1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef USER_BLK_DRV_CMD_INC_H
3 #define USER_BLK_DRV_CMD_INC_H
4
5 #include <linux/types.h>
6
7 /* ublk server command definition */
8
9 /*
10 * Admin commands, issued by ublk server, and handled by ublk driver.
11 *
12 * Legacy command definition, don't use in new application, and don't
13 * add new such definition any more
14 */
15 #define UBLK_CMD_GET_QUEUE_AFFINITY 0x01
16 #define UBLK_CMD_GET_DEV_INFO 0x02
17 #define UBLK_CMD_ADD_DEV 0x04
18 #define UBLK_CMD_DEL_DEV 0x05
19 #define UBLK_CMD_START_DEV 0x06
20 #define UBLK_CMD_STOP_DEV 0x07
21 #define UBLK_CMD_SET_PARAMS 0x08
22 #define UBLK_CMD_GET_PARAMS 0x09
23 #define UBLK_CMD_START_USER_RECOVERY 0x10
24 #define UBLK_CMD_END_USER_RECOVERY 0x11
25 #define UBLK_CMD_GET_DEV_INFO2 0x12
26
27 /* Any new ctrl command should encode by __IO*() */
28 #define UBLK_U_CMD_GET_QUEUE_AFFINITY \
29 _IOR('u', UBLK_CMD_GET_QUEUE_AFFINITY, struct ublksrv_ctrl_cmd)
30 #define UBLK_U_CMD_GET_DEV_INFO \
31 _IOR('u', UBLK_CMD_GET_DEV_INFO, struct ublksrv_ctrl_cmd)
32 #define UBLK_U_CMD_ADD_DEV \
33 _IOWR('u', UBLK_CMD_ADD_DEV, struct ublksrv_ctrl_cmd)
34 #define UBLK_U_CMD_DEL_DEV \
35 _IOWR('u', UBLK_CMD_DEL_DEV, struct ublksrv_ctrl_cmd)
36 #define UBLK_U_CMD_START_DEV \
37 _IOWR('u', UBLK_CMD_START_DEV, struct ublksrv_ctrl_cmd)
38 #define UBLK_U_CMD_STOP_DEV \
39 _IOWR('u', UBLK_CMD_STOP_DEV, struct ublksrv_ctrl_cmd)
40 #define UBLK_U_CMD_SET_PARAMS \
41 _IOWR('u', UBLK_CMD_SET_PARAMS, struct ublksrv_ctrl_cmd)
42 #define UBLK_U_CMD_GET_PARAMS \
43 _IOR('u', UBLK_CMD_GET_PARAMS, struct ublksrv_ctrl_cmd)
44 #define UBLK_U_CMD_START_USER_RECOVERY \
45 _IOWR('u', UBLK_CMD_START_USER_RECOVERY, struct ublksrv_ctrl_cmd)
46 #define UBLK_U_CMD_END_USER_RECOVERY \
47 _IOWR('u', UBLK_CMD_END_USER_RECOVERY, struct ublksrv_ctrl_cmd)
48 #define UBLK_U_CMD_GET_DEV_INFO2 \
49 _IOR('u', UBLK_CMD_GET_DEV_INFO2, struct ublksrv_ctrl_cmd)
50 #define UBLK_U_CMD_GET_FEATURES \
51 _IOR('u', 0x13, struct ublksrv_ctrl_cmd)
52 #define UBLK_U_CMD_DEL_DEV_ASYNC \
53 _IOR('u', 0x14, struct ublksrv_ctrl_cmd)
54
55 /*
56 * 64bit are enough now, and it should be easy to extend in case of
57 * running out of feature flags
58 */
59 #define UBLK_FEATURES_LEN 8
60
61 /*
62 * IO commands, issued by ublk server, and handled by ublk driver.
63 *
64 * FETCH_REQ: issued via sqe(URING_CMD) beforehand for fetching IO request
65 * from ublk driver, should be issued only when starting device. After
66 * the associated cqe is returned, request's tag can be retrieved via
67 * cqe->userdata.
68 *
69 * COMMIT_AND_FETCH_REQ: issued via sqe(URING_CMD) after ublkserver handled
70 * this IO request, request's handling result is committed to ublk
71 * driver, meantime FETCH_REQ is piggyback, and FETCH_REQ has to be
72 * handled before completing io request.
73 *
74 * NEED_GET_DATA: only used for write requests to set io addr and copy data
75 * When NEED_GET_DATA is set, ublksrv has to issue UBLK_IO_NEED_GET_DATA
76 * command after ublk driver returns UBLK_IO_RES_NEED_GET_DATA.
77 *
78 * It is only used if ublksrv set UBLK_F_NEED_GET_DATA flag
79 * while starting a ublk device.
