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  */
55 bool separate_tx_rx_irq = true;
56 module_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  */
61 unsigned int rx_drain_timeout_msecs = 10000;
62 module_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  */
67 unsigned int rx_stall_timeout_msecs = 60000;
68 module_param(rx_stall_timeout_msecs, uint, 0444);
69 
70 #define MAX_QUEUES_DEFAULT 8
71 unsigned int xenvif_max_queues;
72 module_param_named(max_queues, xenvif_max_queues, uint, 0644);
73 MODULE_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
81 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
82 module_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
95 unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
96 module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
97 MODULE_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  */
103 bool provides_xdp_headroom = true;
104 module_param(provides_xdp_headroom, bool, 0644);
105 
106 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
107 			       u8 status);
108 
109 static void make_tx_response(struct xenvif_queue *queue,
110 			     struct xen_netif_tx_request *txp,
111 			     unsigned int extra_count,
112 			     s8       st);
113 static void push_tx_responses(struct xenvif_queue *queue);
114 
115 static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
116 
117 static inline int tx_work_todo(struct xenvif_queue *queue);
118 
119 static 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 
125 static 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  */
136 static 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 
146 static u16 frag_get_pending_idx(skb_frag_t *frag)
147 {
148 	return (u16)skb_frag_off(frag);
149 }
150 
151 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
152 {
153 	skb_frag_off_set(frag, pending_idx);
154 }
155 
156 static inline pending_ring_idx_t pending_index(unsigned i)
157 {
158 	return i & (MAX_PENDING_REQS-1);
159 }
160 
161 void xenvif_kick_thread(struct xenvif_queue *queue)
162 {
163 	wake_up(&queue->wq);
164 }
165 
166 void 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 
180 static 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 
199 void 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 
206 static 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 
226 static 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 
235 static 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 
334 struct 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 
343 static 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 
359 static 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 
376 static 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 
487 static 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 
501 static 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 
514 static 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 
563 check_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 
644 static 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 
682 static 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 
716 static 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 
745 static 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 
767 static 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 
803 static 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 
825 static 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 
839 bool 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 
855 void 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 
872 static 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  */
1081 static 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 
1143 static 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 
1254 void 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 
1288 static 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 */
1356 int 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 
1391 static 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 
1418 static 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 
1436 static 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 
1445 static 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 
1470 static 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 
1478 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1479 {
1480 	return queue->dealloc_cons != queue->dealloc_prod;
1481 }
1482 
1483 void 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 
1493 int 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 
1535 err:
1536 	xenvif_unmap_frontend_data_rings(queue);
1537 	return err;
1538 }
1539 
1540 static 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 
1549 int 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 
1571 static 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 
1587 static 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 
1596 static 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 
1644 static 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 
1672 static 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 
1680 irqreturn_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 
1695 static 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 
1725 failed_init:
1726 	return rc;
1727 }
1728 
1729 module_init(netback_init);
1730 
1731 static 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 }
1738 module_exit(netback_fini);
1739 
1740 MODULE_LICENSE("Dual BSD/GPL");
1741 MODULE_ALIAS("xen-backend:vif");
1742