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
8 * Copyright (c) 2002-2005, K A Fraser
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:
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:
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
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
37 #include <linux/kthread.h>
38 #include <linux/if_vlan.h>
39 #include <linux/udp.h>
40 #include <linux/highmem.h>
45 #include <xen/events.h>
46 #include <xen/interface/memory.h>
48 #include <asm/xen/hypercall.h>
49 #include <asm/xen/page.h>
51 /* Provide an option to disable split event channels at load time as
52 * event channels are limited resource. Split event channels are
55 bool separate_tx_rx_irq = 1;
56 module_param(separate_tx_rx_irq, bool, 0644);
58 /* When guest ring is filled up, qdisc queues the packets for us, but we have
59 * to timeout them, otherwise other guests' packets can get stuck there
61 unsigned int rx_drain_timeout_msecs = 10000;
62 module_param(rx_drain_timeout_msecs, uint, 0444);
63 unsigned int rx_drain_timeout_jiffies;
66 * This is the maximum slots a skb can have. If a guest sends a skb
67 * which exceeds this limit it is considered malicious.
69 #define FATAL_SKB_SLOTS_DEFAULT 20
70 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
71 module_param(fatal_skb_slots, uint, 0444);
73 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
76 static void make_tx_response(struct xenvif *vif,
77 struct xen_netif_tx_request *txp,
80 static inline int tx_work_todo(struct xenvif *vif);
81 static inline int rx_work_todo(struct xenvif *vif);
83 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
90 static inline unsigned long idx_to_pfn(struct xenvif *vif,
93 return page_to_pfn(vif->mmap_pages[idx]);
96 static inline unsigned long idx_to_kaddr(struct xenvif *vif,
99 return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
102 #define callback_param(vif, pending_idx) \
103 (vif->pending_tx_info[pending_idx].callback_struct)
105 /* Find the containing VIF's structure from a pointer in pending_tx_info array
107 static inline struct xenvif *ubuf_to_vif(const struct ubuf_info *ubuf)
109 u16 pending_idx = ubuf->desc;
110 struct pending_tx_info *temp =
111 container_of(ubuf, struct pending_tx_info, callback_struct);
112 return container_of(temp - pending_idx,
117 /* This is a miniumum size for the linear area to avoid lots of
118 * calls to __pskb_pull_tail() as we set up checksum offsets. The
119 * value 128 was chosen as it covers all IPv4 and most likely
122 #define PKT_PROT_LEN 128
124 static u16 frag_get_pending_idx(skb_frag_t *frag)
126 return (u16)frag->page_offset;
129 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
131 frag->page_offset = pending_idx;
134 static inline pending_ring_idx_t pending_index(unsigned i)
136 return i & (MAX_PENDING_REQS-1);
139 bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed)
144 prod = vif->rx.sring->req_prod;
145 cons = vif->rx.req_cons;
147 if (prod - cons >= needed)
150 vif->rx.sring->req_event = prod + 1;
152 /* Make sure event is visible before we check prod
156 } while (vif->rx.sring->req_prod != prod);
162 * Returns true if we should start a new receive buffer instead of
163 * adding 'size' bytes to a buffer which currently contains 'offset'
166 static bool start_new_rx_buffer(int offset, unsigned long size, int head)
168 /* simple case: we have completely filled the current buffer. */
169 if (offset == MAX_BUFFER_OFFSET)
173 * complex case: start a fresh buffer if the current frag
174 * would overflow the current buffer but only if:
175 * (i) this frag would fit completely in the next buffer
176 * and (ii) there is already some data in the current buffer
177 * and (iii) this is not the head buffer.
180 * - (i) stops us splitting a frag into two copies
181 * unless the frag is too large for a single buffer.
182 * - (ii) stops us from leaving a buffer pointlessly empty.
183 * - (iii) stops us leaving the first buffer
184 * empty. Strictly speaking this is already covered
185 * by (ii) but is explicitly checked because
186 * netfront relies on the first buffer being
187 * non-empty and can crash otherwise.
189 * This means we will effectively linearise small
190 * frags but do not needlessly split large buffers
191 * into multiple copies tend to give large frags their
192 * own buffers as before.
194 BUG_ON(size > MAX_BUFFER_OFFSET);
195 if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head)
201 struct netrx_pending_operations {
202 unsigned copy_prod, copy_cons;
203 unsigned meta_prod, meta_cons;
204 struct gnttab_copy *copy;
205 struct xenvif_rx_meta *meta;
207 grant_ref_t copy_gref;
210 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
211 struct netrx_pending_operations *npo)
213 struct xenvif_rx_meta *meta;
214 struct xen_netif_rx_request *req;
216 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
218 meta = npo->meta + npo->meta_prod++;
219 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
225 npo->copy_gref = req->gref;
231 * Set up the grant operations for this fragment. If it's a flipping
232 * interface, we also set up the unmap request from here.
234 static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
235 struct netrx_pending_operations *npo,
236 struct page *page, unsigned long size,
237 unsigned long offset, int *head,
238 struct xenvif *foreign_vif,
239 grant_ref_t foreign_gref)
241 struct gnttab_copy *copy_gop;
242 struct xenvif_rx_meta *meta;
244 int gso_type = XEN_NETIF_GSO_TYPE_NONE;
246 /* Data must not cross a page boundary. */
247 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
249 meta = npo->meta + npo->meta_prod - 1;
251 /* Skip unused frames from start of page */
252 page += offset >> PAGE_SHIFT;
253 offset &= ~PAGE_MASK;
256 BUG_ON(offset >= PAGE_SIZE);
257 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
259 bytes = PAGE_SIZE - offset;
264 if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
266 * Netfront requires there to be some data in the head
271 meta = get_next_rx_buffer(vif, npo);
274 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
275 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
277 copy_gop = npo->copy + npo->copy_prod++;
278 copy_gop->flags = GNTCOPY_dest_gref;
279 copy_gop->len = bytes;
282 copy_gop->source.domid = foreign_vif->domid;
283 copy_gop->source.u.ref = foreign_gref;
284 copy_gop->flags |= GNTCOPY_source_gref;
286 copy_gop->source.domid = DOMID_SELF;
287 copy_gop->source.u.gmfn =
288 virt_to_mfn(page_address(page));
290 copy_gop->source.offset = offset;
292 copy_gop->dest.domid = vif->domid;
293 copy_gop->dest.offset = npo->copy_off;
294 copy_gop->dest.u.ref = npo->copy_gref;
296 npo->copy_off += bytes;
303 if (offset == PAGE_SIZE && size) {
304 BUG_ON(!PageCompound(page));
309 /* Leave a gap for the GSO descriptor. */
310 if (skb_is_gso(skb)) {
311 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
312 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
313 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
314 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
317 if (*head && ((1 << gso_type) & vif->gso_mask))
320 *head = 0; /* There must be something in this buffer now. */
326 * Find the grant ref for a given frag in a chain of struct ubuf_info's
327 * skb: the skb itself
328 * i: the frag's number
329 * ubuf: a pointer to an element in the chain. It should not be NULL
331 * Returns a pointer to the element in the chain where the page were found. If
332 * not found, returns NULL.
