689 netbk_add_frag_responses(vif, status,
690 netbk->meta + npo.meta_cons + 1,
691 sco->meta_slots_used);
692
693 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
694 irq = vif->irq;
695 if (ret && list_empty(&vif->notify_list))
696 list_add_tail(&vif->notify_list, ¬ify);
697
698 xenvif_notify_tx_completion(vif);
699
700 xenvif_put(vif);
701 npo.meta_cons += sco->meta_slots_used;
702 dev_kfree_skb(skb);
703 }
704
705 list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) {
706 notify_remote_via_irq(vif->irq);
707 list_del_init(&vif->notify_list);
708 }
709
710 /* More work to do? */
711 if (!skb_queue_empty(&netbk->rx_queue) &&
712 !timer_pending(&netbk->net_timer))
713 xen_netbk_kick_thread(netbk);
714}
715
716void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
717{
718 struct xen_netbk *netbk = vif->netbk;
719
720 skb_queue_tail(&netbk->rx_queue, skb);
721
722 xen_netbk_kick_thread(netbk);
723}
724
725static void xen_netbk_alarm(unsigned long data)
726{
727 struct xen_netbk *netbk = (struct xen_netbk *)data;
728 xen_netbk_kick_thread(netbk);
729}
730
731static int __on_net_schedule_list(struct xenvif *vif)
732{
733 return !list_empty(&vif->schedule_list);
734}
735
736/* Must be called with net_schedule_list_lock held */
737static void remove_from_net_schedule_list(struct xenvif *vif)
738{
739 if (likely(__on_net_schedule_list(vif))) {
740 list_del_init(&vif->schedule_list);
741 xenvif_put(vif);
742 }
743}
744
745static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
746{
747 struct xenvif *vif = NULL;
748
749 spin_lock_irq(&netbk->net_schedule_list_lock);
750 if (list_empty(&netbk->net_schedule_list))
751 goto out;
752
753 vif = list_first_entry(&netbk->net_schedule_list,
754 struct xenvif, schedule_list);
755 if (!vif)
756 goto out;
757
758 xenvif_get(vif);
759
760 remove_from_net_schedule_list(vif);
761out:
762 spin_unlock_irq(&netbk->net_schedule_list_lock);
763 return vif;
764}
765
766void xen_netbk_schedule_xenvif(struct xenvif *vif)
767{
768 unsigned long flags;
769 struct xen_netbk *netbk = vif->netbk;
770
771 if (__on_net_schedule_list(vif))
772 goto kick;
773
774 spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
775 if (!__on_net_schedule_list(vif) &&
776 likely(xenvif_schedulable(vif))) {
777 list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
778 xenvif_get(vif);
779 }
780 spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
781
782kick:
783 smp_mb();
784 if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
785 !list_empty(&netbk->net_schedule_list))
786 xen_netbk_kick_thread(netbk);
787}
788
789void xen_netbk_deschedule_xenvif(struct xenvif *vif)
790{
791 struct xen_netbk *netbk = vif->netbk;
792 spin_lock_irq(&netbk->net_schedule_list_lock);
793 remove_from_net_schedule_list(vif);
794 spin_unlock_irq(&netbk->net_schedule_list_lock);
795}
796
797void xen_netbk_check_rx_xenvif(struct xenvif *vif)
798{
799 int more_to_do;
800
801 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
802
803 if (more_to_do)
804 xen_netbk_schedule_xenvif(vif);
805}
806
807static void tx_add_credit(struct xenvif *vif)
808{
809 unsigned long max_burst, max_credit;
810
811 /*
812 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
813 * Otherwise the interface can seize up due to insufficient credit.
