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xen-netback: reintroduce guest Rx stall detection
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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>
f51de243 47#include <linux/debugfs.h>
f942dc25 48
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49typedef unsigned int pending_ring_idx_t;
50#define INVALID_PENDING_RING_IDX (~0U)
51
b3f980bd 52struct pending_tx_info {
62bad319 53 struct xen_netif_tx_request req; /* tx request */
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54 /* Callback data for released SKBs. The callback is always
55 * xenvif_zerocopy_callback, desc contains the pending_idx, which is
56 * also an index in pending_tx_info array. It is initialized in
57 * xenvif_alloc and it never changes.
58 * skb_shinfo(skb)->destructor_arg points to the first mapped slot's
59 * callback_struct in this array of struct pending_tx_info's, then ctx
60 * to the next, or NULL if there is no more slot for this skb.
61 * ubuf_to_vif is a helper which finds the struct xenvif from a pointer
62 * to this field.
63 */
64 struct ubuf_info callback_struct;
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65};
66
67#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
68#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
69
70struct xenvif_rx_meta {
71 int id;
72 int size;
82cada22 73 int gso_type;
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74 int gso_size;
75};
76
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77#define GSO_BIT(type) \
78 (1 << XEN_NETIF_GSO_TYPE_ ## type)
79
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80/* Discriminate from any valid pending_idx value. */
81#define INVALID_PENDING_IDX 0xFFFF
82
83#define MAX_BUFFER_OFFSET PAGE_SIZE
84
869b9b19 85#define MAX_PENDING_REQS XEN_NETIF_TX_RING_SIZE
f942dc25 86
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87/* It's possible for an skb to have a maximal number of frags
88 * but still be less than MAX_BUFFER_OFFSET in size. Thus the
89 * worst-case number of copy operations is MAX_SKB_FRAGS per
90 * ring slot.
91 */
92#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
93
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94#define NETBACK_INVALID_HANDLE -1
95
96/* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
97 * the maximum slots a valid packet can use. Now this value is defined
98 * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
99 * all backend.
100 */
101#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
102
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103/* Queue name is interface name with "-qNNN" appended */
104#define QUEUE_NAME_SIZE (IFNAMSIZ + 5)
f942dc25 105
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106/* IRQ name is queue name with "-tx" or "-rx" appended */
107#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
108
109struct xenvif;
110
111struct xenvif_stats {
112 /* Stats fields to be updated per-queue.
113 * A subset of struct net_device_stats that contains only the
114 * fields that are updated in netback.c for each queue.
e9d8b2c2 115 */
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116 unsigned int rx_bytes;
117 unsigned int rx_packets;
118 unsigned int tx_bytes;
119 unsigned int tx_packets;
120
121 /* Additional stats used by xenvif */
122 unsigned long rx_gso_checksum_fixup;
123 unsigned long tx_zerocopy_sent;
124 unsigned long tx_zerocopy_success;
125 unsigned long tx_zerocopy_fail;
126 unsigned long tx_frag_overflow;
127};
128
129struct xenvif_queue { /* Per-queue data for xenvif */
130 unsigned int id; /* Queue ID, 0-based */
131 char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
132 struct xenvif *vif; /* Parent VIF */
e9d8b2c2 133
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134 /* Use NAPI for guest TX */
135 struct napi_struct napi;
136 /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
137 unsigned int tx_irq;
138 /* Only used when feature-split-event-channels = 1 */
e9ce7cb6 139 char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
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140 struct xen_netif_tx_back_ring tx;
141 struct sk_buff_head tx_queue;
142 struct page *mmap_pages[MAX_PENDING_REQS];
143 pending_ring_idx_t pending_prod;
144 pending_ring_idx_t pending_cons;
145 u16 pending_ring[MAX_PENDING_REQS];
146 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
f53c3fe8 147 grant_handle_t grant_tx_handle[MAX_PENDING_REQS];
b3f980bd 148
bdab8275 149 struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
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150 struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
151 struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
152 /* passed to gnttab_[un]map_refs with pages under (un)mapping */
153 struct page *pages_to_map[MAX_PENDING_REQS];
154 struct page *pages_to_unmap[MAX_PENDING_REQS];
155
156 /* This prevents zerocopy callbacks to race over dealloc_ring */
157 spinlock_t callback_lock;
158 /* This prevents dealloc thread and NAPI instance to race over response
159 * creation and pending_ring in xenvif_idx_release. In xenvif_tx_err
160 * it only protect response creation
161 */
162 spinlock_t response_lock;
163 pending_ring_idx_t dealloc_prod;
164 pending_ring_idx_t dealloc_cons;
165 u16 dealloc_ring[MAX_PENDING_REQS];
166 struct task_struct *dealloc_task;
167 wait_queue_head_t dealloc_wq;
a64bd934 168 atomic_t inflight_packets;
f942dc25 169
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170 /* Use kthread for guest RX */
171 struct task_struct *task;
172 wait_queue_head_t wq;
e1f00a69 173 /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
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174 unsigned int rx_irq;
175 /* Only used when feature-split-event-channels = 1 */
e9ce7cb6 176 char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
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177 struct xen_netif_rx_back_ring rx;
178 struct sk_buff_head rx_queue;
09350788 179
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180 unsigned int rx_queue_max;
181 unsigned int rx_queue_len;
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182 unsigned long last_rx_time;
183 bool stalled;
b3f980bd 184
a55d9766 185 struct gnttab_copy grant_copy_op[MAX_GRANT_COPY_OPS];
f942dc25 186
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187 /* We create one meta structure per ring request we consume, so
188 * the maximum number is the same as the ring size.
