diff options
Diffstat (limited to 'drivers/net/xen-netback/netback.c')
| -rw-r--r-- | drivers/net/xen-netback/netback.c | 1745 |
1 files changed, 1745 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c new file mode 100644 index 00000000000..0e4851b8a77 --- /dev/null +++ b/drivers/net/xen-netback/netback.c @@ -0,0 +1,1745 @@ +/* + * 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/events.h> +#include <xen/interface/memory.h> + +#include <asm/xen/hypercall.h> +#include <asm/xen/page.h> + +struct pending_tx_info { + struct xen_netif_tx_request req; + struct xenvif *vif; +}; +typedef unsigned int pending_ring_idx_t; + +struct netbk_rx_meta { + int id; + int size; + int gso_size; +}; + +#define MAX_PENDING_REQS 256 + +#define MAX_BUFFER_OFFSET PAGE_SIZE + +/* extra field used in struct page */ +union page_ext { + struct { +#if BITS_PER_LONG < 64 +#define IDX_WIDTH 8 +#define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH) + unsigned int group:GROUP_WIDTH; + unsigned int idx:IDX_WIDTH; +#else + unsigned int group, idx; +#endif + } e; + void *mapping; +}; + +struct xen_netbk { + wait_queue_head_t wq; + struct task_struct *task; + + struct sk_buff_head rx_queue; + struct sk_buff_head tx_queue; + + struct timer_list net_timer; + + struct page *mmap_pages[MAX_PENDING_REQS]; + + pending_ring_idx_t pending_prod; + pending_ring_idx_t pending_cons; + struct list_head net_schedule_list; + + /* Protect the net_schedule_list in netif. */ + spinlock_t net_schedule_list_lock; + + atomic_t netfront_count; + + struct pending_tx_info pending_tx_info[MAX_PENDING_REQS]; + struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS]; + + u16 pending_ring[MAX_PENDING_REQS]; + + /* + * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each + * head/fragment page uses 2 copy operations because it + * straddles two buffers in the frontend. + */ + struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE]; + struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE]; +}; + +static struct xen_netbk *xen_netbk; +static int xen_netbk_group_nr; + +void xen_netbk_add_xenvif(struct xenvif *vif) +{ + int i; + int min_netfront_count; + int min_group = 0; + struct xen_netbk *netbk; + + min_netfront_count = atomic_read(&xen_netbk[0].netfront_count); + for (i = 0; i < xen_netbk_group_nr; i++) { + int netfront_count = atomic_read(&xen_netbk[i].netfront_count); + if (netfront_count < min_netfront_count) { + min_group = i; + min_netfront_count = netfront_count; + } + } + + netbk = &xen_netbk[min_group]; + + vif->netbk = netbk; + atomic_inc(&netbk->netfront_count); +} + +void xen_netbk_remove_xenvif(struct xenvif *vif) +{ + struct xen_netbk *netbk = vif->netbk; + vif->netbk = NULL; + atomic_dec(&netbk->netfront_count); +} + +static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx); +static void make_tx_response(struct xenvif *vif, + struct xen_netif_tx_request *txp, + s8 st); +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 xen_netbk *netbk, + unsigned int idx) +{ + return page_to_pfn(netbk->mmap_pages[idx]); +} + +static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk, + unsigned int idx) +{ + return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx)); +} + +/* extra field used in struct page */ +static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk, + unsigned int idx) +{ + unsigned int group = netbk - xen_netbk; + union page_ext ext = { .e = { .group = group + 1, .idx = idx } }; + + BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping)); + pg->mapping = ext.mapping; +} + +static int get_page_ext(struct page *pg, + unsigned int *pgroup, unsigned int *pidx) +{ + union page_ext ext = { .mapping = pg->mapping }; + struct xen_netbk *netbk; + unsigned int group, idx; + + group = ext.e.group - 1; + + if (group < 0 || group >= xen_netbk_group_nr) + return 0; + + netbk = &xen_netbk[group]; + + idx = ext.e.idx; + + if ((idx < 0) || (idx >= MAX_PENDING_REQS)) + return 0; + + if (netbk->mmap_pages[idx] != pg) + return 0; + + *pgroup = group; + *pidx = idx; + + return 1; +} + +/* + * This is the amount of packet we copy rather than map, so that the + * guest can't fiddle with the contents of the headers while we do + * packet processing on them (netfilter, routing, etc). + */ +#define PKT_PROT_LEN (ETH_HLEN + \ + VLAN_HLEN + \ + sizeof(struct iphdr) + MAX_IPOPTLEN + \ + sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE) + +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 xen_netbk *netbk) +{ + return MAX_PENDING_REQS - + netbk->pending_prod + netbk->pending_cons; +} + +static void xen_netbk_kick_thread(struct xen_netbk *netbk) +{ + wake_up(&netbk->wq); +} + +static int max_required_rx_slots(struct xenvif *vif) +{ + int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE); + + if (vif->can_sg || vif->gso || vif->gso_prefix) + max += MAX_SKB_FRAGS + 1; /* extra_info + frags */ + + return max; +} + +int xen_netbk_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 xen_netbk_must_stop_queue(struct xenvif *vif) +{ + if (!xen_netbk_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 xen_netbk_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; +} + +/* + * 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 + * netbk_gop_frag_copy. + */ +unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb) +{ + unsigned int count; + int i, copy_off; + + count = DIV_ROUND_UP( + offset_in_page(skb->data)+skb_headlen(skb), PAGE_SIZE); + + copy_off = skb_headlen(skb) % PAGE_SIZE; + + if (skb_shinfo(skb)->gso_size) + count++; + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + unsigned long size = skb_shinfo(skb)->frags[i].size; + unsigned long bytes; + while (size > 0) { + BUG_ON(copy_off > MAX_BUFFER_OFFSET); + + if (start_new_rx_buffer(copy_off, size, 0)) { + count++; + copy_off = 0; + } + + bytes = size; + if (copy_off + bytes > MAX_BUFFER_OFFSET) + bytes = MAX_BUFFER_OFFSET - copy_off; + + copy_off += bytes; + size -= bytes; + } + } + return count; +} + +struct netrx_pending_operations { + unsigned copy_prod, copy_cons; + unsigned meta_prod, meta_cons; + struct gnttab_copy *copy; + struct netbk_rx_meta *meta; + int copy_off; + grant_ref_t copy_gref; +}; + +static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif, + struct netrx_pending_operations *npo) +{ + struct netbk_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_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 netbk_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 netbk_rx_meta *meta; + /* + * These variables a used iff get_page_ext returns true, + * in which case they are guaranteed to be initialized. + */ + unsigned int uninitialized_var(group), uninitialized_var(idx); + int foreign = get_page_ext(page, &group, &idx); + unsigned long bytes; + + /* Data must not cross a page boundary. */ + BUG_ON(size + offset > PAGE_SIZE); + + meta = npo->meta + npo->meta_prod - 1; + + while (size > 0) { + BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET); + + if (start_new_rx_buffer(npo->copy_off, size, *head)) { + /* + * Netfront requires there to be some data in the head + * buffer. + */ + BUG_ON(*head); + + meta = get_next_rx_buffer(vif, npo); + } + + 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; + if (foreign) { + struct xen_netbk *netbk = &xen_netbk[group]; + struct pending_tx_info *src_pend; + + src_pend = &netbk->pending_tx_info[idx]; + + copy_gop->source.domid = src_pend->vif->domid; + copy_gop->source.u.ref = src_pend->req.gref; + copy_gop->flags |= GNTCOPY_source_gref; + } else { + void *vaddr = page_address(page); + copy_gop->source.domid = DOMID_SELF; + copy_gop->source.u.gmfn = virt_to_mfn(vaddr); + } + 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; + copy_gop->len = bytes; + + npo->copy_off += bytes; + meta->size += bytes; + + offset += bytes; + size -= bytes; + + /* Leave a gap for the GSO descriptor. */ + if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix) + 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 netbk_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 netbk_rx_meta *meta; + unsigned char *data; + int head = 1; + int old_meta_prod; + + old_meta_prod = npo->meta_prod; + + /* Set up a GSO prefix descriptor, if necessary */ + if (skb_shinfo(skb)->gso_size && vif->gso_prefix) { + req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++); + meta = npo->meta + npo->meta_prod++; + meta->gso_size = skb_shinfo(skb)->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 (!vif->gso_prefix) + meta->gso_size = skb_shinfo(skb)->gso_size; + else + 