814 */
815 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
816 max_burst = min(max_burst, 131072UL);
817 max_burst = max(max_burst, vif->credit_bytes);
818
819 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
820 max_credit = vif->remaining_credit + vif->credit_bytes;
821 if (max_credit < vif->remaining_credit)
822 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
823
824 vif->remaining_credit = min(max_credit, max_burst);
825}
826
827static void tx_credit_callback(unsigned long data)
828{
829 struct xenvif *vif = (struct xenvif *)data;
830 tx_add_credit(vif);
831 xen_netbk_check_rx_xenvif(vif);
832}
833
834static void netbk_tx_err(struct xenvif *vif,
835 struct xen_netif_tx_request *txp, RING_IDX end)
836{
837 RING_IDX cons = vif->tx.req_cons;
838
839 do {
840 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
841 if (cons >= end)
842 break;
843 txp = RING_GET_REQUEST(&vif->tx, cons++);
844 } while (1);
845 vif->tx.req_cons = cons;
846 xen_netbk_check_rx_xenvif(vif);
847 xenvif_put(vif);
848}
849
850static int netbk_count_requests(struct xenvif *vif,
851 struct xen_netif_tx_request *first,
852 struct xen_netif_tx_request *txp,
853 int work_to_do)
854{
855 RING_IDX cons = vif->tx.req_cons;
856 int frags = 0;
857
858 if (!(first->flags & XEN_NETTXF_more_data))
859 return 0;
860
861 do {
862 if (frags >= work_to_do) {
863 netdev_dbg(vif->dev, "Need more frags\n");
864 return -frags;
865 }
866
867 if (unlikely(frags >= MAX_SKB_FRAGS)) {
868 netdev_dbg(vif->dev, "Too many frags\n");
869 return -frags;
870 }
871
872 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags),
873 sizeof(*txp));
874 if (txp->size > first->size) {
875 netdev_dbg(vif->dev, "Frags galore\n");
876 return -frags;
877 }
878
879 first->size -= txp->size;
880 frags++;
881
882 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
883 netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n",
884 txp->offset, txp->size);
885 return -frags;
886 }
887 } while ((txp++)->flags & XEN_NETTXF_more_data);
888 return frags;
889}
890
891static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
892 struct sk_buff *skb,
893 unsigned long pending_idx)
894{
895 struct page *page;
896 page = alloc_page(GFP_KERNEL|__GFP_COLD);
897 if (!page)
898 return NULL;
899 set_page_ext(page, netbk, pending_idx);
900 netbk->mmap_pages[pending_idx] = page;
901 return page;
902}
903
904static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
905 struct xenvif *vif,
906 struct sk_buff *skb,
907 struct xen_netif_tx_request *txp,
908 struct gnttab_copy *gop)
909{
910 struct skb_shared_info *shinfo = skb_shinfo(skb);
911 skb_frag_t *frags = shinfo->frags;
912 unsigned long pending_idx = *((u16 *)skb->data);
913 int i, start;
914
915 /* Skip first skb fragment if it is on same page as header fragment. */
916 start = ((unsigned long)shinfo->frags[0].page == pending_idx);
917
918 for (i = start; i < shinfo->nr_frags; i++, txp++) {
919 struct page *page;
920 pending_ring_idx_t index;
921 struct pending_tx_info *pending_tx_info =
922 netbk->pending_tx_info;
923
924 index = pending_index(netbk->pending_cons++);
925 pending_idx = netbk->pending_ring[index];
926 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
927 if (!page)
928 return NULL;
929
930 netbk->mmap_pages[pending_idx] = page;
931
932 gop->source.u.ref = txp->gref;
933 gop->source.domid = vif->domid;
934 gop->source.offset = txp->offset;
935
936 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
937 gop->dest.domid = DOMID_SELF;
938 gop->dest.offset = txp->offset;
939
940 gop->len = txp->size;
941 gop->flags = GNTCOPY_source_gref;
942
943 gop++;
944
945 memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp));
946 xenvif_get(vif);
947 pending_tx_info[pending_idx].vif = vif;
948 frags[i].page = (void *)pending_idx;
949 }
950
951 return gop;
952}
953
954static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
955 struct sk_buff *skb,
956 struct gnttab_copy **gopp)
957{
958 struct gnttab_copy *gop = *gopp;
959 int pending_idx = *((u16 *)skb->data);
960 struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
961 struct xenvif *vif = pending_tx_info[pending_idx].vif;
962 struct xen_netif_tx_request *txp;
963 struct skb_shared_info *shinfo = skb_shinfo(skb);
964 int nr_frags = shinfo->nr_frags;
965 int i, err, start;
966
967 /* Check status of header. */
968 err = gop->status;
969 if (unlikely(err)) {
970 pending_ring_idx_t index;
971 index = pending_index(netbk->pending_prod++);
