diff options
Diffstat (limited to 'drivers/net/xen-netfront.c')
| -rw-r--r-- | drivers/net/xen-netfront.c | 2389 |
1 files changed, 2389 insertions, 0 deletions
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c new file mode 100644 index 000000000..70af7830e --- /dev/null +++ b/drivers/net/xen-netfront.c @@ -0,0 +1,2389 @@ +/* + * Virtual network driver for conversing with remote driver backends. + * + * Copyright (c) 2002-2005, K A Fraser + * Copyright (c) 2005, XenSource Ltd + * + * 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. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/skbuff.h> +#include <linux/ethtool.h> +#include <linux/if_ether.h> +#include <net/tcp.h> +#include <linux/udp.h> +#include <linux/moduleparam.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <net/ip.h> + +#include <xen/xen.h> +#include <xen/xenbus.h> +#include <xen/events.h> +#include <xen/page.h> +#include <xen/platform_pci.h> +#include <xen/grant_table.h> + +#include <xen/interface/io/netif.h> +#include <xen/interface/memory.h> +#include <xen/interface/grant_table.h> + +/* Module parameters */ +#define MAX_QUEUES_DEFAULT 8 +static unsigned int xennet_max_queues; +module_param_named(max_queues, xennet_max_queues, uint, 0644); +MODULE_PARM_DESC(max_queues, + "Maximum number of queues per virtual interface"); + +#define XENNET_TIMEOUT (5 * HZ) + +static const struct ethtool_ops xennet_ethtool_ops; + +struct netfront_cb { + int pull_to; +}; + +#define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb)) + +#define RX_COPY_THRESHOLD 256 + +#define GRANT_INVALID_REF 0 + +#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE) +#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE) + +/* Minimum number of Rx slots (includes slot for GSO metadata). */ +#define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1) + +/* Queue name is interface name with "-qNNN" appended */ +#define QUEUE_NAME_SIZE (IFNAMSIZ + 6) + +/* IRQ name is queue name with "-tx" or "-rx" appended */ +#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3) + +static DECLARE_WAIT_QUEUE_HEAD(module_wq); + +struct netfront_stats { + u64 packets; + u64 bytes; + struct u64_stats_sync syncp; +}; + +struct netfront_info; + +struct netfront_queue { + unsigned int id; /* Queue ID, 0-based */ + char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */ + struct netfront_info *info; + + struct napi_struct napi; + + /* Split event channels support, tx_* == rx_* when using + * single event channel. + */ + unsigned int tx_evtchn, rx_evtchn; + unsigned int tx_irq, rx_irq; + /* Only used when split event channels support is enabled */ + char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */ + char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */ + + spinlock_t tx_lock; + struct xen_netif_tx_front_ring tx; + int tx_ring_ref; + + /* + * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries + * are linked from tx_skb_freelist through tx_link. + */ + struct sk_buff *tx_skbs[NET_TX_RING_SIZE]; + unsigned short tx_link[NET_TX_RING_SIZE]; +#define TX_LINK_NONE 0xffff +#define TX_PENDING 0xfffe + grant_ref_t gref_tx_head; + grant_ref_t grant_tx_ref[NET_TX_RING_SIZE]; + struct page *grant_tx_page[NET_TX_RING_SIZE]; + unsigned tx_skb_freelist; + unsigned int tx_pend_queue; + + spinlock_t rx_lock ____cacheline_aligned_in_smp; + struct xen_netif_rx_front_ring rx; + int rx_ring_ref; + + struct timer_list rx_refill_timer; + + struct sk_buff *rx_skbs[NET_RX_RING_SIZE]; + grant_ref_t gref_rx_head; + grant_ref_t grant_rx_ref[NET_RX_RING_SIZE]; + + unsigned int rx_rsp_unconsumed; + spinlock_t rx_cons_lock; +}; + +struct netfront_info { + struct list_head list; + struct net_device *netdev; + + struct xenbus_device *xbdev; + + /* Multi-queue support */ + struct netfront_queue *queues; + + /* Statistics */ + struct netfront_stats __percpu *rx_stats; + struct netfront_stats __percpu *tx_stats; + + /* Is device behaving sane? */ + bool broken; + + atomic_t rx_gso_checksum_fixup; +}; + +struct netfront_rx_info { + struct xen_netif_rx_response rx; + struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1]; +}; + +/* + * Access macros for acquiring freeing slots in tx_skbs[]. + */ + +static void add_id_to_list(unsigned *head, unsigned short *list, + unsigned short id) +{ + list[id] = *head; + *head = id; +} + +static unsigned short get_id_from_list(unsigned *head, unsigned short *list) +{ + unsigned int id = *head; + + if (id != TX_LINK_NONE) { + *head = list[id]; + list[id] = TX_LINK_NONE; + } + return id; +} + +static int xennet_rxidx(RING_IDX idx) +{ + return idx & (NET_RX_RING_SIZE - 1); +} + +static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue, + RING_IDX ri) +{ + int i = xennet_rxidx(ri); + struct sk_buff *skb = queue->rx_skbs[i]; + queue->rx_skbs[i] = NULL; + return skb; +} + +static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue, + RING_IDX ri) +{ + int i = xennet_rxidx(ri); + grant_ref_t ref = queue->grant_rx_ref[i]; + queue->grant_rx_ref[i] = GRANT_INVALID_REF; + return ref; +} + +#ifdef CONFIG_SYSFS +static const struct attribute_group xennet_dev_group; +#endif + +static bool xennet_can_sg(struct net_device *dev) +{ + return dev->features & NETIF_F_SG; +} + + +static void rx_refill_timeout(struct timer_list *t) +{ + struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer); + napi_schedule(&queue->napi); +} + +static int netfront_tx_slot_available(struct netfront_queue *queue) +{ + return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) < + (NET_TX_RING_SIZE - XEN_NETIF_NR_SLOTS_MIN - 1); +} + +static void xennet_maybe_wake_tx(struct netfront_queue *queue) +{ + struct net_device *dev = queue->info->netdev; + struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id); + + if (unlikely(netif_tx_queue_stopped(dev_queue)) && + netfront_tx_slot_available(queue) && + likely(netif_running(dev))) + netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id)); +} + + +static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue) +{ + struct sk_buff *skb; + struct page *page; + + skb = __netdev_alloc_skb(queue->info->netdev, + RX_COPY_THRESHOLD + NET_IP_ALIGN, + GFP_ATOMIC | __GFP_NOWARN); + if (unlikely(!skb)) + return NULL; + + page = alloc_page(GFP_ATOMIC | __GFP_NOWARN); + if (!page) { + kfree_skb(skb); + return NULL; + } + skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE); + + /* Align ip header to a 16 bytes boundary */ + skb_reserve(skb, NET_IP_ALIGN); + skb->dev = queue->info->netdev; + + return skb; +} + + +static void xennet_alloc_rx_buffers(struct netfront_queue *queue) +{ + RING_IDX req_prod = queue->rx.req_prod_pvt; + int notify; + int err = 0; + + if (unlikely(!netif_carrier_ok(queue->info->netdev))) + return; + + for (req_prod = queue->rx.req_prod_pvt; + req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE; + req_prod++) { + struct sk_buff *skb; + unsigned short id; + grant_ref_t ref; + struct page *page; + struct xen_netif_rx_request *req; + + skb = xennet_alloc_one_rx_buffer(queue); + if (!skb) { + err = -ENOMEM; + break; + } + + id = xennet_rxidx(req_prod); + + BUG_ON(queue->rx_skbs[id]); + queue->rx_skbs[id] = skb; + + ref = gnttab_claim_grant_reference(&queue->gref_rx_head); + WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref)); + queue->grant_rx_ref[id] = ref; + + page = skb_frag_page(&skb_shinfo(skb)->frags[0]); + + req = RING_GET_REQUEST(&queue->rx, req_prod); + gnttab_page_grant_foreign_access_ref_one(ref, + queue->info->xbdev->otherend_id, + page, + 0); + req->id = id; + req->gref = ref; + } + + queue->rx.req_prod_pvt = req_prod; + + /* Try again later if there are not enough requests or skb allocation + * failed. + * Enough requests is quantified as the sum of newly created slots and + * the unconsumed slots at the backend. + */ + if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN || + unlikely(err)) { + mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10)); + return; + } + + wmb(); /* barrier so backend seens requests */ + + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify); + if (notify) + notify_remote_via_irq(queue->rx_irq); +} + +static int xennet_open(struct net_device *dev) +{ + struct netfront_info *np = netdev_priv(dev); + unsigned int num_queues = dev->real_num_tx_queues; + unsigned int i = 0; + struct netfront_queue *queue = NULL; + + if (!np->queues || np->broken) + return -ENODEV; + + for (i = 0; i < num_queues; ++i) { + queue = &np->queues[i]; + napi_enable(&queue->napi); + + spin_lock_bh(&queue->rx_lock); + if (netif_carrier_ok(dev)) { + xennet_alloc_rx_buffers(queue); + queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1; + if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)) + napi_schedule(&queue->napi); + } + spin_unlock_bh(&queue->rx_lock); + } + + netif_tx_start_all_queues(dev); + + return 0; +} + +static bool xennet_tx_buf_gc(struct netfront_queue *queue) +{ + RING_IDX cons, prod; + unsigned short id; + struct sk_buff *skb; + bool more_to_do; + bool work_done = false; + const struct device *dev = &queue->info->netdev->dev; + + BUG_ON(!netif_carrier_ok(queue->info->netdev)); + + do { + prod = queue->tx.sring->rsp_prod; + if (RING_RESPONSE_PROD_OVERFLOW(&queue->tx, prod)) { + dev_alert(dev, "Illegal number of responses %u\n", + prod - queue->tx.rsp_cons); + goto err; + } + rmb(); /* Ensure we see responses up to 'rp'. */ + + for (cons = queue->tx.rsp_cons; cons != prod; cons++) { + struct xen_netif_tx_response txrsp; + + work_done = true; + + RING_COPY_RESPONSE(&queue->tx, cons, &txrsp); + if (txrsp.status == XEN_NETIF_RSP_NULL) + continue; + + id = txrsp.id; + if (id >= RING_SIZE(&queue->tx)) { + dev_alert(dev, + "Response has incorrect id (%u)\n", + id); + goto err; + } + if (queue->tx_link[id] != TX_PENDING) { + dev_alert(dev, + "Response for inactive request\n"); + goto err; + } + + queue->tx_link[id] = TX_LINK_NONE; + skb = queue->tx_skbs[id]; + queue->tx_skbs[id] = NULL; + if (unlikely(!gnttab_end_foreign_access_ref( + queue->grant_tx_ref[id], GNTMAP_readonly))) { + dev_alert(dev, + "Grant still in use by backend domain\n"); + goto err; + } + gnttab_release_grant_reference( + &queue->gref_tx_head, queue->grant_tx_ref[id]); + queue->grant_tx_ref[id] = GRANT_INVALID_REF; + queue->grant_tx_page[id] = NULL; + add_id_to_list(&queue->tx_skb_freelist, queue->tx_link, id); + dev_kfree_skb_irq(skb); + } + + queue->tx.rsp_cons = prod; + + RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do); + } while (more_to_do); + + xennet_maybe_wake_tx(queue); + + return work_done; + + err: + queue->info->broken = true; + dev_alert(dev, "Disabled for further use\n"); + + return work_done; +} + +struct xennet_gnttab_make_txreq { + struct netfront_queue *queue; + struct sk_buff *skb; + struct page *page; + struct xen_netif_tx_request *tx; /* Last request on ring page */ + struct xen_netif_tx_request tx_local; /* Last request local copy*/ + unsigned int size; +}; + +static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset, + unsigned int len, void *data) +{ + struct xennet_gnttab_make_txreq *info = data; + unsigned int id; + struct xen_netif_tx_request *tx; + grant_ref_t ref; + /* convenient aliases */ + struct page *page = info->page; + struct netfront_queue *queue = info->queue; + struct sk_buff *skb = info->skb; + + id = get_id_from_list(&queue->tx_skb_freelist, queue->tx_link); + tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++); + ref = gnttab_claim_grant_reference(&queue->gref_tx_head); + WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref)); + + gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id, + gfn, GNTMAP_readonly); + + queue->tx_skbs[id] = skb; + queue->grant_tx_page[id] = page; + queue->grant_tx_ref[id] = ref; + + info->tx_local.id = id; + info->tx_local.gref = ref; + info->tx_local.offset = offset; + info->tx_local.size = len; + info->tx_local.flags = 0; + + *tx = info->tx_local; + + /* + * Put the request in the pending queue, it will be set to be pending + * when the producer index is about to be raised. + */ + add_id_to_list(&queue->tx_pend_queue, queue->tx_link, id); + + info->tx = tx; + info->size += info->tx_local.size; +} + +static struct xen_netif_tx_request *xennet_make_first_txreq( + struct xennet_gnttab_make_txreq *info, + unsigned int offset, unsigned int len) +{ + info->size = 0; + + gnttab_for_one_grant(info->page, offset, len, xennet_tx_setup_grant, info); + + return info->tx; +} + +static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset, + unsigned int len, void *data) +{ + struct xennet_gnttab_make_txreq *info = data; + + info->tx->flags |= XEN_NETTXF_more_data; + skb_get(info->skb); + xennet_tx_setup_grant(gfn, offset, len, data); +} + +static void xennet_make_txreqs( + struct xennet_gnttab_make_txreq *info, + struct page *page, + unsigned int offset, unsigned int len) +{ + /* Skip unused frames from start of page */ + page += offset >> PAGE_SHIFT; + offset &= ~PAGE_MASK; + + while (len) { + info->page = page; + info->size = 0; + + gnttab_foreach_grant_in_range(page, offset, len, + xennet_make_one_txreq, + info); + + page++; + offset = 0; + len -= info->size; + } +} + +/* + * Count how many ring slots are required to send this skb. Each frag + * might be a compound page. + */ +static int xennet_count_skb_slots(struct sk_buff *skb) +{ + int i, frags = skb_shinfo(skb)->nr_frags; + int slots; + + slots = gnttab_count_grant(offset_in_page(skb->data), + skb_headlen(skb)); + + for (i = 0; i < frags; i++) { + skb_frag_t *frag = skb_shinfo(skb)->frags + i; + unsigned long size = skb_frag_size(frag); + unsigned long offset = frag->page_offset; + + /* Skip unused frames from start of page */ + offset &= ~PAGE_MASK; + + slots += gnttab_count_grant(offset, size); + } + + return slots; +} + +static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb, + struct net_device *sb_dev, + select_queue_fallback_t fallback) +{ + unsigned int num_queues = dev->real_num_tx_queues; + u32 hash; + u16 queue_idx; + + /* First, check if there is only one queue */ + if (num_queues == 1) { + queue_idx = 0; + } else { + hash = skb_get_hash(skb); + queue_idx = hash % num_queues; + } + + return queue_idx; +} + +static void xennet_mark_tx_pending(struct netfront_queue *queue) +{ + unsigned int i; + + while ((i = get_id_from_list(&queue->tx_pend_queue, queue->tx_link)) != + TX_LINK_NONE) + queue->tx_link[i] = TX_PENDING; +} + +#define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1) + +static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct netfront_info *np = netdev_priv(dev); + struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats); + struct xen_netif_tx_request *first_tx; + unsigned int i; + int notify; + int slots; + struct page *page; + unsigned int offset; + unsigned