xref: /openbmc/linux/drivers/net/xen-netback/common.h (revision b34e08d5)
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 struct pending_tx_info {
52 	struct xen_netif_tx_request req; /* tx request */
53 	/* Callback data for released SKBs. The callback is always
54 	 * xenvif_zerocopy_callback, desc contains the pending_idx, which is
55 	 * also an index in pending_tx_info array. It is initialized in
56 	 * xenvif_alloc and it never changes.
57 	 * skb_shinfo(skb)->destructor_arg points to the first mapped slot's
58 	 * callback_struct in this array of struct pending_tx_info's, then ctx
59 	 * to the next, or NULL if there is no more slot for this skb.
60 	 * ubuf_to_vif is a helper which finds the struct xenvif from a pointer
61 	 * to this field.
62 	 */
63 	struct ubuf_info callback_struct;
64 };
65 
66 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
67 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
68 
69 struct xenvif_rx_meta {
70 	int id;
71 	int size;
72 	int gso_type;
73 	int gso_size;
74 };
75 
76 #define GSO_BIT(type) \
77 	(1 << XEN_NETIF_GSO_TYPE_ ## type)
78 
79 /* Discriminate from any valid pending_idx value. */
80 #define INVALID_PENDING_IDX 0xFFFF
81 
82 #define MAX_BUFFER_OFFSET PAGE_SIZE
83 
84 #define MAX_PENDING_REQS XEN_NETIF_TX_RING_SIZE
85 
86 /* It's possible for an skb to have a maximal number of frags
87  * but still be less than MAX_BUFFER_OFFSET in size. Thus the
88  * worst-case number of copy operations is MAX_SKB_FRAGS per
89  * ring slot.
90  */
91 #define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
92 
93 #define NETBACK_INVALID_HANDLE -1
94 
95 /* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
96  * the maximum slots a valid packet can use. Now this value is defined
97  * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
98  * all backend.
99  */
100 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
101 
102 struct xenvif {
103 	/* Unique identifier for this interface. */
104 	domid_t          domid;
105 	unsigned int     handle;
106 
107 	/* Is this interface disabled? True when backend discovers
108 	 * frontend is rogue.
109 	 */
110 	bool disabled;
111 
112 	/* Use NAPI for guest TX */
113 	struct napi_struct napi;
114 	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
115 	unsigned int tx_irq;
116 	/* Only used when feature-split-event-channels = 1 */
117 	char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
118 	struct xen_netif_tx_back_ring tx;
119 	struct sk_buff_head tx_queue;
120 	struct page *mmap_pages[MAX_PENDING_REQS];
121 	pending_ring_idx_t pending_prod;
122 	pending_ring_idx_t pending_cons;
123 	u16 pending_ring[MAX_PENDING_REQS];
124 	struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
125 	grant_handle_t grant_tx_handle[MAX_PENDING_REQS];
126 
127 	struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
128 	struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
129 	struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
130 	/* passed to gnttab_[un]map_refs with pages under (un)mapping */
131 	struct page *pages_to_map[MAX_PENDING_REQS];
132 	struct page *pages_to_unmap[MAX_PENDING_REQS];
133 
134 	/* This prevents zerocopy callbacks  to race over dealloc_ring */
135 	spinlock_t callback_lock;
136 	/* This prevents dealloc thread and NAPI instance to race over response
137 	 * creation and pending_ring in xenvif_idx_release. In xenvif_tx_err
138 	 * it only protect response creation
139 	 */
140 	spinlock_t response_lock;
141 	pending_ring_idx_t dealloc_prod;
142 	pending_ring_idx_t dealloc_cons;
143 	u16 dealloc_ring[MAX_PENDING_REQS];
144 	struct task_struct *dealloc_task;
145 	wait_queue_head_t dealloc_wq;
146 
147 	/* Use kthread for guest RX */
148 	struct task_struct *task;
149 	wait_queue_head_t wq;
150 	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
151 	unsigned int rx_irq;
152 	/* Only used when feature-split-event-channels = 1 */
153 	char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
154 	struct xen_netif_rx_back_ring rx;
155 	struct sk_buff_head rx_queue;
156 	RING_IDX rx_last_skb_slots;
157 	bool rx_queue_purge;
158 
159 	struct timer_list wake_queue;
160 
161 	/* This array is allocated seperately as it is large */
162 	struct gnttab_copy *grant_copy_op;
163 
164 	/* We create one meta structure per ring request we consume, so
165 	 * the maximum number is the same as the ring size.
166 	 */
167 	struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
168 
169 	u8               fe_dev_addr[6];
170 
171 	/* Frontend feature information. */
172 	int gso_mask;
173 	int gso_prefix_mask;
174 
175 	u8 can_sg:1;
176 	u8 ip_csum:1;
177 	u8 ipv6_csum:1;
178 
179 	/* Internal feature information. */
180 	u8 can_queue:1;	    /* can queue packets for receiver? */
181 
182 	/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
183 	unsigned long   credit_bytes;
184 	unsigned long   credit_usec;
185 	unsigned long   remaining_credit;
186 	struct timer_list credit_timeout;
187 	u64 credit_window_start;
188 
189 	/* Statistics */
190 	unsigned long rx_gso_checksum_fixup;
191 	unsigned long tx_zerocopy_sent;
192 	unsigned long tx_zerocopy_success;
193 	unsigned long tx_zerocopy_fail;
194 	unsigned long tx_frag_overflow;
195 
196 	/* Miscellaneous private stuff. */
197 	struct net_device *dev;
198 };
199 
200 static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
201 {
202 	return to_xenbus_device(vif->dev->dev.parent);
203 }
204 
205 struct xenvif *xenvif_alloc(struct device *parent,
206 			    domid_t domid,
207 			    unsigned int handle);
208 
209 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
210 		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
211 		   unsigned int rx_evtchn);
212 void xenvif_disconnect(struct xenvif *vif);
213 void xenvif_free(struct xenvif *vif);
214 
215 int xenvif_xenbus_init(void);
216 void xenvif_xenbus_fini(void);
217 
218 int xenvif_schedulable(struct xenvif *vif);
219 
220 int xenvif_must_stop_queue(struct xenvif *vif);
221 
222 /* (Un)Map communication rings. */
223 void xenvif_unmap_frontend_rings(struct xenvif *vif);
224 int xenvif_map_frontend_rings(struct xenvif *vif,
225 			      grant_ref_t tx_ring_ref,
226 			      grant_ref_t rx_ring_ref);
227 
228 /* Check for SKBs from frontend and schedule backend processing */
229 void xenvif_check_rx_xenvif(struct xenvif *vif);
230 
231 /* Prevent the device from generating any further traffic. */
232 void xenvif_carrier_off(struct xenvif *vif);
233 
234 int xenvif_tx_action(struct xenvif *vif, int budget);
235 
236 int xenvif_kthread_guest_rx(void *data);
237 void xenvif_kick_thread(struct xenvif *vif);
238 
239 int xenvif_dealloc_kthread(void *data);
240 
241 /* Determine whether the needed number of slots (req) are available,
242  * and set req_event if not.
243  */
244 bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);
245 
246 void xenvif_stop_queue(struct xenvif *vif);
247 
248 /* Callback from stack when TX packet can be released */
249 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
250 
251 /* Unmap a pending page and release it back to the guest */
252 void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx);
253 
254 static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
255 {
256 	return MAX_PENDING_REQS -
257 		vif->pending_prod + vif->pending_cons;
258 }
259 
260 /* Callback from stack when TX packet can be released */
261 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
262 
263 extern bool separate_tx_rx_irq;
264 
265 extern unsigned int rx_drain_timeout_msecs;
266 extern unsigned int rx_drain_timeout_jiffies;
267 
268 #endif /* __XEN_NETBACK__COMMON_H__ */
269