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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_BLKIF__BACKEND__COMMON_H__
28#define __XEN_BLKIF__BACKEND__COMMON_H__
29
30#include <linux/version.h>
31#include <linux/module.h>
32#include <linux/interrupt.h>
33#include <linux/slab.h>
34#include <linux/blkdev.h>
35#include <linux/vmalloc.h>
36#include <linux/wait.h>
37#include <linux/io.h>
38#include <asm/setup.h>
39#include <asm/pgalloc.h>
40#include <asm/hypervisor.h>
41#include <xen/grant_table.h>
42#include <xen/xenbus.h>
43#include <xen/interface/io/ring.h>
44#include <xen/interface/io/blkif.h>
45#include <xen/interface/io/protocols.h>
46
47#define DRV_PFX "xen-blkback:"
48#define DPRINTK(fmt, args...) \
49 pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
50 __func__, __LINE__, ##args)
51
52
53/* Not a real protocol. Used to generate ring structs which contain
54 * the elements common to all protocols only. This way we get a
55 * compiler-checkable way to use common struct elements, so we can
56 * avoid using switch(protocol) in a number of places. */
57struct blkif_common_request {
58 char dummy;
59};
60struct blkif_common_response {
61 char dummy;
62};
63
64/* i386 protocol version */
65#pragma pack(push, 4)
66struct blkif_x86_32_request {
67 uint8_t operation; /* BLKIF_OP_??? */
68 uint8_t nr_segments; /* number of segments */
69 blkif_vdev_t handle; /* only for read/write requests */
70 uint64_t id; /* private guest value, echoed in resp */
71 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
72 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
73};
74struct blkif_x86_32_response {
75 uint64_t id; /* copied from request */
76 uint8_t operation; /* copied from request */
77 int16_t status; /* BLKIF_RSP_??? */
78};
79#pragma pack(pop)
80
81/* x86_64 protocol version */
82struct blkif_x86_64_request {
83 uint8_t operation; /* BLKIF_OP_??? */
84 uint8_t nr_segments; /* number of segments */
85 blkif_vdev_t handle; /* only for read/write requests */
86 uint64_t __attribute__((__aligned__(8))) id;
87 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
88 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
89};
90struct blkif_x86_64_response {
91 uint64_t __attribute__((__aligned__(8))) id;
92 uint8_t operation; /* copied from request */
93 int16_t status; /* BLKIF_RSP_??? */
94};
95
96DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
97 struct blkif_common_response);
98DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
99 struct blkif_x86_32_response);
100DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
101 struct blkif_x86_64_response);
102
103union blkif_back_rings {
104 struct blkif_back_ring native;
105 struct blkif_common_back_ring common;
106 struct blkif_x86_32_back_ring x86_32;
107 struct blkif_x86_64_back_ring x86_64;
108};
109
110enum blkif_protocol {
111 BLKIF_PROTOCOL_NATIVE = 1,
112 BLKIF_PROTOCOL_X86_32 = 2,
113 BLKIF_PROTOCOL_X86_64 = 3,
114};
115
116struct xen_vbd {
117 /* What the domain refers to this vbd as. */
118 blkif_vdev_t handle;
119 /* Non-zero -> read-only */
120 unsigned char readonly;
121 /* VDISK_xxx */
122 unsigned char type;
123 /* phys device that this vbd maps to. */
124 u32 pdevice;
125 struct block_device *bdev;
126 /* Cached size parameter. */
127 sector_t size;
128 bool flush_support;
129};
130
131struct backend_info;
132
133struct xen_blkif {
134 /* Unique identifier for this interface. */
135 domid_t domid;
136 unsigned int handle;
137 /* Physical parameters of the comms window. */
138 unsigned int irq;
139 /* Comms information. */
140 enum blkif_protocol blk_protocol;
141 union blkif_back_rings blk_rings;