972 txp = &pending_tx_info[pending_idx].req;
973 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
974 netbk->pending_ring[index] = pending_idx;
975 xenvif_put(vif);
976 }
977
978 /* Skip first skb fragment if it is on same page as header fragment. */
979 start = ((unsigned long)shinfo->frags[0].page == pending_idx);
980
981 for (i = start; i < nr_frags; i++) {
982 int j, newerr;
983 pending_ring_idx_t index;
984
985 pending_idx = (unsigned long)shinfo->frags[i].page;
986
987 /* Check error status: if okay then remember grant handle. */
988 newerr = (++gop)->status;
989 if (likely(!newerr)) {
990 /* Had a previous error? Invalidate this fragment. */
991 if (unlikely(err))
992 xen_netbk_idx_release(netbk, pending_idx);
993 continue;
994 }
995
996 /* Error on this fragment: respond to client with an error. */
997 txp = &netbk->pending_tx_info[pending_idx].req;
998 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
999 index = pending_index(netbk->pending_prod++);
1000 netbk->pending_ring[index] = pending_idx;
1001 xenvif_put(vif);
1002
1003 /* Not the first error? Preceding frags already invalidated. */
1004 if (err)
1005 continue;
1006
1007 /* First error: invalidate header and preceding fragments. */
1008 pending_idx = *((u16 *)skb->data);
1009 xen_netbk_idx_release(netbk, pending_idx);
1010 for (j = start; j < i; j++) {
1011 pending_idx = (unsigned long)shinfo->frags[i].page;
1012 xen_netbk_idx_release(netbk, pending_idx);
1013 }
1014
1015 /* Remember the error: invalidate all subsequent fragments. */
1016 err = newerr;
1017 }
1018
1019 *gopp = gop + 1;
1020 return err;
1021}
1022
1023static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
1024{
1025 struct skb_shared_info *shinfo = skb_shinfo(skb);
1026 int nr_frags = shinfo->nr_frags;
1027 int i;
1028
1029 for (i = 0; i < nr_frags; i++) {
1030 skb_frag_t *frag = shinfo->frags + i;
1031 struct xen_netif_tx_request *txp;
1032 unsigned long pending_idx;
1033
1034 pending_idx = (unsigned long)frag->page;
1035
1036 txp = &netbk->pending_tx_info[pending_idx].req;
1037 frag->page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
1038 frag->size = txp->size;
1039 frag->page_offset = txp->offset;
1040
1041 skb->len += txp->size;
1042 skb->data_len += txp->size;
1043 skb->truesize += txp->size;
1044
1045 /* Take an extra reference to offset xen_netbk_idx_release */
1046 get_page(netbk->mmap_pages[pending_idx]);
1047 xen_netbk_idx_release(netbk, pending_idx);
1048 }
1049}
1050
1051static int xen_netbk_get_extras(struct xenvif *vif,
1052 struct xen_netif_extra_info *extras,
1053 int work_to_do)
1054{
1055 struct xen_netif_extra_info extra;
1056 RING_IDX cons = vif->tx.req_cons;
1057
1058 do {
1059 if (unlikely(work_to_do-- <= 0)) {
1060 netdev_dbg(vif->dev, "Missing extra info\n");
1061 return -EBADR;
1062 }
1063
1064 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1065 sizeof(extra));
1066 if (unlikely(!extra.type ||
1067 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1068 vif->tx.req_cons = ++cons;
1069 netdev_dbg(vif->dev,
1070 "Invalid extra type: %d\n", extra.type);
1071 return -EINVAL;
1072 }
1073
1074 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1075 vif->tx.req_cons = ++cons;
1076 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1077
1078 return work_to_do;
1079}
1080
1081static int netbk_set_skb_gso(struct xenvif *vif,
1082 struct sk_buff *skb,
1083 struct xen_netif_extra_info *gso)
1084{
1085 if (!gso->u.gso.size) {
1086 netdev_dbg(vif->dev, "GSO size must not be zero.\n");
1087 return -EINVAL;
1088 }
1089
1090 /* Currently only TCPv4 S.O. is supported. */
1091 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1092 netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1093 return -EINVAL;
1094 }
1095
1096 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1097 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1098
1099 /* Header must be checked, and gso_segs computed. */
1100 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1101 skb_shinfo(skb)->gso_segs = 0;
1102
1103 return 0;
1104}
1105
1106static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1107{
1108 struct iphdr *iph;
1109 unsigned char *th;
1110 int err = -EPROTO;
1111 int recalculate_partial_csum = 0;
1112
1113 /*
1114 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1115 * peers can fail to set NETRXF_csum_blank when sending a GSO
1116 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1117 * recalculate the partial checksum.