int len; + unsigned long flags; + struct netfront_queue *queue = NULL; + struct xennet_gnttab_make_txreq info = { }; + unsigned int num_queues = dev->real_num_tx_queues; + u16 queue_index; + struct sk_buff *nskb; + + /* Drop the packet if no queues are set up */ + if (num_queues < 1) + goto drop; + if (unlikely(np->broken)) + goto drop; + /* Determine which queue to transmit this SKB on */ + queue_index = skb_get_queue_mapping(skb); + queue = &np->queues[queue_index]; + + /* If skb->len is too big for wire format, drop skb and alert + * user about misconfiguration. + */ + if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) { + net_alert_ratelimited( + "xennet: skb->len = %u, too big for wire format\n", + skb->len); + goto drop; + } + + slots = xennet_count_skb_slots(skb); + if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) { + net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n", + slots, skb->len); + if (skb_linearize(skb)) + goto drop; + } + + page = virt_to_page(skb->data); + offset = offset_in_page(skb->data); + + /* The first req should be at least ETH_HLEN size or the packet will be + * dropped by netback. + */ + if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) { + nskb = skb_copy(skb, GFP_ATOMIC); + if (!nskb) + goto drop; + dev_consume_skb_any(skb); + skb = nskb; + page = virt_to_page(skb->data); + offset = offset_in_page(skb->data); + } + + len = skb_headlen(skb); + + spin_lock_irqsave(&queue->tx_lock, flags); + + if (unlikely(!netif_carrier_ok(dev) || + (slots > 1 && !xennet_can_sg(dev)) || + netif_needs_gso(skb, netif_skb_features(skb)))) { + spin_unlock_irqrestore(&queue->tx_lock, flags); + goto drop; + } + + /* First request for the linear area. */ + info.queue = queue; + info.skb = skb; + info.page = page; + first_tx = xennet_make_first_txreq(&info, offset, len); + offset += info.tx_local.size; + if (offset == PAGE_SIZE) { + page++; + offset = 0; + } + len -= info.tx_local.size; + + if (skb->ip_summed == CHECKSUM_PARTIAL) + /* local packet? */ + first_tx->flags |= XEN_NETTXF_csum_blank | + XEN_NETTXF_data_validated; + else if (skb->ip_summed == CHECKSUM_UNNECESSARY) + /* remote but checksummed. */ + first_tx->flags |= XEN_NETTXF_data_validated; + + /* Optional extra info after the first request. */ + if (skb_shinfo(skb)->gso_size) { + struct xen_netif_extra_info *gso; + + gso = (struct xen_netif_extra_info *) + RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++); + + first_tx->flags |= XEN_NETTXF_extra_info; + + gso->u.gso.size = skb_shinfo(skb)->gso_size; + gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ? + XEN_NETIF_GSO_TYPE_TCPV6 : + 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; + } + + /* Requests for the rest of the linear area. */ + xennet_make_txreqs(&info, page, offset, len); + + /* Requests for all the frags. */ + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + xennet_make_txreqs(&info, skb_frag_page(frag), + frag->page_offset, + skb_frag_size(frag)); + } + + /* First request has the packet length. */ + first_tx->size = skb->len; + + xennet_mark_tx_pending(queue); + + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify); + if (notify) + notify_remote_via_irq(queue->tx_irq); + + u64_stats_update_begin(&tx_stats->syncp); + tx_stats->bytes += skb->len; + tx_stats->packets++; + u64_stats_update_end(&tx_stats->syncp); + + /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */ + xennet_tx_buf_gc(queue); + + if (!netfront_tx_slot_available(queue)) + netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id)); + + spin_unlock_irqrestore(&queue->tx_lock, flags); + + return NETDEV_TX_OK; + + drop: + dev->stats.tx_dropped++; + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; +} + +static int xennet_close(struct net_device *dev) +{ + struct netfront_info *np = netdev_priv(dev); + unsigned int num_queues = dev->real_num_tx_queues; + unsigned int i; + struct netfront_queue *queue; + netif_tx_stop_all_queues(np->netdev); + for (i = 0; i < num_queues; ++i) { + queue = &np->queues[i]; + napi_disable(&queue->napi); + } + return 0; +} + +static void xennet_destroy_queues(struct netfront_info *info) +{ + unsigned int i; + + for (i = 0; i < info->netdev->real_num_tx_queues; i++) { + struct netfront_queue *queue = &info->queues[i]; + + if (netif_running(info->netdev)) + napi_disable(&queue->napi); + netif_napi_del(&queue->napi); + } + + kfree(info->queues); + info->queues = NULL; +} + +static void xennet_uninit(struct net_device *dev) +{ + struct netfront_info *np = netdev_priv(dev); + xennet_destroy_queues(np); +} + +static void xennet_set_rx_rsp_cons(struct netfront_queue *queue, RING_IDX val) +{ + unsigned long flags; + + spin_lock_irqsave(&queue->rx_cons_lock, flags); + queue->rx.rsp_cons = val; + queue->rx_rsp_unconsumed = RING_HAS_UNCONSUMED_RESPONSES(&queue->rx); + spin_unlock_irqrestore(&queue->rx_cons_lock, flags); +} + +static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb, + grant_ref_t ref) +{ + int new = xennet_rxidx(queue->rx.req_prod_pvt); + + BUG_ON(queue->rx_skbs[new]); + queue->rx_skbs[new] = skb; + queue->grant_rx_ref[new] = ref; + RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new; + RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref; + queue->rx.req_prod_pvt++; +} + +static int xennet_get_extras(struct netfront_queue *queue, + struct xen_netif_extra_info *extras, + RING_IDX rp) + +{ + struct xen_netif_extra_info extra; + struct device *dev = &queue->info->netdev->dev; + RING_IDX cons = queue->rx.rsp_cons; + int err = 0; + + do { + struct sk_buff *skb; + grant_ref_t ref; + + if (unlikely(cons + 1 == rp)) { + if (net_ratelimit()) + dev_warn(dev, "Missing extra info\n"); + err = -EBADR; + break; + } + + RING_COPY_RESPONSE(&queue->rx, ++cons, &extra); + + if (unlikely(!extra.type || + extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { + if (net_ratelimit()) + dev_warn(dev, "Invalid extra type: %d\n", + extra.type); + err = -EINVAL; + } else { + extras[extra.type - 1] = extra; + } + + skb = xennet_get_rx_skb(queue, cons); + ref = xennet_get_rx_ref(queue, cons); + xennet_move_rx_slot(queue, skb, ref); + } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE); + + xennet_set_rx_rsp_cons(queue, cons); + return err; +} + +static int xennet_get_responses(struct netfront_queue *queue, + struct netfront_rx_info *rinfo, RING_IDX rp, + struct sk_buff_head *list) +{ + struct xen_netif_rx_response *rx = &rinfo->rx, rx_local; + struct xen_netif_extra_info *extras = rinfo->extras; + struct device *dev = &queue->info->netdev->dev; + RING_IDX cons = queue->rx.rsp_cons; + struct sk_buff *skb = xennet_get_rx_skb(queue, cons); + grant_ref_t ref = xennet_get_rx_ref(queue, cons); + int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD); + int slots = 1; + int err = 0; + + if (rx->flags & XEN_NETRXF_extra_info) { + err = xennet_get_extras(queue, extras, rp); + cons = queue->rx.rsp_cons; + } + + for (;;) { + if (unlikely(rx->status < 0 || + rx->offset + rx->status > XEN_PAGE_SIZE)) { + if (net_ratelimit()) + dev_warn(dev, "rx->offset: %u, size: %d\n", + rx->offset, rx->status); + xennet_move_rx_slot(queue, skb, ref); + err = -EINVAL; + goto next; + } + + /* + * This definitely indicates a bug, either in this driver or in + * the backend driver. In future this should flag the bad + * situation to the system controller to reboot the backend. + */ + if (ref == GRANT_INVALID_REF) { + if (net_ratelimit()) + dev_warn(dev, "Bad rx response id %d.