/* * 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 <linux/kthread.h> #include <linux/if_vlan.h> #include <linux/udp.h> #include <net/tcp.h> #include <xen/xen.h> #include <xen/events.h> #include <xen/interface/memory.h> #include <asm/xen/hypercall.h> #include <asm/xen/page.h> /* 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 = 1; module_param(separate_tx_rx_irq, bool, 0644); /* * 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); /* * To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating * the maximum slots a valid packet can use. Now this value is defined * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by * all backend. */ #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN /* * If head != INVALID_PENDING_RING_IDX, it means this tx request is head of * one or more merged tx requests, otherwise it is the continuation of * previous tx request. */ static inline int pending_tx_is_head(struct xenvif *vif, RING_IDX idx) { return vif->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX; } static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx, u8 status); static void make_tx_response(struct xenvif *vif, struct xen_netif_tx_request *txp, s8 st); static inline int tx_work_todo(struct xenvif *vif); static inline int rx_work_todo(struct xenvif *vif); static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif, u16 id, s8 st, u16 offset, u16 size, u16 flags); static inline unsigned long idx_to_pfn(struct xenvif *vif, u16 idx) { return page_to_pfn(vif->mmap_pages[idx]); } static inline unsigned long idx_to_kaddr(struct xenvif *vif, u16 idx) { return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx)); } /* This is a miniumum size for the linear area to avoid lots of * calls to __pskb_pull_tail() as we set up checksum offsets. The * value 128 was chosen as it covers all IPv4 and most likely * IPv6 headers. */ #define PKT_PROT_LEN 128 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); } static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif) { return MAX_PENDING_REQS - vif->pending_prod + vif->pending_cons; } static int max_required_rx_slots(struct xenvif *vif) { int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE); /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */ if (vif->can_sg || vif->gso_mask || vif->gso_prefix_mask) max += MAX_SKB_FRAGS + 1; /* extra_info + frags */ return max; } int xenvif_rx_ring_full(struct xenvif *vif) { RING_IDX peek = vif->rx_req_cons_peek; RING_IDX needed = max_required_rx_slots(vif); return ((vif->rx.sring->req_prod - peek) < needed) || ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed); } int xenvif_must_stop_queue(struct xenvif *vif) { if (!xenvif_rx_ring_full(vif)) return 0; vif->rx.sring->req_event = vif->rx_req_cons_peek + max_required_rx_slots(vif); mb(); /* request notification /then/ check the queue */ return xenvif_rx_ring_full(vif); } /* * Returns true if we should start a new receive buffer instead of * adding 'size' bytes to a buffer which currently contains 'offset' * bytes. */ static bool start_new_rx_buffer(int offset, unsigned long size, int head) { /* simple case: we have completely filled the current buffer. */ if (offset == MAX_BUFFER_OFFSET) return true; /* * complex case: start a fresh buffer if the current frag * would overflow the current buffer but only if: * (i) this frag would fit completely in the next buffer * and (ii) there is already some data in the current buffer * and (iii) this is not the head buffer. * * Where: * - (i) stops us splitting a frag into two copies * unless the frag is too large for a single buffer. * - (ii) stops us from leaving a buffer pointlessly empty. * - (iii) stops us leaving the first buffer * empty. Strictly speaking this is already covered * by (ii) but is explicitly checked because * netfront relies on the first buffer being * non-empty and can crash otherwise. * * This means we will effectively linearise small * frags but do not needlessly split large buffers * into multiple copies tend to give large frags their * own buffers as before. */ if ((offset + size > MAX_BUFFER_OFFSET) && (size <= MAX_BUFFER_OFFSET) && offset && !head) return true; return false; } struct xenvif_count_slot_state { unsigned long copy_off; bool head; }; unsigned