333 * See the definition of callback_struct in common.h for more details about
336 static const struct ubuf_info *xenvif_find_gref(const struct sk_buff *const skb,
338 const struct ubuf_info *ubuf)
340 struct xenvif *foreign_vif = ubuf_to_vif(ubuf);
343 u16 pending_idx = ubuf->desc;
345 if (skb_shinfo(skb)->frags[i].page.p ==
346 foreign_vif->mmap_pages[pending_idx])
348 ubuf = (struct ubuf_info *) ubuf->ctx;
355 * Prepare an SKB to be transmitted to the frontend.
357 * This function is responsible for allocating grant operations, meta
360 * It returns the number of meta structures consumed. The number of
361 * ring slots used is always equal to the number of meta slots used
362 * plus the number of GSO descriptors used. Currently, we use either
363 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
364 * frontend-side LRO).
366 static int xenvif_gop_skb(struct sk_buff *skb,
367 struct netrx_pending_operations *npo)
369 struct xenvif *vif = netdev_priv(skb->dev);
370 int nr_frags = skb_shinfo(skb)->nr_frags;
372 struct xen_netif_rx_request *req;
373 struct xenvif_rx_meta *meta;
378 const struct ubuf_info *ubuf = skb_shinfo(skb)->destructor_arg;
379 const struct ubuf_info *const head_ubuf = ubuf;
381 old_meta_prod = npo->meta_prod;
383 gso_type = XEN_NETIF_GSO_TYPE_NONE;
384 if (skb_is_gso(skb)) {
385 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
386 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
387 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
388 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
391 /* Set up a GSO prefix descriptor, if necessary */
392 if ((1 << gso_type) & vif->gso_prefix_mask) {
393 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
394 meta = npo->meta + npo->meta_prod++;
395 meta->gso_type = gso_type;
396 meta->gso_size = skb_shinfo(skb)->gso_size;
401 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
402 meta = npo->meta + npo->meta_prod++;
404 if ((1 << gso_type) & vif->gso_mask) {
405 meta->gso_type = gso_type;
406 meta->gso_size = skb_shinfo(skb)->gso_size;
408 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
415 npo->copy_gref = req->gref;
418 while (data < skb_tail_pointer(skb)) {
419 unsigned int offset = offset_in_page(data);
420 unsigned int len = PAGE_SIZE - offset;
422 if (data + len > skb_tail_pointer(skb))
423 len = skb_tail_pointer(skb) - data;
425 xenvif_gop_frag_copy(vif, skb, npo,
426 virt_to_page(data), len, offset, &head,
432 for (i = 0; i < nr_frags; i++) {
433 /* This variable also signals whether foreign_gref has a real
436 struct xenvif *foreign_vif = NULL;
437 grant_ref_t foreign_gref;
439 if ((skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) &&
440 (ubuf->callback == &xenvif_zerocopy_callback)) {
441 const struct ubuf_info *const startpoint = ubuf;
443 /* Ideally ubuf points to the chain element which
444 * belongs to this frag. Or if frags were removed from
445 * the beginning, then shortly before it.
447 ubuf = xenvif_find_gref(skb, i, ubuf);
449 /* Try again from the beginning of the list, if we
450 * haven't tried from there. This only makes sense in
451 * the unlikely event of reordering the original frags.
452 * For injected local pages it's an unnecessary second
455 if (unlikely(!ubuf) && startpoint != head_ubuf)
456 ubuf = xenvif_find_gref(skb, i, head_ubuf);
459 u16 pending_idx = ubuf->desc;
461 foreign_vif = ubuf_to_vif(ubuf);
462 foreign_gref = foreign_vif->pending_tx_info[pending_idx].req.gref;
463 /* Just a safety measure. If this was the last
464 * element on the list, the for loop will
465 * iterate again if a local page were added to
466 * the end. Using head_ubuf here prevents the
467 * second search on the chain. Or the original
468 * frags changed order, but that's less likely.
469 * In any way, ubuf shouldn't be NULL.
472 (struct ubuf_info *) ubuf->ctx :
475 /* This frag was a local page, added to the
476 * array after the skb left netback.
480 xenvif_gop_frag_copy(vif, skb, npo,
481 skb_frag_page(&skb_shinfo(skb)->frags[i]),
482 skb_frag_size(&skb_shinfo(skb)->frags[i]),
483 skb_shinfo(skb)->frags[i].page_offset,
486 foreign_vif ? foreign_gref : UINT_MAX);
489 return npo->meta_prod - old_meta_prod;
493 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
494 * used to set up the operations on the top of
495 * netrx_pending_operations, which have since been done. Check that
496 * they didn't give any errors and advance over them.