80 */
81
82 /*
83 * Legacy IO command definition, don't use in new application, and don't
84 * add new such definition any more
85 */
86 #define UBLK_IO_FETCH_REQ 0x20
87 #define UBLK_IO_COMMIT_AND_FETCH_REQ 0x21
88 #define UBLK_IO_NEED_GET_DATA 0x22
89
90 /* Any new IO command should encode by __IOWR() */
91 #define UBLK_U_IO_FETCH_REQ \
92 _IOWR('u', UBLK_IO_FETCH_REQ, struct ublksrv_io_cmd)
93 #define UBLK_U_IO_COMMIT_AND_FETCH_REQ \
94 _IOWR('u', UBLK_IO_COMMIT_AND_FETCH_REQ, struct ublksrv_io_cmd)
95 #define UBLK_U_IO_NEED_GET_DATA \
96 _IOWR('u', UBLK_IO_NEED_GET_DATA, struct ublksrv_io_cmd)
97
98 /* only ABORT means that no re-fetch */
99 #define UBLK_IO_RES_OK 0
100 #define UBLK_IO_RES_NEED_GET_DATA 1
101 #define UBLK_IO_RES_ABORT (-ENODEV)
102
103 #define UBLKSRV_CMD_BUF_OFFSET 0
104 #define UBLKSRV_IO_BUF_OFFSET 0x80000000
105
106 /* tag bit is 16bit, so far limit at most 4096 IOs for each queue */
107 #define UBLK_MAX_QUEUE_DEPTH 4096
108
109 /* single IO buffer max size is 32MB */
110 #define UBLK_IO_BUF_OFF 0
111 #define UBLK_IO_BUF_BITS 25
112 #define UBLK_IO_BUF_BITS_MASK ((1ULL << UBLK_IO_BUF_BITS) - 1)
113
114 /* so at most 64K IOs for each queue */
115 #define UBLK_TAG_OFF UBLK_IO_BUF_BITS
116 #define UBLK_TAG_BITS 16
117 #define UBLK_TAG_BITS_MASK ((1ULL << UBLK_TAG_BITS) - 1)
118
119 /* max 4096 queues */
120 #define UBLK_QID_OFF (UBLK_TAG_OFF + UBLK_TAG_BITS)
121 #define UBLK_QID_BITS 12
122 #define UBLK_QID_BITS_MASK ((1ULL << UBLK_QID_BITS) - 1)
123
124 #define UBLK_MAX_NR_QUEUES (1U << UBLK_QID_BITS)
125
126 #define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_QID_OFF + UBLK_QID_BITS)
127 #define UBLKSRV_IO_BUF_TOTAL_SIZE (1ULL << UBLKSRV_IO_BUF_TOTAL_BITS)
128
129 /*
130 * zero copy requires 4k block size, and can remap ublk driver's io
131 * request into ublksrv's vm space
132 */
133 #define UBLK_F_SUPPORT_ZERO_COPY (1ULL << 0)
134
135 /*
136 * Force to complete io cmd via io_uring_cmd_complete_in_task so that
137 * performance comparison is done easily with using task_work_add
138 */
139 #define UBLK_F_URING_CMD_COMP_IN_TASK (1ULL << 1)
140
141 /*
142 * User should issue io cmd again for write requests to
143 * set io buffer address and copy data from bio vectors
144 * to the userspace io buffer.
145 *
146 * In this mode, task_work is not used.
147 */
148 #define UBLK_F_NEED_GET_DATA (1UL << 2)
149
150 #define UBLK_F_USER_RECOVERY (1UL << 3)
151
152 #define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4)
153
154 /*
155 * Unprivileged user can create /dev/ublkcN and /dev/ublkbN.
156 *
157 * /dev/ublk-control needs to be available for unprivileged user, and it
158 * can be done via udev rule to make all control commands available to
159 * unprivileged user. Except for the command of UBLK_CMD_ADD_DEV, all
160 * other commands are only allowed for the owner of the specified device.
161 *
162 * When userspace sends UBLK_CMD_ADD_DEV, the device pair's owner_uid and
163 * owner_gid are stored to ublksrv_ctrl_dev_info by kernel, so far only
164 * the current user's uid/gid is stored, that said owner of the created
165 * device is always the current user.
166 *
167 * We still need udev rule to apply OWNER/GROUP with the stored owner_uid
168 * and owner_gid.
169 *
170 * Then ublk server can be run as unprivileged user, and /dev/ublkbN can
171 * be accessed and managed by its owner represented by owner_uid/owner_gid.
172 */
173 #define UBLK_F_UNPRIVILEGED_DEV (1UL << 5)
174
175 /* use ioctl encoding for uring command */
176 #define UBLK_F_CMD_IOCTL_ENCODE (1UL << 6)
177
178 /* Copy between request and user buffer by pread()/pwrite() */
179 #define UBLK_F_USER_COPY (1UL << 7)
180
181 /* device state */
182 #define UBLK_S_DEV_DEAD 0
183 #define UBLK_S_DEV_LIVE 1
184 #define UBLK_S_DEV_QUIESCED 2
185
186 /* shipped via sqe->cmd of io_uring command */
187 struct ublksrv_ctrl_cmd {
188 /* sent to which device, must be valid */
189 __u32 dev_id;
190
191 /* sent to which queue, must be -1 if the cmd isn't for queue */
192 __u16 queue_id;
193 /*
194 * cmd specific buffer, can be IN or OUT.