int xenvif_count_frag_slots(struct xenvif *vif, unsigned long offset, unsigned long size, struct xenvif_count_slot_state *state) { unsigned count = 0; offset &= ~PAGE_MASK; while (size > 0) { unsigned long bytes; bytes = PAGE_SIZE - offset; if (bytes > size) bytes = size; if (start_new_rx_buffer(state->copy_off, bytes, state->head)) { count++; state->copy_off = 0; } if (state->copy_off + bytes > MAX_BUFFER_OFFSET) bytes = MAX_BUFFER_OFFSET - state->copy_off; state->copy_off += bytes; offset += bytes; size -= bytes; if (offset == PAGE_SIZE) offset = 0; state->head = false; } return count; } /* * Figure out how many ring slots we're going to need to send @skb to * the guest. This function is essentially a dry run of * xenvif_gop_frag_copy. */ unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb) { struct xenvif_count_slot_state state; unsigned int count; unsigned char *data; unsigned i; state.head = true; state.copy_off = 0; /* Slot for the first (partial) page of data. */ count = 1; /* Need a slot for the GSO prefix for GSO extra data? */ if (skb_shinfo(skb)->gso_size) count++; data = skb->data; while (data < skb_tail_pointer(skb)) { unsigned long offset = offset_in_page(data); unsigned long size = PAGE_SIZE - offset; if (data + size > skb_tail_pointer(skb)) size = skb_tail_pointer(skb) - data; count += xenvif_count_frag_slots(vif, offset, size, &state); data += size; } for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]); unsigned long offset = skb_shinfo(skb)->frags[i].page_offset; count += xenvif_count_frag_slots(vif, offset, size, &state); } return count; } 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 *vif, struct netrx_pending_operations *npo) { struct xenvif_rx_meta *meta; struct xen_netif_rx_request *req; req = RING_GET_REQUEST(&vif->rx, vif->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 *vif, 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; /* Data must not cross a page boundary. */ BUG_ON(size + offset > PAGE_SIZE<<compound_order(page)); meta = npo->meta + npo->meta_prod - 1; /* Skip unused frames from start of page */ page += offset >> PAGE_SHIFT; offset &= ~PAGE_MASK; while (size > 0) { BUG_ON(offset >= PAGE_SIZE); BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET); bytes = PAGE_SIZE - offset; if (bytes > size) bytes = size; if (start_new_rx_buffer(npo->copy_off, bytes, *head)) { /* * Netfront requires there to be some data in the head * buffer. */ BUG_ON(*head); meta = get_next_rx_buffer(vif, npo); } 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; copy_gop->source.domid = DOMID_SELF; copy_gop->source.u.gmfn = virt_to_mfn(page_address(page)); copy_gop->source.offset = offset; copy_gop->dest.domid = 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_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; else gso_type = XEN_NETIF_GSO_TYPE_NONE; if (*head && ((1 << gso_type) & vif->gso_mask)) vif->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 *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; int gso_size; old_meta_prod = npo->meta_prod; if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) { gso_type = XEN_NETIF_GSO_TYPE_TCPV4; gso_size = skb_shinfo(skb)->gso_size; } else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) { gso_type = XEN_NETIF_GSO_TYPE_TCPV6; gso_size = skb_shinfo(skb)->gso_size; } else { gso_type = XEN_NETIF_GSO_TYPE_NONE; gso_size = 0; } /* Set up a GSO prefix descriptor, if necessary */ if ((1 << skb_shinfo(skb)->gso_type) & vif->gso_prefix_mask) { req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++); meta = npo->meta + npo->meta_prod++; meta->gso_type = gso_type; meta->gso_size = gso_size; meta->size = 0; meta->id = req->id; } req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++); meta = npo->meta + npo->meta_prod++; if ((1 << gso_type) & vif->gso_mask) { meta->gso_type = gso_type; meta->gso_size = 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(vif, skb, npo, virt_to_page(data), len, offset, &head); data += len; } for (i = 0; i < nr_frags; i++) { xenvif_gop_frag_copy(vif, 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 *vif, 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(vif, meta[i].id, status, offset, meta[i].size, flags); } } struct skb_cb_overlay { int meta_slots_used; }; static void xenvif_kick_thread(struct xenvif *vif) { wake_up(&vif->wq); } void xenvif_rx_action(struct xenvif *vif) { s8 status; u16 flags; struct xen_netif_rx_response *resp; struct sk_buff_head rxq; struct sk_buff *skb; LIST_HEAD(notify); int ret; int nr_frags; int count; unsigned long offset; struct skb_cb_overlay *sco; int need_to_notify = 0; struct netrx_pending_operations npo = { .copy = vif->grant_copy_op, .meta = vif->meta, }; skb_queue_head_init(&rxq); count = 0; while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) { vif = netdev_priv(skb->dev); nr_frags = skb_shinfo(skb)->nr_frags; sco = (struct skb_cb_overlay *)skb->cb; sco->meta_slots_used = xenvif_gop_skb(skb, &npo); count += nr_frags + 1; __skb_queue_tail(&rxq, skb); /* Filled the batch queue? */ /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */ if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE) break; } BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta)); if (!npo.copy_prod) return; BUG_ON(npo.copy_prod > ARRAY_SIZE(vif->grant_copy_op)); gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod); while ((skb = __skb_dequeue(&rxq)) != NULL) { sco = (struct skb_cb_overlay *)skb->cb; vif = netdev_priv(skb->dev); if ((1 << vif->meta[npo.meta_cons].gso_type) & vif->gso_prefix_mask) { resp = RING_GET_RESPONSE(&vif->rx, vif->rx.rsp_prod_pvt++); resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data; resp->offset = vif->meta[npo.meta_cons].gso_size; resp->id = vif->meta[npo.meta_cons].id; resp->status = sco->meta_slots_used; npo.meta_cons++; sco->meta_slots_used--; } vif->dev->stats.tx_bytes += skb->len; vif->dev->stats.tx_packets++; status = xenvif_check_gop(vif, sco->meta_slots_used, &npo); if (sco->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(vif, vif->meta[npo.meta_cons].id, status, offset, vif->meta[npo.meta_cons].size, flags); if ((1 << vif->meta[npo.meta_cons].gso_type) & vif->gso_mask) { struct xen_netif_extra_info *gso = (struct xen_netif_extra_info *) RING_GET_RESPONSE(&vif->rx, vif->rx.rsp_prod_pvt++); resp->flags |= XEN_NETRXF_extra_info; gso->u.gso.type = vif->meta[npo.meta_cons].gso_type; gso->u.gso.size = vif->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(vif, status, vif->meta + npo.meta_cons + 1, sco->meta_slots_used); RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret); if (ret) need_to_notify = 1; xenvif_notify_tx_completion(vif); npo.meta_cons += sco->meta_slots_used; dev_kfree_skb(skb); } if (need_to_notify) notify_remote_via_irq(vif->rx_irq); /* More work to do? */ if (!skb_queue_empty(&vif->rx_queue)) xenvif_kick_thread(vif); } void xenvif_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb) { skb_queue_tail(&vif->rx_queue, skb); xenvif_kick_thread(vif); } void xenvif_check_rx_xenvif(struct xenvif *vif) { int more_to_do; RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do); if (more_to_do) napi_schedule(&vif->napi); } static void tx_add_credit(struct xenvif *vif) { 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(&vif->tx, vif->tx.req_cons)->size; max_burst = min(max_burst, 131072UL); max_burst = max(max_burst, vif->credit_bytes); /* Take care that adding a new chunk of credit doesn't wrap to zero. */ max_credit = vif->remaining_credit + vif->credit_bytes; if (max_credit < vif->remaining_credit) max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */ vif->remaining_credit = min(max_credit, max_burst); } static void tx_credit_callback(unsigned long data) { struct xenvif *vif = (struct xenvif *)data; tx_add_credit(vif); xenvif_check_rx_xenvif(vif); } static void xenvif_tx_err(struct xenvif *vif, struct xen_netif_tx_request *txp, RING_IDX end) { RING_IDX cons = vif->tx.req_cons; do { make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR); if (cons == end) break; txp = RING_GET_REQUEST(&vif->tx, cons++); } while (1); vif->tx.req_cons = cons; } static void xenvif_fatal_tx_err(struct xenvif *vif) { netdev_err(vif->dev, "fatal error; disabling device\n"); xenvif_carrier_off(vif); } static int xenvif_count_requests(struct xenvif *vif, struct xen_netif_tx_request *first, struct xen_netif_tx_request *txp, int work_to_do) { RING_IDX cons = vif->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(vif->dev, "Asked for %d slots