/* * Back-end of the driver for virtual network devices. This portion of the * driver exports a 'unified' network-device interface that can be accessed * by any operating system that implements a compatible front end. A * reference front-end implementation can be found in: * drivers/net/xen-netfront.c * * Copyright (c) 2002-2005, K A Fraser * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #include "common.h" #include #include #include #include #include #include #include #include #include #include /* Provide an option to disable split event channels at load time as * event channels are limited resource. Split event channels are * enabled by default. */ bool separate_tx_rx_irq = true; module_param(separate_tx_rx_irq, bool, 0644); /* The time that packets can stay on the guest Rx internal queue * before they are dropped. */ unsigned int rx_drain_timeout_msecs = 10000; module_param(rx_drain_timeout_msecs, uint, 0444); /* The length of time before the frontend is considered unresponsive * because it isn't providing Rx slots. */ unsigned int rx_stall_timeout_msecs = 60000; module_param(rx_stall_timeout_msecs, uint, 0444); unsigned int xenvif_max_queues; module_param_named(max_queues, xenvif_max_queues, uint, 0644); MODULE_PARM_DESC(max_queues, "Maximum number of queues per virtual interface"); /* * This is the maximum slots a skb can have. If a guest sends a skb * which exceeds this limit it is considered malicious. */ #define FATAL_SKB_SLOTS_DEFAULT 20 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT; module_param(fatal_skb_slots, uint, 0444); /* The amount to copy out of the first guest Tx slot into the skb's * linear area. If the first slot has more data, it will be mapped * and put into the first frag. * * This is sized to avoid pulling headers from the frags for most * TCP/IP packets. */ #define XEN_NETBACK_TX_COPY_LEN 128 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, u8 status); static void make_tx_response(struct xenvif_queue *queue, struct xen_netif_tx_request *txp, s8 st); static void push_tx_responses(struct xenvif_queue *queue); static inline int tx_work_todo(struct xenvif_queue *queue); static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, u16 id, s8 st, u16 offset, u16 size, u16 flags); static inline unsigned long idx_to_pfn(struct xenvif_queue *queue, u16 idx) { return page_to_pfn(queue->mmap_pages[idx]); } static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue, u16 idx) { return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx)); } #define callback_param(vif, pending_idx) \ (vif->pending_tx_info[pending_idx].callback_struct) /* Find the containing VIF's structure from a pointer in pending_tx_info array */ static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf) { u16 pending_idx = ubuf->desc; struct pending_tx_info *temp = container_of(ubuf, struct pending_tx_info, callback_struct); return container_of(temp - pending_idx, struct xenvif_queue, pending_tx_info[0]); } static u16 frag_get_pending_idx(skb_frag_t *frag) { return (u16)frag->page_offset; } static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx) { frag->page_offset = pending_idx; } static inline pending_ring_idx_t pending_index(unsigned i) { return i & (MAX_PENDING_REQS-1); } bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed) { RING_IDX prod, cons; do { prod = queue->rx.sring->req_prod; cons = queue->rx.req_cons; if (prod - cons >= needed) return true; queue->rx.sring->req_event = prod + 1; /* Make sure event is visible before we check prod * again. */ mb(); } while (queue->rx.sring->req_prod != prod); return false; } void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb) { unsigned long flags; spin_lock_irqsave(&queue->rx_queue.lock, flags); __skb_queue_tail(&queue->rx_queue, skb); queue->rx_queue_len += skb->len; if (queue->rx_queue_len > queue->rx_queue_max) netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id)); spin_unlock_irqrestore(&queue->rx_queue.lock, flags); } static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue) { struct sk_buff *skb; spin_lock_irq(&queue->rx_queue.lock); skb = __skb_dequeue(&queue->rx_queue); if (skb) queue->rx_queue_len -= skb->len; spin_unlock_irq(&queue->rx_queue.lock); return skb; } static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue) { spin_lock_irq(&queue->rx_queue.lock); if (queue->rx_queue_len < queue->rx_queue_max) netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id)); spin_unlock_irq(&queue->rx_queue.lock); } static void xenvif_rx_queue_purge(struct xenvif_queue *queue) { struct sk_buff *skb; while ((skb = xenvif_rx_dequeue(queue)) != NULL) kfree_skb(skb); } static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue) { struct sk_buff *skb; for(;;) { skb = skb_peek(&queue->rx_queue); if (!skb) break; if (time_before(jiffies, XENVIF_RX_CB(skb)->expires)) break; xenvif_rx_dequeue(queue); kfree_skb(skb); } } struct netrx_pending_operations { unsigned copy_prod, copy_cons; unsigned meta_prod, meta_cons; struct gnttab_copy *copy; struct xenvif_rx_meta *meta; int copy_off; grant_ref_t copy_gref; }; static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue, struct netrx_pending_operations *npo) { struct xenvif_rx_meta *meta; struct xen_netif_rx_request *req; req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++); meta = npo->meta + npo->meta_prod++; meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; meta->gso_size = 0; meta->size = 0; meta->id = req->id; npo->copy_off = 0; npo->copy_gref = req->gref; return meta; } /* * Set up the grant operations for this fragment. If it's a flipping * interface, we also set up the unmap request from here. */ static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb, struct netrx_pending_operations *npo, struct page *page, unsigned long size, unsigned long offset, int *head) { struct gnttab_copy *copy_gop; struct xenvif_rx_meta *meta; unsigned long bytes; int gso_type = XEN_NETIF_GSO_TYPE_NONE; /* Data must not cross a page boundary. */ BUG_ON(size + offset > PAGE_SIZE<meta + npo->meta_prod - 1; /* Skip unused frames from start of page */ page += offset >> PAGE_SHIFT; offset &= ~PAGE_MASK; while (size > 0) { struct xen_page_foreign *foreign; BUG_ON(offset >= PAGE_SIZE); BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET); if (npo->copy_off == MAX_BUFFER_OFFSET) meta = get_next_rx_buffer(queue, npo); bytes = PAGE_SIZE - offset; if (bytes > size) bytes = size; if (npo->copy_off + bytes > MAX_BUFFER_OFFSET) bytes = MAX_BUFFER_OFFSET - npo->copy_off; copy_gop = npo->copy + npo->copy_prod++; copy_gop->flags = GNTCOPY_dest_gref; copy_gop->len = bytes; foreign = xen_page_foreign(page); if (foreign) { copy_gop->source.domid = foreign->domid; copy_gop->source.u.ref = foreign->gref; copy_gop->flags |= GNTCOPY_source_gref; } else { copy_gop->source.domid = DOMID_SELF; copy_gop->source.u.gmfn = virt_to_gfn(page_address(page)); } copy_gop->source.offset = offset; copy_gop->dest.domid = queue->vif->domid; copy_gop->dest.offset = npo->copy_off; copy_gop->dest.u.ref = npo->copy_gref; npo->copy_off += bytes; meta->size += bytes; offset += bytes; size -= bytes; /* Next frame */ if (offset == PAGE_SIZE && size) { BUG_ON(!PageCompound(page)); page++; offset = 0; } /* Leave a gap for the GSO descriptor. */ if (skb_is_gso(skb)) { if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) gso_type = XEN_NETIF_GSO_TYPE_TCPV4; else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) gso_type = XEN_NETIF_GSO_TYPE_TCPV6; } if (*head && ((1 << gso_type) & queue->vif->gso_mask)) queue->rx.req_cons++; *head = 0; /* There must be something in this buffer now. */ } } /* * Prepare an SKB to be transmitted to the frontend. * * This function is responsible for allocating grant operations, meta * structures, etc. * * It returns the number of meta structures consumed. The number of * ring slots used is always equal to the number of meta slots used * plus the number of GSO descriptors used. Currently, we use either * zero GSO descriptors (for non-GSO packets) or one descriptor (for * frontend-side LRO). */ static int xenvif_gop_skb(struct sk_buff *skb, struct netrx_pending_operations *npo, struct xenvif_queue *queue) { struct xenvif *vif = netdev_priv(skb->dev); int nr_frags = skb_shinfo(skb)->nr_frags; int i; struct xen_netif_rx_request *req; struct xenvif_rx_meta *meta; unsigned char *data; int head = 1; int old_meta_prod; int gso_type; old_meta_prod = npo->meta_prod; gso_type = XEN_NETIF_GSO_TYPE_NONE; if (skb_is_gso(skb)) { if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) gso_type = XEN_NETIF_GSO_TYPE_TCPV4; else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) gso_type = XEN_NETIF_GSO_TYPE_TCPV6; } /* Set up a GSO prefix descriptor, if necessary */ if ((1 << gso_type) & vif->gso_prefix_mask) { req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++); meta = npo->meta + npo->meta_prod++; meta->gso_type = gso_type; meta->gso_size = skb_shinfo(skb)->gso_size; meta->size = 0; meta->id = req->id; } req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++); meta = npo->meta + npo->meta_prod++; if ((1 << gso_type) & vif->gso_mask) { meta->gso_type = gso_type; meta->gso_size = skb_shinfo(skb)->gso_size; } else { meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; meta->gso_size = 0; } meta->size = 0; meta->id = req->id; npo->copy_off = 0; npo->copy_gref = req->gref; data = skb->data; while (data < skb_tail_pointer(skb)) { unsigned int offset = offset_in_page(data); unsigned int len = PAGE_SIZE - offset; if (data + len > skb_tail_pointer(skb)) len = skb_tail_pointer(skb) - data; xenvif_gop_frag_copy(queue, skb, npo, virt_to_page(data), len, offset, &head); data += len; } for (i = 0; i < nr_frags; i++) { xenvif_gop_frag_copy(queue, skb, npo, skb_frag_page(&skb_shinfo(skb)->frags[i]), skb_frag_size(&skb_shinfo(skb)->frags[i]), skb_shinfo(skb)->frags[i].page_offset, &head); } return npo->meta_prod - old_meta_prod; } /* * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was * used to set up the operations on the top of * netrx_pending_operations, which have since been done. Check that * they didn't give any errors and advance over them. */ static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots, struct netrx_pending_operations *npo) { struct gnttab_copy *copy_op; int status = XEN_NETIF_RSP_OKAY; int i; for (i = 0; i < nr_meta_slots; i++) { copy_op = npo->copy + npo->copy_cons++; if (copy_op->status != GNTST_okay) { netdev_dbg(vif->dev, "Bad status %d from copy to DOM%d.\n", copy_op->status, vif->domid); status = XEN_NETIF_RSP_ERROR; } } return status; } static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status, struct xenvif_rx_meta *meta, int nr_meta_slots) { int i; unsigned long offset; /* No fragments used */ if (nr_meta_slots <= 1) return; nr_meta_slots--; for (i = 0; i < nr_meta_slots; i++) { int flags; if (i == nr_meta_slots - 1) flags = 0; else flags = XEN_NETRXF_more_data; offset = 0; make_rx_response(queue, meta[i].id, status, offset, meta[i].size, flags); } } void xenvif_kick_thread(struct xenvif_queue *queue) { wake_up(&queue->wq); } static void xenvif_rx_action(struct xenvif_queue *queue) { s8 status; u16 flags; struct xen_netif_rx_response *resp; struct sk_buff_head rxq; struct sk_buff *skb; LIST_HEAD(notify); int ret; unsigned long offset; bool need_to_notify = false; struct netrx_pending_operations npo = { .copy = queue->grant_copy_op, .meta = queue->meta, }; skb_queue_head_init(&rxq); while (xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX) && (skb = xenvif_rx_dequeue(queue)) != NULL) { queue->last_rx_time = jiffies; XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue); __skb_queue_tail(&rxq, skb); } BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta)); if (!npo.copy_prod) goto done; BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS); gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod); while ((skb = __skb_dequeue(&rxq)) != NULL) { if ((1 << queue->meta[npo.meta_cons].gso_type) & queue->vif->gso_prefix_mask) { resp = RING_GET_RESPONSE(&queue->rx, queue->rx.rsp_prod_pvt++); resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data; resp->offset = queue->meta[npo.meta_cons].gso_size; resp->id = queue->meta[npo.meta_cons].id; resp->status = XENVIF_RX_CB(skb)->meta_slots_used; npo.meta_cons++; XENVIF_RX_CB(skb)->meta_slots_used--; } queue->stats.tx_bytes += skb->len; queue->stats.tx_packets++; status = xenvif_check_gop(queue->vif, XENVIF_RX_CB(skb)->meta_slots_used, &npo); if (XENVIF_RX_CB(skb)->meta_slots_used == 1) flags = 0; else flags = XEN_NETRXF_more_data; if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */ flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated; else if (skb->ip_summed == CHECKSUM_UNNECESSARY) /* remote but checksummed. */ flags |= XEN_NETRXF_data_validated; offset = 0; resp = make_rx_response(queue, queue->meta[npo.meta_cons].id, status, offset, queue->meta[npo.meta_cons].size, flags); if ((1 << queue->meta[npo.meta_cons].gso_type) & queue->vif->gso_mask) { struct xen_netif_extra_info *gso = (struct xen_netif_extra_info *) RING_GET_RESPONSE(&queue->rx, queue->rx.rsp_prod_pvt++); resp->flags |= XEN_NETRXF_extra_info; gso->u.gso.type = queue->meta[npo.meta_cons].gso_type; gso->u.gso.size = queue->meta[npo.meta_cons].gso_size; gso->u.gso.pad = 0; gso->u.gso.features = 0; gso->type = XEN_NETIF_EXTRA_TYPE_GSO; gso->flags = 0; } xenvif_add_frag_responses(queue, status, queue->meta + npo.meta_cons + 1, XENVIF_RX_CB(skb)->meta_slots_used); RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret); need_to_notify |= !!ret; npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used; dev_kfree_skb(skb); } done: if (need_to_notify) notify_remote_via_irq(queue->rx_irq); } void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue) { int more_to_do; RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do); if (more_to_do) napi_schedule(&queue->napi); } static void tx_add_credit(struct xenvif_queue *queue) { unsigned long max_burst, max_credit; /* * Allow a burst big enough to transmit a jumbo packet of up to 128kB. * Otherwise the interface can seize up due to insufficient credit. */ max_burst = RING_GET_REQUEST(&queue->tx, queue->tx.req_cons)->size; max_burst = min(max_burst, 131072UL); max_burst = max(max_burst, queue->credit_bytes); /* Take care that adding a new chunk of credit doesn't wrap to zero. */ max_credit = queue->remaining_credit + queue->credit_bytes; if (max_credit < queue->remaining_credit) max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */ queue->remaining_credit = min(max_credit, max_burst); } void xenvif_tx_credit_callback(unsigned long data) { struct xenvif_queue *queue = (struct xenvif_queue *)data; tx_add_credit(queue); xenvif_napi_schedule_or_enable_events(queue); } static void xenvif_tx_err(struct xenvif_queue *queue, struct xen_netif_tx_request *txp, RING_IDX end) { RING_IDX cons = queue->tx.req_cons; unsigned long flags; do { spin_lock_irqsave(&queue->response_lock, flags); make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR); push_tx_responses(queue); spin_unlock_irqrestore(&queue->response_lock, flags); if (cons == end) break; txp = RING_GET_REQUEST(&queue->tx, cons++); } while (1); queue->tx.req_cons = cons; } static void xenvif_fatal_tx_err(struct xenvif *vif) { netdev_err(vif->dev, "fatal error; disabling device\n"); vif->disabled = true; /* Disable the vif from queue 0's kthread */ if (vif->queues) xenvif_kick_thread(&vif->queues[0]); } static int xenvif_count_requests(struct xenvif_queue *queue, struct xen_netif_tx_request *first, struct xen_netif_tx_request *txp, int work_to_do) { RING_IDX cons = queue->tx.req_cons; int slots = 0; int drop_err = 0; int more_data; if (!(first->flags & XEN_NETTXF_more_data)) return 0; do { struct xen_netif_tx_request dropped_tx = { 0 }; if (slots >= work_to_do) { netdev_err(queue->vif->dev, "Asked for %d slots but exceeds this limit\n", work_to_do); xenvif_fatal_tx_err(queue->vif); return -ENODATA; } /* This guest is really using too many slots and * considered malicious. */ if (unlikely(slots >= fatal_skb_slots)) { netdev_err(queue->vif->dev, "Malicious frontend using %d slots, threshold %u\n", slots, fatal_skb_slots); xenvif_fatal_tx_err(queue->vif); return -E2BIG; } /* Xen network protocol had implicit dependency on * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to * the historical MAX_SKB_FRAGS value 18 to honor the * same behavior as before. Any packet using more than * 18 slots but less than fatal_skb_slots slots is * dropped */ if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) { if (net_ratelimit()) netdev_dbg(queue->vif->dev, "Too many slots (%d) exceeding limit (%d), dropping packet\n", slots, XEN_NETBK_LEGACY_SLOTS_MAX); drop_err = -E2BIG; } if (drop_err) txp = &dropped_tx; memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots), sizeof(*txp)); /* If the guest submitted a frame >= 64 KiB then * first->size overflowed and following slots will * appear to be larger than the frame. * * This cannot be fatal error as there are buggy * frontends that do this. * * Consume all slots and drop the packet. */ if (!drop_err && txp->size > first->size) { if (net_ratelimit()) netdev_dbg(queue->vif->dev, "Invalid tx request, slot size %u > remaining size %u\n", txp->size, first->size); drop_err = -EIO; } first->size -= txp->size; slots++; if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) { netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n", txp->offset, txp->size); xenvif_fatal_tx_err(queue->vif); return -EINVAL; } more_data = txp->flags & XEN_NETTXF_more_data; if (!drop_err) txp++; } while (more_data); if (drop_err) { xenvif_tx_err(queue, first, cons + slots); return drop_err; } return slots; } struct xenvif_tx_cb { u16 pending_idx; }; #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb) static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue, u16 pending_idx, struct xen_netif_tx_request *txp, struct gnttab_map_grant_ref *mop) { queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx]; gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx), GNTMAP_host_map | GNTMAP_readonly, txp->gref, queue->vif->domid); memcpy(&queue->pending_tx_info[pending_idx].req, txp, sizeof(*txp)); } static inline struct sk_buff *xenvif_alloc_skb(unsigned int