drivers/net/xen-netback/common.h - maze/linux - Git at Google

 /*
  * 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 __XEN_NETBACK__COMMON_H__
 #define __XEN_NETBACK__COMMON_H__

 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/ip.h>
 #include <linux/in.h>
 #include <linux/io.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/wait.h>
 #include <linux/sched.h>

 #include <xen/interface/io/netif.h>
 #include <xen/interface/grant_table.h>
 #include <xen/grant_table.h>
 #include <xen/xenbus.h>

 typedef unsigned int pending_ring_idx_t;
 #define INVALID_PENDING_RING_IDX (~0U)

 struct pending_tx_info {
 	struct xen_netif_tx_request req; /* tx request */
 	/* Callback data for released SKBs. The callback is always
 	 * xenvif_zerocopy_callback, desc contains the pending_idx, which is
 	 * also an index in pending_tx_info array. It is initialized in
 	 * xenvif_alloc and it never changes.
 	 * skb_shinfo(skb)->destructor_arg points to the first mapped slot's
 	 * callback_struct in this array of struct pending_tx_info's, then ctx
 	 * to the next, or NULL if there is no more slot for this skb.
 	 * ubuf_to_vif is a helper which finds the struct xenvif from a pointer
 	 * to this field.
 	 */
 	struct ubuf_info callback_struct;
 };

 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)

 struct xenvif_rx_meta {
 	int id;
 	int size;
 	int gso_type;
 	int gso_size;
 };

 #define GSO_BIT(type) \
 	(1 << XEN_NETIF_GSO_TYPE_ ## type)

 /* Discriminate from any valid pending_idx value. */
 #define INVALID_PENDING_IDX 0xFFFF

 #define MAX_BUFFER_OFFSET PAGE_SIZE

 #define MAX_PENDING_REQS XEN_NETIF_TX_RING_SIZE

 /* It's possible for an skb to have a maximal number of frags
  * but still be less than MAX_BUFFER_OFFSET in size. Thus the
  * worst-case number of copy operations is MAX_SKB_FRAGS per
  * ring slot.
  */
 #define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)

 #define NETBACK_INVALID_HANDLE -1

 /* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
  * the maximum slots a valid packet can use. Now this value is defined
  * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
  * all backend.
  */
 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN

 struct xenvif {
 	/* Unique identifier for this interface. */
 	domid_t          domid;
 	unsigned int     handle;

 	/* Is this interface disabled? True when backend discovers
 	 * frontend is rogue.
 	 */
 	bool disabled;

 	/* Use NAPI for guest TX */
 	struct napi_struct napi;
 	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 	unsigned int tx_irq;
 	/* Only used when feature-split-event-channels = 1 */
 	char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
 	struct xen_netif_tx_back_ring tx;
 	struct sk_buff_head tx_queue;
 	struct page *mmap_pages[MAX_PENDING_REQS];
 	pending_ring_idx_t pending_prod;
 	pending_ring_idx_t pending_cons;
 	u16 pending_ring[MAX_PENDING_REQS];
 	struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
 	grant_handle_t grant_tx_handle[MAX_PENDING_REQS];

 	struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
 	struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
 	struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
 	/* passed to gnttab_[un]map_refs with pages under (un)mapping */
 	struct page *pages_to_map[MAX_PENDING_REQS];
 	struct page *pages_to_unmap[MAX_PENDING_REQS];

 	/* This prevents zerocopy callbacks  to race over dealloc_ring */
 	spinlock_t callback_lock;
 	/* This prevents dealloc thread and NAPI instance to race over response
 	 * creation and pending_ring in xenvif_idx_release. In xenvif_tx_err
 	 * it only protect response creation
 	 */
 	spinlock_t response_lock;
 	pending_ring_idx_t dealloc_prod;
 	pending_ring_idx_t dealloc_cons;
 	u16 dealloc_ring[MAX_PENDING_REQS];
 	struct task_struct *dealloc_task;
 	wait_queue_head_t dealloc_wq;

 	/* Use kthread for guest RX */
 	struct task_struct *task;
 	wait_queue_head_t wq;
 	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 	unsigned int rx_irq;
 	/* Only used when feature-split-event-channels = 1 */
 	char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
 	struct xen_netif_rx_back_ring rx;
 	struct sk_buff_head rx_queue;
 	RING_IDX rx_last_skb_slots;
 	bool rx_queue_purge;

 	struct timer_list wake_queue;

 	/* This array is allocated seperately as it is large */
 	struct gnttab_copy *grant_copy_op;

 	/* We create one meta structure per ring request we consume, so
 	 * the maximum number is the same as the ring size.
 	 */
 	struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];

 	u8               fe_dev_addr[6];

 	/* Frontend feature information. */
 	int gso_mask;
 	int gso_prefix_mask;

 	u8 can_sg:1;
 	u8 ip_csum:1;
 	u8 ipv6_csum:1;

 	/* Internal feature information. */
 	u8 can_queue:1;	    /* can queue packets for receiver? */

 	/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
 	unsigned long   credit_bytes;
 	unsigned long   credit_usec;
 	unsigned long   remaining_credit;
 	struct timer_list credit_timeout;
 	u64 credit_window_start;

 	/* Statistics */
 	unsigned long rx_gso_checksum_fixup;
 	unsigned long tx_zerocopy_sent;
 	unsigned long tx_zerocopy_success;
 	unsigned long tx_zerocopy_fail;
 	unsigned long tx_frag_overflow;

 	/* Miscellaneous private stuff. */
 	struct net_device *dev;
 };

 static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
 {
 	return to_xenbus_device(vif->dev->dev.parent);
 }

 struct xenvif *xenvif_alloc(struct device *parent,
 			    domid_t domid,
 			    unsigned int handle);

 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
 		   unsigned int rx_evtchn);
 void xenvif_disconnect(struct xenvif *vif);
 void xenvif_free(struct xenvif *vif);

 int xenvif_xenbus_init(void);
 void xenvif_xenbus_fini(void);

 int xenvif_schedulable(struct xenvif *vif);

 int xenvif_must_stop_queue(struct xenvif *vif);

 /* (Un)Map communication rings. */
 void xenvif_unmap_frontend_rings(struct xenvif *vif);
 int xenvif_map_frontend_rings(struct xenvif *vif,
 			      grant_ref_t tx_ring_ref,
 			      grant_ref_t rx_ring_ref);

 /* Check for SKBs from frontend and schedule backend processing */
 void xenvif_check_rx_xenvif(struct xenvif *vif);

 /* Prevent the device from generating any further traffic. */
 void xenvif_carrier_off(struct xenvif *vif);

 int xenvif_tx_action(struct xenvif *vif, int budget);

 int xenvif_kthread_guest_rx(void *data);
 void xenvif_kick_thread(struct xenvif *vif);

 int xenvif_dealloc_kthread(void *data);

 /* Determine whether the needed number of slots (req) are available,
  * and set req_event if not.
  */
 bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);

 void xenvif_stop_queue(struct xenvif *vif);

 /* Callback from stack when TX packet can be released */
 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);

 /* Unmap a pending page and release it back to the guest */
 void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx);

 static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
 {
 	return MAX_PENDING_REQS -
 		vif->pending_prod + vif->pending_cons;
 }

 /* Callback from stack when TX packet can be released */
 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);

 extern bool separate_tx_rx_irq;

 extern unsigned int rx_drain_timeout_msecs;
 extern unsigned int rx_drain_timeout_jiffies;

 #endif /* __XEN_NETBACK__COMMON_H__ */
	/*
	* 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 __XEN_NETBACK__COMMON_H__
	#define __XEN_NETBACK__COMMON_H__

	#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/slab.h>
	#include <linux/ip.h>
	#include <linux/in.h>
	#include <linux/io.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/wait.h>
	#include <linux/sched.h>

	#include <xen/interface/io/netif.h>
	#include <xen/interface/grant_table.h>
	#include <xen/grant_table.h>
	#include <xen/xenbus.h>

	typedef unsigned int pending_ring_idx_t;
	#define INVALID_PENDING_RING_IDX (~0U)

	struct pending_tx_info {
	struct xen_netif_tx_request req; /* tx request */
	/* Callback data for released SKBs. The callback is always
	* xenvif_zerocopy_callback, desc contains the pending_idx, which is
	* also an index in pending_tx_info array. It is initialized in
	* xenvif_alloc and it never changes.
	* skb_shinfo(skb)->destructor_arg points to the first mapped slot's
	* callback_struct in this array of struct pending_tx_info's, then ctx
	* to the next, or NULL if there is no more slot for this skb.
	* ubuf_to_vif is a helper which finds the struct xenvif from a pointer
	* to this field.
	*/
	struct ubuf_info callback_struct;
	};

	#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
	#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)

	struct xenvif_rx_meta {
	int id;
	int size;
	int gso_type;
	int gso_size;
	};

	#define GSO_BIT(type) \
	(1 << XEN_NETIF_GSO_TYPE_ ## type)

	/* Discriminate from any valid pending_idx value. */
	#define INVALID_PENDING_IDX 0xFFFF

	#define MAX_BUFFER_OFFSET PAGE_SIZE

	#define MAX_PENDING_REQS XEN_NETIF_TX_RING_SIZE

	/* It's possible for an skb to have a maximal number of frags
	* but still be less than MAX_BUFFER_OFFSET in size. Thus the
	* worst-case number of copy operations is MAX_SKB_FRAGS per
	* ring slot.
	*/
	#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)

	#define NETBACK_INVALID_HANDLE -1

	/* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
	* the maximum slots a valid packet can use. Now this value is defined
	* to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
	* all backend.
	*/
	#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN

	struct xenvif {
	/* Unique identifier for this interface. */
	domid_t domid;
	unsigned int handle;

	/* Is this interface disabled? True when backend discovers
	* frontend is rogue.
	*/
	bool disabled;

	/* Use NAPI for guest TX */
	struct napi_struct napi;
	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
	unsigned int tx_irq;
	/* Only used when feature-split-event-channels = 1 */
	char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
	struct xen_netif_tx_back_ring tx;
	struct sk_buff_head tx_queue;
	struct page *mmap_pages[MAX_PENDING_REQS];
	pending_ring_idx_t pending_prod;
	pending_ring_idx_t pending_cons;
	u16 pending_ring[MAX_PENDING_REQS];
	struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
	grant_handle_t grant_tx_handle[MAX_PENDING_REQS];

	struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
	struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
	struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
	/* passed to gnttab_[un]map_refs with pages under (un)mapping */
	struct page *pages_to_map[MAX_PENDING_REQS];
	struct page *pages_to_unmap[MAX_PENDING_REQS];

	/* This prevents zerocopy callbacks to race over dealloc_ring */
	spinlock_t callback_lock;
	/* This prevents dealloc thread and NAPI instance to race over response
	* creation and pending_ring in xenvif_idx_release. In xenvif_tx_err
	* it only protect response creation
	*/
	spinlock_t response_lock;
	pending_ring_idx_t dealloc_prod;
	pending_ring_idx_t dealloc_cons;
	u16 dealloc_ring[MAX_PENDING_REQS];
	struct task_struct *dealloc_task;
	wait_queue_head_t dealloc_wq;

	/* Use kthread for guest RX */
	struct task_struct *task;
	wait_queue_head_t wq;
	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
	unsigned int rx_irq;
	/* Only used when feature-split-event-channels = 1 */
	char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
	struct xen_netif_rx_back_ring rx;
	struct sk_buff_head rx_queue;
	RING_IDX rx_last_skb_slots;
	bool rx_queue_purge;

	struct timer_list wake_queue;

	/* This array is allocated seperately as it is large */
	struct gnttab_copy *grant_copy_op;

	/* We create one meta structure per ring request we consume, so
	* the maximum number is the same as the ring size.
	*/
	struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];

	u8 fe_dev_addr[6];

	/* Frontend feature information. */
	int gso_mask;
	int gso_prefix_mask;

	u8 can_sg:1;
	u8 ip_csum:1;
	u8 ipv6_csum:1;

	/* Internal feature information. */
	u8 can_queue:1; /* can queue packets for receiver? */

	/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
	unsigned long credit_bytes;
	unsigned long credit_usec;
	unsigned long remaining_credit;
	struct timer_list credit_timeout;
	u64 credit_window_start;

	/* Statistics */
	unsigned long rx_gso_checksum_fixup;
	unsigned long tx_zerocopy_sent;
	unsigned long tx_zerocopy_success;
	unsigned long tx_zerocopy_fail;
	unsigned long tx_frag_overflow;

	/* Miscellaneous private stuff. */
	struct net_device *dev;
	};

	static inline struct xenbus_device xenvif_to_xenbus_device(struct xenvif vif)
	{
	return to_xenbus_device(vif->dev->dev.parent);
	}

	struct xenvif xenvif_alloc(struct device parent,
	domid_t domid,
	unsigned int handle);

	int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
	unsigned long rx_ring_ref, unsigned int tx_evtchn,
	unsigned int rx_evtchn);
	void xenvif_disconnect(struct xenvif *vif);
	void xenvif_free(struct xenvif *vif);

	int xenvif_xenbus_init(void);
	void xenvif_xenbus_fini(void);

	int xenvif_schedulable(struct xenvif *vif);

	int xenvif_must_stop_queue(struct xenvif *vif);

	/* (Un)Map communication rings. */
	void xenvif_unmap_frontend_rings(struct xenvif *vif);
	int xenvif_map_frontend_rings(struct xenvif *vif,
	grant_ref_t tx_ring_ref,
	grant_ref_t rx_ring_ref);

	/* Check for SKBs from frontend and schedule backend processing */
	void xenvif_check_rx_xenvif(struct xenvif *vif);

	/* Prevent the device from generating any further traffic. */
	void xenvif_carrier_off(struct xenvif *vif);

	int xenvif_tx_action(struct xenvif *vif, int budget);

	int xenvif_kthread_guest_rx(void *data);
	void xenvif_kick_thread(struct xenvif *vif);

	int xenvif_dealloc_kthread(void *data);

	/* Determine whether the needed number of slots (req) are available,
	* and set req_event if not.
	*/
	bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);

	void xenvif_stop_queue(struct xenvif *vif);

	/* Callback from stack when TX packet can be released */
	void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);

	/* Unmap a pending page and release it back to the guest */
	void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx);

	static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
	{
	return MAX_PENDING_REQS -
	vif->pending_prod + vif->pending_cons;
	}

	/* Callback from stack when TX packet can be released */
	void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);

	extern bool separate_tx_rx_irq;

	extern unsigned int rx_drain_timeout_msecs;
	extern unsigned int rx_drain_timeout_jiffies;

	#endif /* __XEN_NETBACK__COMMON_H__ */