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_type;
  91         int gso_size;
  92 };
  93
  94 #define GSO_BIT(type) \
  95         (1 << XEN_NETIF_GSO_TYPE_ ## type)
  96
  97 /* Discriminate from any valid pending_idx value. */
  98 #define INVALID_PENDING_IDX 0xFFFF
  99
 100 #define MAX_BUFFER_OFFSET PAGE_SIZE
 101
 102 #define MAX_PENDING_REQS 256
 103
 104 /* It's possible for an skb to have a maximal number of frags
 105  * but still be less than MAX_BUFFER_OFFSET in size. Thus the
 106  * worst-case number of copy operations is MAX_SKB_FRAGS per
 107  * ring slot.
 108  */
 109 #define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
 110
 111 struct xenvif {
 112         /* Unique identifier for this interface. */
 113         domid_t          domid;
 114         unsigned int     handle;
 115
 116         /* Use NAPI for guest TX */
 117         struct napi_struct napi;
 118         /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 119         unsigned int tx_irq;
 120         /* Only used when feature-split-event-channels = 1 */
 121         char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
 122         struct xen_netif_tx_back_ring tx;
 123         struct sk_buff_head tx_queue;
 124         struct page *mmap_pages[MAX_PENDING_REQS];
 125         pending_ring_idx_t pending_prod;
 126         pending_ring_idx_t pending_cons;
 127         u16 pending_ring[MAX_PENDING_REQS];
 128         struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
 129
 130         /* Coalescing tx requests before copying makes number of grant
 131          * copy ops greater or equal to number of slots required. In
 132          * worst case a tx request consumes 2 gnttab_copy.
 133          */
 134         struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
 135
 136
 137         /* Use kthread for guest RX */
 138         struct task_struct *task;
 139         wait_queue_head_t wq;
 140         /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 141         unsigned int rx_irq;
 142         /* Only used when feature-split-event-channels = 1 */
 143         char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
 144         struct xen_netif_rx_back_ring rx;
 145         struct sk_buff_head rx_queue;
 146         RING_IDX rx_last_skb_slots;
 147
 148         /* This array is allocated seperately as it is large */
 149         struct gnttab_copy *grant_copy_op;
 150
 151         /* We create one meta structure per ring request we consume, so
 152          * the maximum number is the same as the ring size.
 153          */
 154         struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
 155
 156         u8               fe_dev_addr[6];
 157
 158         /* Frontend feature information. */
 159         int gso_mask;
 160         int gso_prefix_mask;
 161
 162         u8 can_sg:1;
 163         u8 ip_csum:1;
 164         u8 ipv6_csum:1;
 165
 166         /* Internal feature information. */
 167         u8 can_queue:1;     /* can queue packets for receiver? */
 168
 169         /* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
 170         unsigned long   credit_bytes;
 171         unsigned long   credit_usec;
 172         unsigned long   remaining_credit;
 173         struct timer_list credit_timeout;
 174         u64 credit_window_start;
 175
 176         /* Statistics */
 177         unsigned long rx_gso_checksum_fixup;
 178
 179         /* Miscellaneous private stuff. */
 180         struct net_device *dev;
 181 };
 182
 183 static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
 184 {
 185         return to_xenbus_device(vif->dev->dev.parent);
 186 }
 187
 188 struct xenvif *xenvif_alloc(struct device *parent,
 189                             domid_t domid,
 190                             unsigned int handle);
 191
 192 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 193                    unsigned long rx_ring_ref, unsigned int tx_evtchn,
 194                    unsigned int rx_evtchn);
 195 void xenvif_disconnect(struct xenvif *vif);
 196 void xenvif_free(struct xenvif *vif);
 197
 198 int xenvif_xenbus_init(void);
 199 void xenvif_xenbus_fini(void);
 200
 201 int xenvif_schedulable(struct xenvif *vif);
 202
 203 int xenvif_must_stop_queue(struct xenvif *vif);
 204
 205 /* (Un)Map communication rings. */
 206 void xenvif_unmap_frontend_rings(struct xenvif *vif);
 207 int xenvif_map_frontend_rings(struct xenvif *vif,
 208                               grant_ref_t tx_ring_ref,
 209                               grant_ref_t rx_ring_ref);
 210
 211 /* Check for SKBs from frontend and schedule backend processing */
 212 void xenvif_check_rx_xenvif(struct xenvif *vif);
 213
 214 /* Prevent the device from generating any further traffic. */
 215 void xenvif_carrier_off(struct xenvif *vif);
 216
 217 int xenvif_tx_action(struct xenvif *vif, int budget);
 218
 219 int xenvif_kthread(void *data);
 220 void xenvif_kick_thread(struct xenvif *vif);
 221
 222 /* Determine whether the needed number of slots (req) are available,
 223  * and set req_event if not.
 224  */
 225 bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);
 226
 227 void xenvif_stop_queue(struct xenvif *vif);
 228
 229 extern bool separate_tx_rx_irq;
 230
 231 #endif /* __XEN_NETBACK__COMMON_H__ */