diff options
Diffstat (limited to 'drivers/net/xen-netback/netback.c')
| -rw-r--r-- | drivers/net/xen-netback/netback.c | 2049 |
1 files changed, 2049 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c new file mode 100644 index 000000000..0d2594395 --- /dev/null +++ b/drivers/net/xen-netback/netback.c @@ -0,0 +1,2049 @@ +/* + * 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 <linux/highmem.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); + +/* 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<<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) { + 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_mfn(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) { + RING_IDX old_req_cons; + RING_IDX ring_slots_used; + + queue->last_rx_time = jiffies; + + old_req_cons = queue->rx.req_cons; + XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue); + ring_slots_used = queue->rx.req_cons - old_req_cons; + + __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: %x, 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) +{ + 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, frag_overflow = 0; + + /* At this point shinfo->nr_frags is in fact the number of + * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. + */ + if (shinfo->nr_frags > MAX_SKB_FRAGS) { + frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS; + BUG_ON(frag_overflow > MAX_SKB_FRAGS); + shinfo->nr_frags = MAX_SKB_FRAGS; + } + 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) { + struct sk_buff *nskb = xenvif_alloc_skb(0); + if (unlikely(nskb == NULL)) { + if (net_ratelimit()) + netdev_err(queue->vif->dev, + "Can't allocate the frag_list skb.\n"); + return NULL; + } + + 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: %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: %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, *request_gop; + struct sk_buff *skb; + int ret; + + 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: %x, 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; + } + + 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); + 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_mfn(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)++; + + 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); + 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++; + + request_gop = xenvif_get_requests(queue, skb, txfrags, gop); + if (request_gop == NULL) { + kfree_skb(skb); + xenvif_tx_err(queue, &txreq, idx); + break; + } + gop = request_gop; + + __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); + wake_up(&queue->dealloc_wq); + 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 %tx 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: %llx handle: %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: %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"); |