1118 */
1119 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1120 vif->rx_gso_checksum_fixup++;
1121 skb->ip_summed = CHECKSUM_PARTIAL;
1122 recalculate_partial_csum = 1;
1123 }
1124
1125 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1126 if (skb->ip_summed != CHECKSUM_PARTIAL)
1127 return 0;
1128
1129 if (skb->protocol != htons(ETH_P_IP))
1130 goto out;
1131
1132 iph = (void *)skb->data;
1133 th = skb->data + 4 * iph->ihl;
1134 if (th >= skb_tail_pointer(skb))
1135 goto out;
1136
1137 skb->csum_start = th - skb->head;
1138 switch (iph->protocol) {
1139 case IPPROTO_TCP:
1140 skb->csum_offset = offsetof(struct tcphdr, check);
1141
1142 if (recalculate_partial_csum) {
1143 struct tcphdr *tcph = (struct tcphdr *)th;
1144 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1145 skb->len - iph->ihl*4,
1146 IPPROTO_TCP, 0);
1147 }
1148 break;
1149 case IPPROTO_UDP:
1150 skb->csum_offset = offsetof(struct udphdr, check);
1151
1152 if (recalculate_partial_csum) {
1153 struct udphdr *udph = (struct udphdr *)th;
1154 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1155 skb->len - iph->ihl*4,
1156 IPPROTO_UDP, 0);
1157 }
1158 break;
1159 default:
1160 if (net_ratelimit())
1161 netdev_err(vif->dev,
1162 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1163 iph->protocol);
1164 goto out;
1165 }
1166
1167 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
1168 goto out;
1169
1170 err = 0;
1171
1172out:
1173 return err;
1174}
1175
1176static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1177{
1178 unsigned long now = jiffies;
1179 unsigned long next_credit =
1180 vif->credit_timeout.expires +
1181 msecs_to_jiffies(vif->credit_usec / 1000);
1182
1183 /* Timer could already be pending in rare cases. */
1184 if (timer_pending(&vif->credit_timeout))
1185 return true;
1186
1187 /* Passed the point where we can replenish credit? */
1188 if (time_after_eq(now, next_credit)) {
1189 vif->credit_timeout.expires = now;
1190 tx_add_credit(vif);
1191 }
1192
1193 /* Still too big to send right now? Set a callback. */
1194 if (size > vif->remaining_credit) {
1195 vif->credit_timeout.data =
1196 (unsigned long)vif;
1197 vif->credit_timeout.function =
1198 tx_credit_callback;
1199 mod_timer(&vif->credit_timeout,
1200 next_credit);
1201
1202 return true;
1203 }
1204
1205 return false;
1206}
1207
1208static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
1209{
1210 struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
1211 struct sk_buff *skb;
1212 int ret;
1213
1214 while (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1215 !list_empty(&netbk->net_schedule_list)) {
1216 struct xenvif *vif;
1217 struct xen_netif_tx_request txreq;
1218 struct xen_netif_tx_request txfrags[MAX_SKB_FRAGS];
1219 struct page *page;
1220 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1221 u16 pending_idx;
1222 RING_IDX idx;
1223 int work_to_do;
1224 unsigned int data_len;
1225 pending_ring_idx_t index;
1226
1227 /* Get a netif from the list with work to do. */
1228 vif = poll_net_schedule_list(netbk);
1229 if (!vif)
1230 continue;
1231
1232 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1233 if (!work_to_do) {
1234 xenvif_put(vif);
1235 continue;
1236 }
1237
1238 idx = vif->tx.req_cons;
1239 rmb(); /* Ensure that we see the request before we copy it. */
1240 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1241
1242 /* Credit-based scheduling. */
1243 if (txreq.size > vif->remaining_credit &&
1244 tx_credit_exceeded(vif, txreq.size)) {
1245 xenvif_put(vif);
1246 continue;
1247 }
1248
1249 vif->remaining_credit -= txreq.size;
1250
1251 work_to_do--;
1252 vif->tx.req_cons = ++idx;
1253
1254 memset(extras, 0, sizeof(extras));
1255 if (txreq.flags & XEN_NETTXF_extra_info) {
1256 work_to_do = xen_netbk_get_extras(vif, extras,
1257 work_to_do);
1258 idx = vif->tx.req_cons;
1259 if (unlikely(work_to_do < 0)) {
1260 netbk_tx_err(vif, &txreq, idx);
1261 continue;
1262 }
1263 }
1264
1265 ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
1266 if (unlikely(ret < 0)) {
1267 netbk_tx_err(vif, &txreq, idx - ret);
1268 continue;
1269 }
1270 idx += ret;
1271
1272 if (unlikely(txreq.size < ETH_HLEN)) {
1273 netdev_dbg(vif->dev,
1274 "Bad packet size: %d\n", txreq.size);
1275 netbk_tx_err(vif, &txreq, idx);
1276 continue;
1277 }
1278
1279 /* No crossing a page as the payload mustn't fragment. */
1280 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1281 netdev_dbg(vif->dev,
1282 "txreq.offset: %x, size: %u, end: %lu\n",
1283 txreq.offset, txreq.size,
1284 (txreq.offset&~PAGE_MASK) + txreq.size);
1285 netbk_tx_err(vif, &txreq, idx);
1286 continue;
1287 }
1288
1289 index = pending_index(netbk->pending_cons);
1290 pending_idx = netbk->pending_ring[index];
1291
1292 data_len = (txreq.size > PKT_PROT_LEN &&
1293 ret < MAX_SKB_FRAGS) ?
1294 PKT_PROT_LEN : txreq.size;
1295
1296 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1297 GFP_ATOMIC | __GFP_NOWARN);
1298 if (unlikely(skb == NULL)) {
1299 netdev_dbg(vif->dev,
1300 "Can't allocate a skb in start_xmit.\n");
1301 netbk_tx_err(vif, &txreq, idx);
1302 break;
1303 }
1304
1305 /* Packets passed to netif_rx() must have some headroom. */
1306 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1307
1308 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1309 struct xen_netif_extra_info *gso;
1310 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1311
1312 if (netbk_set_skb_gso(vif, skb, gso)) {
1313 kfree_skb(skb);
1314 netbk_tx_err(vif, &txreq, idx);
1315 continue;
1316 }
1317 }
1318
1319 /* XXX could copy straight to head */
1320 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
1321 if (!page) {
1322 kfree_skb(skb);
1323 netbk_tx_err(vif, &txreq, idx);
1324 continue;
1325 }
1326
1327 netbk->mmap_pages[pending_idx] = page;
1328
1329 gop->source.u.ref = txreq.gref;
1330 gop->source.domid = vif->domid;
1331 gop->source.offset = txreq.offset;
1332
1333 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1334 gop->dest.domid = DOMID_SELF;
1335 gop->dest.offset = txreq.offset;
1336
1337 gop->len = txreq.size;
1338 gop->flags = GNTCOPY_source_gref;
1339
1340 gop++;
1341
1342 memcpy(&netbk->pending_tx_info[pending_idx].req,
1343 &txreq, sizeof(txreq));
1344 netbk->pending_tx_info[pending_idx].vif = vif;
1345 *((u16 *)skb->data) = pending_idx;
1346
1347 __skb_put(skb, data_len);
1348
1349 skb_shinfo(skb)->nr_frags = ret;
1350 if (data_len < txreq.size) {
1351 skb_shinfo(skb)->nr_frags++;
1352 skb_shinfo(skb)->frags[0].page =
1353 (void *)(unsigned long)pending_idx;
1354 } else {
1355 /* Discriminate from any valid pending_idx value. */
1356 skb_shinfo(skb)->frags[0].page = (void *)~0UL;
1357 }
1358
1359 __skb_queue_tail(&netbk->tx_queue, skb);
1360
1361 netbk->pending_cons++;
1362
1363 request_gop = xen_netbk_get_requests(netbk, vif,
1364 skb, txfrags, gop);
1365 if (request_gop == NULL) {
1366 kfree_skb(skb);
1367 netbk_tx_err(vif, &txreq, idx);
1368 continue;
1369 }
1370 gop = request_gop;
1371
1372 vif->tx.req_cons = idx;
1373 xen_netbk_check_rx_xenvif(vif);
1374
1375 if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
1376 break;
1377 }
1378
1379 return gop - netbk->tx_copy_ops;
1380}
1381
1382static void xen_netbk_tx_submit(struct xen_netbk *netbk)
1383{
1384 struct gnttab_copy *gop = netbk->tx_copy_ops;
1385 struct sk_buff *skb;
1386
1387 while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
1388 struct xen_netif_tx_request *txp;
1389 struct xenvif *vif;
1390 u16 pending_idx;
1391 unsigned data_len;
1392
1393 pending_idx = *((u16 *)skb->data);
1394 vif = netbk->pending_tx_info[pending_idx].vif;
1395 txp = &netbk->pending_tx_info[pending_idx].req;
1396
1397 /* Check the remap error code. */
1398 if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
1399 netdev_dbg(vif->dev, "netback grant failed.\n");
1400 skb_shinfo(skb)->nr_frags = 0;
1401 kfree_skb(skb);
1402 continue;
1403 }
1404
1405 data_len = skb->len;
1406 memcpy(skb->data,
1407 (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
1408 data_len);
1409 if (data_len < txp->size) {
1410 /* Append the packet payload as a fragment. */
1411 txp->offset += data_len;
1412 txp->size -= data_len;
1413 } else {
1414 /* Schedule a response immediately. */
1415 xen_netbk_idx_release(netbk, pending_idx);
1416 }
1417
1418 if (txp->flags & XEN_NETTXF_csum_blank)
1419 skb->ip_summed = CHECKSUM_PARTIAL;
1420 else if (txp->flags & XEN_NETTXF_data_validated)
1421 skb->ip_summed = CHECKSUM_UNNECESSARY;
1422
1423 xen_netbk_fill_frags(netbk, skb);
1424
1425 /*
1426 * If the initial fragment was < PKT_PROT_LEN then
1427 * pull through some bytes from the other fragments to
1428 * increase the linear region to PKT_PROT_LEN bytes.
1429 */
1430 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1431 int target = min_t(int, skb->len, PKT_PROT_LEN);
1432 __pskb_pull_tail(skb, target - skb_headlen(skb));
1433 }
1434
1435 skb->dev = vif->dev;
1436 skb->protocol = eth_type_trans(skb, skb->dev);
1437
1438 if (checksum_setup(vif, skb)) {
1439 netdev_dbg(vif->dev,
1440 "Can't setup checksum in net_tx_action\n");
1441 kfree_skb(skb);
1442 continue;
1443 }
1444
1445 vif->dev->stats.rx_bytes += skb->len;
1446 vif->dev->stats.rx_packets++;
1447
1448 xenvif_receive_skb(vif, skb);
1449 }
1450}
1451
1452/* Called after netfront has transmitted */
1453static void xen_netbk_tx_action(struct xen_netbk *netbk)
1454{
1455 unsigned nr_gops;
1456 int ret;
1457
1458 nr_gops = xen_netbk_tx_build_gops(netbk);
1459
1460 if (nr_gops == 0)
1461 return;
1462 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
1463 netbk->tx_copy_ops, nr_gops);
1464 BUG_ON(ret);
1465
1466 xen_netbk_tx_submit(netbk);
1467
1468}
1469
1470static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
1471{
1472 struct xenvif *vif;
1473 struct pending_tx_info *pending_tx_info;
1474 pending_ring_idx_t index;
1475
1476 /* Already complete? */
1477 if (netbk->mmap_pages[pending_idx] == NULL)
1478 return;
1479
1480 pending_tx_info = &netbk->pending_tx_info[pending_idx];
1481
1482 vif = pending_tx_info->vif;
1483