498 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
499 struct netrx_pending_operations *npo)
501 struct gnttab_copy *copy_op;
502 int status = XEN_NETIF_RSP_OKAY;
505 for (i = 0; i < nr_meta_slots; i++) {
506 copy_op = npo->copy + npo->copy_cons++;
507 if (copy_op->status != GNTST_okay) {
509 "Bad status %d from copy to DOM%d.\n",
510 copy_op->status, vif->domid);
511 status = XEN_NETIF_RSP_ERROR;
518 static void xenvif_add_frag_responses(struct xenvif *vif, int status,
519 struct xenvif_rx_meta *meta,
523 unsigned long offset;
525 /* No fragments used */
526 if (nr_meta_slots <= 1)
531 for (i = 0; i < nr_meta_slots; i++) {
533 if (i == nr_meta_slots - 1)
536 flags = XEN_NETRXF_more_data;
539 make_rx_response(vif, meta[i].id, status, offset,
540 meta[i].size, flags);
544 struct xenvif_rx_cb {
548 #define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb)
550 void xenvif_kick_thread(struct xenvif *vif)
555 static void xenvif_rx_action(struct xenvif *vif)
559 struct xen_netif_rx_response *resp;
560 struct sk_buff_head rxq;
564 unsigned long offset;
565 bool need_to_notify = false;
567 struct netrx_pending_operations npo = {
568 .copy = vif->grant_copy_op,
572 skb_queue_head_init(&rxq);
574 while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
575 RING_IDX max_slots_needed;
576 RING_IDX old_req_cons;
577 RING_IDX ring_slots_used;
580 /* We need a cheap worse case estimate for the number of
584 max_slots_needed = DIV_ROUND_UP(offset_in_page(skb->data) +
587 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
591 size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
592 offset = skb_shinfo(skb)->frags[i].page_offset;
594 /* For a worse-case estimate we need to factor in
595 * the fragment page offset as this will affect the
596 * number of times xenvif_gop_frag_copy() will
597 * call start_new_rx_buffer().
599 max_slots_needed += DIV_ROUND_UP(offset + size,
603 /* To avoid the estimate becoming too pessimal for some
604 * frontends that limit posted rx requests, cap the estimate
607 if (max_slots_needed > MAX_SKB_FRAGS)
608 max_slots_needed = MAX_SKB_FRAGS;
610 /* We may need one more slot for GSO metadata */
611 if (skb_is_gso(skb) &&
612 (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
613 skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
616 /* If the skb may not fit then bail out now */
617 if (!xenvif_rx_ring_slots_available(vif, max_slots_needed)) {
618 skb_queue_head(&vif->rx_queue, skb);
619 need_to_notify = true;
620 vif->rx_last_skb_slots = max_slots_needed;
623 vif->rx_last_skb_slots = 0;
625 old_req_cons = vif->rx.req_cons;
626 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo);
627 ring_slots_used = vif->rx.req_cons - old_req_cons;
629 BUG_ON(ring_slots_used > max_slots_needed);
631 __skb_queue_tail(&rxq, skb);
634 BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta));
639 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
640 gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod);
642 while ((skb = __skb_dequeue(&rxq)) != NULL) {
644 if ((1 << vif->meta[npo.meta_cons].gso_type) &
645 vif->gso_prefix_mask) {
646 resp = RING_GET_RESPONSE(&vif->rx,
647 vif->rx.rsp_prod_pvt++);
649 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
651 resp->offset = vif->meta[npo.meta_cons].gso_size;
652 resp->id = vif->meta[npo.meta_cons].id;
653 resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
656 XENVIF_RX_CB(skb)->meta_slots_used--;
660 vif->dev->stats.tx_bytes += skb->len;
661 vif->dev->stats.tx_packets++;
663 status = xenvif_check_gop(vif,
664 XENVIF_RX_CB(skb)->meta_slots_used,
667 if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
670 flags = XEN_NETRXF_more_data;
672 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
673 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
674 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
675 /* remote but checksummed. */
676 flags |= XEN_NETRXF_data_validated;
679 resp = make_rx_response(vif, vif->meta[npo.meta_cons].id,
681 vif->meta[npo.meta_cons].size,
684 if ((1 << vif->meta[npo.meta_cons].gso_type) &
686 struct xen_netif_extra_info *gso =
687 (struct xen_netif_extra_info *)
688 RING_GET_RESPONSE(&vif->rx,
689 vif->rx.rsp_prod_pvt++);
691 resp->flags |= XEN_NETRXF_extra_info;
693 gso->u.gso.type = vif->meta[npo.meta_cons].gso_type;
694 gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
696 gso->u.gso.features = 0;
698 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
702 xenvif_add_frag_responses(vif, status,
703 vif->meta + npo.meta_cons + 1,
704 XENVIF_RX_CB(skb)->meta_slots_used);
706 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
708 need_to_notify |= !!ret;
710 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
716 notify_remote_via_irq(vif->rx_irq);
719 void xenvif_napi_schedule_or_enable_events(struct xenvif *vif)
723 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
726 napi_schedule(&vif->napi);
729 static void tx_add_credit(struct xenvif *vif)
731 unsigned long max_burst, max_credit;
734 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
735 * Otherwise the interface can seize up due to insufficient credit.
737 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
738 max_burst = min(max_burst, 131072UL);
739 max_burst = max(max_burst, vif->credit_bytes);
741 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
742 max_credit = vif->remaining_credit + vif->credit_bytes;
743 if (max_credit < vif->remaining_credit)
744 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
746 vif->remaining_credit = min(max_credit, max_burst);
749 static void tx_credit_callback(unsigned long data)
751 struct xenvif *vif = (struct xenvif *)data;
753 xenvif_napi_schedule_or_enable_events(vif);
756 static void xenvif_tx_err(struct xenvif *vif,
757 struct xen_netif_tx_request *txp, RING_IDX end)
759 RING_IDX cons = vif->tx.req_cons;
763 spin_lock_irqsave(&vif->response_lock, flags);
764 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
765 spin_unlock_irqrestore(&vif->response_lock, flags);
768 txp = RING_GET_REQUEST(&vif->tx, cons++);
770 vif->tx.req_cons = cons;
773 static void xenvif_fatal_tx_err(struct xenvif *vif)
775 netdev_err(vif->dev, "fatal error; disabling device\n");
776 vif->disabled = true;
777 xenvif_kick_thread(vif);
780 static int xenvif_count_requests(struct xenvif *vif,
781 struct xen_netif_tx_request *first,
782 struct xen_netif_tx_request *txp,
785 RING_IDX cons = vif->tx.req_cons;
790 if (!(first->flags & XEN_NETTXF_more_data))
794 struct xen_netif_tx_request dropped_tx = { 0 };
796 if (slots >= work_to_do) {
798 "Asked for %d slots but exceeds this limit\n",
800 xenvif_fatal_tx_err(vif);
804 /* This guest is really using too many slots and
805 * considered malicious.
807 if (unlikely(slots >= fatal_skb_slots)) {
809 "Malicious frontend using %d slots, threshold %u\n",
810 slots, fatal_skb_slots);
811 xenvif_fatal_tx_err(vif);
815 /* Xen network protocol had implicit dependency on
816 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
817 * the historical MAX_SKB_FRAGS value 18 to honor the
818 * same behavior as before. Any packet using more than
819 * 18 slots but less than fatal_skb_slots slots is
822 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
825 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
826 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
833 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
836 /* If the guest submitted a frame >= 64 KiB then
837 * first->size overflowed and following slots will
838 * appear to be larger than the frame.
840 * This cannot be fatal error as there are buggy
841 * frontends that do this.
843 * Consume all slots and drop the packet.
845 if (!drop_err && txp->size > first->size) {
848 "Invalid tx request, slot size %u > remaining size %u\n",
849 txp->size, first->size);
853 first->size -= txp->size;
856 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
857 netdev_err(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
858 txp->offset, txp->size);
859 xenvif_fatal_tx_err(vif);
863 more_data = txp->flags & XEN_NETTXF_more_data;
871 xenvif_tx_err(vif, first, cons + slots);
879 struct xenvif_tx_cb {
883 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
885 static inline void xenvif_tx_create_map_op(struct xenvif *vif,
887 struct xen_netif_tx_request *txp,
888 struct gnttab_map_grant_ref *mop)
890 vif->pages_to_map[mop-vif->tx_map_ops] = vif->mmap_pages[pending_idx];
891 gnttab_set_map_op(mop, idx_to_kaddr(vif, pending_idx),
892 GNTMAP_host_map | GNTMAP_readonly,
893 txp->gref, vif->domid);
895 memcpy(&vif->pending_tx_info[pending_idx].req, txp,
899 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
901 struct sk_buff *skb =
902 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
903 GFP_ATOMIC | __GFP_NOWARN);
904 if (unlikely(skb == NULL))
907 /* Packets passed to netif_rx() must have some headroom. */
908 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
910 /* Initialize it here to avoid later surprises */
911 skb_shinfo(skb)->destructor_arg = NULL;
916 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
918 struct xen_netif_tx_request *txp,
919 struct gnttab_map_grant_ref *gop)
921 struct skb_shared_info *shinfo = skb_shinfo(skb);
922 skb_frag_t *frags = shinfo->frags;
923 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
925 pending_ring_idx_t index;
926 unsigned int nr_slots, frag_overflow = 0;
928 /* At this point shinfo->nr_frags is in fact the number of
929 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
931 if (shinfo->nr_frags > MAX_SKB_FRAGS) {
932 frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS;
933 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
934 shinfo->nr_frags = MAX_SKB_FRAGS;
936 nr_slots = shinfo->nr_frags;
938 /* Skip first skb fragment if it is on same page as header fragment. */
939 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
941 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
942 shinfo->nr_frags++, txp++, gop++) {
943 index = pending_index(vif->pending_cons++);
944 pending_idx = vif->pending_ring[index];
945 xenvif_tx_create_map_op(vif, pending_idx, txp, gop);
946 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
950 struct sk_buff *nskb = xenvif_alloc_skb(0);
951 if (unlikely(nskb == NULL)) {
954 "Can't allocate the frag_list skb.\n");
958 shinfo = skb_shinfo(nskb);
959 frags = shinfo->frags;
961 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
962 shinfo->nr_frags++, txp++, gop++) {
963 index = pending_index(vif->pending_cons++);
964 pending_idx = vif->pending_ring[index];
965 xenvif_tx_create_map_op(vif, pending_idx, txp, gop);
966 frag_set_pending_idx(&frags[shinfo->nr_frags],
970 skb_shinfo(skb)->frag_list = nskb;
976 static inline void xenvif_grant_handle_set(struct xenvif *vif,
978 grant_handle_t handle)
980 if (unlikely(vif->grant_tx_handle[pending_idx] !=
981 NETBACK_INVALID_HANDLE)) {
983 "Trying to overwrite active handle! pending_idx: %x\n",
987 vif->grant_tx_handle[pending_idx] = handle;
990 static inline void xenvif_grant_handle_reset(struct xenvif *vif,
993 if (unlikely(vif->grant_tx_handle[pending_idx] ==
994 NETBACK_INVALID_HANDLE)) {
996 "Trying to unmap invalid handle! pending_idx: %x\n",
1000 vif->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
1003 static int xenvif_tx_check_gop(struct xenvif *vif,
1004 struct sk_buff *skb,
1005 struct gnttab_map_grant_ref **gopp_map,
1006 struct gnttab_copy **gopp_copy)
1008 struct gnttab_map_grant_ref *gop_map = *gopp_map;
1009 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1010 struct skb_shared_info *shinfo = skb_shinfo(skb);
1011 int nr_frags = shinfo->nr_frags;
1013 struct sk_buff *first_skb = NULL;
1015 /* Check status of header. */
1016 err = (*gopp_copy)->status;
1018 if (unlikely(err)) {
1019 if (net_ratelimit())
1020 netdev_dbg(vif->dev,
1021 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
1022 (*gopp_copy)->status,
1024 (*gopp_copy)->source.u.ref);
1025 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
1029 for (i = 0; i < nr_frags; i++, gop_map++) {
1032 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
1034 /* Check error status: if okay then remember grant handle. */
1035 newerr = gop_map->status;
1037 if (likely(!newerr)) {
1038 xenvif_grant_handle_set(vif,
1041 /* Had a previous error? Invalidate this fragment. */
1043 xenvif_idx_unmap(vif, pending_idx);
1047 /* Error on this fragment: respond to client with an error. */
1048 if (net_ratelimit())
1049 netdev_dbg(vif->dev,
1050 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
1055 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
1057 /* Not the first error? Preceding frags already invalidated. */
1060 /* First error: invalidate preceding fragments. */
1061 for (j = 0; j < i; j++) {
1062 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1063 xenvif_idx_unmap(vif, pending_idx);
1066 /* Remember the error: invalidate all subsequent fragments. */
1070 if (skb_has_frag_list(skb)) {
1072 skb = shinfo->frag_list;
1073 shinfo = skb_shinfo(skb);
1074 nr_frags = shinfo->nr_frags;
1079 /* There was a mapping error in the frag_list skb. We have to unmap
1080 * the first skb's frags
1082 if (first_skb && err) {
1084 shinfo = skb_shinfo(first_skb);
1085 for (j = 0; j < shinfo->nr_frags; j++) {
1086 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1087 xenvif_idx_unmap(vif, pending_idx);
1091 *gopp_map = gop_map;
1095 static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
1097 struct skb_shared_info *shinfo = skb_shinfo(skb);
1098 int nr_frags = shinfo->nr_frags;
1100 u16 prev_pending_idx = INVALID_PENDING_IDX;
1102 for (i = 0; i < nr_frags; i++) {
1103 skb_frag_t *frag = shinfo->frags + i;
1104 struct xen_netif_tx_request *txp;
1108 pending_idx = frag_get_pending_idx(frag);
1110 /* If this is not the first frag, chain it to the previous*/
1111 if (prev_pending_idx == INVALID_PENDING_IDX)
1112 skb_shinfo(skb)->destructor_arg =
1113 &callback_param(vif, pending_idx);
1115 callback_param(vif, prev_pending_idx).ctx =
1116 &callback_param(vif, pending_idx);
1118 callback_param(vif, pending_idx).ctx = NULL;
1119 prev_pending_idx = pending_idx;
1121 txp = &vif->pending_tx_info[pending_idx].req;
1122 page = virt_to_page(idx_to_kaddr(vif, pending_idx));
1123 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1124 skb->len += txp->size;
1125 skb->data_len += txp->size;
1126 skb->truesize += txp->size;
1128 /* Take an extra reference to offset network stack's put_page */
1129 get_page(vif->mmap_pages[pending_idx]);
1131 /* FIXME: __skb_fill_page_desc set this to true because page->pfmemalloc
1132 * overlaps with "index", and "mapping" is not set. I think mapping
1133 * should be set. If delivered to local stack, it would drop this
1134 * skb in sk_filter unless the socket has the right to use it.
1136 skb->pfmemalloc = false;
1139 static int xenvif_get_extras(struct xenvif *vif,
1140 struct xen_netif_extra_info *extras,
1143 struct xen_netif_extra_info extra;
1144 RING_IDX cons = vif->tx.req_cons;
1147 if (unlikely(work_to_do-- <= 0)) {
1148 netdev_err(vif->dev, "Missing extra info\n");
1149 xenvif_fatal_tx_err(vif);
1153 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1155 if (unlikely(!extra.type ||
1156 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1157 vif->tx.req_cons = ++cons;
1158 netdev_err(vif->dev,
1159 "Invalid extra type: %d\n", extra.type);
1160 xenvif_fatal_tx_err(vif);
1164 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1165 vif->tx.req_cons = ++cons;
1166 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1171 static int xenvif_set_skb_gso(struct xenvif *vif,
1172 struct sk_buff *skb,
1173 struct xen_netif_extra_info *gso)
1175 if (!gso->u.gso.size) {
1176 netdev_err(vif->dev, "GSO size must not be zero.\n");
1177 xenvif_fatal_tx_err(vif);
1181 switch (gso->u.gso.type) {
1182 case XEN_NETIF_GSO_TYPE_TCPV4:
1183 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1185 case XEN_NETIF_GSO_TYPE_TCPV6:
1186 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1189 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1190 xenvif_fatal_tx_err(vif);
1194 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1195 /* gso_segs will be calculated later */
1200 static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1202 bool recalculate_partial_csum = false;
1204 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1205 * peers can fail to set NETRXF_csum_blank when sending a GSO
1206 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1207 * recalculate the partial checksum.
1209 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1210 vif->rx_gso_checksum_fixup++;
1211 skb->ip_summed = CHECKSUM_PARTIAL;
1212 recalculate_partial_csum = true;
1215 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1216 if (skb->ip_summed != CHECKSUM_PARTIAL)
1219 return skb_checksum_setup(skb, recalculate_partial_csum);
1222 static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1224 u64 now = get_jiffies_64();
1225 u64 next_credit = vif->credit_window_start +
1226 msecs_to_jiffies(vif->credit_usec / 1000);
1228 /* Timer could already be pending in rare cases. */
1229 if (timer_pending(&vif->credit_timeout))
1232 /* Passed the point where we can replenish credit? */
1233 if (time_after_eq64(now, next_credit)) {
1234 vif->credit_window_start = now;
1238 /* Still too big to send right now? Set a callback. */
1239 if (size > vif->remaining_credit) {
1240 vif->credit_timeout.data =
1242 vif->credit_timeout.function =
1244 mod_timer(&vif->credit_timeout,
1246 vif->credit_window_start = next_credit;
1254 static void xenvif_tx_build_gops(struct xenvif *vif,
