Frontend net driver acceleration diff -r cd3ade350f3f drivers/xen/netfront/netfront.c --- a/drivers/xen/netfront/netfront.c Thu Jun 14 15:04:32 2007 +0100 +++ b/drivers/xen/netfront/netfront.c Fri Jun 15 09:34:41 2007 +0100 @@ -3,6 +3,7 @@ * * Copyright (c) 2002-2005, K A Fraser * Copyright (c) 2005, XenSource Ltd + * Copyright (C) 2007 Solarflare Communications, Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 @@ -47,6 +48,7 @@ #include #include #include +#include #include #include #include @@ -73,6 +75,8 @@ struct netfront_cb { }; #define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb)) + +#include "netfront.h" /* * Mutually-exclusive module options to select receive data path: @@ -144,57 +148,6 @@ static inline int netif_needs_gso(struct #define GRANT_INVALID_REF 0 -#define NET_TX_RING_SIZE __RING_SIZE((struct netif_tx_sring *)0, PAGE_SIZE) -#define NET_RX_RING_SIZE __RING_SIZE((struct netif_rx_sring *)0, PAGE_SIZE) - -struct netfront_info { - struct list_head list; - struct net_device *netdev; - - struct net_device_stats stats; - - struct netif_tx_front_ring tx; - struct netif_rx_front_ring rx; - - spinlock_t tx_lock; - spinlock_t rx_lock; - - unsigned int irq; - unsigned int copying_receiver; - unsigned int carrier; - - /* Receive-ring batched refills. */ -#define RX_MIN_TARGET 8 -#define RX_DFL_MIN_TARGET 64 -#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) - unsigned rx_min_target, rx_max_target, rx_target; - struct sk_buff_head rx_batch; - - struct timer_list rx_refill_timer; - - /* - * {tx,rx}_skbs store outstanding skbuffs. The first entry in tx_skbs - * is an index into a chain of free entries. - */ - struct sk_buff *tx_skbs[NET_TX_RING_SIZE+1]; - struct sk_buff *rx_skbs[NET_RX_RING_SIZE]; - -#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) - grant_ref_t gref_tx_head; - grant_ref_t grant_tx_ref[NET_TX_RING_SIZE + 1]; - grant_ref_t gref_rx_head; - grant_ref_t grant_rx_ref[NET_RX_RING_SIZE]; - - struct xenbus_device *xbdev; - int tx_ring_ref; - int rx_ring_ref; - u8 mac[ETH_ALEN]; - - unsigned long rx_pfn_array[NET_RX_RING_SIZE]; - struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1]; - struct mmu_update rx_mmu[NET_RX_RING_SIZE]; -}; - struct netfront_rx_info { struct netif_rx_response rx; struct netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1]; @@ -278,6 +231,369 @@ static void xennet_sysfs_delif(struct ne #define xennet_sysfs_delif(dev) do { } while(0) #endif +/* + * List of all netfront accelerator plugin modules available. Each + * list entry is of type struct netfront_accelerator. + */ +static struct list_head accelerators_list; +/* + * Lock to protect access to accelerators_list, and also used to + * protect the hooks_usecount field in struct netfront_accelerator + * against concurrent access + */ +static spinlock_t accelerators_lock; + +/* + * Safely remove the accelerator function hooks from a netfront state. + * Must only be called when there are no current users of the hooks. + */ +static void accelerator_remove_hooks(struct netfront_accelerator *accelerator) +{ + struct netfront_accel_vif_state *vif_state; + + list_for_each_entry( vif_state, + &accelerator->vif_states, + link ) { + /* Make sure there are no data path operations going on */ + netif_poll_disable(vif_state->np->netdev); + netif_tx_lock_bh(vif_state->np->netdev); + + /* + * Remove the hooks, but leave the vif_state on the + * accelerator's list as that signifies this vif is + * interested in using that accelerator if it becomes + * available again + */ + vif_state->hooks = NULL; + + netif_tx_unlock_bh(vif_state->np->netdev); + netif_poll_enable(vif_state->np->netdev); + } + + accelerator->hooks = NULL; + + /* Signal that all users of hooks are done */ + up(&accelerator->exit_semaphore); +} + + +/* + * Compare