drivers/net/xen-netback/common.h

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public License version 2
   4  * as published by the Free Software Foundation; or, when distributed
   5  * separately from the Linux kernel or incorporated into other
   6  * software packages, subject to the following license:
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this source file (the "Software"), to deal in the Software without
  10  * restriction, including without limitation the rights to use, copy, modify,
  11  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  12  * and to permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  24  * IN THE SOFTWARE.
  25  */
  26
  27 #ifndef __XEN_NETBACK__COMMON_H__
  28 #define __XEN_NETBACK__COMMON_H__
  29
  30 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
  31
  32 #include <linux/module.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/slab.h>
  35 #include <linux/ip.h>
  36 #include <linux/in.h>
  37 #include <linux/io.h>
  38 #include <linux/netdevice.h>
  39 #include <linux/etherdevice.h>
  40 #include <linux/wait.h>
  41 #include <linux/sched.h>
  42
  43 #include <xen/interface/io/netif.h>
  44 #include <xen/interface/grant_table.h>
  45 #include <xen/grant_table.h>
  46 #include <xen/xenbus.h>
  47
  48 typedef unsigned int pending_ring_idx_t;
  49 #define INVALID_PENDING_RING_IDX (~0U)
  50
  51 /* For the head field in pending_tx_info: it is used to indicate
  52  * whether this tx info is the head of one or more coalesced requests.
  53  *
  54  * When head != INVALID_PENDING_RING_IDX, it means the start of a new
  55  * tx requests queue and the end of previous queue.
  56  *
  57  * An example sequence of head fields (I = INVALID_PENDING_RING_IDX):
  58  *
  59  * ...|0 I I I|5 I|9 I I I|...
  60  * -->|<-INUSE----------------
  61  *
  62  * After consuming the first slot(s) we have:
  63  *
  64  * ...|V V V V|5 I|9 I I I|...
  65  * -----FREE->|<-INUSE--------
  66  *
  67  * where V stands for "valid pending ring index". Any number other
  68  * than INVALID_PENDING_RING_IDX is OK. These entries are considered
  69  * free and can contain any number other than
  70  * INVALID_PENDING_RING_IDX. In practice we use 0.
  71  *
  72  * The in use non-INVALID_PENDING_RING_IDX (say 0, 5 and 9 in the
  73  * above example) number is the index into pending_tx_info and
  74  * mmap_pages arrays.
  75  */
  76 struct pending_tx_info {
  77         struct xen_netif_tx_request req; /* coalesced tx request */
  78         pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
  79                                   * if it is head of one or more tx
  80                                   * reqs
  81                                   */
  82 };
  83
  84 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
  85 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
  86
  87 struct xenvif_rx_meta {
  88         int id;
  89         int size;
  90         int gso_size;
  91 };
  92
  93 /* Discriminate from any valid pending_idx value. */
  94 #define INVALID_PENDING_IDX 0xFFFF
  95
  96 #define MAX_BUFFER_OFFSET PAGE_SIZE
  97
  98 #define MAX_PENDING_REQS 256
  99
 100 struct xenvif {
 101         /* Unique identifier for this interface. */
 102         domid_t          domid;
 103         unsigned int     handle;
 104
 105         /* Use NAPI for guest TX */
 106         struct napi_struct napi;
 107         /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 108         unsigned int tx_irq;
 109         /* Only used when feature-split-event-channels = 1 */
 110         char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
 111         struct xen_netif_tx_back_ring tx;
 112         struct sk_buff_head tx_queue;
 113         struct page *mmap_pages[MAX_PENDING_REQS];
 114         pending_ring_idx_t pending_prod;
 115         pending_ring_idx_t pending_cons;
 116         u16 pending_ring[MAX_PENDING_REQS];
 117         struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
 118
 119         /* Coalescing tx requests before copying makes number of grant
 120          * copy ops greater or equal to number of slots required. In
 121          * worst case a tx request consumes 2 gnttab_copy.
 122          */
 123         struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
 124
 125
 126         /* Use kthread for guest RX */
 127         struct task_struct *task;
 128         wait_queue_head_t wq;
 129         /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 130         unsigned int rx_irq;
 131         /* Only used when feature-split-event-channels = 1 */
 132         char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
 133         struct xen_netif_rx_back_ring rx;
 134         struct sk_buff_head rx_queue;
 135
 136         /* Allow xenvif_start_xmit() to peek ahead in the rx request
 137          * ring.  This is a prediction of what rx_req_cons will be
 138          * once all queued skbs are put on the ring.
 139          */
 140         RING_IDX rx_req_cons_peek;
 141
 142         /* Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
 143          * head/fragment page uses 2 copy operations because it
 144          * straddles two buffers in the frontend.
 145          */
 146         struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
 147         struct xenvif_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
 148
 149
 150         u8               fe_dev_addr[6];
 151
 152         /* Frontend feature information. */
 153         u8 can_sg:1;
 154         u8 gso:1;
 155         u8 gso_prefix:1;
 156         u8 csum:1;
 157
 158         /* Internal feature information. */
 159         u8 can_queue:1;     /* can queue packets for receiver? */
 160
 161         /* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
 162         unsigned long   credit_bytes;
 163         unsigned long   credit_usec;
 164         unsigned long   remaining_credit;
 165         struct timer_list credit_timeout;
 166
 167         /* Statistics */
 168         unsigned long rx_gso_checksum_fixup;
 169
 170         /* Miscellaneous private stuff. */
 171         struct net_device *dev;
 172 };
 173
 174 static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
 175 {
 176         return to_xenbus_device(vif->dev->dev.parent);
 177 }
 178
 179 struct xenvif *xenvif_alloc(struct device *parent,
 180                             domid_t domid,
 181                             unsigned int handle);
 182
 183 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 184                    unsigned long rx_ring_ref, unsigned int tx_evtchn,
 185                    unsigned int rx_evtchn);
 186 void xenvif_disconnect(struct xenvif *vif);
 187 void xenvif_free(struct xenvif *vif);
 188
 189 int xenvif_xenbus_init(void);
 190 void xenvif_xenbus_fini(void);
 191
 192 int xenvif_schedulable(struct xenvif *vif);
 193
 194 int xenvif_rx_ring_full(struct xenvif *vif);
 195
 196 int xenvif_must_stop_queue(struct xenvif *vif);
 197
 198 /* (Un)Map communication rings. */
 199 void xenvif_unmap_frontend_rings(struct xenvif *vif);
 200 int xenvif_map_frontend_rings(struct xenvif *vif,
 201                               grant_ref_t tx_ring_ref,
 202                               grant_ref_t rx_ring_ref);
 203
 204 /* Check for SKBs from frontend and schedule backend processing */
 205 void xenvif_check_rx_xenvif(struct xenvif *vif);
 206
 207 /* Queue an SKB for transmission to the frontend */
 208 void xenvif_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb);
 209 /* Notify xenvif that ring now has space to send an skb to the frontend */
 210 void xenvif_notify_tx_completion(struct xenvif *vif);
 211
 212 /* Prevent the device from generating any further traffic. */
 213 void xenvif_carrier_off(struct xenvif *vif);
 214
 215 /* Returns number of ring slots required to send an skb to the frontend */
 216 unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb);
 217
 218 int xenvif_tx_action(struct xenvif *vif, int budget);
 219 void xenvif_rx_action(struct xenvif *vif);
 220
 221 int xenvif_kthread(void *data);
 222
 223 extern bool separate_tx_rx_irq;
 224
 225 #endif /* __XEN_NETBACK__COMMON_H__ */