1484 make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
1485
1486 index = pending_index(netbk->pending_prod++);
1487 netbk->pending_ring[index] = pending_idx;
1488
1489 xenvif_put(vif);
1490
1491 netbk->mmap_pages[pending_idx]->mapping = 0;
1492 put_page(netbk->mmap_pages[pending_idx]);
1493 netbk->mmap_pages[pending_idx] = NULL;
1494}
1495
1496static void make_tx_response(struct xenvif *vif,
1497 struct xen_netif_tx_request *txp,
1498 s8 st)
1499{
1500 RING_IDX i = vif->tx.rsp_prod_pvt;
1501 struct xen_netif_tx_response *resp;
1502 int notify;
1503
1504 resp = RING_GET_RESPONSE(&vif->tx, i);
1505 resp->id = txp->id;
1506 resp->status = st;
1507
1508 if (txp->flags & XEN_NETTXF_extra_info)
1509 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1510
1511 vif->tx.rsp_prod_pvt = ++i;
1512 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1513 if (notify)
1514 notify_remote_via_irq(vif->irq);
1515}
1516
1517static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1518 u16 id,
1519 s8 st,
1520 u16 offset,
1521 u16 size,
1522 u16 flags)
1523{
1524 RING_IDX i = vif->rx.rsp_prod_pvt;
1525 struct xen_netif_rx_response *resp;
1526
1527 resp = RING_GET_RESPONSE(&vif->rx, i);
1528 resp->offset = offset;
1529 resp->flags = flags;
1530 resp->id = id;
1531 resp->status = (s16)size;
1532 if (st < 0)
1533 resp->status = (s16)st;
1534
1535 vif->rx.rsp_prod_pvt = ++i;
1536
1537 return resp;
1538}
1539
1540static inline int rx_work_todo(struct xen_netbk *netbk)
1541{
1542 return !skb_queue_empty(&netbk->rx_queue);
1543}
1544
1545static inline int tx_work_todo(struct xen_netbk *netbk)
1546{
1547
1548 if (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1549 !list_empty(&netbk->net_schedule_list))
1550 return 1;
1551
1552 return 0;
1553}
1554
1555static int xen_netbk_kthread(void *data)
1556{
1557 struct xen_netbk *netbk = data;
1558 while (!kthread_should_stop()) {
1559 wait_event_interruptible(netbk->wq,
1560 rx_work_todo(netbk) ||
1561 tx_work_todo(netbk) ||
1562 kthread_should_stop());
1563 cond_resched();
1564
1565 if (kthread_should_stop())
1566 break;
1567
1568 if (rx_work_todo(netbk))
1569 xen_netbk_rx_action(netbk);
1570
1571 if (tx_work_todo(netbk))
1572 xen_netbk_tx_action(netbk);
1573 }
1574
1575 return 0;
1576}
1577
1578void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
1579{
1580 struct gnttab_unmap_grant_ref op;
1581
1582 if (vif->tx.sring) {
1583 gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
1584 GNTMAP_host_map, vif->tx_shmem_handle);
1585
1586 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
1587 BUG();
1588 }
1589
1590 if (vif->rx.sring) {
1591 gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
1592 GNTMAP_host_map, vif->rx_shmem_handle);
1593
1594 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
1595 BUG();
1596 }
1597 if (vif->rx_comms_area)
1598 free_vm_area(vif->rx_comms_area);
1599 if (vif->tx_comms_area)
1600 free_vm_area(vif->tx_comms_area);
1601}
1602
1603int xen_netbk_map_frontend_rings(struct xenvif *vif,
1604 grant_ref_t tx_ring_ref,
1605 grant_ref_t rx_ring_ref)
1606{
1607 struct gnttab_map_grant_ref op;
1608 struct xen_netif_tx_sring *txs;
1609 struct xen_netif_rx_sring *rxs;
1610
1611 int err = -ENOMEM;
1612
1613 vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
1614 if (vif->tx_comms_area == NULL)
1615 goto err;
1616