a frontend description string against an accelerator to see + * if they match. Would ultimately be nice to replace the string with + * a unique numeric identifier for each accelerator. + */ +static int match_accelerator(const char *frontend, + struct netfront_accelerator *accelerator) +{ + return strcmp(frontend, accelerator->frontend) == 0; +} + + +/* + * Add a frontend vif to the list of vifs that is using a netfront + * accelerator plugin module. + */ +static void add_accelerator_vif(struct netfront_accelerator *accelerator, + struct netfront_info *np, + struct xenbus_device *dev) +{ + np->accelerator = accelerator; + np->accel_vif_state.np = np; + np->accel_vif_state.dev = dev; + + list_add(&np->accel_vif_state.link, &accelerator->vif_states); +} + +/* + * Initialise the netfront state of an accelerator plugin module. + */ +static int init_accelerator(const char *frontend, + struct netfront_accelerator **result) +{ + struct netfront_accelerator *accelerator = + kmalloc(sizeof(struct netfront_accelerator), GFP_KERNEL); + int frontend_len; + + if ( !accelerator ) { + DPRINTK("%s: no memory for accelerator", __FUNCTION__); + return -ENOMEM; + } + + frontend_len = strlen(frontend) + 1; + accelerator->frontend = kmalloc(frontend_len, GFP_KERNEL); + if ( !accelerator->frontend ) { + DPRINTK("%s: no memory for accelerator", __FUNCTION__); + kfree(accelerator); + return -ENOMEM; + } + strlcpy(accelerator->frontend, frontend, frontend_len); + + INIT_LIST_HEAD(&accelerator->vif_states); + + accelerator->hooks = NULL; + accelerator->hooks_usecount = 0; + + list_add(&accelerator->link, &accelerators_list); + + *result = accelerator; + + return 0; +} + +/* + * Modify the hooks stored in the per-vif state to match that in the + * netfront accelerator's state. + */ +static void +accelerator_set_vif_state_hooks(struct netfront_accel_vif_state *vif_state) +{ + /* Make sure there are no data path operations going on */ + netif_poll_disable(vif_state->np->netdev); + netif_tx_lock_bh(vif_state->np->netdev); + + vif_state->hooks = vif_state->np->accelerator->hooks; + + netif_tx_unlock_bh(vif_state->np->netdev); + netif_poll_enable(vif_state->np->netdev); +} + + +/* + * Request that a particular netfront accelerator plugin is loaded. + * Usually called as a result of the vif configuration specifying + * which one to use. + */ +static int netfront_load_accelerator(struct netfront_info *np, + struct xenbus_device *dev, + const char *frontend) +{ + struct netfront_accelerator *accelerator; + int rc; + unsigned flags; + + spin_lock_irqsave(&accelerators_lock, flags); + + /* + * Look at list of loaded accelerators to see if the requested + * one is already there + */ + list_for_each_entry( accelerator, &accelerators_list, link ) { + if ( match_accelerator(frontend, accelerator) ) { + /* + * Include this frontend device on the + * accelerator's list + */ + add_accelerator_vif(accelerator, np, dev); + + ++accelerator->hooks_usecount; + + if ( accelerator->hooks == NULL ) + DPRINTK("%s: no hooks set", __FUNCTION__); + else { + spin_unlock_irqrestore(&accelerators_lock, flags); + accelerator->hooks->new_device(np->netdev, dev); + spin_lock_irqsave(&accelerators_lock, flags); + } + + if ( (--accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + + /* + * Hooks will get linked into vif_state by a + * future call by the accelerator to + * netfront_accelerator_ready() + */ + + return 0; + } + } + + /* Couldn't find it, so create a new one and load the module */ + if ( ( rc = init_accelerator(frontend, &accelerator) ) < 0 ) { + spin_unlock_irqrestore(&accelerators_lock, flags); + return rc; + } + + /* Include this frontend device on the accelerator's list */ + add_accelerator_vif(accelerator, np, dev); + + spin_unlock_irqrestore(&accelerators_lock, flags); + + DPRINTK("%s: loading module %s\n", __FUNCTION__, frontend); + + /* load module */ + request_module("%s", frontend); + + /* + * Module should now call netfront_accelerator_loaded() once + * it's up and running, and we can continue from there + */ + + return 0; +} + +/* + * Go through all the netfront vifs and see if they have requested + * this accelerator. Notify the accelerator plugin of the relevant + * device if so. Called when an accelerator plugin module is first + * loaded and connects to netfront. + */ +static void +accelerator_probe_vifs_on_load(struct netfront_accelerator *accelerator) +{ + struct netfront_accel_vif_state *accel_vif_state; + + DPRINTK("%s: %p\n", __FUNCTION__, accelerator); + + list_for_each_entry( accel_vif_state, + &accelerator->vif_states, link ) { + struct netfront_info *np = accel_vif_state->np; + + accelerator->hooks->new_device(np->netdev, + accel_vif_state->dev); + + /* + * Hooks will get linked into vif_state by a call to + * netfront_accelerator_ready() once accelerator + * plugin is ready for action + */ + } +} + + +/* + * Called by the netfront accelerator plugin module when it has loaded + */ +int netfront_accelerator_loaded(const char *frontend, + struct netfront_accel_hooks *hooks) +{ + struct netfront_accelerator *accelerator; + unsigned flags; + + spin_lock_irqsave(&accelerators_lock, flags); + + /* Look through list of accelerators to see if it has already + been requested */ + list_for_each_entry( accelerator, &accelerators_list, link ) { + if ( match_accelerator(frontend, accelerator) ) { + /* + * Deliberate double inc of usecount here - + * one to initialise it to 1 now hooks is + * being set (which persists until unloaded), + * and one for the use of hooks in this + * function (we don't want an unload to + * succeed in clearing hooks in the middle) + */ + BUG_ON(accelerator->hooks != NULL || + accelerator->hooks_usecount != 0); + accelerator->hooks_usecount = 2; + + accelerator->hooks = hooks; + + spin_unlock_irqrestore(&accelerators_lock, flags); + + accelerator_probe_vifs_on_load(accelerator); + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + + return 0; + } + } + + /* If it wasn't in the list, add it now so that when it is + requested the caller will find it */ + DPRINTK("%s: Couldn't find matching accelerator (%s)\n", + __FUNCTION__, frontend); + + init_accelerator(frontend, &accelerator); + + spin_unlock_irqrestore(&accelerators_lock, flags); + + return 0; +} +EXPORT_SYMBOL_GPL(netfront_accelerator_loaded); + + +/* + * Called by the accelerator module after it has been probed with a + * network device to say that it is ready to start accelerating + * traffic on that device + */ +void netfront_accelerator_ready(const char *frontend, + struct xenbus_device *dev) +{ + struct netfront_accelerator *accelerator; + struct netfront_accel_vif_state *accel_vif_state; + unsigned flags; + + spin_lock_irqsave(&accelerators_lock, flags); + + list_for_each_entry( accelerator, &accelerators_list, link ) { + if ( match_accelerator(frontend, accelerator) ) { + ++accelerator->hooks_usecount; + spin_unlock_irqrestore(&accelerators_lock, flags); + + list_for_each_entry( accel_vif_state, + &accelerator->vif_states, link ) { + if ( accel_vif_state->dev == dev ) + accelerator_set_vif_state_hooks + (accel_vif_state); + } + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + + return; + } + } + + spin_unlock_irqrestore(&accelerators_lock, flags); +} +EXPORT_SYMBOL_GPL(netfront_accelerator_ready); + + +/* + * Called by a netfront accelerator when it is unloaded. This safely + * removes the hooks into the plugin and blocks until all devices have + * finished using it, so on return it is safe to unload. + */ +void netfront_accelerator_unloaded(const