195 */
196 __u16 len;
197 __u64 addr;
198
199 /* inline data */
200 __u64 data[1];
201
202 /*
203 * Used for UBLK_F_UNPRIVILEGED_DEV and UBLK_CMD_GET_DEV_INFO2
204 * only, include null char
205 */
206 __u16 dev_path_len;
207 __u16 pad;
208 __u32 reserved;
209 };
210
211 struct ublksrv_ctrl_dev_info {
212 __u16 nr_hw_queues;
213 __u16 queue_depth;
214 __u16 state;
215 __u16 pad0;
216
217 __u32 max_io_buf_bytes;
218 __u32 dev_id;
219
220 __s32 ublksrv_pid;
221 __u32 pad1;
222
223 __u64 flags;
224
225 /* For ublksrv internal use, invisible to ublk driver */
226 __u64 ublksrv_flags;
227
228 __u32 owner_uid; /* store by kernel */
229 __u32 owner_gid; /* store by kernel */
230 __u64 reserved1;
231 __u64 reserved2;
232 };
233
234 #define UBLK_IO_OP_READ 0
235 #define UBLK_IO_OP_WRITE 1
236 #define UBLK_IO_OP_FLUSH 2
237 #define UBLK_IO_OP_DISCARD 3
238 #define UBLK_IO_OP_WRITE_SAME 4
239 #define UBLK_IO_OP_WRITE_ZEROES 5
240
241 #define UBLK_IO_F_FAILFAST_DEV (1U << 8)
242 #define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9)
243 #define UBLK_IO_F_FAILFAST_DRIVER (1U << 10)
244 #define UBLK_IO_F_META (1U << 11)
245 #define UBLK_IO_F_FUA (1U << 13)
246 #define UBLK_IO_F_NOUNMAP (1U << 15)
247 #define UBLK_IO_F_SWAP (1U << 16)
248
249 /*
250 * io cmd is described by this structure, and stored in share memory, indexed
251 * by request tag.
252 *
253 * The data is stored by ublk driver, and read by ublksrv after one fetch command
254 * returns.
255 */
256 struct ublksrv_io_desc {
257 /* op: bit 0-7, flags: bit 8-31 */
258 __u32 op_flags;
259
260 __u32 nr_sectors;
261
262 /* start sector for this io */
263 __u64 start_sector;
264
265 /* buffer address in ublksrv daemon vm space, from ublk driver */
266 __u64 addr;
267 };
268
ublksrv_get_op(const struct ublksrv_io_desc * iod)269 static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod)
270 {
271 return iod->op_flags & 0xff;
272 }
273
ublksrv_get_flags(const struct ublksrv_io_desc * iod)274 static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod)
275 {
276 return iod->op_flags >> 8;
277 }
278
279 /* issued to ublk driver via /dev/ublkcN */
280 struct ublksrv_io_cmd {
281 __u16 q_id;
282
283 /* for fetch/commit which result */
284 __u16 tag;
285
286 /* io result, it is valid for COMMIT* command only */
287 __s32 result;
288
289 /*
290 * userspace buffer address in ublksrv daemon process, valid for
291 * FETCH* command only
292 */
293 __u64 addr;
294 };
295
296 struct ublk_param_basic {
297 #define UBLK_ATTR_READ_ONLY (1 << 0)
298 #define UBLK_ATTR_ROTATIONAL (1 << 1)
299 #define UBLK_ATTR_VOLATILE_CACHE (1 << 2)
300 #define UBLK_ATTR_FUA (1 << 3)
301 __u32 attrs;
302 __u8 logical_bs_shift;
303 __u8 physical_bs_shift;
304 __u8 io_opt_shift;
305 __u8 io_min_shift;
306
307 __u32 max_sectors;
308 __u32 chunk_sectors;
309
310 __u64 dev_sectors;
311 __u64 virt_boundary_mask;
312 };
313
314 struct ublk_param_discard {
315 __u32 discard_alignment;
316
317 __u32 discard_granularity;
318 __u32 max_discard_sectors;
319
320 __u32 max_write_zeroes_sectors;
321 __u16 max_discard_segments;
322 __u16 reserved0;
323 };
324
325 /*
326 * read-only, can't set via UBLK_CMD_SET_PARAMS, disk_devt is available
327 * after device is started
328 */
329 struct ublk_param_devt {
330 __u32 char_major;
331 __u32 char_minor;
332 __u32 disk_major;
333 __u32 disk_minor;
334 };
335
336 struct ublk_params {
337 /*
338 * Total length of parameters, userspace has to set 'len' for both
339 * SET_PARAMS and GET_PARAMS command, and driver may update len
340 * if two sides use different version of 'ublk_params', same with
341 * 'types' fields.
342 */
343 __u32 len;
344 #define UBLK_PARAM_TYPE_BASIC (1 << 0)
345 #define UBLK_PARAM_TYPE_DISCARD (1 << 1)
346 #define UBLK_PARAM_TYPE_DEVT (1 << 2)
347 __u32 types; /* types of parameter included */
348
349 struct ublk_param_basic basic;
350 struct ublk_param_discard discard;
351 struct ublk_param_devt devt;
352 };
353
354 #endif
355