189 */
190 struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
b3f980bd 191
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192 /* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
193 unsigned long credit_bytes;
194 unsigned long credit_usec;
195 unsigned long remaining_credit;
196 struct timer_list credit_timeout;
197 u64 credit_window_start;
198
199 /* Statistics */
200 struct xenvif_stats stats;
201};
202
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203/* Maximum number of Rx slots a to-guest packet may use, including the
204 * slot needed for GSO meta-data.
205 */
206#define XEN_NETBK_RX_SLOTS_MAX (MAX_SKB_FRAGS + 1)
207
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208enum state_bit_shift {
209 /* This bit marks that the vif is connected */
f34a4cf9 210 VIF_STATUS_CONNECTED,
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211};
212
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213struct xenvif {
214 /* Unique identifier for this interface. */
215 domid_t domid;
216 unsigned int handle;
217
b3f980bd 218 u8 fe_dev_addr[6];
f942dc25 219
f942dc25 220 /* Frontend feature information. */
82cada22
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221 int gso_mask;
222 int gso_prefix_mask;
223
f942dc25 224 u8 can_sg:1;
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225 u8 ip_csum:1;
226 u8 ipv6_csum:1;
f942dc25 227
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228 /* Is this interface disabled? True when backend discovers
229 * frontend is rogue.
230 */
231 bool disabled;
3d1af1df 232 unsigned long status;
f942dc25 233
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234 /* Queues */
235 struct xenvif_queue *queues;
f7b50c4e 236 unsigned int num_queues; /* active queues, resource allocated */
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237 unsigned int stalled_queues;
238
239 spinlock_t lock;
f942dc25 240
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241#ifdef CONFIG_DEBUG_FS
242 struct dentry *xenvif_dbg_root;
243#endif
244
f942dc25 245 /* Miscellaneous private stuff. */
f942dc25 246 struct net_device *dev;
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247};
248
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249struct xenvif_rx_cb {
250 unsigned long expires;
251 int meta_slots_used;
252 bool full_coalesce;
253};
254
255#define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb)
256
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257static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
258{
259 return to_xenbus_device(vif->dev->dev.parent);
260}
261
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262struct xenvif *xenvif_alloc(struct device *parent,
263 domid_t domid,
264 unsigned int handle);
265
e9ce7cb6 266int xenvif_init_queue(struct xenvif_queue *queue);
8d3d53b3 267void xenvif_deinit_queue(struct xenvif_queue *queue);
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268
269int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
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270 unsigned long rx_ring_ref, unsigned int tx_evtchn,
271 unsigned int rx_evtchn);
f942dc25 272void xenvif_disconnect(struct xenvif *vif);
279f438e 273void xenvif_free(struct xenvif *vif);
f942dc25 274
f942dc25 275int xenvif_xenbus_init(void);
b103f358 276void xenvif_xenbus_fini(void);
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277
278int xenvif_schedulable(struct xenvif *vif);
279
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280int xenvif_queue_stopped(struct xenvif_queue *queue);
281void xenvif_wake_queue(struct xenvif_queue *queue);
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282
283/* (Un)Map communication rings. */
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284void xenvif_unmap_frontend_rings(struct xenvif_queue *queue);
285int xenvif_map_frontend_rings(struct xenvif_queue *queue,
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286 grant_ref_t tx_ring_ref,
287 grant_ref_t rx_ring_ref);
f942dc25 288
f942dc25 289/* Check for SKBs from frontend and schedule backend processing */
e9ce7cb6 290void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue);
f942dc25 291
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292/* Prevent the device from generating any further traffic. */
293void xenvif_carrier_off(struct xenvif *vif);
294
e9ce7cb6 295int xenvif_tx_action(struct xenvif_queue *queue, int budget);
b3f980bd 296
121fa4b7 297int xenvif_kthread_guest_rx(void *data);
e9ce7cb6 298void xenvif_kick_thread(struct xenvif_queue *queue);
ca2f09f2 299
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300int xenvif_dealloc_kthread(void *data);
301
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302void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
303
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304/* Determine whether the needed number of slots (req) are available,
305 * and set req_event if not.
306 */
e9ce7cb6 307bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed);
ca2f09f2 308
e9ce7cb6 309void xenvif_carrier_on(struct xenvif *vif);
b3f980bd 310
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311/* Callback from stack when TX packet can be released */
312void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
313
314/* Unmap a pending page and release it back to the guest */
e9ce7cb6 315void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
f53c3fe8 316
e9ce7cb6 317static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
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318{
319 return MAX_PENDING_REQS -
e9ce7cb6 320 queue->pending_prod + queue->pending_cons;
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321}
322
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323/* Callback from stack when TX packet can be released */
324void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
325
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326irqreturn_t xenvif_interrupt(int irq, void *dev_id);
327
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328extern bool separate_tx_rx_irq;
329
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330extern unsigned int rx_drain_timeout_msecs;
331extern unsigned int rx_drain_timeout_jiffies;
8d3d53b3 332extern unsigned int xenvif_max_queues;
09350788 333
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334#ifdef CONFIG_DEBUG_FS
335extern struct dentry *xen_netback_dbg_root;
336#endif
337
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338void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
339 struct sk_buff *skb);
340void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue);
341
f942dc25 342#endif /* __XEN_NETBACK__COMMON_H__ */