char *frontend) +{ + struct netfront_accelerator *accelerator; + unsigned flags; + + spin_lock_irqsave(&accelerators_lock, flags); + + list_for_each_entry( accelerator, &accelerators_list, link ) { + if ( match_accelerator(frontend, accelerator) ) { + /* + * Use semaphore to ensure we know when all + * uses of hooks are complete + */ + sema_init(&accelerator->exit_semaphore, 0); + + if ( (--accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(accelerator); + + spin_unlock_irqrestore(&accelerators_lock, flags); + + /* Wait for hooks to be unused, then return */ + down(&accelerator->exit_semaphore); + + return; + } + } + spin_unlock_irqrestore(&accelerators_lock, flags); +} +EXPORT_SYMBOL_GPL(netfront_accelerator_unloaded); + + static inline int xennet_can_sg(struct net_device *dev) { return dev->features & NETIF_F_SG; @@ -331,8 +647,29 @@ static int __devexit netfront_remove(str static int __devexit netfront_remove(struct xenbus_device *dev) { struct netfront_info *info = dev->dev.driver_data; + unsigned flags; DPRINTK("%s\n", dev->nodename); + + /* + * Call the remove accelerator hook. The use count for the + * accelerator's hooks is incremented for the duration of the + * call to prevent the accelerator being able to modify the + * hooks in the middle (by, for example, unloading) + */ + if ( info->accel_vif_state.hooks ) { + spin_lock_irqsave(&accelerators_lock, flags); + ++info->accelerator->hooks_usecount; + spin_unlock_irqrestore(&accelerators_lock, flags); + + if ( info->accel_vif_state.hooks ) + info->accel_vif_state.hooks->remove(dev); + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--info->accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(info->accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + } netif_disconnect_backend(info); @@ -356,8 +693,29 @@ static int netfront_resume(struct xenbus static int netfront_resume(struct xenbus_device *dev) { struct netfront_info *info = dev->dev.driver_data; + unsigned flags; DPRINTK("%s\n", dev->nodename); + + /* + * Call the resume accelerator hook. The use count for the + * accelerator's hooks is incremented for the duration of + * the call to prevent the accelerator being able to modify + * the * hooks in the middle (by, for example, unloading) + */ + if ( info->accel_vif_state.hooks ) { + spin_lock_irqsave(&accelerators_lock, flags); + ++info->accelerator->hooks_usecount; + spin_unlock_irqrestore(&accelerators_lock, flags); + + if ( info->accel_vif_state.hooks ) + info->accel_vif_state.hooks->resume(dev); + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--info->accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(info->accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + } netif_disconnect_backend(info); return 0; @@ -553,6 +911,7 @@ static void backend_changed(struct xenbu { struct netfront_info *np = dev->dev.driver_data; struct net_device *netdev = np->netdev; + unsigned flags; DPRINTK("%s\n", xenbus_strstate(backend_state)); @@ -577,6 +936,27 @@ static void backend_changed(struct xenbu xenbus_frontend_closed(dev); break; } + + /* + * Call the backend_changed accelerator hook. The use count + * for the accelerator's hooks is incremented for the duration + * of the call to prevent the accelerator being able to modify + * the hooks in the middle (by, for example, unloading) + */ + if ( np->accel_vif_state.hooks ) { + spin_lock_irqsave(&accelerators_lock, flags); + ++np->accelerator->hooks_usecount; + spin_unlock_irqrestore(&accelerators_lock, flags); + + if ( np->accel_vif_state.hooks ) + np->accel_vif_state.hooks->backend_changed + (dev, backend_state); + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--np->accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(np->accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + } } /** Send a packet on a net device to encourage switches to learn the @@ -613,19 +993,65 @@ static inline int netfront_tx_slot_avail (TX_MAX_TARGET - MAX_SKB_FRAGS - 2)); } + +static inline +int netfront_check_accelerator_queue_busy(struct net_device *dev, + struct netfront_info *np) +{ + int rc = 1; + unsigned flags; + + /* + * Call the check busy accelerator hook. The use count for the + * accelerator's hooks is incremented for the duration of the + * call to prevent the accelerator being able to modify the + * hooks in the middle (by, for example, unloading) + */ + if ( np->accel_vif_state.hooks ) { + spin_lock_irqsave(&accelerators_lock, flags); + ++(np->accelerator->hooks_usecount); + spin_unlock_irqrestore(&accelerators_lock, flags); + + if ( np->accel_vif_state.hooks ) + rc = np->accel_vif_state.hooks->check_busy(dev); + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--(np->accelerator->hooks_usecount) == 0 ) ) + accelerator_remove_hooks(np->accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + } + + return rc; +} + + static inline void network_maybe_wake_tx(struct net_device *dev) { struct netfront_info *np = netdev_priv(dev); if (unlikely(netif_queue_stopped(dev)) && netfront_tx_slot_available(np) && - likely(netif_running(dev))) + likely(netif_running(dev)) && + netfront_check_accelerator_queue_busy(dev, np)) netif_wake_queue(dev); } + +int netfront_check_queue_busy(struct net_device *dev) +{ + struct netfront_info *np = netdev_priv(dev); + + return unlikely(netif_queue_stopped(dev)) && + netfront_tx_slot_available(np) && + likely(netif_running(dev)); +} +EXPORT_SYMBOL(netfront_check_queue_busy); + + static int network_open(struct net_device *dev) { struct netfront_info *np = netdev_priv(dev); + unsigned flags; memset(&np->stats, 0, sizeof(np->stats)); @@ -633,8 +1059,34 @@ static int network_open(struct net_devic if (netfront_carrier_ok(np)) { network_alloc_rx_buffers(dev); np->rx.sring->rsp_event = np->rx.rsp_cons + 1; - if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)) + if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)){ + /* + * Call the stop_napi_interrupts accelerator + * hook. The use count for the accelerator's + * hooks is incremented for the duration of + * the call to prevent the accelerator being + * able to modify the hooks in the middle (by, + * for example, unloading) + */ + if ( np->accel_vif_state.hooks ) { + spin_lock_irqsave(&accelerators_lock, flags); + ++np->accelerator->hooks_usecount; + spin_unlock_irqrestore(&accelerators_lock, + flags); + + if ( np->accel_vif_state.hooks ) + np->accel_vif_state.hooks->stop_napi_interrupts(dev); + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--np->accelerator->hooks_usecount)==0 ) + accelerator_remove_hooks + (np->accelerator); + spin_unlock_irqrestore(&accelerators_lock, + flags); + } + netif_rx_schedule(dev); + } } spin_unlock_bh(&np->rx_lock); @@ -702,6 +1154,30 @@ static void rx_refill_timeout(unsigned l static void rx_refill_timeout(unsigned long data) { struct net_device *dev = (struct net_device *)data; + struct netfront_info *np = netdev_priv(dev); + unsigned flags; + + /* + * Call the stop_napi_interrupts accelerator hook. The use + * count for the accelerator's hooks is incremented for the + * duration of the call to prevent the accelerator being able + * to modify the hooks in the middle (by, for example, + * unloading) + */ + if ( np->accel_vif_state.hooks ) { + spin_lock_irqsave(&accelerators_lock, flags); + ++np->accelerator->hooks_usecount; + spin_unlock_irqrestore(&accelerators_lock, flags); + + if ( np->accel_vif_state.hooks ) + np->accel_vif_state.hooks->stop_napi_interrupts(dev); + + spin_lock_irqsave(&accelerators_lock, flags); + if ( (--np->accelerator->hooks_usecount) == 0 ) + accelerator_remove_hooks(np->accelerator); + spin_unlock_irqrestore(&accelerators_lock, flags); + } + netif_rx_schedule(dev); } @@ -941,6 +1417,12 @@ static int network_start_xmit(struct sk_ unsigned int offset = offset_in_page(data); unsigned int len = skb_headlen(skb); + /* Check the fast path, if hooks are available */ + if ( np->accel_vif_state.hooks && + np->accel_vif_state.hooks->start_xmit(skb, dev) ) { + return 0; + } + frags += (offset + len + PAGE_SIZE - 1) / PAGE_SIZE; if (unlikely(frags > MAX_SKB_FRAGS + 1)) { printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n", @@ -1037,15 +1519,41 @@ static irqreturn_t netif_int(int irq, vo { struct net_device *dev = dev_id; struct netfront_info *np = netdev_priv(dev); - unsigned long flags; + unsigned long flags, flags1; spin_lock_irqsave(&np->tx_lock, flags); if (likely(netfront_carrier_ok(np))) { network_tx_buf_gc(dev); /* Under tx_lock: protects access to rx shared-ring indexes. */ - if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)) + if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)) { + /* + * Call the stop_napi_interrupts accelerator + * hook. The use count for the accelerator's + * hooks is incremented for the duration of + * the call to prevent the accelerator being + * able to modify the hooks in the middle (by, + * for example, unloading) + */ + if ( np->accel_vif_state.hooks ) { + spin_lock_irqsave(&accelerators_lock, flags1); + ++np->accelerator->hooks_usecount; + spin_unlock_irqrestore(&accelerators_lock, + flags1); + + if ( np->accel_vif_state.hooks ) + np->accel_vif_state.hooks->stop_napi_interrupts(dev); + + spin_lock_irqsave(&accelerators_lock, flags1); + if ( (--np->accelerator->hooks_usecount)==0 ) + accelerator_remove_hooks + (np->accelerator); + spin_unlock_irqrestore(&accelerators_lock, + flags1); + } + netif_rx_schedule(dev); + } } spin_unlock_irqrestore(&np->tx_lock, flags); @@ -1305,7 +1813,7 @@ static int netif_poll(struct net_device struct netif_extra_info *extras = rinfo.extras; RING_IDX i, rp; struct multicall_entry *mcl; - int work_done, budget, more_to_do = 1; + int work_done, budget, more_to_do = 1, accel_more_to_do = 1; struct sk_buff_head rxq; struct sk_buff_head errq; struct sk_buff_head tmpq; @@ -1472,6 +1980,20 @@ err: network_alloc_rx_buffers(dev); + if (work_done < budget) { + /* there's some spare capacity, try the accelerated path */ + int accel_budget = budget - work_done; + int accel_budget_start = accel_budget; + + if ( np->accel_vif_state.hooks ) { + accel_more_to_do = + np->accel_vif_state.hooks->netdev_poll + (dev, &accel_budget); + work_done += (accel_budget_start - accel_budget); + } else + accel_more_to_do = 0; + } + *pbudget -= work_done; dev->quota -= work_done; @@ -1479,15 +2001,28 @@ err: local_irq_save(flags); RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do); - if (!more_to_do) + + if (!more_to_do && !accel_more_to_do) { + /* + * Slow path has nothing more to do, see if + * fast path is likewise + */ + if ( np->accel_vif_state.hooks ) { + accel_more_to_do = + np->accel_vif_state.hooks->start_napi_interrupts(dev); + } + } + + if (!more_to_do && !accel_more_to_do) { __netif_rx_complete(dev); + } local_irq_restore(flags); } spin_unlock(&np->rx_lock); - - return more_to_do; + + return more_to_do | accel_more_to_do; } static void netif_release_tx_bufs(struct netfront_info *np) @@ -1687,7 +2222,9 @@ static int network_connect(struct net_de struct sk_buff *skb; grant_ref_t ref; netif_rx_request_t *req; - unsigned int feature_rx_copy, feature_rx_flip; + unsigned int feature_rx_copy, feature_rx_flip, feature_accel; + char *accel_frontend; + int accel_len; err = xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-rx-copy", "%u", &feature_rx_copy); @@ -1698,6 +2235,13 @@ static int network_connect(struct net_de if (err != 1) feature_rx_flip = 1; + feature_accel = 1; + accel_frontend = xenbus_read(XBT_NIL, np->xbdev->otherend, + "accel", &accel_len); + if ( IS_ERR(accel_frontend) ) { + feature_accel = 0; + } + /* * Copy packets on receive path if: * (a) This was requested by user, and the backend supports it; or @@ -1709,6 +2253,11 @@ static int network_connect(struct net_de err = talk_to_backend(np->xbdev, np); if (err) return err; + + if ( feature_accel ) { + netfront_load_accelerator(np, np->xbdev, accel_frontend); + kfree(accel_frontend); + } xennet_set_features(dev); @@ -1955,6 +2504,7 @@ static struct net_device * __devinit cre spin_lock_init(&np->tx_lock); spin_lock_init(&np->rx_lock); + np->accel_vif_state.hooks = NULL; skb_queue_head_init(&np->rx_batch); np->rx_target = RX_DFL_MIN_TARGET; @@ -2110,6 +2660,9 @@ static int __init netif_init(void) if (is_initial_xendomain()) return 0; + INIT_LIST_HEAD(&accelerators_list); + spin_lock_init(&accelerators_lock); + IPRINTK("Initialising virtual ethernet driver.\n"); (void)register_inetaddr_notifier(¬ifier_inetdev); diff -r cd3ade350f3f drivers/xen/netfront/netfront.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/drivers/xen/netfront/netfront.h Thu Jun 14 14:57:34 2007 +0100 @@ -0,0 +1,198 @@ +/****************************************************************************** + * Virtual network driver for conversing with remote driver backends. + * + * Copyright (c) 2002-2005, K A Fraser + * Copyright (c) 2005, XenSource Ltd + * Copyright (C) 2007 Solarflare Communications, Inc. + * + * 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. + */ + +#ifndef NETFRONT_H +#define NETFRONT_H + +#include +#include +#include +#include + +#define NET_TX_RING_SIZE __RING_SIZE((struct netif_tx_sring *)0, PAGE_SIZE) +#define NET_RX_RING_SIZE __RING_SIZE((struct netif_rx_sring *)0, PAGE_SIZE) + +#include +/* Function pointer table for hooks into a network acceleration + plugin. These are called at appropriate points from the netfront + driver */ +struct netfront_accel_hooks { + /* new_device: The plugin is asked to support a new network interface */ + int (*new_device)(struct net_device *net_dev, struct xenbus_device *dev); + /* suspend, resume, remove: Equivalent to the normal xenbus_* callbacks */ + int (*suspend)(struct xenbus_device *dev); + int (*resume)(struct xenbus_device *dev); + int (*remove)(struct xenbus_device *dev); + /* backend_changed: Callback from watch based on backend's + xenbus state changing */ + void (*backend_changed)(struct xenbus_device *dev, + enum xenbus_state backend_state); + /* The net_device is being polled, check the accelerated + hardware for any pending packets */ + int (*netdev_poll)(struct net_device *dev, int *pbudget); + /* start_xmit: Used to give the accelerated plugin the option + of sending a packet. Returns non-zero if has done so, or + zero to decline and force the packet onto normal send path */ + int (*start_xmit)(struct sk_buff *skb, struct net_device *dev); + /* start/stop_napi_interrupts Used by netfront to indicate + when napi interrupts should be enabled or disabled */ + int (*start_napi_interrupts)(struct net_device *dev); + void (*stop_napi_interrupts)(struct net_device *dev); + /* Called before re-enabling the TX queue to check the fast + path has slots too */ + int (*check_busy)(struct net_device *dev); +}; + +/* Per-netfront device state for the accelerator. This is used to + allow efficient per-netfront device access to the accelerator hooks */ +struct netfront_accel_vif_state { + struct list_head link; + + struct xenbus_device *dev; + struct netfront_info *np; + struct netfront_accel_hooks *hooks; +}; + +/* Per-accelerator state stored in netfront. These form a list that + is used to track which devices are accelerated by which plugins, + and what plugins are available/have been requested */ +struct netfront_accelerator { + /* Used to make a list */ + struct list_head link; + /* ID of the accelerator */ + int id; + /* String describing the accelerator. Currently this is the + name of the accelerator module. This is provided by the + backend accelerator through xenstore */ + char *frontend; + /* The hooks into the accelerator plugin module */ + struct netfront_accel_hooks *hooks; + /* Protect against removal of hooks while in use, must hold + accelerators_lock to change */ + unsigned hooks_usecount; + /* List of per-netfront device state (struct netfront_accel_vif_state) + for each netfront device that is using this accelerator */ + struct list_head vif_states; + /* Semaphore to signal that all users of this accelerator have + finished using it before module is unloaded */ + struct semaphore exit_semaphore; +}; + + +struct netfront_info { + struct list_head list; + struct net_device *netdev; + + struct net_device_stats stats; + + struct netif_tx_front_ring tx; + struct netif_rx_front_ring rx; + + spinlock_t tx_lock; + spinlock_t rx_lock; + + unsigned int irq; + unsigned int copying_receiver; + unsigned int carrier; + + /* Receive-ring batched refills. */ +#define RX_MIN_TARGET 8 +#define RX_DFL_MIN_TARGET 64 +#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) + unsigned rx_min_target, rx_max_target, rx_target; + struct sk_buff_head rx_batch; + + struct timer_list rx_refill_timer; + + /* + * {tx,rx}_skbs store outstanding skbuffs. The first entry in tx_skbs + * is an index into a chain of free entries. + */ + struct sk_buff *tx_skbs[NET_TX_RING_SIZE+1]; + struct sk_buff *rx_skbs[NET_RX_RING_SIZE]; + +#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) + grant_ref_t gref_tx_head; + grant_ref_t grant_tx_ref[NET_TX_RING_SIZE + 1]; + grant_ref_t gref_rx_head; + grant_ref_t grant_rx_ref[NET_RX_RING_SIZE]; + + struct xenbus_device *xbdev; + int tx_ring_ref; + int rx_ring_ref; + u8 mac[ETH_ALEN]; + + unsigned long rx_pfn_array[NET_RX_RING_SIZE]; + struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1]; + struct mmu_update rx_mmu[NET_RX_RING_SIZE]; + + /* Private pointer to state internal to accelerator module */ + void *accel_priv; + /* The (list of) accelerator(s) used by this netfront device */ + struct netfront_accelerator *accelerator; + /* The accelerator state for this netfront device */ + struct netfront_accel_vif_state accel_vif_state; +}; + + +/* Called by an accelerator plugin module when it has loaded. + * + * frontend: the string describing the accelerator, currently the module name + * hooks: the hooks for netfront to use to call into the accelerator + */ +extern int netfront_accelerator_loaded(const char *frontend, + struct netfront_accel_hooks *hooks); + +/* Called when an accelerator plugin is ready to accelerate a device * + * that has been passed to it from netfront using the "new_device" + * hook. + * + * frontend: the string describing the accelerator. Must match the + * one passed to netfront_accelerator_loaded() + * dev: the xenbus device the plugin was asked to accelerate + */ +extern void netfront_accelerator_ready(const char *frontend, + struct xenbus_device *dev); + +/* Called by an accelerator plugin module when it is about to unload. + * + * frontend: the string describing the accelerator. Must match the + * one passed to netfront_accelerator_loaded() + */ +extern void netfront_accelerator_unloaded(const char *frontend); + +/* Called by an accelerator before waking the net device's TX queue to + ensure the slow path has available slots. Returns true if OK to + wake, false if still busy */ +extern int netfront_check_queue_busy(struct net_device *net_dev); + +#endif /* NETFRONT_H */