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; + + netbk_gop_frag_copy(vif, skb, npo, + virt_to_page(data), len, offset, &head); + data += len; + } + + for (i = 0; i < nr_frags; i++) { + netbk_gop_frag_copy(vif, skb, npo, + skb_shinfo(skb)->frags[i].page, + skb_shinfo(skb)->frags[i].size, + skb_shinfo(skb)->frags[i].page_offset, + &head); + } + + return npo->meta_prod - old_meta_prod; +} + +/* + * This is a twin to netbk_gop_skb. Assume that netbk_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 netbk_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 netbk_add_frag_responses(struct xenvif *vif, int status, + struct netbk_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 xen_netbk_rx_action(struct xen_netbk *netbk) +{ + struct xenvif *vif = NULL, *tmp; + s8 status; + u16 irq, 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; + + struct netrx_pending_operations npo = { + .copy = netbk->grant_copy_op, + .meta = netbk->meta, + }; + + skb_queue_head_init(&rxq); + + count = 0; + + while ((skb = skb_dequeue(&netbk->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 = netbk_gop_skb(skb, &npo); + + count += nr_frags + 1; + + __skb_queue_tail(&rxq, skb); + + /* Filled the batch queue? */ + if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE) + break; + } + + BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta)); + + if (!npo.copy_prod) + return; + + BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op)); + ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, &netbk->grant_copy_op, + npo.copy_prod); + BUG_ON(ret != 0); + + while ((skb = __skb_dequeue(&rxq)) != NULL) { + sco = (struct skb_cb_overlay *)skb->cb; + + vif = netdev_priv(skb->dev); + + if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) { + resp = RING_GET_RESPONSE(&vif->rx, + vif->rx.rsp_prod_pvt++); + + resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data; + + resp->offset = netbk->meta[npo.meta_cons].gso_size; + resp->id = netbk->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 = netbk_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, netbk->meta[npo.meta_cons].id, + status, offset, + netbk->meta[npo.meta_cons].size, + flags); + + if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) { + 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.size = netbk->meta[npo.meta_cons].gso_size; + gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4; + gso->u.gso.pad = 0; + gso->u.gso.features = 0; + + gso->type = XEN_NETIF_EXTRA_TYPE_GSO; + gso->flags = 0; + } + + netbk_add_frag_responses(vif, status, + netbk->meta + npo.meta_cons + 1, + sco->meta_slots_used); + + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret); + irq = vif->irq; + if (ret && list_empty(&vif->notify_list)) + list_add_tail(&vif->notify_list, ¬ify); + + xenvif_notify_tx_completion(vif); + + xenvif_put(vif); + npo.meta_cons += sco->meta_slots_used; + dev_kfree_skb(skb); + } + + list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) { + notify_remote_via_irq(vif->irq); + list_del_init(&vif->notify_list); + } + + /* More work to do? */ + if (!skb_queue_empty(&netbk->rx_queue) && + !timer_pending(&netbk->net_timer)) + xen_netbk_kick_thread(netbk); +} + +void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb) +{ + struct xen_netbk *netbk = vif->netbk; + + skb_queue_tail(&netbk->rx_queue, skb); + + xen_netbk_kick_thread(netbk); +} + +static void xen_netbk_alarm(unsigned long data) +{ + struct xen_netbk *netbk = (struct xen_netbk *)data; + xen_netbk_kick_thread(netbk); +} + +static int __on_net_schedule_list(struct xenvif *vif) +{ + return !list_empty(&vif->schedule_list); +} + +/* Must be called with net_schedule_list_lock held */ +static void remove_from_net_schedule_list(struct xenvif *vif) +{ + if (likely(__on_net_schedule_list(vif))) { + list_del_init(&vif->schedule_list); + xenvif_put(vif); + } +} + +static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk) +{ + struct xenvif *vif = NULL; + + spin_lock_irq(&netbk->net_schedule_list_lock); + if (list_empty(&netbk->net_schedule_list)) + goto out; + + vif = list_first_entry(&netbk->net_schedule_list, + struct xenvif, schedule_list); + if (!vif) + goto out; + + xenvif_get(vif); + + remove_from_net_schedule_list(vif); +out: + spin_unlock_irq(&netbk->net_schedule_list_lock); + return vif; +} + +void xen_netbk_schedule_xenvif(struct xenvif *vif) +{ + unsigned long flags; + struct xen_netbk *netbk = vif->netbk; + + if (__on_net_schedule_list(vif)) + goto kick; + + spin_lock_irqsave(&netbk->net_schedule_list_lock, flags); + if (!