\n", + rx->id); + err = -EINVAL; + goto next; + } + + if (!gnttab_end_foreign_access_ref(ref, 0)) { + dev_alert(dev, + "Grant still in use by backend domain\n"); + queue->info->broken = true; + dev_alert(dev, "Disabled for further use\n"); + return -EINVAL; + } + + gnttab_release_grant_reference(&queue->gref_rx_head, ref); + + __skb_queue_tail(list, skb); + +next: + if (!(rx->flags & XEN_NETRXF_more_data)) + break; + + if (cons + slots == rp) { + if (net_ratelimit()) + dev_warn(dev, "Need more slots\n"); + err = -ENOENT; + break; + } + + RING_COPY_RESPONSE(&queue->rx, cons + slots, &rx_local); + rx = &rx_local; + skb = xennet_get_rx_skb(queue, cons + slots); + ref = xennet_get_rx_ref(queue, cons + slots); + slots++; + } + + if (unlikely(slots > max)) { + if (net_ratelimit()) + dev_warn(dev, "Too many slots\n"); + err = -E2BIG; + } + + if (unlikely(err)) + xennet_set_rx_rsp_cons(queue, cons + slots); + + return err; +} + +static int xennet_set_skb_gso(struct sk_buff *skb, + struct xen_netif_extra_info *gso) +{ + if (!gso->u.gso.size) { + if (net_ratelimit()) + pr_warn("GSO size must not be zero\n"); + return -EINVAL; + } + + if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 && + gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) { + if (net_ratelimit()) + pr_warn("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 = + (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ? + SKB_GSO_TCPV4 : + SKB_GSO_TCPV6; + + /* 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 xennet_fill_frags(struct netfront_queue *queue, + struct sk_buff *skb, + struct sk_buff_head *list) +{ + RING_IDX cons = queue->rx.rsp_cons; + struct sk_buff *nskb; + + while ((nskb = __skb_dequeue(list))) { + struct xen_netif_rx_response rx; + skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0]; + + RING_COPY_RESPONSE(&queue->rx, ++cons, &rx); + + if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) { + unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to; + + BUG_ON(pull_to < skb_headlen(skb)); + __pskb_pull_tail(skb, pull_to - skb_headlen(skb)); + } + if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) { + xennet_set_rx_rsp_cons(queue, + ++cons + skb_queue_len(list)); + kfree_skb(nskb); + return -ENOENT; + } + + skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, + skb_frag_page(nfrag), + rx.offset, rx.status, PAGE_SIZE); + + skb_shinfo(nskb)->nr_frags = 0; + kfree_skb(nskb); + } + + xennet_set_rx_rsp_cons(queue, cons); + + return 0; +} + +static int checksum_setup(struct net_device *dev, 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)) { + struct netfront_info *np = netdev_priv(dev); + atomic_inc(&np->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 int handle_incoming_queue(struct netfront_queue *queue, + struct sk_buff_head *rxq) +{ + struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats); + int packets_dropped = 0; + struct sk_buff *skb; + + while ((skb = __skb_dequeue(rxq)) != NULL) { + int pull_to = NETFRONT_SKB_CB(skb)->pull_to; + + if (pull_to > skb_headlen(skb)) + __pskb_pull_tail(skb, pull_to - skb_headlen(skb)); + + /* Ethernet work: Delayed to here as it peeks the header. */ + skb->protocol = eth_type_trans(skb, queue->info->netdev); + skb_reset_network_header(skb); + + if (checksum_setup(queue->info->netdev, skb)) { + kfree_skb(skb); + packets_dropped++; + queue->info->netdev->stats.rx_errors++; + continue; + } + + u64_stats_update_begin(&rx_stats->syncp); + rx_stats->packets++; + rx_stats->bytes += skb->len; + u64_stats_update_end(&rx_stats->syncp); + + /* Pass it up. */ + napi_gro_receive(&queue->napi, skb); + } + + return packets_dropped; +} + +static int xennet_poll(struct napi_struct *napi, int budget) +{ + struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi); + struct net_device *dev = queue->info->netdev; + struct sk_buff *skb; + struct netfront_rx_info rinfo; + struct xen_netif_rx_response *rx = &rinfo.rx; + struct xen_netif_extra_info *extras = rinfo.extras; + RING_IDX i, rp; + int work_done; + struct sk_buff_head rxq; + struct sk_buff_head errq; + struct sk_buff_head tmpq; + int err; + + spin_lock(&queue->rx_lock); + + skb_queue_head_init(&rxq); + skb_queue_head_init(&errq); + skb_queue_head_init(&tmpq); + + rp = queue->rx.sring->rsp_prod; + if (RING_RESPONSE_PROD_OVERFLOW(&queue->rx, rp)) { + dev_alert(&dev->dev, "Illegal number of responses %u\n", + rp - queue->rx.rsp_cons); + queue->info->broken = true; + spin_unlock(&queue->rx_lock); + return 0; + } + rmb(); /* Ensure we see queued responses up to 'rp'. */ + + i = queue->rx.rsp_cons; + work_done = 0; + while ((i != rp) && (work_done < budget)) { + RING_COPY_RESPONSE(&queue->rx, i, rx); + memset(extras, 0, sizeof(rinfo.extras)); + + err = xennet_get_responses(queue, &rinfo, rp, &tmpq); + + if (unlikely(err)) { + if (queue->info->broken) { + spin_unlock(&queue->rx_lock); + return 0; + } +err: + while ((skb = __skb_dequeue(&tmpq))) + __skb_queue_tail(&errq, skb); + dev->stats.rx_errors++; + i = queue->rx.rsp_cons; + continue; + } + + skb = __skb_dequeue(&tmpq); + + if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) { + struct xen_netif_extra_info *gso; + gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; + + if (unlikely(xennet_set_skb_gso(skb, gso))) { + __skb_queue_head(&tmpq, skb); + xennet_set_rx_rsp_cons(queue, + queue->rx.rsp_cons + + skb_queue_len(&tmpq)); + goto err; + } + } + + NETFRONT_SKB_CB(skb)->pull_to = rx->status; + if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD) + NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD; + + skb_shinfo(skb)->frags[0].page_offset = rx->offset; + skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status); + skb->data_len = rx->status; + skb->len += rx->status; + + if (unlikely(xennet_fill_frags(queue, skb, &tmpq))) + goto err; + + if (rx->flags & XEN_NETRXF_csum_blank) + skb->ip_summed = CHECKSUM_PARTIAL; + else if (rx->flags & XEN_NETRXF_data_validated) + skb->ip_summed = CHECKSUM_UNNECESSARY; + + __skb_queue_tail(&rxq, skb); + + i = queue->rx.rsp_cons + 1; + xennet_set_rx_rsp_cons(queue, i); + work_done++; + } + + __skb_queue_purge(&errq); + + work_done -= handle_incoming_queue(queue, &rxq); + + xennet_alloc_rx_buffers(queue); + + if (work_done < budget) { + int more_to_do = 0; + + napi_complete_done(napi, work_done); + + RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do); + if (more_to_do) + napi_schedule(napi); + } + + spin_unlock(&queue->rx_lock); + + return work_done; +} + +static int xennet_change_mtu(struct net_device *dev, int mtu) +{ + int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN; + + if (mtu > max) + return -EINVAL; + dev->mtu = mtu; + return 0; +} + +static void xennet_get_stats64(struct net_device *dev, + struct rtnl_link_stats64 *tot) +{ + struct netfront_info *np = netdev_priv(dev); + int cpu; + + for_each_possible_cpu(cpu) { + struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu); + struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu); + u64 rx_packets, rx_bytes, tx_packets, tx_bytes; + unsigned int start; + + do { + start = u64_stats_fetch_begin_irq(&tx_stats->syncp); + tx_packets = tx_stats->packets; + tx_bytes = tx_stats->bytes; + } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start)); + + do { + start = u64_stats_fetch_begin_irq(&rx_stats->syncp); + rx_packets = rx_stats->packets; + rx_bytes = rx_stats->bytes; + } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start)); + + tot->rx_packets += rx_packets; + tot->tx_packets += tx_packets; + tot->rx_bytes += rx_bytes; + tot->tx_bytes += tx_bytes; + } + + tot->rx_errors = dev->stats.rx_errors; + tot->tx_dropped = dev->stats.tx_dropped; +} + +static void xennet_release_tx_bufs(struct netfront_queue *queue) +{ + struct sk_buff *skb; + int i; + + for (i = 0; i < NET_TX_RING_SIZE; i++) { + /* Skip over entries which are actually freelist references */ + if (!queue->tx_skbs[i]) + continue; + + skb = queue->tx_skbs[i]; + queue->tx_skbs[i] = NULL; + get_page(queue->grant_tx_page[i]); + gnttab_end_foreign_access(queue->grant_tx_ref[i], + GNTMAP_readonly, + (unsigned long)page_address(queue->grant_tx_page[i])); + queue->grant_tx_page[i] = NULL; + queue->grant_tx_ref[i] = GRANT_INVALID_REF; + add_id_to_list(&queue->tx_skb_freelist, queue->tx_link, i); + dev_kfree_skb_irq(skb); + } +} + +static void xennet_release_rx_bufs(struct netfront_queue *queue) +{ + int id, ref; + + spin_lock_bh(&queue->rx_lock); + + for (id = 0; id < NET_RX_RING_SIZE; id++) { + struct sk_buff *skb; + struct page *page; + + skb = queue->rx_skbs[id]; + if (!skb) + continue; + + ref = queue->grant_rx_ref[id]; + if (ref == GRANT_INVALID_REF) + continue; + + page = skb_frag_page(&skb_shinfo(skb)->frags[0]); + + /* gnttab_end_foreign_access() needs a page ref until + * foreign access is ended (which may be deferred). + */ + get_page(page); + gnttab_end_foreign_access(ref, 0, + (unsigned long)page_address(page)); + queue->grant_rx_ref[id] = GRANT_INVALID_REF; + + kfree_skb(skb); + } + + spin_unlock_bh(&queue->rx_lock); +} + +static netdev_features_t xennet_fix_features(struct net_device *dev, + netdev_features_t features) +{ + struct netfront_info *np = netdev_priv(dev); + + if (features & NETIF_F_SG && + !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0)) + features &= ~NETIF_F_SG; + + if (features & NETIF_F_IPV6_CSUM && + !xenbus_read_unsigned(np->xbdev->otherend, + "feature-ipv6-csum-offload", 0)) + features &= ~NETIF_F_IPV6_CSUM; + + if (features & NETIF_F_TSO && + !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0)) + features &= ~NETIF_F_TSO; + + if (features & NETIF_F_TSO6 && + !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0)) + features &= ~NETIF_F_TSO6; + + return features; +} + +static int xennet_set_features(struct net_device *dev, + netdev_features_t features) +{ + if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) { + netdev_info(dev, "Reducing MTU because no SG offload"); + dev->mtu = ETH_DATA_LEN; + } + + return 0; +} + +static bool xennet_handle_tx(struct netfront_queue *queue, unsigned int *eoi) +{ + unsigned long flags; + + if (unlikely(queue->info->broken)) + return false; + + spin_lock_irqsave(&queue->tx_lock, flags); + if (xennet_tx_buf_gc(queue)) + *eoi = 0; + spin_unlock_irqrestore(&queue->tx_lock, flags); + + return true; +} + +static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id) +{ + unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS; + + if (likely(xennet_handle_tx(dev_id, &eoiflag))) + xen_irq_lateeoi(irq, eoiflag); + + return IRQ_HANDLED; +} + +static bool xennet_handle_rx(struct netfront_queue *queue, unsigned int *eoi) +{ + unsigned int work_queued; + unsigned long flags; + + if (unlikely(queue->info->broken)) + return false; + + spin_lock_irqsave(&queue->rx_cons_lock, flags); + work_queued = RING_HAS_UNCONSUMED_RESPONSES(&queue->rx); + if (work_queued > queue->rx_rsp_unconsumed) { + queue->rx_rsp_unconsumed = work_queued; + *eoi = 0; + } else if (unlikely(work_queued < queue->rx_rsp_unconsumed)) { + const struct device *dev = &queue->info->netdev->dev; + + spin_unlock_irqrestore(&queue->rx_cons_lock, flags); + dev_alert(dev, "RX producer index going backwards\n"); + dev_alert(dev, "Disabled for further use\n"); + queue->info->broken = true; + return false; + } + spin_unlock_irqrestore(&queue->rx_cons_lock, flags); + + if (likely(netif_carrier_ok(queue->info->netdev) && work_queued)) + napi_schedule(&queue->napi); + + return true; +} + +static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id) +{ + unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS; + + if (likely(xennet_handle_rx(dev_id, &eoiflag))) + xen_irq_lateeoi(irq, eoiflag); + + return IRQ_HANDLED; +} + +static irqreturn_t xennet_interrupt(int irq, void *dev_id) +{ + unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS; + + if (xennet_handle_tx(dev_id, &eoiflag) && + xennet_handle_rx(dev_id, &eoiflag)) + xen_irq_lateeoi(irq, eoiflag); + + return IRQ_HANDLED; +} + +#ifdef CONFIG_NET_POLL_CONTROLLER +static void xennet_poll_controller(struct net_device *dev) +{ + /* Poll each queue */ + struct netfront_info *info = netdev_priv(dev); + unsigned int num_queues = dev->real_num_tx_queues; + unsigned int i; + + if (info->broken) + return; + + for (i = 0; i < num_queues; ++i) + xennet_interrupt(0, &info->queues[i]); +} +#endif + +static const struct net_device_ops xennet_netdev_ops = { + .ndo_uninit = xennet_uninit, + .ndo_open = xennet_open, + .ndo_stop = xennet_close, + .ndo_start_xmit = xennet_start_xmit, + .ndo_change_mtu = xennet_change_mtu, + .ndo_get_stats64 = xennet_get_stats64, + .ndo_set_mac_address = eth_mac_addr, + .ndo_validate_addr = eth_validate_addr, + .ndo_fix_features = xennet_fix_features, + .ndo_set_features = xennet_set_features, + .ndo_select_queue = xennet_select_queue, +#ifdef CONFIG_NET_POLL_CONTROLLER + .ndo_poll_controller = xennet_poll_controller, +#endif +}; + +static void xennet_free_netdev(struct net_device *netdev) +{ + struct netfront_info *np = netdev_priv(netdev); + + free_percpu(np->rx_stats); + free_percpu(np->tx_stats); + free_netdev(netdev); +} + +static struct net_device *xennet_create_dev(struct xenbus_device *dev) +{ + int err; + struct net_device *netdev; + struct netfront_info *np; + + netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues); + if (!netdev) + return ERR_PTR(-ENOMEM); + + np = netdev_priv(netdev); + np->xbdev = dev; + + np->queues = NULL; + + err = -ENOMEM; + np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats); + if (np->rx_stats == NULL) + goto exit; + np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats); + if (np->tx_stats == NULL) + goto exit; + + netdev->netdev_ops = &xennet_netdev_ops; + + netdev->features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM | + NETIF_F_GSO_ROBUST; + netdev->hw_features = NETIF_F_SG | + NETIF_F_IPV6_CSUM | + NETIF_F_TSO | NETIF_F_TSO6; + + /* + * Assume that all hw features are available for now. This set + * will be adjusted by the call to netdev_update_features() in + * xennet_connect() which is the earliest point where we can + * negotiate with the backend regarding supported features. + */ + netdev->features |= netdev->hw_features; + + netdev->ethtool_ops = &xennet_ethtool_ops; + netdev->min_mtu = ETH_MIN_MTU; + netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE; + SET_NETDEV_DEV(netdev, &dev->dev); + + np->netdev = netdev; + + netif_carrier_off(netdev); + + do { + xenbus_switch_state(dev, XenbusStateInitialising); + err = wait_event_timeout(module_wq, + xenbus_read_driver_state(dev->otherend) != + XenbusStateClosed && + xenbus_read_driver_state(dev->otherend) != + XenbusStateUnknown, XENNET_TIMEOUT); + } while (!err); + + return netdev; + + exit: + xennet_free_netdev(netdev); + return ERR_PTR(err); +} + +/** + * Entry point to this code when a new device is created. Allocate the basic + * structures and the ring buffers for communication with the backend, and + * inform the backend of the appropriate details for those. + */ +static int netfront_probe(struct xenbus_device *dev, + const struct xenbus_device_id *id) +{ + int err; + struct net_device *netdev; + struct netfront_info *info; + + netdev = xennet_create_dev(dev); + if (IS_ERR(netdev)) { + err = PTR_ERR(netdev); + xenbus_dev_fatal(dev, err, "creating netdev"); + return err; + } + + info = netdev_priv(netdev); + dev_set_drvdata(&dev->dev, info); +#ifdef CONFIG_SYSFS + info->netdev->sysfs_groups[0] = &xennet_dev_group; +#endif + + return 0; +} + +static void xennet_end_access(int ref, void *page) +{ + /* This frees the page as a side-effect */ + if (ref != GRANT_INVALID_REF) + gnttab_end_foreign_access(ref, 0, (unsigned long)page); +} + +static void xennet_disconnect_backend(struct netfront_info *info) +{ + unsigned int i = 0; + unsigned int num_queues = info->netdev->real_num_tx_queues; + + netif_carrier_off(info->netdev); + + for (i = 0; i < num_queues && info->queues; ++i) { + struct netfront_queue *queue = &info->queues[i]; + + del_timer_sync(&queue->rx_refill_timer); + + if (queue->tx_irq && (queue->tx_irq == queue->rx_irq)) + unbind_from_irqhandler(queue->tx_irq, queue); + if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) { + unbind_from_irqhandler(queue->tx_irq, queue); + unbind_from_irqhandler(queue->rx_irq, queue); + } + queue->tx_evtchn = queue->rx_evtchn = 0; + queue->tx_irq = queue->rx_irq = 0; + + if (netif_running(info->netdev)) + napi_synchronize(&queue->napi); + + xennet_release_tx_bufs(queue); + xennet_release_rx_bufs(queue); + gnttab_free_grant_references(queue->gref_tx_head); + gnttab_free_grant_references(queue->gref_rx_head); + + /* End access and free the pages */ + xennet_end_access(queue->tx_ring_ref, queue->tx.sring); + xennet_end_access(queue->rx_ring_ref, queue->rx.sring); + + queue->tx_ring_ref = GRANT_INVALID_REF; + queue->rx_ring_ref = GRANT_INVALID_REF; + queue->tx.sring = NULL; + queue->rx.sring = NULL; + } +} + +/** + * We are reconnecting to the backend, due to a suspend/resume, or a backend + * driver restart. We tear down our netif structure and recreate it, but + * leave the device-layer structures intact so that this is transparent to the + * rest of the kernel. + */ +static int netfront_resume(struct xenbus_device *dev) +{ + struct netfront_info *info = dev_get_drvdata(&dev->dev); + + dev_dbg(&dev->dev, "%s\n", dev->nodename); + + netif_tx_lock_bh(info->netdev); + netif_device_detach(info->netdev); + netif_tx_unlock_bh(info->netdev); + + xennet_disconnect_backend(info); + return 0; +} + +static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) +{ + char *s, *e, *macstr; + int i; + + macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); + if (IS_ERR(macstr)) + return PTR_ERR(macstr); + + for (i = 0; i < ETH_ALEN; i++) { + mac[i] = simple_strtoul(s, &e, 16); + if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { + kfree(macstr); + return -ENOENT; + } + s = e+1; + } + + kfree(macstr); + return 0; +} + +static int setup_netfront_single(struct netfront_queue *queue) +{ + int err; + + err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn); + if (err < 0) + goto fail; + + err = bind_evtchn_to_irqhandler_lateeoi(queue->tx_evtchn, + xennet_interrupt, 0, + queue->info->netdev->name, + queue); + if (err < 0) + goto bind_fail; + queue->rx_evtchn = queue->tx_evtchn; + queue->rx_irq = queue->tx_irq = err; + + return 0; + +bind_fail: + xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn); + queue->tx_evtchn = 0; +fail: + return err; +} + +static int setup_netfront_split(struct netfront_queue *queue) +{ + int err; + + err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn); + if (err < 0) + goto fail; + err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn); + if (err < 0) + goto alloc_rx_evtchn_fail; + + snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name), + "%s-tx", queue->name); + err = bind_evtchn_to_irqhandler_lateeoi(queue->tx_evtchn, + xennet_tx_interrupt, 0, + queue->tx_irq_name, queue); + if (err < 0) + goto bind_tx_fail; + queue->tx_irq = err; + + snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name), + "%s-rx", queue->name); + err = bind_evtchn_to_irqhandler_lateeoi(queue->rx_evtchn, + xennet_rx_interrupt, 0, + queue->rx_irq_name, queue); + if (err < 0) + goto bind_rx_fail; + queue->rx_irq = err; + + return 0; + +bind_rx_fail: + unbind_from_irqhandler(queue->tx_irq, queue); + queue->tx_irq = 0; +bind_tx_fail: + xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn); + queue->rx_evtchn = 0; +alloc_rx_evtchn_fail: + xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn); + queue->tx_evtchn = 0; +fail: + return err; +} + +static int setup_netfront(struct xenbus_device *dev, + struct netfront_queue *queue, unsigned int feature_split_evtchn) +{ + struct xen_netif_tx_sring *txs; + struct xen_netif_rx_sring *rxs = NULL; + grant_ref_t gref; + int err; + + queue->tx_ring_ref = GRANT_INVALID_REF; + queue->rx_ring_ref = GRANT_INVALID_REF; + queue->rx.sring = NULL; + queue->tx.sring = NULL; + + txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); + if (!txs) { + err = -ENOMEM; + xenbus_dev_fatal(dev, err, "allocating tx ring page"); + goto fail; + } + SHARED_RING_INIT(txs); + FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE); + + err = xenbus_grant_ring(dev, txs, 1, &gref); + if (err < 0) + goto fail; + queue->tx_ring_ref = gref; + + rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); + if (!rxs) { + err = -ENOMEM; + xenbus_dev_fatal(dev, err, "allocating rx ring page"); + goto fail; + } + SHARED_RING_INIT(rxs); + FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE); + + err = xenbus_grant_ring(dev, rxs, 1, &gref); + if (err < 0) + goto fail; + queue->rx_ring_ref = gref; + + if (feature_split_evtchn) + err = setup_netfront_split(queue); + /* setup single event channel if + * a) feature-split-event-channels == 0 + * b) feature-split-event-channels == 1 but failed to setup + */ + if (!feature_split_evtchn || (feature_split_evtchn && err)) + err = setup_netfront_single(queue); + + if (err) + goto fail; + + return 0; + + /* If we fail to setup netfront, it is safe to just revoke access to + * granted pages because backend is not accessing it at this point. + */ + fail: + if (queue->rx_ring_ref != GRANT_INVALID_REF) { + gnttab_end_foreign_access(queue->rx_ring_ref, 0, + (unsigned long)rxs); + queue->rx_ring_ref = GRANT_INVALID_REF; + } else { + free_page((unsigned long)rxs); + } + if (queue->tx_ring_ref != GRANT_INVALID_REF) { + gnttab_end_foreign_access(queue->tx_ring_ref, 0, + (unsigned long)txs); + queue->tx_ring_ref = GRANT_INVALID_REF; + } else { + free_page((unsigned long)txs); + } + return err; +} + +/* Queue-specific initialisation + * This used to be done in xennet_create_dev() but must now + * be run per-queue. + */ +static int xennet_init_queue(struct netfront_queue *queue) +{ + unsigned short i; + int err = 0; + char *devid; + + spin_lock_init(&queue->tx_lock); + spin_lock_init(&queue->rx_lock); + spin_lock_init(&queue->rx_cons_lock); + + timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0); + + devid = strrchr(queue->info->xbdev->nodename, '/') + 1; + snprintf(queue->name, sizeof(queue->name), "vif%s-q%u", + devid, queue->id); + + /* Initialise tx_skb_freelist as a free chain containing every entry. */ + queue->tx_skb_freelist = 0; + queue->tx_pend_queue = TX_LINK_NONE; + for (i = 0; i < NET_TX_RING_SIZE; i++) { + queue->tx_link[i] = i + 1; + queue->grant_tx_ref[i] = GRANT_INVALID_REF; + queue->grant_tx_page[i] = NULL; + } + queue->tx_link[NET_TX_RING_SIZE - 1] = TX_LINK_NONE; + + /* Clear out rx_skbs */ + for (i = 0; i < NET_RX_RING_SIZE; i++) { + queue->rx_skbs[i] = NULL; + queue->grant_rx_ref[i] = GRANT_INVALID_REF; + } + + /* A grant for every tx ring slot */ + if (gnttab_alloc_grant_references(NET_TX_RING_SIZE, + &queue->gref_tx_head) < 0) { + pr_alert("can't alloc tx grant refs\n"); + err = -ENOMEM; + goto exit; + } + + /* A grant for every rx ring slot */ + if (gnttab_alloc_grant_references(NET_RX_RING_SIZE, + &queue->gref_rx_head) < 0) { + pr_alert("can't alloc rx grant refs\n"); + err = -ENOMEM; + goto exit_free_tx; + } + + return 0; + + exit_free_tx: + gnttab_free_grant_references(queue->gref_tx_head); + exit: + return err; +} + +static int write_queue_xenstore_keys(struct netfront_queue *queue, + struct xenbus_transaction *xbt, int write_hierarchical) +{ + /* Write the queue-specific keys into XenStore in the traditional + * way for a single queue, or in a queue subkeys for multiple + * queues. + */ + struct xenbus_device *dev = queue->info->xbdev; + int err; + const char *message; + char *path; + size_t pathsize; + + /* Choose the correct place to write the keys */ + if (write_hierarchical) { + pathsize = strlen(dev->nodename) + 10; + path = kzalloc(pathsize, GFP_KERNEL); + if (!path) { + err = -ENOMEM; + message = "out of memory while writing ring references"; + goto error; + } + snprintf(path, pathsize, "%s/queue-%u", + dev->nodename, queue->id); + } else { + path = (char *)dev->nodename; + } + + /* Write ring references */ + err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u", + queue->tx_ring_ref); + if (err) { + message = "writing tx-ring-ref"; + goto error; + } + + err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u", + queue->rx_ring_ref); + if (err) { + message = "writing rx-ring-ref"; + goto error; + } + + /* Write event channels; taking into account both shared + * and split event channel scenarios. + */ + if (queue->tx_evtchn == queue->rx_evtchn) { + /* Shared event channel */ + err = xenbus_printf(*xbt, path, + "event-channel", "%u", queue->tx_evtchn); + if (err) { + message = "writing event-channel"; + goto error; + } + } else { + /* Split event channels */ + err = xenbus_printf(*xbt, path, + "event-channel-tx", "%u", queue->tx_evtchn); + if (err) { + message = "writing event-channel-tx"; + goto error; + } + + err = xenbus_printf(*xbt, path, + "event-channel-rx", "%u", queue->rx_evtchn); + if (err) { + message = "writing event-channel-rx"; + goto error; + } + } + + if (write_hierarchical) + kfree(path); + return 0; + +error: + if (write_hierarchical) + kfree(path); + xenbus_dev_fatal(dev, err, "%s", message); + return err; +} + +static int xennet_create_queues(struct netfront_info *info, + unsigned int *num_queues) +{ + unsigned int i; + int ret; + + info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue), + GFP_KERNEL); + if (!info->queues) + return -ENOMEM; + + for (i = 0; i < *num_queues; i++) { + struct netfront_queue *queue = &info->queues[i]; + + queue->id = i; + queue->info = info; + + ret = xennet_init_queue(queue); + if (ret < 0) { + dev_warn(&info->xbdev->dev, + "only created %d queues\n", i); + *num_queues = i; + break; + } + + netif_napi_add(queue->info->netdev, &queue->napi, + xennet_poll, 64); + if (netif_running(info->netdev)) + napi_enable(&queue->napi); + } + + netif_set_real_num_tx_queues(info->netdev, *num_queues); + + if (*num_queues == 0) { + dev_err(&info->xbdev->dev, "no queues\n"); + return -EINVAL; + } + return 0; +} + +/* Common code used when first setting up, and when resuming. */ +static int talk_to_netback(struct xenbus_device *dev, + struct netfront_info *info) +{ + const char *message; + struct xenbus_transaction xbt; + int err; + unsigned int feature_split_evtchn; + unsigned int i = 0; + unsigned int max_queues = 0; + struct netfront_queue *queue = NULL; + unsigned int num_queues = 1; + + info->netdev->irq = 0; + + /* Check if backend supports multiple queues */ + max_queues = xenbus_read_unsigned(info->xbdev->otherend, + "multi-queue-max-queues", 1); + num_queues = min(max_queues, xennet_max_queues); + + /* Check feature-split-event-channels */ + feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend, + "feature-split-event-channels", 0); + + /* Read mac addr. */ + err = xen_net_read_mac(dev, info->netdev->dev_addr); + if (err) { + xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); + goto out_unlocked; + } + + rtnl_lock(); + if (info->queues) + xennet_destroy_queues(info); + + /* For the case of a reconnect reset the "broken" indicator. */ + info->broken = false; + + err = xennet_create_queues(info, &num_queues); + if (err < 0) { + xenbus_dev_fatal(dev, err, "creating queues"); + kfree(info->queues); + info->queues = NULL; + goto out; + } + rtnl_unlock(); + + /* Create shared ring, alloc event channel -- for each queue */ + for (i = 0; i < num_queues; ++i) { + queue = &info->queues[i]; + err = setup_netfront(dev, queue, feature_split_evtchn); + if (err) + goto destroy_ring; + } + +again: + err = xenbus_transaction_start(&xbt); + if (err) { + xenbus_dev_fatal(dev, err, "starting transaction"); + goto destroy_ring; + } + + if (xenbus_exists(XBT_NIL, + info->xbdev->otherend, "multi-queue-max-queues")) { + /* Write the number of queues */ + err = xenbus_printf(xbt, dev->nodename, + "multi-queue-num-queues", "%u", num_queues); + if (err) { + message = "writing multi-queue-num-queues"; + goto abort_transaction_no_dev_fatal; + } + } + + if (num_queues == 1) { + err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */ + if (err) + goto abort_transaction_no_dev_fatal; + } else { + /* Write the keys for each queue */ + for (i = 0; i < num_queues; ++i) { + queue = &info->queues[i]; + err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */ + if (err) + goto abort_transaction_no_dev_fatal; + } + } + + /* The remaining keys are not queue-specific */ + err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u", + 1); + if (err) { + message = "writing request-rx-copy"; + goto abort_transaction; + } + + err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1); + if (err) { + message = "writing feature-rx-notify"; + goto abort_transaction; + } + + err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1); + if (err) { + message = "writing feature-sg"; + goto abort_transaction; + } + + err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1); + if (err) { + message = "writing feature-gso-tcpv4"; + goto abort_transaction; + } + + err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1"); + if (err) { + message = "writing feature-gso-tcpv6"; + goto abort_transaction; + } + + err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload", + "1"); + if (err) { + message = "writing feature-ipv6-csum-offload"; + goto abort_transaction; + } + + err = xenbus_transaction_end(xbt, 0); + if (err) { + if (err == -EAGAIN) + goto again; + xenbus_dev_fatal(dev, err, "completing transaction"); + goto destroy_ring; + } + + return 0; + + abort_transaction: + xenbus_dev_fatal(dev, err, "%s", message); +abort_transaction_no_dev_fatal: + xenbus_transaction_end(xbt, 1); + destroy_ring: + xennet_disconnect_backend(info); + rtnl_lock(); + xennet_destroy_queues(info); + out: + rtnl_unlock(); +out_unlocked: + device_unregister(&dev->dev); + return err; +} + +static int xennet_connect(struct net_device *dev) +{ + struct netfront_info *np = netdev_priv(dev); + unsigned int num_queues = 0; + int err; + unsigned int j = 0; + struct netfront_queue *queue = NULL; + + if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) { + dev_info(&dev->dev, + "backend does not support copying receive path\n"); + return -ENODEV; + } + + err = talk_to_netback(np->xbdev, np); + if (err) + return err; + + /* talk_to_netback() sets the correct number of queues */ + num_queues = dev->real_num_tx_queues; + + if (dev->reg_state == NETREG_UNINITIALIZED) { + err = register_netdev(dev); + if (err) { + pr_warn("%s: register_netdev err=%d\n", __func__, err); + device_unregister(&np->xbdev->dev); + return err; + } + } + + rtnl_lock(); + netdev_update_features(dev); + rtnl_unlock(); + + /* + * All public and private state should now be sane. Get + * ready to start sending and receiving packets and give the driver + * domain a kick because we've probably just requeued some + * packets. + */ + netif_tx_lock_bh(np->netdev); + netif_device_attach(np->netdev); + netif_tx_unlock_bh(np->netdev); + + netif_carrier_on(np->netdev); + for (j = 0; j < num_queues; ++j) { + queue = &np->queues[j]; + + notify_remote_via_irq(queue->tx_irq); + if (queue->tx_irq != queue->rx_irq) + notify_remote_via_irq(queue->rx_irq); + + spin_lock_irq(&queue->tx_lock); + xennet_tx_buf_gc(queue); + spin_unlock_irq(&queue->tx_lock); + + spin_lock_bh(&queue->rx_lock); + xennet_alloc_rx_buffers(queue); + spin_unlock_bh(&queue->rx_lock); + } + + return 0; +} + +/** + * Callback received when the backend's state changes. + */ +static void netback_changed(struct xenbus_device *dev, + enum xenbus_state backend_state) +{ + struct netfront_info *np = dev_get_drvdata(&dev->dev); + struct net_device *netdev = np->netdev; + + dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state)); + + wake_up_all(&module_wq); + + switch (backend_state) { + case XenbusStateInitialising: + case XenbusStateInitialised: + case XenbusStateReconfiguring: + case XenbusStateReconfigured: + case XenbusStateUnknown: + break; + + case XenbusStateInitWait: + if (dev->state != XenbusStateInitialising) + break; + if (xennet_connect(netdev) != 0) + break; + xenbus_switch_state(dev, XenbusStateConnected); + break; + + case XenbusStateConnected: + netdev_notify_peers(netdev); + break; + + case XenbusStateClosed: + if (dev->state == XenbusStateClosed) + break; + /* Missed the backend's CLOSING state -- fallthrough */ + case XenbusStateClosing: + xenbus_frontend_closed(dev); + break; + } +} + +static const struct xennet_stat { + char name[ETH_GSTRING_LEN]; + u16 offset; +} xennet_stats[] = { + { + "rx_gso_checksum_fixup", + offsetof(struct netfront_info, rx_gso_checksum_fixup) + }, +}; + +static int xennet_get_sset_count(struct net_device *dev, int string_set) +{ + switch (string_set) { + case ETH_SS_STATS: + return ARRAY_SIZE(xennet_stats); + default: + return -EINVAL; + } +} + +static void xennet_get_ethtool_stats(struct net_device *dev, + struct ethtool_stats *stats, u64 * data) +{ + void *np = netdev_priv(dev); + int i; + + for (i = 0; i < ARRAY_SIZE(xennet_stats); i++) + data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset)); +} + +static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data) +{ + int i; + + switch (stringset) { + case ETH_SS_STATS: + for (i = 0; i < ARRAY_SIZE(xennet_stats); i++) + memcpy(data + i * ETH_GSTRING_LEN, + xennet_stats[i].name, ETH_GSTRING_LEN); + break; + } +} + +static const struct ethtool_ops xennet_ethtool_ops = +{ + .get_link = ethtool_op_get_link, + + .get_sset_count = xennet_get_sset_count, + .get_ethtool_stats = xennet_get_ethtool_stats, + .get_strings = xennet_get_strings, +}; + +#ifdef CONFIG_SYSFS +static ssize_t show_rxbuf(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%lu\n", NET_RX_RING_SIZE); +} + +static ssize_t store_rxbuf(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + char *endp; + unsigned long target; + + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + + target = simple_strtoul(buf, &endp, 0); + if (endp == buf) + return -EBADMSG; + + /* rxbuf_min and rxbuf_max are no longer configurable. */ + + return len; +} + +static DEVICE_ATTR(rxbuf_min, 0644, show_rxbuf, store_rxbuf); +static DEVICE_ATTR(rxbuf_max, 0644, show_rxbuf, store_rxbuf); +static DEVICE_ATTR(rxbuf_cur, 0444, show_rxbuf, NULL); + +static struct attribute *xennet_dev_attrs[] = { + &dev_attr_rxbuf_min.attr, + &dev_attr_rxbuf_max.attr, + &dev_attr_rxbuf_cur.attr, + NULL +}; + +static const struct attribute_group xennet_dev_group = { + .attrs = xennet_dev_attrs +}; +#endif /* CONFIG_SYSFS */ + +static void xennet_bus_close(struct xenbus_device *dev) +{ + int ret; + + if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed) + return; + do { + xenbus_switch_state(dev, XenbusStateClosing); + ret = wait_event_timeout(module_wq, + xenbus_read_driver_state(dev->otherend) == + XenbusStateClosing || + xenbus_read_driver_state(dev->otherend) == + XenbusStateClosed || + xenbus_read_driver_state(dev->otherend) == + XenbusStateUnknown, + XENNET_TIMEOUT); + } while (!ret); + + if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed) + return; + + do { + xenbus_switch_state(dev, XenbusStateClosed); + ret = wait_event_timeout(module_wq, + xenbus_read_driver_state(dev->otherend) == + XenbusStateClosed || + xenbus_read_driver_state(dev->otherend) == + XenbusStateUnknown, + XENNET_TIMEOUT); + } while (!ret); +} + +static int xennet_remove(struct xenbus_device *dev) +{ + struct netfront_info *info = dev_get_drvdata(&dev->dev); + + xennet_bus_close(dev); + xennet_disconnect_backend(info); + + if (info->netdev->reg_state == NETREG_REGISTERED) + unregister_netdev(info->netdev); + + if (info->queues) { + rtnl_lock(); + xennet_destroy_queues(info); + rtnl_unlock(); + } + xennet_free_netdev(info->netdev); + + return 0; +} + +static const struct xenbus_device_id netfront_ids[] = { + { "vif" }, + { "" } +}; + +static struct xenbus_driver netfront_driver = { + .ids = netfront_ids, + .probe = netfront_probe, + .remove = xennet_remove, + .resume = netfront_resume, + .otherend_changed = netback_changed, +}; + +static int __init netif_init(void) +{ + if (!xen_domain()) + return -ENODEV; + + if (!xen_has_pv_nic_devices()) + return -ENODEV; + + pr_info("Initialising Xen virtual ethernet driver\n"); + + /* Allow as many queues as there are CPUs inut max. 8 if user has not + * specified a value. + */ + if (xennet_max_queues == 0) + xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT, + num_online_cpus()); + + return xenbus_register_frontend(&netfront_driver); +} +module_init(netif_init); + + +static void __exit netif_exit(void) +{ + xenbus_unregister_driver(&netfront_driver); +} +module_exit(netif_exit); + +MODULE_DESCRIPTION("Xen virtual network device frontend"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("xen:vif"); +MODULE_ALIAS("xennet"); |