but exceeds this limit\n", work_to_do); xenvif_fatal_tx_err(vif); return -ENODATA; } /* This guest is really using too many slots and * considered malicious. */ if (unlikely(slots >= fatal_skb_slots)) { netdev_err(vif->dev, "Malicious frontend using %d slots, threshold %u\n", slots, fatal_skb_slots); xenvif_fatal_tx_err(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(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(&vif->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(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(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n", txp->offset, txp->size); xenvif_fatal_tx_err(vif); return -EINVAL; } more_data = txp->flags & XEN_NETTXF_more_data; if (!drop_err) txp++; } while (more_data); if (drop_err) { xenvif_tx_err(vif, first, cons + slots); return drop_err; } return slots; } static struct page *xenvif_alloc_page(struct xenvif *vif, u16 pending_idx) { struct page *page; page = alloc_page(GFP_ATOMIC|__GFP_COLD); if (!page) return NULL; vif->mmap_pages[pending_idx] = page; return page; } static struct gnttab_copy *xenvif_get_requests(struct xenvif *vif, struct sk_buff *skb, struct xen_netif_tx_request *txp, struct gnttab_copy *gop) { struct skb_shared_info *shinfo = skb_shinfo(skb); skb_frag_t *frags = shinfo->frags; u16 pending_idx = *((u16 *)skb->data); u16 head_idx = 0; int slot, start; struct page *page; pending_ring_idx_t index, start_idx = 0; uint16_t dst_offset; unsigned int nr_slots; struct pending_tx_info *first = NULL; /* At this point shinfo->nr_frags is in fact the number of * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. */ 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); /* Coalesce tx requests, at this point the packet passed in * should be <= 64K. Any packets larger than 64K have been * handled in xenvif_count_requests(). */ for (shinfo->nr_frags = slot = start; slot < nr_slots; shinfo->nr_frags++) { struct pending_tx_info *pending_tx_info = vif->pending_tx_info; page = alloc_page(GFP_ATOMIC|__GFP_COLD); if (!page) goto err; dst_offset = 0; first = NULL; while (dst_offset < PAGE_SIZE && slot < nr_slots) { gop->flags = GNTCOPY_source_gref; gop->source.u.ref = txp->gref; gop->source.domid = vif->domid; gop->source.offset = txp->offset; gop->dest.domid = DOMID_SELF; gop->dest.offset = dst_offset; gop->dest.u.gmfn = virt_to_mfn(page_address(page)); if (dst_offset + txp->size > PAGE_SIZE) { /* This page can only merge a portion * of tx request. Do not increment any * pointer / counter here. The txp * will be dealt with in future * rounds, eventually hitting the * `else` branch. */ gop->len = PAGE_SIZE - dst_offset; txp->offset += gop->len; txp->size -= gop->len; dst_offset += gop->len; /* quit loop */ } else { /* This tx request can be merged in the page */ gop->len = txp->size; dst_offset += gop->len; index = pending_index(vif->pending_cons++); pending_idx = vif->pending_ring[index]; memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp)); /* Poison these fields, corresponding * fields for head tx req will be set * to correct values after the loop. */ vif->mmap_pages[pending_idx] = (void *)(~0UL); pending_tx_info[pending_idx].head = INVALID_PENDING_RING_IDX; if (!first) { first = &pending_tx_info[pending_idx]; start_idx = index; head_idx = pending_idx; } txp++; slot++; } gop++; } first->req.offset = 0; first->req.size = dst_offset; first->head = start_idx; vif->mmap_pages[head_idx] = page; frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx); } BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS); return gop; err: /* Unwind, freeing all pages and sending error responses. */ while (shinfo->nr_frags-- > start) { xenvif_idx_release(vif, frag_get_pending_idx(&frags[shinfo->nr_frags]), XEN_NETIF_RSP_ERROR); } /* The head too, if necessary. */ if (start) xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR); return NULL; } static int xenvif_tx_check_gop(struct xenvif *vif, struct sk_buff *skb, struct gnttab_copy **gopp) { struct gnttab_copy *gop = *gopp; u16 pending_idx = *((u16 *)skb->data); struct skb_shared_info *shinfo = skb_shinfo(skb); struct pending_tx_info *tx_info; int nr_frags = shinfo->nr_frags; int i, err, start; u16 peek; /* peek into next tx request */ /* Check status of header. */ err = gop->status; if (unlikely(err)) xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR); /* Skip first skb fragment if it is on same page as header fragment. */ start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx); for (i = start; i < nr_frags; i++) { int j, newerr; pending_ring_idx_t head; pending_idx = frag_get_pending_idx(&shinfo->frags[i]); tx_info = &vif->pending_tx_info[pending_idx]; head = tx_info->head; /* Check error status: if okay then remember grant handle. */ do { newerr = (++gop)->status; if (newerr) break; peek = vif->pending_ring[pending_index(++head)]; } while (!pending_tx_is_head(vif, peek)); if (likely(!newerr)) { /* Had a previous error? Invalidate this fragment. */ if (unlikely(err)) xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY); continue; } /* Error on this fragment: respond to client with an error. */ xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR); /* Not the first error? Preceding frags already invalidated. */ if (err) continue; /* First error: invalidate header and preceding fragments. */ pending_idx = *((u16 *)skb->data); xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY); for (j = start; j < i; j++) { pending_idx = frag_get_pending_idx(&shinfo->frags[j]); xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY); } /* Remember the error: invalidate all subsequent fragments. */ err = newerr; } *gopp = gop + 1; return err; } static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb) { struct skb_shared_info *shinfo = skb_shinfo(skb); int nr_frags = shinfo->nr_frags; int i; 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); txp = &vif->pending_tx_info[pending_idx].req; page = virt_to_page(idx_to_kaddr(vif, 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 xenvif_idx_release */ get_page(vif->mmap_pages[pending_idx]); xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY); } } static int xenvif_get_extras(struct xenvif *vif, struct xen_netif_extra_info *extras, int work_to_do) { struct xen_netif_extra_info extra; RING_IDX cons = vif->tx.req_cons; do { if (unlikely(work_to_do-- <= 0)) { netdev_err(vif->dev, "Missing extra info\n"); xenvif_fatal_tx_err(vif); return -EBADR; } memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons), sizeof(extra)); if (unlikely(!extra.type || extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { vif->tx.req_cons = ++cons; netdev_err(vif->dev, "Invalid extra type: %d\n", extra.type); xenvif_fatal_tx_err(vif); return -EINVAL; } memcpy(&extras[extra.type - 1], &extra, sizeof(extra)); vif->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; /* Header must be checked, and gso_segs computed. */ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; skb_shinfo(skb)->gso_segs = 0; return 0; } static inline void maybe_pull_tail(struct sk_buff *skb, unsigned int len) { if (skb_is_nonlinear(skb) && skb_headlen(skb) < len) { /* If we need to pullup then pullup to the max, so we * won't need to do it again. */ int target = min_t(int, skb->len, MAX_TCP_HEADER); __pskb_pull_tail(skb, target - skb_headlen(skb)); } } static int checksum_setup_ip(struct xenvif *vif, struct sk_buff *skb, int recalculate_partial_csum) { struct iphdr *iph = (void *)skb->data; unsigned int header_size; unsigned int off; int err = -EPROTO; off = sizeof(struct iphdr); header_size = skb->network_header + off + MAX_IPOPTLEN; maybe_pull_tail(skb, header_size); off = iph->ihl * 4; switch (iph->protocol) { case IPPROTO_TCP: if (!skb_partial_csum_set(skb, off, offsetof(struct tcphdr, check))) goto out; if (recalculate_partial_csum) { struct tcphdr *tcph = tcp_hdr(skb); header_size = skb->network_header + off + sizeof(struct tcphdr); maybe_pull_tail(skb, header_size); tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len - off, IPPROTO_TCP, 0); } break; case IPPROTO_UDP: if (!skb_partial_csum_set(skb, off, offsetof(struct udphdr, check))) goto out; if (recalculate_partial_csum) { struct udphdr *udph = udp_hdr(skb); header_size = skb->network_header + off + sizeof(struct udphdr); maybe_pull_tail(skb, header_size); udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len - off, IPPROTO_UDP, 0); } break; default: if (net_ratelimit()) netdev_err(vif->dev, "Attempting to checksum a non-TCP/UDP packet, " "dropping a