__on_net_schedule_list(vif) && + likely(xenvif_schedulable(vif))) { + list_add_tail(&vif->schedule_list, &netbk->net_schedule_list); + xenvif_get(vif); + } + spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags); + +kick: + smp_mb(); + if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) && + !list_empty(&netbk->net_schedule_list)) + xen_netbk_kick_thread(netbk); +} + +void xen_netbk_deschedule_xenvif(struct xenvif *vif) +{ + struct xen_netbk *netbk = vif->netbk; + spin_lock_irq(&netbk->net_schedule_list_lock); + remove_from_net_schedule_list(vif); + spin_unlock_irq(&netbk->net_schedule_list_lock); +} + +void xen_netbk_check_rx_xenvif(struct xenvif *vif) +{ + int more_to_do; + + RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do); + + if (more_to_do) + xen_netbk_schedule_xenvif(vif); +} + +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); + xen_netbk_check_rx_xenvif(vif); +} + +static void netbk_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; + xen_netbk_check_rx_xenvif(vif); + xenvif_put(vif); +} + +static int netbk_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 frags = 0; + + if (!(first->flags & XEN_NETTXF_more_data)) + return 0; + + do { + if (frags >= work_to_do) { + netdev_dbg(vif->dev, "Need more frags\n"); + return -frags; + } + + if (unlikely(frags >= MAX_SKB_FRAGS)) { + netdev_dbg(vif->dev, "Too many frags\n"); + return -frags; + } + + memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags), + sizeof(*txp)); + if (txp->size > first->size) { + netdev_dbg(vif->dev, "Frags galore\n"); + return -frags; + } + + first->size -= txp->size; + frags++; + + if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) { + netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n", + txp->offset, txp->size); + return -frags; + } + } while ((txp++)->flags & XEN_NETTXF_more_data); + return frags; +} + +static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk, + struct sk_buff *skb, + unsigned long pending_idx) +{ + struct page *page; + page = alloc_page(GFP_KERNEL|__GFP_COLD); + if (!page) + return NULL; + set_page_ext(page, netbk, pending_idx); + netbk->mmap_pages[pending_idx] = page; + return page; +} + +static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk, + 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; + unsigned long pending_idx = *((u16 *)skb->data); + int i, start; + + /* Skip first skb fragment if it is on same page as header fragment. */ + start = ((unsigned long)shinfo->frags[0].page == pending_idx); + + for (i = start; i < shinfo->nr_frags; i++, txp++) { + struct page *page; + pending_ring_idx_t index; + struct pending_tx_info *pending_tx_info = + netbk->pending_tx_info; + + index = pending_index(netbk->pending_cons++); + pending_idx = netbk->pending_ring[index]; + page = xen_netbk_alloc_page(netbk, skb, pending_idx); + if (!page) + return NULL; + + netbk->mmap_pages[pending_idx] = page; + + gop->source.u.ref = txp->gref; + gop->source.domid = vif->domid; + gop->source.offset = txp->offset; + + gop->dest.u.gmfn = virt_to_mfn(page_address(page)); + gop->dest.domid = DOMID_SELF; + gop->dest.offset = txp->offset; + + gop->len = txp->size; + gop->flags = GNTCOPY_source_gref; + + gop++; + + memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp)); + xenvif_get(vif); + pending_tx_info[pending_idx].vif = vif; + frags[i].page = (void *)pending_idx; + } + + return gop; +} + +static int xen_netbk_tx_check_gop(struct xen_netbk *netbk, + struct sk_buff *skb, + struct gnttab_copy **gopp) +{ + struct gnttab_copy *gop = *gopp; + int pending_idx = *((u16 *)skb->data); + struct pending_tx_info *pending_tx_info = netbk->pending_tx_info; + struct xenvif *vif = pending_tx_info[pending_idx].vif; + struct xen_netif_tx_request *txp; + struct skb_shared_info *shinfo = skb_shinfo(skb); + int nr_frags = shinfo->nr_frags; + int i, err, start; + + /* Check status of header. */ + err = gop->status; + if (unlikely(err)) { + pending_ring_idx_t index; + index = pending_index(netbk->pending_prod++); + txp = &pending_tx_info[pending_idx].req; + make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR); + netbk->pending_ring[index] = pending_idx; + xenvif_put(vif); + } + + /* Skip first skb fragment if it is on same page as header fragment. */ + start = ((unsigned long)shinfo->frags[0].page == pending_idx); + + for (i = start; i < nr_frags; i++) { + int j, newerr; + pending_ring_idx_t index; + + pending_idx = (unsigned long)shinfo->frags[i].page; + + /* Check error status: if okay then remember grant handle. */ + newerr = (++gop)->status; + if (likely(!newerr)) { + /* Had a previous error? Invalidate this fragment. */ + if (unlikely(err)) + xen_netbk_idx_release(netbk, pending_idx); + continue; + } + + /* Error on this fragment: respond to client with an error. */ + txp = &netbk->pending_tx_info[pending_idx].req; + make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR); + index = pending_index(netbk->pending_prod++); + netbk->pending_ring[index] = pending_idx; + xenvif_put(vif); + + /* Not the first error? Preceding frags already invalidated. */ + if (err) + continue; + + /* First error: invalidate header and preceding fragments. */ + pending_idx = *((u16 *)skb->data); + xen_netbk_idx_release(netbk, pending_idx); + for (j = start; j < i; j++) { + pending_idx = (unsigned long)shinfo->frags[i].page; + xen_netbk_idx_release(netbk, pending_idx); + } + + /* Remember the error: invalidate all subsequent fragments. */ + err = newerr; + } + + *gopp = gop + 1; + return err; +} + +static void xen_netbk_fill_frags(struct xen_netbk *netbk, 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; + unsigned long pending_idx; + + pending_idx = (unsigned long)frag->page; + + txp = &netbk->pending_tx_info[pending_idx].req; + frag->page = virt_to_page(idx_to_kaddr(netbk, pending_idx)); + frag->size = txp->size; + frag->page_offset = txp->offset; + + skb->len += txp->size; + skb->data_len += txp->size; + skb->truesize += txp->size; + + /* Take an extra reference to offset xen_netbk_idx_release */ + get_page(netbk->mmap_pages[pending_idx]); + xen_netbk_idx_release(netbk, pending_idx); + } +} + +static int xen_netbk_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_dbg(vif->dev, "Missing extra info\n"); + 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_dbg(vif->dev, + "Invalid extra type: %d\n", extra.type); + 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 netbk_set_skb_gso(struct xenvif *vif, + struct sk_buff *skb, + struct xen_netif_extra_info *gso) +{ + if (!gso->u.gso.size) { + netdev_dbg(vif->dev, "GSO size must not be zero.\n"); + return -EINVAL; + } + + /* Currently only TCPv4 S.O. is supported. */ + if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) { + netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type); + return -EINVAL; + } + + skb_shinfo(skb)->gso_size = gso->u.gso.size; + skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; + + /* 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 int checksum_setup(struct xenvif *vif, struct sk_buff *skb) +{ + struct iphdr *iph; + unsigned char *th; + 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)) + goto out; + + iph = (void *)skb->data; + th = skb->data + 4 * iph->ihl; + if (th >= skb_tail_pointer(skb)) + goto out; + + skb->csum_start = th - skb->head; + switch (iph->protocol) { + case IPPROTO_TCP: + skb->csum_offset = offsetof(struct tcphdr, check); + + if (recalculate_partial_csum) { + struct tcphdr *tcph = (struct tcphdr *)th; + tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, + skb->len - iph->ihl*4, + IPPROTO_TCP, 0); + } + break; + case IPPROTO_UDP: + skb->csum_offset = offsetof(struct udphdr, check); + + if (recalculate_partial_csum) { + struct udphdr *udph = (struct udphdr *)th; + udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, + skb->len - iph->ihl*4, + 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; + } + + if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb)) + goto out; + + err = 0; + +out: + return err; +} + +static bool tx_credit_exceeded(struct xenvif *vif, unsigned size) +{ + unsigned long now = jiffies; + unsigned long next_credit = + vif->credit_timeout.expires + + 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_eq(now, next_credit)) { + vif->credit_timeout.expires = now; + tx_add_credit(vif); + } + + /* Still too big to send right now? Set a callback. */< |