1259 struct gnttab_map_grant_ref *gop = vif->tx_map_ops, *request_gop;
1260 struct sk_buff *skb;
1263 while (skb_queue_len(&vif->tx_queue) < budget) {
1264 struct xen_netif_tx_request txreq;
1265 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1266 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1270 unsigned int data_len;
1271 pending_ring_idx_t index;
1273 if (vif->tx.sring->req_prod - vif->tx.req_cons >
1274 XEN_NETIF_TX_RING_SIZE) {
1275 netdev_err(vif->dev,
1276 "Impossible number of requests. "
1277 "req_prod %d, req_cons %d, size %ld\n",
1278 vif->tx.sring->req_prod, vif->tx.req_cons,
1279 XEN_NETIF_TX_RING_SIZE);
1280 xenvif_fatal_tx_err(vif);
1284 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx);
1288 idx = vif->tx.req_cons;
1289 rmb(); /* Ensure that we see the request before we copy it. */
1290 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1292 /* Credit-based scheduling. */
1293 if (txreq.size > vif->remaining_credit &&
1294 tx_credit_exceeded(vif, txreq.size))
1297 vif->remaining_credit -= txreq.size;
1300 vif->tx.req_cons = ++idx;
1302 memset(extras, 0, sizeof(extras));
1303 if (txreq.flags & XEN_NETTXF_extra_info) {
1304 work_to_do = xenvif_get_extras(vif, extras,
1306 idx = vif->tx.req_cons;
1307 if (unlikely(work_to_do < 0))
1311 ret = xenvif_count_requests(vif, &txreq, txfrags, work_to_do);
1312 if (unlikely(ret < 0))
1317 if (unlikely(txreq.size < ETH_HLEN)) {
1318 netdev_dbg(vif->dev,
1319 "Bad packet size: %d\n", txreq.size);
1320 xenvif_tx_err(vif, &txreq, idx);
1324 /* No crossing a page as the payload mustn't fragment. */
1325 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1326 netdev_err(vif->dev,
1327 "txreq.offset: %x, size: %u, end: %lu\n",
1328 txreq.offset, txreq.size,
1329 (txreq.offset&~PAGE_MASK) + txreq.size);
1330 xenvif_fatal_tx_err(vif);
1334 index = pending_index(vif->pending_cons);
1335 pending_idx = vif->pending_ring[index];
1337 data_len = (txreq.size > PKT_PROT_LEN &&
1338 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1339 PKT_PROT_LEN : txreq.size;
1341 skb = xenvif_alloc_skb(data_len);
1342 if (unlikely(skb == NULL)) {
1343 netdev_dbg(vif->dev,
1344 "Can't allocate a skb in start_xmit.\n");
1345 xenvif_tx_err(vif, &txreq, idx);
1349 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1350 struct xen_netif_extra_info *gso;
1351 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1353 if (xenvif_set_skb_gso(vif, skb, gso)) {
1354 /* Failure in xenvif_set_skb_gso is fatal. */
1360 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
1362 __skb_put(skb, data_len);
1363 vif->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1364 vif->tx_copy_ops[*copy_ops].source.domid = vif->domid;
1365 vif->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1367 vif->tx_copy_ops[*copy_ops].dest.u.gmfn =
1368 virt_to_mfn(skb->data);
1369 vif->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1370 vif->tx_copy_ops[*copy_ops].dest.offset =
1371 offset_in_page(skb->data);
1373 vif->tx_copy_ops[*copy_ops].len = data_len;
1374 vif->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1378 skb_shinfo(skb)->nr_frags = ret;
1379 if (data_len < txreq.size) {
1380 skb_shinfo(skb)->nr_frags++;
1381 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1383 xenvif_tx_create_map_op(vif, pending_idx, &txreq, gop);
1386 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1387 INVALID_PENDING_IDX);
1388 memcpy(&vif->pending_tx_info[pending_idx].req, &txreq,
1392 vif->pending_cons++;
1394 request_gop = xenvif_get_requests(vif, skb, txfrags, gop);
1395 if (request_gop == NULL) {
1397 xenvif_tx_err(vif, &txreq, idx);
1402 __skb_queue_tail(&vif->tx_queue, skb);
1404 vif->tx.req_cons = idx;
1406 if (((gop-vif->tx_map_ops) >= ARRAY_SIZE(vif->tx_map_ops)) ||
1407 (*copy_ops >= ARRAY_SIZE(vif->tx_copy_ops)))
1411 (*map_ops) = gop - vif->tx_map_ops;
1415 /* Consolidate skb with a frag_list into a brand new one with local pages on
1416 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1418 static int xenvif_handle_frag_list(struct xenvif *vif, struct sk_buff *skb)
1420 unsigned int offset = skb_headlen(skb);
1421 skb_frag_t frags[MAX_SKB_FRAGS];
1423 struct ubuf_info *uarg;
1424 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1426 vif->tx_zerocopy_sent += 2;
1427 vif->tx_frag_overflow++;
1429 xenvif_fill_frags(vif, nskb);
1430 /* Subtract frags size, we will correct it later */
1431 skb->truesize -= skb->data_len;
1432 skb->len += nskb->len;
1433 skb->data_len += nskb->len;
1435 /* create a brand new frags array and coalesce there */
1436 for (i = 0; offset < skb->len; i++) {
1440 BUG_ON(i >= MAX_SKB_FRAGS);
1441 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
1444 skb->truesize += skb->data_len;
1445 for (j = 0; j < i; j++)
1446 put_page(frags[j].page.p);
1450 if (offset + PAGE_SIZE < skb->len)
1453 len = skb->len - offset;
1454 if (skb_copy_bits(skb, offset, page_address(page), len))
1458 frags[i].page.p = page;
1459 frags[i].page_offset = 0;
1460 skb_frag_size_set(&frags[i], len);
1462 /* swap out with old one */
1463 memcpy(skb_shinfo(skb)->frags,
1465 i * sizeof(skb_frag_t));
1466 skb_shinfo(skb)->nr_frags = i;
1467 skb->truesize += i * PAGE_SIZE;
1469 /* remove traces of mapped pages and frag_list */
1470 skb_frag_list_init(skb);
1471 uarg = skb_shinfo(skb)->destructor_arg;
1472 uarg->callback(uarg, true);
1473 skb_shinfo(skb)->destructor_arg = NULL;
1475 skb_shinfo(nskb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1481 static int xenvif_tx_submit(struct xenvif *vif)
1483 struct gnttab_map_grant_ref *gop_map = vif->tx_map_ops;
1484 struct gnttab_copy *gop_copy = vif->tx_copy_ops;
1485 struct sk_buff *skb;
1488 while ((skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
1489 struct xen_netif_tx_request *txp;
1493 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1494 txp = &vif->pending_tx_info[pending_idx].req;
1496 /* Check the remap error code. */
1497 if (unlikely(xenvif_tx_check_gop(vif, skb, &gop_map, &gop_copy))) {
1498 skb_shinfo(skb)->nr_frags = 0;
1503 data_len = skb->len;
1504 callback_param(vif, pending_idx).ctx = NULL;
1505 if (data_len < txp->size) {
1506 /* Append the packet payload as a fragment. */
1507 txp->offset += data_len;
1508 txp->size -= data_len;
1510 /* Schedule a response immediately. */
1511 xenvif_idx_release(vif, pending_idx,
1512 XEN_NETIF_RSP_OKAY);
1515 if (txp->flags & XEN_NETTXF_csum_blank)
1516 skb->ip_summed = CHECKSUM_PARTIAL;
1517 else if (txp->flags & XEN_NETTXF_data_validated)
1518 skb->ip_summed = CHECKSUM_UNNECESSARY;
1520 xenvif_fill_frags(vif, skb);
1522 if (unlikely(skb_has_frag_list(skb))) {
1523 if (xenvif_handle_frag_list(vif, skb)) {
1524 if (net_ratelimit())
1525 netdev_err(vif->dev,
1526 "Not enough memory to consolidate frag_list!\n");
1527 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1533 if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) {
1534 int target = min_t(int, skb->len, PKT_PROT_LEN);
1535 __pskb_pull_tail(skb, target - skb_headlen(skb));
1538 skb->dev = vif->dev;
1539 skb->protocol = eth_type_trans(skb, skb->dev);
1540 skb_reset_network_header(skb);
1542 if (checksum_setup(vif, skb)) {
1543 netdev_dbg(vif->dev,
1544 "Can't setup checksum in net_tx_action\n");
1545 /* We have to set this flag to trigger the callback */
1546 if (skb_shinfo(skb)->destructor_arg)
1547 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1552 skb_probe_transport_header(skb, 0);
1554 /* If the packet is GSO then we will have just set up the
1555 * transport header offset in checksum_setup so it's now
1556 * straightforward to calculate gso_segs.
1558 if (skb_is_gso(skb)) {
1559 int mss = skb_shinfo(skb)->gso_size;
1560 int hdrlen = skb_transport_header(skb) -
1561 skb_mac_header(skb) +
1564 skb_shinfo(skb)->gso_segs =
1565 DIV_ROUND_UP(skb->len - hdrlen, mss);
1568 vif->dev->stats.rx_bytes += skb->len;
1569 vif->dev->stats.rx_packets++;
1573 /* Set this flag right before netif_receive_skb, otherwise
1574 * someone might think this packet already left netback, and
1575 * do a skb_copy_ubufs while we are still in control of the
1576 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1578 if (skb_shinfo(skb)->destructor_arg) {
1579 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1580 vif->tx_zerocopy_sent++;
1583 netif_receive_skb(skb);
1589 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1591 unsigned long flags;
1592 pending_ring_idx_t index;
1593 struct xenvif *vif = ubuf_to_vif(ubuf);
1595 /* This is the only place where we grab this lock, to protect callbacks
1598 spin_lock_irqsave(&vif->callback_lock, flags);
1600 u16 pending_idx = ubuf->desc;
1601 ubuf = (struct ubuf_info *) ubuf->ctx;
1602 BUG_ON(vif->dealloc_prod - vif->dealloc_cons >=
1604 index = pending_index(vif->dealloc_prod);
1605 vif->dealloc_ring[index] = pending_idx;
1606 /* Sync with xenvif_tx_dealloc_action:
1607 * insert idx then incr producer.
1610 vif->dealloc_prod++;
1612 wake_up(&vif->dealloc_wq);
1613 spin_unlock_irqrestore(&vif->callback_lock, flags);
1615 if (likely(zerocopy_success))
1616 vif->tx_zerocopy_success++;
1618 vif->tx_zerocopy_fail++;
1621 static inline void xenvif_tx_dealloc_action(struct xenvif *vif)
1623 struct gnttab_unmap_grant_ref *gop;
1624 pending_ring_idx_t dc, dp;
1625 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1628 dc = vif->dealloc_cons;
1629 gop = vif->tx_unmap_ops;
1631 /* Free up any grants we have finished using */
1633 dp = vif->dealloc_prod;
1635 /* Ensure we see all indices enqueued by all
1636 * xenvif_zerocopy_callback().
1641 BUG_ON(gop - vif->tx_unmap_ops > MAX_PENDING_REQS);
1643 vif->dealloc_ring[pending_index(dc++)];
1645 pending_idx_release[gop-vif->tx_unmap_ops] =
1647 vif->pages_to_unmap[gop-vif->tx_unmap_ops] =
1648 vif->mmap_pages[pending_idx];
1649 gnttab_set_unmap_op(gop,
1650 idx_to_kaddr(vif, pending_idx),
1652 vif->grant_tx_handle[pending_idx]);
1653 xenvif_grant_handle_reset(vif, pending_idx);
1657 } while (dp != vif->dealloc_prod);
1659 vif->dealloc_cons = dc;
1661 if (gop - vif->tx_unmap_ops > 0) {
1663 ret = gnttab_unmap_refs(vif->tx_unmap_ops,
1665 vif->pages_to_unmap,
1666 gop - vif->tx_unmap_ops);
1668 netdev_err(vif->dev, "Unmap fail: nr_ops %tx ret %d\n",
1669 gop - vif->tx_unmap_ops, ret);
1670 for (i = 0; i < gop - vif->tx_unmap_ops; ++i) {
1671 if (gop[i].status != GNTST_okay)
1672 netdev_err(vif->dev,
1673 " host_addr: %llx handle: %x status: %d\n",
1682 for (i = 0; i < gop - vif->tx_unmap_ops; ++i)
1683 xenvif_idx_release(vif, pending_idx_release[i],
1684 XEN_NETIF_RSP_OKAY);
1688 /* Called after netfront has transmitted */
1689 int xenvif_tx_action(struct xenvif *vif, int budget)
1691 unsigned nr_mops, nr_cops = 0;
1694 if (unlikely(!tx_work_todo(vif)))
1697 xenvif_tx_build_gops(vif, budget, &nr_cops, &nr_mops);
1702 gnttab_batch_copy(vif->tx_copy_ops, nr_cops);
1704 ret = gnttab_map_refs(vif->tx_map_ops,
1711 work_done = xenvif_tx_submit(vif);
1716 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
1719 struct pending_tx_info *pending_tx_info;
1720 pending_ring_idx_t index;
1721 unsigned long flags;
1723 pending_tx_info = &vif->pending_tx_info[pending_idx];
1724 spin_lock_irqsave(&vif->response_lock, flags);
1725 make_tx_response(vif, &pending_tx_info->req, status);
1726 index = pending_index(vif->pending_prod);
1727 vif->pending_ring[index] = pending_idx;
1728 /* TX shouldn't use the index before we give it back here */
1730 vif->pending_prod++;
1731 spin_unlock_irqrestore(&vif->response_lock, flags);
1735 static void make_tx_response(struct xenvif *vif,
1736 struct xen_netif_tx_request *txp,
1739 RING_IDX i = vif->tx.rsp_prod_pvt;
1740 struct xen_netif_tx_response *resp;
1743 resp = RING_GET_RESPONSE(&vif->tx, i);
1747 if (txp->flags & XEN_NETTXF_extra_info)
1748 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1750 vif->tx.rsp_prod_pvt = ++i;
1751 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1753 notify_remote_via_irq(vif->tx_irq);
1756 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1763 RING_IDX i = vif->rx.rsp_prod_pvt;
1764 struct xen_netif_rx_response *resp;
1766 resp = RING_GET_RESPONSE(&vif->rx, i);
1767 resp->offset = offset;
1768 resp->flags = flags;
1770 resp->status = (s16)size;
1772 resp->status = (s16)st;
1774 vif->rx.rsp_prod_pvt = ++i;
1779 void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx)
1782 struct gnttab_unmap_grant_ref tx_unmap_op;
1784 gnttab_set_unmap_op(&tx_unmap_op,
1785 idx_to_kaddr(vif, pending_idx),
1787 vif->grant_tx_handle[pending_idx]);
1788 xenvif_grant_handle_reset(vif, pending_idx);
1790 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1791 &vif->mmap_pages[pending_idx], 1);
1793 netdev_err(vif->dev,
1794 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n",
1797 tx_unmap_op.host_addr,
1799 tx_unmap_op.status);
1803 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
1806 static inline int rx_work_todo(struct xenvif *vif)
1808 return (!skb_queue_empty(&vif->rx_queue) &&
1809 xenvif_rx_ring_slots_available(vif, vif->rx_last_skb_slots)) ||
1810 vif->rx_queue_purge;
1813 static inline int tx_work_todo(struct xenvif *vif)
1816 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)))
1822 static inline bool tx_dealloc_work_todo(struct xenvif *vif)
1824 return vif->dealloc_cons != vif->dealloc_prod;
1827 void xenvif_unmap_frontend_rings(struct xenvif *vif)
1830 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1833 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1837 int xenvif_map_frontend_rings(struct xenvif *vif,
1838 grant_ref_t tx_ring_ref,
1839 grant_ref_t rx_ring_ref)
1842 struct xen_netif_tx_sring *txs;
1843 struct xen_netif_rx_sring *rxs;
1847 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1848 tx_ring_ref, &addr);
1852 txs = (struct xen_netif_tx_sring *)addr;
1853 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1855 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1856 rx_ring_ref, &addr);
1860 rxs = (struct xen_netif_rx_sring *)addr;
1861 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1866 xenvif_unmap_frontend_rings(vif);
1870 void xenvif_stop_queue(struct xenvif *vif)
1872 if (!vif->can_queue)
1875 netif_stop_queue(vif->dev);
1878 static void xenvif_start_queue(struct xenvif *vif)
1880 if (xenvif_schedulable(vif))
1881 netif_wake_queue(vif->dev);
1884 int xenvif_kthread_guest_rx(void *data)
1886 struct xenvif *vif = data;
1887 struct sk_buff *skb;
1889 while (!kthread_should_stop()) {
1890 wait_event_interruptible(vif->wq,
1891 rx_work_todo(vif) ||
1893 kthread_should_stop());
1895 /* This frontend is found to be rogue, disable it in
1896 * kthread context. Currently this is only set when
1897 * netback finds out frontend sends malformed packet,
1898 * but we cannot disable the interface in softirq
1899 * context so we defer it here.
1901 if (unlikely(vif->disabled && netif_carrier_ok(vif->dev)))
1902 xenvif_carrier_off(vif);
1904 if (kthread_should_stop())
1907 if (vif->rx_queue_purge) {
1908 skb_queue_purge(&vif->rx_queue);
1909 vif->rx_queue_purge = false;
1912 if (!skb_queue_empty(&vif->rx_queue))
1913 xenvif_rx_action(vif);
1915 if (skb_queue_empty(&vif->rx_queue) &&
1916 netif_queue_stopped(vif->dev)) {
1917 del_timer_sync(&vif->wake_queue);
1918 xenvif_start_queue(vif);
1924 /* Bin any remaining skbs */
1925 while ((skb = skb_dequeue(&vif->rx_queue)) != NULL)
1931 int xenvif_dealloc_kthread(void *data)
1933 struct xenvif *vif = data;
1935 while (!kthread_should_stop()) {
1936 wait_event_interruptible(vif->dealloc_wq,
1937 tx_dealloc_work_todo(vif) ||
1938 kthread_should_stop());
1939 if (kthread_should_stop())
1942 xenvif_tx_dealloc_action(vif);
1946 /* Unmap anything remaining*/
1947 if (tx_dealloc_work_todo(vif))
1948 xenvif_tx_dealloc_action(vif);
1953 static int __init netback_init(void)
1960 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1961 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1962 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1963 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1966 rc = xenvif_xenbus_init();
1970 rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs);
1978 module_init(netback_init);
1980 static void __exit netback_fini(void)
1982 xenvif_xenbus_fini();
1984 module_exit(netback_fini);
1986 MODULE_LICENSE("Dual BSD/GPL");
1987 MODULE_ALIAS("xen-backend:vif");