size) { struct sk_buff *skb = alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN, GFP_ATOMIC | __GFP_NOWARN); if (unlikely(skb == NULL)) return NULL; /* Packets passed to netif_rx() must have some headroom. */ skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); /* Initialize it here to avoid later surprises */ skb_shinfo(skb)->destructor_arg = NULL; return skb; } static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue, struct sk_buff *skb, struct xen_netif_tx_request *txp, struct gnttab_map_grant_ref *gop, unsigned int frag_overflow, struct sk_buff *nskb) { struct skb_shared_info *shinfo = skb_shinfo(skb); skb_frag_t *frags = shinfo->frags; u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; int start; pending_ring_idx_t index; unsigned int nr_slots; nr_slots = shinfo->nr_frags; /* Skip first skb fragment if it is on same page as header fragment. */ start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx); for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots; shinfo->nr_frags++, txp++, gop++) { index = pending_index(queue->pending_cons++); pending_idx = queue->pending_ring[index]; xenvif_tx_create_map_op(queue, pending_idx, txp, gop); frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx); } if (frag_overflow) { shinfo = skb_shinfo(nskb); frags = shinfo->frags; for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow; shinfo->nr_frags++, txp++, gop++) { index = pending_index(queue->pending_cons++); pending_idx = queue->pending_ring[index]; xenvif_tx_create_map_op(queue, pending_idx, txp, gop); frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx); } skb_shinfo(skb)->frag_list = nskb; } return gop; } static inline void xenvif_grant_handle_set(struct xenvif_queue *queue, u16 pending_idx, grant_handle_t handle) { if (unlikely(queue->grant_tx_handle[pending_idx] != NETBACK_INVALID_HANDLE)) { netdev_err(queue->vif->dev, "Trying to overwrite active handle! pending_idx: 0x%x\n", pending_idx); BUG(); } queue->grant_tx_handle[pending_idx] = handle; } static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue, u16 pending_idx) { if (unlikely(queue->grant_tx_handle[pending_idx] == NETBACK_INVALID_HANDLE)) { netdev_err(queue->vif->dev, "Trying to unmap invalid handle! pending_idx: 0x%x\n", pending_idx); BUG(); } queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE; } static int xenvif_tx_check_gop(struct xenvif_queue *queue, struct sk_buff *skb, struct gnttab_map_grant_ref **gopp_map, struct gnttab_copy **gopp_copy) { struct gnttab_map_grant_ref *gop_map = *gopp_map; u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; /* This always points to the shinfo of the skb being checked, which * could be either the first or the one on the frag_list */ struct skb_shared_info *shinfo = skb_shinfo(skb); /* If this is non-NULL, we are currently checking the frag_list skb, and * this points to the shinfo of the first one */ struct skb_shared_info *first_shinfo = NULL; int nr_frags = shinfo->nr_frags; const bool sharedslot = nr_frags && frag_get_pending_idx(&shinfo->frags[0]) == pending_idx; int i, err; /* Check status of header. */ err = (*gopp_copy)->status; if (unlikely(err)) { if (net_ratelimit()) netdev_dbg(queue->vif->dev, "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n", (*gopp_copy)->status, pending_idx, (*gopp_copy)->source.u.ref); /* The first frag might still have this slot mapped */ if (!sharedslot) xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR); } (*gopp_copy)++; check_frags: for (i = 0; i < nr_frags; i++, gop_map++) { int j, newerr; pending_idx = frag_get_pending_idx(&shinfo->frags[i]); /* Check error status: if okay then remember grant handle. */ newerr = gop_map->status; if (likely(!newerr)) { xenvif_grant_handle_set(queue, pending_idx, gop_map->handle); /* Had a previous error? Invalidate this fragment. */ if (unlikely(err)) { xenvif_idx_unmap(queue, pending_idx); /* If the mapping of the first frag was OK, but * the header's copy failed, and they are * sharing a slot, send an error */ if (i == 0 && sharedslot) xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR); else xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_OKAY); } continue; } /* Error on this fragment: respond to client with an error. */ if (net_ratelimit()) netdev_dbg(queue->vif->dev, "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n", i, gop_map->status, pending_idx, gop_map->ref); xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR); /* Not the first error? Preceding frags already invalidated. */ if (err) continue; /* First error: if the header haven't shared a slot with the * first frag, release it as well. */ if (!sharedslot) xenvif_idx_release(queue, XENVIF_TX_CB(skb)->pending_idx, XEN_NETIF_RSP_OKAY); /* Invalidate preceding fragments of this skb. */ for (j = 0; j < i; j++) { pending_idx = frag_get_pending_idx(&shinfo->frags[j]); xenvif_idx_unmap(queue, pending_idx); xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_OKAY); } /* And if we found the error while checking the frag_list, unmap * the first skb's frags */ if (first_shinfo) { for (j = 0; j < first_shinfo->nr_frags; j++) { pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]); xenvif_idx_unmap(queue, pending_idx); xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_OKAY); } } /* Remember the error: invalidate all subsequent fragments. */ err = newerr; } if (skb_has_frag_list(skb) && !first_shinfo) { first_shinfo = skb_shinfo(skb); shinfo = skb_shinfo(skb_shinfo(skb)->frag_list); nr_frags = shinfo->nr_frags; goto check_frags; } *gopp_map = gop_map; return err; } static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb) { struct skb_shared_info *shinfo = skb_shinfo(skb); int nr_frags = shinfo->nr_frags; int i; u16 prev_pending_idx = INVALID_PENDING_IDX; for (i = 0; i < nr_frags; i++) { skb_frag_t *frag = shinfo->frags + i; struct xen_netif_tx_request *txp; struct page *page; u16 pending_idx; pending_idx = frag_get_pending_idx(frag); /* If this is not the first frag, chain it to the previous*/ if (prev_pending_idx == INVALID_PENDING_IDX) skb_shinfo(skb)->destructor_arg = &callback_param(queue, pending_idx); else callback_param(queue, prev_pending_idx).ctx = &callback_param(queue, pending_idx); callback_param(queue, pending_idx).ctx = NULL; prev_pending_idx = pending_idx; txp = &queue->pending_tx_info[pending_idx].req; page = virt_to_page(idx_to_kaddr(queue, pending_idx)); __skb_fill_page_desc(skb, i, page, txp->offset, txp->size); skb->len += txp->size; skb->data_len += txp->size; skb->truesize += txp->size; /* Take an extra reference to offset network stack's put_page */ get_page(queue->mmap_pages[pending_idx]); } } static int xenvif_get_extras(struct xenvif_queue *queue, struct xen_netif_extra_info *extras, int work_to_do) { struct xen_netif_extra_info extra; RING_IDX cons = queue->tx.req_cons; do { if (unlikely(work_to_do-- <= 0)) { netdev_err(queue->vif->dev, "Missing extra info\n"); xenvif_fatal_tx_err(queue->vif); return -EBADR; } memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons), sizeof(extra)); if (unlikely(!extra.type || extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { queue->tx.req_cons = ++cons; netdev_err(queue->vif->dev, "Invalid extra type: %d\n", extra.type); xenvif_fatal_tx_err(queue->vif); return -EINVAL; } memcpy(&extras[extra.type - 1], &extra, sizeof(extra)); queue->tx.req_cons = ++cons; } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE); return work_to_do; } static int xenvif_set_skb_gso(struct xenvif *vif, struct sk_buff *skb, struct xen_netif_extra_info *gso) { if (!gso->u.gso.size) { netdev_err(vif->dev, "GSO size must not be zero.\n"); xenvif_fatal_tx_err(vif); return -EINVAL; } switch (gso->u.gso.type) { case XEN_NETIF_GSO_TYPE_TCPV4: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; break; case XEN_NETIF_GSO_TYPE_TCPV6: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; break; default: netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type); xenvif_fatal_tx_err(vif); return -EINVAL; } skb_shinfo(skb)->gso_size = gso->u.gso.size; /* gso_segs will be calculated later */ return 0; } static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb) { bool recalculate_partial_csum = false; /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy * peers can fail to set NETRXF_csum_blank when sending a GSO * frame. In this case force the SKB to CHECKSUM_PARTIAL and * recalculate the partial checksum. */ if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) { queue->stats.rx_gso_checksum_fixup++; skb->ip_summed = CHECKSUM_PARTIAL; recalculate_partial_csum = true; } /* A non-CHECKSUM_PARTIAL SKB does not require setup. */ if (skb->ip_summed != CHECKSUM_PARTIAL) return 0; return skb_checksum_setup(skb, recalculate_partial_csum); } static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size) { u64 now = get_jiffies_64(); u64 next_credit = queue->credit_window_start + msecs_to_jiffies(queue->credit_usec / 1000); /* Timer could already be pending in rare cases. */ if (timer_pending(&queue->credit_timeout)) return true; /* Passed the point where we can replenish credit? */ if (time_after_eq64(now, next_credit)) { queue->credit_window_start = now; tx_add_credit(queue); } /* Still too big to send right now? Set a callback. */ if (size > queue->remaining_credit) { queue->credit_timeout.data = (unsigned long)queue; mod_timer(&queue->credit_timeout, next_credit); queue->credit_window_start = next_credit; return true; } return false; } static void xenvif_tx_build_gops(struct xenvif_queue *queue, int budget, unsigned *copy_ops, unsigned *map_ops) { struct gnttab_map_grant_ref *gop = queue->tx_map_ops; struct sk_buff *skb, *nskb; int ret; unsigned int frag_overflow; while (skb_queue_len(&queue->tx_queue) < budget) { struct xen_netif_tx_request txreq; struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX]; struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1]; u16 pending_idx; RING_IDX idx; int work_to_do; unsigned int data_len; pending_ring_idx_t index; if (queue->tx.sring->req_prod - queue->tx.req_cons > XEN_NETIF_TX_RING_SIZE) { netdev_err(queue->vif->dev, "Impossible number of requests. " "req_prod %d, req_cons %d, size %ld\n", queue->tx.sring->req_prod, queue->tx.req_cons, XEN_NETIF_TX_RING_SIZE); xenvif_fatal_tx_err(queue->vif); break; } work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx); if (!work_to_do) break; idx = queue->tx.req_cons; rmb(); /* Ensure that we see the request before we copy it. */ memcpy(&txreq, RING_GET_REQUEST(&queue->tx, idx), sizeof(txreq)); /* Credit-based scheduling. */ if (txreq.size > queue->remaining_credit && tx_credit_exceeded(queue, txreq.size)) break; queue->remaining_credit -= txreq.size; work_to_do--; queue->tx.req_cons = ++idx; memset(extras, 0, sizeof(extras)); if (txreq.flags & XEN_NETTXF_extra_info) { work_to_do = xenvif_get_extras(queue, extras, work_to_do); idx = queue->tx.req_cons; if (unlikely(work_to_do < 0)) break; } ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do); if (unlikely(ret < 0)) break; idx += ret; if (unlikely(txreq.size < ETH_HLEN)) { netdev_dbg(queue->vif->dev, "Bad packet size: %d\n", txreq.size); xenvif_tx_err(queue, &txreq, idx); break; } /* No crossing a page as the payload mustn't fragment. */ if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) { netdev_err(queue->vif->dev, "txreq.offset: %u, size: %u, end: %lu\n", txreq.offset, txreq.size, (unsigned long)(txreq.offset&~PAGE_MASK) + txreq.size); xenvif_fatal_tx_err(queue->vif); break; } index = pending_index(queue->pending_cons); pending_idx = queue->pending_ring[index]; data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN && ret < XEN_NETBK_LEGACY_SLOTS_MAX) ? XEN_NETBACK_TX_COPY_LEN : txreq.size; skb = xenvif_alloc_skb(data_len); if (unlikely(skb == NULL)) { netdev_dbg(queue->vif->dev, "Can't allocate a skb in start_xmit.\n"); xenvif_tx_err(queue, &txreq, idx); break; } skb_shinfo(skb)->nr_frags = ret; if (data_len < txreq.size) skb_shinfo(skb)->nr_frags++; /* At this point shinfo->nr_frags is in fact the number of * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. */ frag_overflow = 0; nskb = NULL; if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) { frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS; BUG_ON(frag_overflow > MAX_SKB_FRAGS); skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS; nskb = xenvif_alloc_skb(0); if (unlikely(nskb == NULL)) { kfree_skb(skb); xenvif_tx_err(queue, &txreq, idx); if (net_ratelimit()) netdev_err(queue->vif->dev, "Can't allocate the frag_list skb.\n"); break; } } if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) { struct xen_netif_extra_info *gso; gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; if (xenvif_set_skb_gso(queue->vif, skb, gso)) { /* Failure in xenvif_set_skb_gso is fatal. */ kfree_skb(skb); kfree_skb(nskb); break; } } XENVIF_TX_CB(skb)->pending_idx = pending_idx; __skb_put(skb, data_len); queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref; queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid; queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset; queue->tx_copy_ops[*copy_ops].dest.u.gmfn = virt_to_gfn(skb->data); queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF; queue->tx_copy_ops[*copy_ops].dest.offset = offset_in_page(skb->data); queue->tx_copy_ops[*copy_ops].len = data_len; queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref; (*copy_ops)++; if (data_len < txreq.size) { frag_set_pending_idx(&skb_shinfo(skb)->frags[0], pending_idx); xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop); gop++; } else { frag_set_pending_idx(&skb_shinfo(skb)->frags[0], INVALID_PENDING_IDX); memcpy(&queue->pending_tx_info[pending_idx].req, &txreq, sizeof(txreq)); } queue->pending_cons++; gop = xenvif_get_requests(queue, skb, txfrags, gop, frag_overflow, nskb); __skb_queue_tail(&queue->tx_queue, skb); queue->tx.req_cons = idx; if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) || (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops))) break; } (*map_ops) = gop - queue->tx_map_ops; return; } /* Consolidate skb with a frag_list into a brand new one with local pages on * frags. Returns 0 or -ENOMEM if can't allocate new pages. */ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb) { unsigned int offset = skb_headlen(skb); skb_frag_t frags[MAX_SKB_FRAGS]; int i, f; struct ubuf_info *uarg; struct sk_buff *nskb = skb_shinfo(skb)->frag_list; queue->stats.tx_zerocopy_sent += 2; queue->stats.tx_frag_overflow++; xenvif_fill_frags(queue, nskb); /* Subtract frags size, we will correct it later */ skb->truesize -= skb->data_len; skb->len += nskb->len; skb->data_len += nskb->len; /* create a brand new frags array and coalesce there */ for (i = 0; offset < skb->len; i++) { struct page *page; unsigned int len; BUG_ON(i >= MAX_SKB_FRAGS); page = alloc_page(GFP_ATOMIC); if (!page) { int j; skb->truesize += skb->data_len; for (j = 0; j < i; j++) put_page(frags[j].page.p); return -ENOMEM; } if (offset + PAGE_SIZE < skb->len) len = PAGE_SIZE; else len = skb->len - offset; if (skb_copy_bits(skb, offset, page_address(page), len)) BUG(); offset += len; frags[i].page.p = page; frags[i].page_offset = 0; skb_frag_size_set(&frags[i], len); } /* Copied all the bits from the frag list -- free it. */ skb_frag_list_init(skb); xenvif_skb_zerocopy_prepare(queue, nskb); kfree_skb(nskb); /* Release all the original (foreign) frags. */ for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) skb_frag_unref(skb, f); uarg = skb_shinfo(skb)->destructor_arg; /* increase inflight counter to offset decrement in callback */ atomic_inc(&queue->inflight_packets); uarg->callback(uarg, true); skb_shinfo(skb)->destructor_arg = NULL; /* Fill the skb with the new (local) frags. */ memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t)); skb_shinfo(skb)->nr_frags = i; skb->truesize += i * PAGE_SIZE; return 0; } static int xenvif_tx_submit(struct xenvif_queue *queue) { struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops; struct gnttab_copy *gop_copy = queue->tx_copy_ops; struct sk_buff *skb; int work_done = 0; while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) { struct xen_netif_tx_request *txp; u16 pending_idx; unsigned data_len; pending_idx = XENVIF_TX_CB(skb)->pending_idx; txp = &queue->pending_tx_info[pending_idx].req; /* Check the remap error code. */ if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) { /* If there was an error, xenvif_tx_check_gop is * expected to release all the frags which were mapped, * so kfree_skb shouldn't do it again */ skb_shinfo(skb)->nr_frags = 0; if (skb_has_frag_list(skb)) { struct sk_buff *nskb = skb_shinfo(skb)->frag_list; skb_shinfo(nskb)->nr_frags = 0; } kfree_skb(skb); continue; } data_len = skb->len; callback_param(queue, pending_idx).ctx = NULL; if (data_len < txp->size) { /* Append the packet payload as a fragment. */ txp->offset += data_len; txp->size -= data_len; } else { /* Schedule a response immediately. */ xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_OKAY); } if (txp->flags & XEN_NETTXF_csum_blank) skb->ip_summed = CHECKSUM_PARTIAL; else if (txp->flags & XEN_NETTXF_data_validated) skb->ip_summed = CHECKSUM_UNNECESSARY; xenvif_fill_frags(queue, skb); if (unlikely(skb_has_frag_list(skb))) { if (xenvif_handle_frag_list(queue, skb)) { if (net_ratelimit()) netdev_err(queue->vif->dev, "Not enough memory to consolidate frag_list!\n"); xenvif_skb_zerocopy_prepare(queue, skb); kfree_skb(skb); continue; } } skb->dev = queue->vif->dev; skb->protocol = eth_type_trans(skb, skb->dev); skb_reset_network_header(skb); if (checksum_setup(queue, skb)) { netdev_dbg(queue->vif->dev, "Can't setup checksum in net_tx_action\n"); /* We have to set this flag to trigger the callback */ if (skb_shinfo(skb)->destructor_arg) xenvif_skb_zerocopy_prepare(queue, skb); kfree_skb(skb); continue; } skb_probe_transport_header(skb, 0); /* If the packet is GSO then we will have just set up the * transport header offset in checksum_setup so it's now * straightforward to calculate gso_segs. */ if (skb_is_gso(skb)) { int mss = skb_shinfo(skb)->gso_size; int hdrlen = skb_transport_header(skb) - skb_mac_header(skb) + tcp_hdrlen(skb); skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len - hdrlen, mss); } queue->stats.rx_bytes += skb->len; queue->stats.rx_packets++; work_done++; /* Set this flag right before netif_receive_skb, otherwise * someone might think this packet already left netback, and * do a skb_copy_ubufs while we are still in control of the * skb. E.g. the __pskb_pull_tail earlier can do such thing. */ if (skb_shinfo(skb)->destructor_arg) { xenvif_skb_zerocopy_prepare(queue, skb); queue->stats.tx_zerocopy_sent++; } netif_receive_skb(skb); } return work_done; } void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success) { unsigned long flags; pending_ring_idx_t index; struct xenvif_queue *queue = ubuf_to_queue(ubuf); /* This is the only place where we grab this lock, to protect callbacks * from each other. */ spin_lock_irqsave(&queue->callback_lock, flags); do { u16 pending_idx = ubuf->desc; ubuf = (struct ubuf_info *) ubuf->ctx; BUG_ON(queue->dealloc_prod - queue->dealloc_cons >= MAX_PENDING_REQS); index = pending_index(queue->dealloc_prod); queue->dealloc_ring[index] = pending_idx; /* Sync with xenvif_tx_dealloc_action: * insert idx then incr producer. */ smp_wmb(); queue->dealloc_prod++; } while (ubuf); spin_unlock_irqrestore(&queue->callback_lock, flags); if (likely(zerocopy_success)) queue->stats.tx_zerocopy_success++; else queue->stats.tx_zerocopy_fail++; xenvif_skb_zerocopy_complete(queue); } static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue) { struct gnttab_unmap_grant_ref *gop; pending_ring_idx_t dc, dp; u16 pending_idx, pending_idx_release[MAX_PENDING_REQS]; unsigned int i = 0; dc = queue->dealloc_cons; gop = queue->tx_unmap_ops; /* Free up any grants we have finished using */ do { dp = queue->dealloc_prod; /* Ensure we see all indices enqueued by all * xenvif_zerocopy_callback(). */ smp_rmb(); while (dc != dp) { BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS); pending_idx = queue->dealloc_ring[pending_index(dc++)]; pending_idx_release[gop - queue->tx_unmap_ops] = pending_idx; queue->pages_to_unmap[gop - queue->tx_unmap_ops] = queue->mmap_pages[pending_idx]; gnttab_set_unmap_op(gop, idx_to_kaddr(queue, pending_idx), GNTMAP_host_map, queue->grant_tx_handle[pending_idx]); xenvif_grant_handle_reset(queue, pending_idx); ++gop; } } while (dp != queue->dealloc_prod); queue->dealloc_cons = dc; if (gop - queue->tx_unmap_ops > 0) { int ret; ret = gnttab_unmap_refs(queue->tx_unmap_ops, NULL, queue->pages_to_unmap, gop - queue->tx_unmap_ops); if (ret) { netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n", gop - queue->tx_unmap_ops, ret); for (i = 0; i < gop - queue->tx_unmap_ops; ++i) { if (gop[i].status != GNTST_okay) netdev_err(queue->vif->dev, " host_addr: 0x%llx handle: 0x%x status: %d\n", gop[i].host_addr, gop[i].handle, gop[i].status); } BUG(); } } for (i = 0; i < gop - queue->tx_unmap_ops; ++i) xenvif_idx_release(queue, pending_idx_release[i], XEN_NETIF_RSP_OKAY); } /* Called after netfront has transmitted */ int xenvif_tx_action(struct xenvif_queue *queue, int budget) { unsigned nr_mops, nr_cops = 0; int work_done, ret; if (unlikely(!tx_work_todo(queue))) return 0; xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops); if (nr_cops == 0) return 0; gnttab_batch_copy(queue->tx_copy_ops, nr_cops); if (nr_mops != 0) { ret = gnttab_map_refs(queue->tx_map_ops, NULL, queue->pages_to_map, nr_mops); BUG_ON(ret); } work_done = xenvif_tx_submit(queue); return work_done; } static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, u8 status) { struct pending_tx_info *pending_tx_info; pending_ring_idx_t index; unsigned long flags; pending_tx_info = &queue->pending_tx_info[pending_idx]; spin_lock_irqsave(&queue->response_lock, flags); make_tx_response(queue, &pending_tx_info->req, status); /* Release the pending index before pusing the Tx response so * its available before a new Tx request is pushed by the * frontend. */ index = pending_index(queue->pending_prod++); queue->pending_ring[index] = pending_idx; push_tx_responses(queue); spin_unlock_irqrestore(&queue->response_lock, flags); } static void make_tx_response(struct xenvif_queue *queue, struct xen_netif_tx_request *txp, s8 st) { RING_IDX i = queue->tx.rsp_prod_pvt; struct xen_netif_tx_response *resp; resp = RING_GET_RESPONSE(&queue->tx, i); resp->id = txp->id; resp->status = st; if (txp->flags & XEN_NETTXF_extra_info) RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL; queue->tx.rsp_prod_pvt = ++i; } static void push_tx_responses(struct xenvif_queue *queue) { int notify; RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); if (notify) notify_remote_via_irq(queue->tx_irq); } static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, u16 id, s8 st, u16 offset, u16 size, u16 flags) { RING_IDX i = queue->rx.rsp_prod_pvt; struct xen_netif_rx_response *resp; resp = RING_GET_RESPONSE(&queue->rx, i); resp->offset = offset; resp->flags = flags; resp->id = id; resp->status = (s16)size; if (st < 0) resp->status = (s16)st; queue->rx.rsp_prod_pvt = ++i; return resp; } void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx) { int ret; struct gnttab_unmap_grant_ref tx_unmap_op; gnttab_set_unmap_op(&tx_unmap_op, idx_to_kaddr(queue, pending_idx), GNTMAP_host_map, queue->grant_tx_handle[pending_idx]); xenvif_grant_handle_reset(queue, pending_idx); ret = gnttab_unmap_refs(&tx_unmap_op, NULL, &queue->mmap_pages[pending_idx], 1); if (ret) { netdev_err(queue->vif->dev, "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n", ret, pending_idx, tx_unmap_op.host_addr, tx_unmap_op.handle, tx_unmap_op.status); BUG(); } } static inline int tx_work_todo(struct xenvif_queue *queue) { if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))) return 1; return 0; } static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue) { return queue->dealloc_cons != queue->dealloc_prod; } void xenvif_unmap_frontend_rings(struct xenvif_queue *queue) { if (queue->tx.sring) xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), queue->tx.sring); if (queue->rx.sring) xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), queue->rx.sring); } int xenvif_map_frontend_rings(struct xenvif_queue *queue, grant_ref_t tx_ring_ref, grant_ref_t rx_ring_ref) { void *addr; struct xen_netif_tx_sring *txs; struct xen_netif_rx_sring *rxs; int err = -ENOMEM; err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), &tx_ring_ref, 1, &addr); if (err) goto err; txs = (struct xen_netif_tx_sring *)addr; BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE); err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), &rx_ring_ref, 1, &addr); if (err) goto err; rxs = (struct xen_netif_rx_sring *)addr; BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE); return 0; err: xenvif_unmap_frontend_rings(queue); return err; } static void xenvif_queue_carrier_off(struct xenvif_queue *queue) { struct xenvif *vif = queue->vif; queue->stalled = true; /* At least one queue has stalled? Disable the carrier. */ spin_lock(&vif->lock); if (vif->stalled_queues++ == 0) { netdev_info(vif->dev, "Guest Rx stalled"); netif_carrier_off(vif->dev); } spin_unlock(&vif->lock); } static void xenvif_queue_carrier_on(struct xenvif_queue *queue) { struct xenvif *vif = queue->vif; queue->last_rx_time = jiffies; /* Reset Rx stall detection. */ queue->stalled = false; /* All queues are ready? Enable the carrier. */ spin_lock(&vif->lock); if (--vif->stalled_queues == 0) { netdev_info(vif->dev, "Guest Rx ready"); netif_carrier_on(vif->dev); } spin_unlock(&vif->lock); } static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue) { RING_IDX prod, cons; prod = queue->rx.sring->req_prod; cons = queue->rx.req_cons; return !queue->stalled && prod - cons < XEN_NETBK_RX_SLOTS_MAX && time_after(jiffies, queue->last_rx_time + queue->vif->stall_timeout); } static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) { RING_IDX prod, cons; prod = queue->rx.sring->req_prod; cons = queue->rx.req_cons; return queue->stalled && prod - cons >= XEN_NETBK_RX_SLOTS_MAX; } static bool xenvif_have_rx_work(struct xenvif_queue *queue) { return (!skb_queue_empty(&queue->rx_queue) && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)) || (queue->vif->stall_timeout && (xenvif_rx_queue_stalled(queue) || xenvif_rx_queue_ready(queue))) || kthread_should_stop() || queue->vif->disabled; } static long xenvif_rx_queue_timeout(struct xenvif_queue *queue) { struct sk_buff *skb; long timeout; skb = skb_peek(&queue->rx_queue); if (!skb) return MAX_SCHEDULE_TIMEOUT; timeout = XENVIF_RX_CB(skb)->expires - jiffies; return timeout < 0 ? 0 : timeout; } /* Wait until the guest Rx thread has work. * * The timeout needs to be adjusted based on the current head of the * queue (and not just the head at the beginning). In particular, if * the queue is initially empty an infinite timeout is used and this * needs to be reduced when a skb is queued. * * This cannot be done with wait_event_timeout() because it only * calculates the timeout once. */ static void xenvif_wait_for_rx_work(struct xenvif_queue *queue) { DEFINE_WAIT(wait); if (xenvif_have_rx_work(queue)) return; for (;;) { long ret; prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE); if (xenvif_have_rx_work(queue)) break; ret = schedule_timeout(xenvif_rx_queue_timeout(queue)); if (!ret) break; } finish_wait(&queue->wq, &wait); } int xenvif_kthread_guest_rx(void *data) { struct xenvif_queue *queue = data; struct xenvif *vif = queue->vif; if (!vif->stall_timeout) xenvif_queue_carrier_on(queue); for (;;) { xenvif_wait_for_rx_work(queue); if (kthread_should_stop()) break; /* This frontend is found to be rogue, disable it in * kthread context. Currently this is only set when * netback finds out frontend sends malformed packet, * but we cannot disable the interface in softirq * context so we defer it here, if this thread is * associated with queue 0. */ if (unlikely(vif->disabled && queue->id == 0)) { xenvif_carrier_off(vif); break; } if (!skb_queue_empty(&queue->rx_queue)) xenvif_rx_action(queue); /* If the guest hasn't provided any Rx slots for a * while it's probably not responsive, drop the * carrier so packets are dropped earlier. */ if (vif->stall_timeout) { if (xenvif_rx_queue_stalled(queue)) xenvif_queue_carrier_off(queue); else if (xenvif_rx_queue_ready(queue)) xenvif_queue_carrier_on(queue); } /* Queued packets may have foreign pages from other * domains. These cannot be queued indefinitely as * this would starve guests of grant refs and transmit * slots. */ xenvif_rx_queue_drop_expired(queue); xenvif_rx_queue_maybe_wake(queue); cond_resched(); } /* Bin any remaining skbs */ xenvif_rx_queue_purge(queue); return 0; } static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue) { /* Dealloc thread must remain running until all inflight * packets complete. */ return kthread_should_stop() && !atomic_read(&queue->inflight_packets); } int xenvif_dealloc_kthread(void *data) { struct xenvif_queue *queue = data; for (;;) { wait_event_interruptible(queue->dealloc_wq, tx_dealloc_work_todo(queue) || xenvif_dealloc_kthread_should_stop(queue)); if (xenvif_dealloc_kthread_should_stop(queue)) break; xenvif_tx_dealloc_action(queue); cond_resched(); } /* Unmap anything remaining*/ if (tx_dealloc_work_todo(queue)) xenvif_tx_dealloc_action(queue); return 0; } static int __init netback_init(void) { int rc = 0; if (!xen_domain()) return -ENODEV; /* Allow as many queues as there are CPUs, by default */ xenvif_max_queues = num_online_cpus(); if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) { pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n", fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX); fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX; } rc = xenvif_xenbus_init(); if (rc) goto failed_init; #ifdef CONFIG_DEBUG_FS xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL); if (IS_ERR_OR_NULL(xen_netback_dbg_root)) pr_warn("Init of debugfs returned %ld!\n", PTR_ERR(xen_netback_dbg_root)); #endif /* CONFIG_DEBUG_FS */ return 0; failed_init: return rc; } module_init(netback_init); static void __exit netback_fini(void) { #ifdef CONFIG_DEBUG_FS if (!IS_ERR_OR_NULL(xen_netback_dbg_root)) debugfs_remove_recursive(xen_netback_dbg_root); #endif /* CONFIG_DEBUG_FS */ xenvif_xenbus_fini(); } module_exit(netback_fini); MODULE_LICENSE("Dual BSD/GPL"); MODULE_ALIAS("xen-backend:vif");