142 struct vm_struct *blk_ring_area;
143 /* The VBD attached to this interface. */
144 struct xen_vbd vbd;
145 /* Back pointer to the backend_info. */
146 struct backend_info *be;
147 /* Private fields. */
148 spinlock_t blk_ring_lock;
149 atomic_t refcnt;
150
151 wait_queue_head_t wq;
152 /* One thread per one blkif. */
153 struct task_struct *xenblkd;
154 unsigned int waiting_reqs;
155
156 /* statistics */
157 unsigned long st_print;
158 int st_rd_req;
159 int st_wr_req;
160 int st_oo_req;
161 int st_f_req;
162 int st_rd_sect;
163 int st_wr_sect;
164
165 wait_queue_head_t waiting_to_free;
166
167 grant_handle_t shmem_handle;
168 grant_ref_t shmem_ref;
169};
170
171
172#define vbd_sz(_v) ((_v)->bdev->bd_part ? \
173 (_v)->bdev->bd_part->nr_sects : \
174 get_capacity((_v)->bdev->bd_disk))
175
176#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
177#define xen_blkif_put(_b) \
178 do { \
179 if (atomic_dec_and_test(&(_b)->refcnt)) \
180 wake_up(&(_b)->waiting_to_free);\
181 } while (0)
182
183struct phys_req {
184 unsigned short dev;
185 unsigned short nr_sects;
186 struct block_device *bdev;
187 blkif_sector_t sector_number;
188};
189int xen_blkif_interface_init(void);
190
191int xen_blkif_xenbus_init(void);
192
193irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
194int xen_blkif_schedule(void *arg);
195
196int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
197 struct backend_info *be, int state);
198
199struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
200
201static inline void blkif_get_x86_32_req(struct blkif_request *dst,
202 struct blkif_x86_32_request *src)
203{
204 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
205 dst->operation = src->operation;
206 dst->nr_segments = src->nr_segments;
207 dst->handle = src->handle;
208 dst->id = src->id;
209 dst->u.rw.sector_number = src->sector_number;
210 barrier();
211 if (n > dst->nr_segments)
212 n = dst->nr_segments;
213 for (i = 0; i < n; i++)
214 dst->u.rw.seg[i] = src->seg[i];
215}
216
217static inline void blkif_get_x86_64_req(struct blkif_request *dst,
218 struct blkif_x86_64_request *src)
219{
220 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
221 dst->operation = src->operation;
222 dst->nr_segments = src->nr_segments;
223 dst->handle = src->handle;
224 dst->id = src->id;
225 dst->u.rw.sector_number = src->sector_number;
226 barrier();
227 if (n > dst->nr_segments)
228 n = dst->nr_segments;
229 for (i = 0; i < n; i++)
230 dst->u.rw.seg[i] = src->seg[i];
231}
232
233#endif /* __XEN_BLKIF__BACKEND__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_BLKIF__BACKEND__COMMON_H__
28#define __XEN_BLKIF__BACKEND__COMMON_H__
29
30#include <linux/module.h>
31#include <linux/interrupt.h>
32#include <linux/slab.h>
33#include <linux/blkdev.h>
34#include <linux/vmalloc.h>
35#include <linux/wait.h>
36#include <linux/io.h>
37#include <asm/setup.h>
38#include <asm/pgalloc.h>
39#include <asm/hypervisor.h>
40#include <xen/grant_table.h>
41#include <xen/xenbus.h>
42#include <xen/interface/io/ring.h>
43#include <xen/interface/io/blkif.h>
44#include <xen/interface/io/protocols.h>
45
46#define DRV_PFX "xen-blkback:"
47#define DPRINTK(fmt, args...) \
48 pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
49 __func__, __LINE__, ##args)
50
51
52/* Not a real protocol. Used to generate ring structs which contain
53 * the elements common to all protocols only. This way we get a
54 * compiler-checkable way to use common struct elements, so we can
55 * avoid using switch(protocol) in a number of places. */
56struct blkif_common_request {
57 char dummy;
58};
59struct blkif_common_response {
60 char dummy;
61};
62