protocol %d packet\n", iph->protocol); goto out; } err = 0; out: return err; } static int checksum_setup_ipv6(struct xenvif *vif, struct sk_buff *skb, int recalculate_partial_csum) { int err = -EPROTO; struct ipv6hdr *ipv6h = (void *)skb->data; u8 nexthdr; unsigned int header_size; unsigned int off; bool fragment; bool done; done = false; off = sizeof(struct ipv6hdr); header_size = skb->network_header + off; maybe_pull_tail(skb, header_size); nexthdr = ipv6h->nexthdr; while ((off <= sizeof(struct ipv6hdr) + ntohs(ipv6h->payload_len)) && !done) { switch (nexthdr) { case IPPROTO_DSTOPTS: case IPPROTO_HOPOPTS: case IPPROTO_ROUTING: { struct ipv6_opt_hdr *hp = (void *)(skb->data + off); header_size = skb->network_header + off + sizeof(struct ipv6_opt_hdr); maybe_pull_tail(skb, header_size); nexthdr = hp->nexthdr; off += ipv6_optlen(hp); break; } case IPPROTO_AH: { struct ip_auth_hdr *hp = (void *)(skb->data + off); header_size = skb->network_header + off + sizeof(struct ip_auth_hdr); maybe_pull_tail(skb, header_size); nexthdr = hp->nexthdr; off += (hp->hdrlen+2)<<2; break; } case IPPROTO_FRAGMENT: fragment = true; /* fall through */ default: done = true; break; } } if (!done) { if (net_ratelimit()) netdev_err(vif->dev, "Failed to parse packet header\n"); goto out; } if (fragment) { if (net_ratelimit()) netdev_err(vif->dev, "Packet is a fragment!\n"); goto out; } switch (nexthdr) { case IPPROTO_TCP: if (!skb_partial_csum_set(skb, off, offsetof(struct tcphdr, check))) goto out; if (recalculate_partial_csum) { struct tcphdr *tcph = tcp_hdr(skb); header_size = skb->network_header + off + sizeof(struct tcphdr); maybe_pull_tail(skb, header_size); tcph->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len - off, IPPROTO_TCP, 0); } break; case IPPROTO_UDP: if (!skb_partial_csum_set(skb, off, offsetof(struct udphdr, check))) goto out; if (recalculate_partial_csum) { struct udphdr *udph = udp_hdr(skb); header_size = skb->network_header + off + sizeof(struct udphdr); maybe_pull_tail(skb, header_size); udph->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len - off, IPPROTO_UDP, 0); } break; default: if (net_ratelimit()) netdev_err(vif->dev, "Attempting to checksum a non-TCP/UDP packet, " "dropping a protocol %d packet\n", nexthdr); goto out; } err = 0; out: return err; } static int checksum_setup(struct xenvif *vif, struct sk_buff *skb) { int err = -EPROTO; int recalculate_partial_csum = 0; /* 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)) { vif->rx_gso_checksum_fixup++; skb->ip_summed = CHECKSUM_PARTIAL; recalculate_partial_csum = 1; } /* A non-CHECKSUM_PARTIAL SKB does not require setup. */ if (skb->ip_summed != CHECKSUM_PARTIAL) return 0; if (skb->protocol == htons(ETH_P_IP)) err = checksum_setup_ip(vif, skb, recalculate_partial_csum); else if (skb->protocol == htons(ETH_P_IPV6)) err = checksum_setup_ipv6(vif, skb, recalculate_partial_csum); return err; } static bool tx_credit_exceeded(struct xenvif *vif, unsigned size) { u64 now = get_jiffies_64(); u64 next_credit = vif->credit_window_start + msecs_to_jiffies(vif->credit_usec / 1000); /* Timer could already be pending in rare cases. */ if (timer_pending(&vif->credit_timeout)) return true; /* Passed the point where we can replenish credit? */ if (time_after_eq64(now, next_credit)) { vif->credit_window_start = now; tx_add_credit(vif); } /* Still too big to send right now? Set a callback. */ if (size > vif->remaining_credit) { vif->credit_timeout.data = (unsigned long)vif; vif->credit_timeout.function = tx_credit_callback; mod_timer(&vif->credit_timeout, next_credit); vif->credit_window_start = next_credit; return true; } return false; } static unsigned xenvif_tx_build_gops(struct xenvif *vif) { struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop; struct sk_buff *skb; int ret; while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX < MAX_PENDING_REQS)) { struct xen_netif_tx_request txreq; struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX]; struct page *page; 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 (vif->tx.sring->req_prod - vif->tx.req_cons > XEN_NETIF_TX_RING_SIZE) { netdev_err(vif->dev, "Impossible number of requests. " "req_prod %d, req_cons %d, size %ld\n", vif->tx.sring->req_prod, vif->tx.req_cons, XEN_NETIF_TX_RING_SIZE); xenvif_fatal_tx_err(vif); continue; } RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do); if (!work_to_do) break; idx = vif->tx.req_cons; rmb(); /* Ensure that we see the request before we copy it. */ memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq)); /* Credit-based scheduling. */ if (txreq.size > vif->remaining_credit && tx_credit_exceeded(vif, txreq.size)) break; vif->remaining_credit -= txreq.size; work_to_do--; vif->tx.req_cons = ++idx; memset(extras, 0, sizeof(extras)); if (txreq.flags & XEN_NETTXF_extra_info) { work_to_do = xenvif_get_extras(vif, extras, work_to_do); idx = vif->tx.req_cons; if (unlikely(work_to_do < 0)) break; } ret = xenvif_count_requests(vif, &txreq, txfrags, work_to_do); if (unlikely(ret < 0)) break; idx += ret; if (unlikely(txreq.size < ETH_HLEN)) { netdev_dbg(vif->dev, "Bad packet size: %d\n", txreq.size); xenvif_tx_err(vif, &txreq, idx); break; } /* No crossing a page as the payload mustn't fragment. */ if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) { netdev_err(vif->dev, "txreq.offset: %x, size: %u, end: %lu\n", txreq.offset, txreq.size, (txreq.offset&~PAGE_MASK) + txreq.size); xenvif_fatal_tx_err(vif); break; } index = pending_index(vif->pending_cons); pending_idx = vif->pending_ring[index]; data_len = (txreq.size > PKT_PROT_LEN && ret < XEN_NETBK_LEGACY_SLOTS_MAX) ? PKT_PROT_LEN : txreq.size; skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN, GFP_ATOMIC | __GFP_NOWARN); if (unlikely(skb == NULL)) { netdev_dbg(vif->dev, "Can't allocate a skb in start_xmit.\n"); xenvif_tx_err(vif, &txreq, idx); break; } /* Packets passed to netif_rx() must have some headroom. */ skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); 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(vif, skb, gso)) { /* Failure in xenvif_set_skb_gso is fatal. */ kfree_skb(skb); break; } } /* XXX could copy straight to head */ page = xenvif_alloc_page(vif, pending_idx); if (!page) { kfree_skb(skb); xenvif_tx_err(vif, &txreq, idx); break; } gop->source.u.ref = txreq.gref; gop->source.domid = vif->domid; gop->source.offset = txreq.offset; gop->dest.u.gmfn = virt_to_mfn(page_address(page)); gop->dest.domid = DOMID_SELF; gop->dest.offset = txreq.offset; gop->len = txreq.size; gop->flags = GNTCOPY_source_gref; gop++; memcpy(&vif->pending_tx_info[pending_idx].req, &txreq, sizeof(txreq)); vif->pending_tx_info[pending_idx].head = index; *((u16 *)skb->data) = pending_idx; __skb_put(skb, data_len); skb_shinfo(skb)->nr_frags = ret; if (data_len < txreq.size) { skb_shinfo(skb)->nr_frags++; frag_set_pending_idx(&skb_shinfo(skb)->frags[0], pending_idx); } else { frag_set_pending_idx(&skb_shinfo(skb)->frags[0], INVALID_PENDING_IDX); } vif->pending_cons++; request_gop = xenvif_get_requests(vif, skb, txfrags, gop); if (request_gop == NULL) { kfree_skb(skb); xenvif_tx_err(vif, &txreq, idx); break; } gop = request_gop; __skb_queue_tail(&vif->tx_queue, skb); vif->tx.req_cons = idx; if ((gop-vif->tx_copy_ops) >= ARRAY_SIZE(vif->tx_copy_ops)) break; } return gop - vif->tx_copy_ops; } static int xenvif_tx_submit(struct xenvif *vif, int budget) { struct gnttab_copy *gop = vif->tx_copy_ops; struct sk_buff *skb; int work_done = 0; while (work_done < budget && (skb = __skb_dequeue(&vif->tx_queue)) != NULL) { struct xen_netif_tx_request *txp; u16 pending_idx; unsigned data_len; pending_idx = *((u16 *)skb->data); txp = &vif->pending_tx_info[pending_idx].req; /* Check the remap error code. */ if (unlikely(xenvif_tx_check_gop(vif, skb, &gop))) { netdev_dbg(vif->dev, "netback grant failed.\n"); skb_shinfo(skb)->nr_frags = 0; kfree_skb(skb); continue; } data_len = skb->len; memcpy(skb->data, (void *)(idx_to_kaddr(vif, pending_idx)|txp->offset), data_len); 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(vif, 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(vif, skb); if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) { int target = min_t(int, skb->len, PKT_PROT_LEN); __pskb_pull_tail(skb, target - skb_headlen(skb)); } skb->dev = vif->dev; skb->protocol = eth_type_trans(skb, skb->dev); skb_reset_network_header(skb); if (checksum_setup(vif, skb)) { netdev_dbg(vif->dev, "Can't setup checksum in net_tx_action\n"); kfree_skb(skb); continue; } skb_probe_transport_header(skb, 0); vif->dev->stats.rx_bytes += skb->len; vif->dev->stats.rx_packets++; work_done++; netif_receive_skb(skb); } return work_done; } /* Called after netfront has transmitted */ int xenvif_tx_action(struct xenvif *vif, int budget) { unsigned nr_gops; int work_done; if (unlikely(!tx_work_todo(vif))) return 0; nr_gops = xenvif_tx_build_gops(vif); if (nr_gops == 0) return 0; gnttab_batch_copy(vif->tx_copy_ops, nr_gops); work_done = xenvif_tx_submit(vif, nr_gops); return work_done; } static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx, u8 status) { struct pending_tx_info *pending_tx_info; pending_ring_idx_t head; u16 peek; /* peek into next tx request */ BUG_ON(vif->mmap_pages[pending_idx] == (void *)(~0UL)); /* Already complete? */ if (vif->mmap_pages[pending_idx] == NULL) return; pending_tx_info = &vif->pending_tx_info[pending_idx]; head = pending_tx_info->head; BUG_ON(!pending_tx_is_head(vif, head)); BUG_ON(vif->pending_ring[pending_index(head)] != pending_idx); do { pending_ring_idx_t index; pending_ring_idx_t idx = pending_index(head); u16 info_idx = vif->pending_ring[idx]; pending_tx_info = &vif->pending_tx_info[info_idx]; make_tx_response(vif, &pending_tx_info->req, status); /* Setting any number other than * INVALID_PENDING_RING_IDX indicates this slot is * starting a new packet / ending a previous packet. */ pending_tx_info->head = 0; index = pending_index(vif->pending_prod++); vif->pending_ring[index] = vif->pending_ring[info_idx]; peek = vif->pending_ring[pending_index(++head)]; } while (!pending_tx_is_head(vif, peek)); put_page(vif->mmap_pages[pending_idx]); vif->mmap_pages[pending_idx] = NULL; } static void make_tx_response(struct xenvif *vif, struct xen_netif_tx_request *txp, s8 st) { RING_IDX i = vif->tx.rsp_prod_pvt; struct xen_netif_tx_response *resp; int notify; resp = RING_GET_RESPONSE(&vif->tx, i); resp->id = txp->id; resp->status = st; if (txp->flags & XEN_NETTXF_extra_info) RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL; vif->tx.rsp_prod_pvt = ++i; RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify); if (notify) notify_remote_via_irq(vif->tx_irq); } static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif, u16 id, s8 st, u16 offset, u16 size, u16 flags) { RING_IDX i = vif->rx.rsp_prod_pvt; struct xen_netif_rx_response *resp; resp = RING_GET_RESPONSE(&vif->rx, i); resp->offset = offset; resp->flags = flags; resp->id = id; resp->status = (s16)size; if (st < 0) resp->status = (s16)st; vif->rx.rsp_prod_pvt = ++i; return resp; } static inline int rx_work_todo(struct xenvif *vif) { return !skb_queue_empty(&vif->rx_queue); } static inline int tx_work_todo(struct xenvif *vif) { if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)) && (nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX < MAX_PENDING_REQS)) return 1; return 0; } void xenvif_unmap_frontend_rings(struct xenvif *vif) { if (vif->tx.sring) xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif), vif->tx.sring); if (vif->rx.sring) xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif), vif->rx.sring); } int xenvif_map_frontend_rings(struct xenvif *vif, 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(vif), tx_ring_ref, &addr); if (err) goto err; txs = (struct xen_netif_tx_sring *)addr; BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE); err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif), rx_ring_ref, &addr); if (err) goto err; rxs = (struct xen_netif_rx_sring *)addr; BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE); vif->rx_req_cons_peek = 0; return 0; err: xenvif_unmap_frontend_rings(vif); return err; } int xenvif_kthread(void *data) { struct xenvif *vif = data; while (!kthread_should_stop()) { wait_event_interruptible(vif->wq, rx_work_todo(vif) || kthread_should_stop()); if (kthread_should_stop()) break; if (rx_work_todo(vif)) xenvif_rx_action(vif); cond_resched(); } return 0; } static int __init netback_init(void) { int rc = 0; if (!xen_domain()) return -ENODEV; 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; return 0; failed_init: return rc; } module_init(netback_init); static void __exit netback_fini(void) { xenvif_xenbus_fini(); } module_exit(netback_fini); MODULE_LICENSE("Dual BSD/GPL"); MODULE_ALIAS("xen-backend:vif");