1617 vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
1618 if (vif->rx_comms_area == NULL)
1619 goto err;
1620
1621 gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
1622 GNTMAP_host_map, tx_ring_ref, vif->domid);
1623
1624 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
1625 BUG();
1626
1627 if (op.status) {
1628 netdev_warn(vif->dev,
1629 "failed to map tx ring. err=%d status=%d\n",
1630 err, op.status);
1631 err = op.status;
1632 goto err;
1633 }
1634
1635 vif->tx_shmem_ref = tx_ring_ref;
1636 vif->tx_shmem_handle = op.handle;
1637
1638 txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
1639 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1640
1641 gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
1642 GNTMAP_host_map, rx_ring_ref, vif->domid);
1643
1644 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
1645 BUG();
1646
1647 if (op.status) {
1648 netdev_warn(vif->dev,
1649 "failed to map rx ring. err=%d status=%d\n",
1650 err, op.status);
1651 err = op.status;
1652 goto err;
1653 }
1654
1655 vif->rx_shmem_ref = rx_ring_ref;
1656 vif->rx_shmem_handle = op.handle;
1657 vif->rx_req_cons_peek = 0;
1658
1659 rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
1660 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1661
1662 return 0;
1663
1664err:
1665 xen_netbk_unmap_frontend_rings(vif);
1666 return err;
1667}
1668
1669static int __init netback_init(void)
1670{
1671 int i;
1672 int rc = 0;
1673 int group;
1674
1675 if (!xen_pv_domain())
1676 return -ENODEV;
1677
1678 xen_netbk_group_nr = num_online_cpus();
1679 xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
1680 if (!xen_netbk) {
1681 printk(KERN_ALERT "%s: out of memory\n", __func__);
1682 return -ENOMEM;
1683 }
1684
1685 for (group = 0; group < xen_netbk_group_nr; group++) {
1686 struct xen_netbk *netbk = &xen_netbk[group];
1687 skb_queue_head_init(&netbk->rx_queue);
1688 skb_queue_head_init(&netbk->tx_queue);
1689
1690 init_timer(&netbk->net_timer);
1691 netbk->net_timer.data = (unsigned long)netbk;
1692 netbk->net_timer.function = xen_netbk_alarm;
1693
1694 netbk->pending_cons = 0;
1695 netbk->pending_prod = MAX_PENDING_REQS;
1696 for (i = 0; i < MAX_PENDING_REQS; i++)
1697 netbk->pending_ring[i] = i;
1698
1699 init_waitqueue_head(&netbk->wq);
1700 netbk->task = kthread_create(xen_netbk_kthread,
1701 (void *)netbk,
1702 "netback/%u", group);
1703
1704 if (IS_ERR(netbk->task)) {
1705 printk(KERN_ALERT "kthread_run() fails at netback\n");
1706 del_timer(&netbk->net_timer);
1707 rc = PTR_ERR(netbk->task);
1708 goto failed_init;
1709 }
1710
1711 kthread_bind(netbk->task, group);
1712
1713 INIT_LIST_HEAD(&netbk->net_schedule_list);
1714
1715 spin_lock_init(&netbk->net_schedule_list_lock);
1716
1717 atomic_set(&netbk->netfront_count, 0);
1718
1719 wake_up_process(netbk->task);
1720 }
1721
1722 rc = xenvif_xenbus_init();
1723 if (rc)
1724 goto failed_init;
1725
1726 return 0;
1727
1728failed_init:
1729 while (--group >= 0) {
1730 struct xen_netbk *netbk = &xen_netbk[group];
1731 for (i = 0; i < MAX_PENDING_REQS; i++) {
1732 if (netbk->mmap_pages[i])
1733 __free_page(netbk->mmap_pages[i]);
1734 }
1735 del_timer(&netbk->net_timer);
1736 kthread_stop(netbk->task);
1737 }
1738 vfree(xen_netbk);
1739 return rc;
1740
1741}
1742
1743module_init(netback_init);
1744
1745MODULE_LICENSE("Dual BSD/GPL");
1746MODULE_ALIAS("xen-backend:vif");