63struct blkif_x86_32_request_rw {
64 uint8_t nr_segments; /* number of segments */
65 blkif_vdev_t handle; /* only for read/write requests */
66 uint64_t id; /* private guest value, echoed in resp */
67 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
68 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
69} __attribute__((__packed__));
70
71struct blkif_x86_32_request_discard {
72 uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
73 blkif_vdev_t _pad1; /* was "handle" for read/write requests */
74 uint64_t id; /* private guest value, echoed in resp */
75 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
76 uint64_t nr_sectors;
77} __attribute__((__packed__));
78
79struct blkif_x86_32_request {
80 uint8_t operation; /* BLKIF_OP_??? */
81 union {
82 struct blkif_x86_32_request_rw rw;
83 struct blkif_x86_32_request_discard discard;
84 } u;
85} __attribute__((__packed__));
86
87/* i386 protocol version */
88#pragma pack(push, 4)
89struct blkif_x86_32_response {
90 uint64_t id; /* copied from request */
91 uint8_t operation; /* copied from request */
92 int16_t status; /* BLKIF_RSP_??? */
93};
94#pragma pack(pop)
95/* x86_64 protocol version */
96
97struct blkif_x86_64_request_rw {
98 uint8_t nr_segments; /* number of segments */
99 blkif_vdev_t handle; /* only for read/write requests */
100 uint32_t _pad1; /* offsetof(blkif_reqest..,u.rw.id)==8 */
101 uint64_t id;
102 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
103 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
104} __attribute__((__packed__));
105
106struct blkif_x86_64_request_discard {
107 uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
108 blkif_vdev_t _pad1; /* was "handle" for read/write requests */
109 uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */
110 uint64_t id;
111 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
112 uint64_t nr_sectors;
113} __attribute__((__packed__));
114
115struct blkif_x86_64_request {
116 uint8_t operation; /* BLKIF_OP_??? */
117 union {
118 struct blkif_x86_64_request_rw rw;
119 struct blkif_x86_64_request_discard discard;
120 } u;
121} __attribute__((__packed__));
122
123struct blkif_x86_64_response {
124 uint64_t __attribute__((__aligned__(8))) id;
125 uint8_t operation; /* copied from request */
126 int16_t status; /* BLKIF_RSP_??? */
127};
128
129DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
130 struct blkif_common_response);
131DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
132 struct blkif_x86_32_response);
133DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
134 struct blkif_x86_64_response);
135
136union blkif_back_rings {
137 struct blkif_back_ring native;
138 struct blkif_common_back_ring common;
139 struct blkif_x86_32_back_ring x86_32;
140 struct blkif_x86_64_back_ring x86_64;
141};
142
143enum blkif_protocol {
144 BLKIF_PROTOCOL_NATIVE = 1,
145 BLKIF_PROTOCOL_X86_32 = 2,
146 BLKIF_PROTOCOL_X86_64 = 3,
147};
148
149struct xen_vbd {
150 /* What the domain refers to this vbd as. */
151 blkif_vdev_t handle;
152 /* Non-zero -> read-only */
153 unsigned char readonly;
154 /* VDISK_xxx */
155 unsigned char type;
156 /* phys device that this vbd maps to. */
157 u32 pdevice;
158 struct block_device *bdev;
159 /* Cached size parameter. */
160 sector_t size;
161 bool flush_support;
162 bool discard_secure;
163};
164
165struct backend_info;
166
167struct xen_blkif {
168 /* Unique identifier for this interface. */
169 domid_t domid;
170 unsigned int handle;
171 /* Physical parameters of the comms window. */
172 unsigned int irq;
173 /* Comms information. */
174 enum blkif_protocol blk_protocol;
175 union blkif_back_rings blk_rings;
176 void *blk_ring;
177 /* The VBD attached to this interface. */
178 struct xen_vbd vbd;
179 /* Back pointer to the backend_info. */
180 struct backend_info *be;
181 /* Private fields. */
182 spinlock_t blk_ring_lock;
183 atomic_t refcnt;
184
185 wait_queue_head_t wq;
186 /* for barrier (drain) requests */
187 struct completion drain_complete;
188 atomic_t drain;
189 /* One thread per one blkif. */
190 struct task_struct *xenblkd;
191 unsigned int waiting_reqs;
192
193 /* statistics */
194 unsigned long st_print;
195 int st_rd_req;
196 int st_wr_req;
197 int st_oo_req;
198 int st_f_req;
199 int st_ds_req;
200 int st_rd_sect;
201 int st_wr_sect;
202
203 wait_queue_head_t waiting_to_free;
204};
205
206
207#define vbd_sz(_v) ((_v)->bdev->bd_part ? \
208 (_v)->bdev->bd_part->nr_sects : \
209 get_capacity((_v)->bdev->bd_disk))
210
211#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
212#define xen_blkif_put(_b) \
213 do { \
214 if (atomic_dec_and_test(&(_b)->refcnt)) \
215 wake_up(&(_b)->waiting_to_free);\
216 } while (0)
217
218struct phys_req {
219 unsigned short dev;
220 blkif_sector_t nr_sects;
221 struct block_device *bdev;
222 blkif_sector_t sector_number;
223};
224int xen_blkif_interface_init(void);
225
226int xen_blkif_xenbus_init(void);
227
228irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
229int xen_blkif_schedule(void *arg);
230
231int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
232 struct backend_info *be, int state);
233
234int xen_blkbk_barrier(struct xenbus_transaction xbt,
235 struct backend_info *be, int state);
236struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
237
238static inline void blkif_get_x86_32_req(struct blkif_request *dst,
239 struct blkif_x86_32_request *src)
240{
241 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
242 dst->operation = src->operation;
243 switch (src->operation) {
244 case BLKIF_OP_READ:
245 case BLKIF_OP_WRITE:
246 case BLKIF_OP_WRITE_BARRIER:
247 case BLKIF_OP_FLUSH_DISKCACHE:
248 dst->u.rw.nr_segments = src->u.rw.nr_segments;
249 dst->u.rw.handle = src->u.rw.handle;
250 dst->u.rw.id = src->u.rw.id;
251 dst->u.rw.sector_number = src->u.rw.sector_number;
252 barrier();
253 if (n > dst->u.rw.nr_segments)
254 n = dst->u.rw.nr_segments;
255 for (i = 0; i < n; i++)
256 dst->u.rw.seg[i] = src->u.rw.seg[i];
257 break;
258 case BLKIF_OP_DISCARD:
259 dst->u.discard.flag = src->u.discard.flag;
260 dst->u.discard.id = src->u.discard.id;
261 dst->u.discard.sector_number = src->u.discard.sector_number;
262 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
263 break;
264 default:
265 break;
266 }
267}
268
269static inline void blkif_get_x86_64_req(struct blkif_request *dst,
270 struct blkif_x86_64_request *src)
271{
272 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
273 dst->operation = src->operation;
274 switch (src->operation) {
275 case BLKIF_OP_READ:
276 case BLKIF_OP_WRITE:
277 case BLKIF_OP_WRITE_BARRIER:
278 case BLKIF_OP_FLUSH_DISKCACHE:
279 dst->u.rw.nr_segments = src->u.rw.nr_segments;
280 dst->u.rw.handle = src->u.rw.handle;
281 dst->u.rw.id = src->u.rw.id;
282 dst->u.rw.sector_number = src->u.rw.sector_number;
283 barrier();
284 if (n > dst->u.rw.nr_segments)
285 n = dst->u.rw.nr_segments;
286 for (i = 0; i < n; i++)
287 dst->u.rw.seg[i] = src->u.rw.seg[i];
288 break;
289 case BLKIF_OP_DISCARD:
290 dst->u.discard.flag = src->u.discard.flag;
291 dst->u.discard.id = src->u.discard.id;
292 dst->u.discard.sector_number = src->u.discard.sector_number;
293 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
294 break;
295 default:
296 break;
297 }
298}
299
300#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */