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 * 64bits 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/*
182 * User space sets this flag when setting up the device to request zoned storage support. Kernel may
183 * deny the request by returning an error.
184 */
185#define UBLK_F_ZONED (1ULL << 8)
186
187/* device state */
188#define UBLK_S_DEV_DEAD 0
189#define UBLK_S_DEV_LIVE 1
190#define UBLK_S_DEV_QUIESCED 2
191
192/* shipped via sqe->cmd of io_uring command */
193struct ublksrv_ctrl_cmd {
194 /* sent to which device, must be valid */
195 __u32 dev_id;
196
197 /* sent to which queue, must be -1 if the cmd isn't for queue */
198 __u16 queue_id;
199 /*
200 * cmd specific buffer, can be IN or OUT.
201 */
202 __u16 len;
203 __u64 addr;
204
205 /* inline data */
206 __u64 data[1];
207
208 /*
209 * Used for UBLK_F_UNPRIVILEGED_DEV and UBLK_CMD_GET_DEV_INFO2
210 * only, include null char
211 */
212 __u16 dev_path_len;
213 __u16 pad;
214 __u32 reserved;
215};
216
217struct ublksrv_ctrl_dev_info {
218 __u16 nr_hw_queues;
219 __u16 queue_depth;
220 __u16 state;
221 __u16 pad0;
222
223 __u32 max_io_buf_bytes;
224 __u32 dev_id;
225
226 __s32 ublksrv_pid;
227 __u32 pad1;
228
229 __u64 flags;
230
231 /* For ublksrv internal use, invisible to ublk driver */
232 __u64 ublksrv_flags;
233
234 __u32 owner_uid; /* store by kernel */
235 __u32 owner_gid; /* store by kernel */
236 __u64 reserved1;
237 __u64 reserved2;
238};
239
240#define UBLK_IO_OP_READ 0
241#define UBLK_IO_OP_WRITE 1
242#define UBLK_IO_OP_FLUSH 2
243#define UBLK_IO_OP_DISCARD 3
244#define UBLK_IO_OP_WRITE_SAME 4
245#define UBLK_IO_OP_WRITE_ZEROES 5
246#define UBLK_IO_OP_ZONE_OPEN 10
247#define UBLK_IO_OP_ZONE_CLOSE 11
248#define UBLK_IO_OP_ZONE_FINISH 12
249#define UBLK_IO_OP_ZONE_APPEND 13
250#define UBLK_IO_OP_ZONE_RESET_ALL 14
251#define UBLK_IO_OP_ZONE_RESET 15
252/*
253 * Construct a zone report. The report request is carried in `struct
254 * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
255 * and shall indicate the first zone of the report. The `nr_zones` shall
256 * indicate how many zones should be reported at most. The report shall be
257 * delivered as a `struct blk_zone` array. To report fewer zones than requested,
258 * zero the last entry of the returned array.
259 *
260 * Related definitions(blk_zone, blk_zone_cond, blk_zone_type, ...) in
261 * include/uapi/linux/blkzoned.h are part of ublk UAPI.
262 */
263#define UBLK_IO_OP_REPORT_ZONES 18
264
265#define UBLK_IO_F_FAILFAST_DEV (1U << 8)
266#define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9)
267#define UBLK_IO_F_FAILFAST_DRIVER (1U << 10)
268#define UBLK_IO_F_META (1U << 11)
269#define UBLK_IO_F_FUA (1U << 13)
270#define UBLK_IO_F_NOUNMAP (1U << 15)
271#define UBLK_IO_F_SWAP (1U << 16)
272
273/*
274 * io cmd is described by this structure, and stored in share memory, indexed
275 * by request tag.
276 *
277 * The data is stored by ublk driver, and read by ublksrv after one fetch command
278 * returns.
279 */
280struct ublksrv_io_desc {
281 /* op: bit 0-7, flags: bit 8-31 */
282 __u32 op_flags;
283
284 union {
285 __u32 nr_sectors;
286 __u32 nr_zones; /* for UBLK_IO_OP_REPORT_ZONES */
287 };
288
289 /* start sector for this io */
290 __u64 start_sector;
291
292 /* buffer address in ublksrv daemon vm space, from ublk driver */
293 __u64 addr;
294};
295
296static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod)
297{
298 return iod->op_flags & 0xff;
299}
300
301static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod)
302{
303 return iod->op_flags >> 8;
304}
305
306/* issued to ublk driver via /dev/ublkcN */
307struct ublksrv_io_cmd {
308 __u16 q_id;
309
310 /* for fetch/commit which result */
311 __u16 tag;
312
313 /* io result, it is valid for COMMIT* command only */
314 __s32 result;
315
316 union {
317 /*
318 * userspace buffer address in ublksrv daemon process, valid for
319 * FETCH* command only
320 *
321 * `addr` should not be used when UBLK_F_USER_COPY is enabled,
322 * because userspace handles data copy by pread()/pwrite() over
323 * /dev/ublkcN. But in case of UBLK_F_ZONED, this union is
324 * re-used to pass back the allocated LBA for
325 * UBLK_IO_OP_ZONE_APPEND which actually depends on
326 * UBLK_F_USER_COPY
327 */
328 __u64 addr;
329 __u64 zone_append_lba;
330 };
331};
332
333struct ublk_param_basic {
334#define UBLK_ATTR_READ_ONLY (1 << 0)
335#define UBLK_ATTR_ROTATIONAL (1 << 1)
336#define UBLK_ATTR_VOLATILE_CACHE (1 << 2)
337#define UBLK_ATTR_FUA (1 << 3)
338 __u32 attrs;
339 __u8 logical_bs_shift;
340 __u8 physical_bs_shift;
341 __u8 io_opt_shift;
342 __u8 io_min_shift;
343
344 __u32 max_sectors;
345 __u32 chunk_sectors;
346
347 __u64 dev_sectors;
348 __u64 virt_boundary_mask;
349};
350
351struct ublk_param_discard {
352 __u32 discard_alignment;
353
354 __u32 discard_granularity;
355 __u32 max_discard_sectors;
356
357 __u32 max_write_zeroes_sectors;
358 __u16 max_discard_segments;
359 __u16 reserved0;
360};
361
362/*
363 * read-only, can't set via UBLK_CMD_SET_PARAMS, disk_devt is available
364 * after device is started
365 */
366struct ublk_param_devt {
367 __u32 char_major;
368 __u32 char_minor;
369 __u32 disk_major;
370 __u32 disk_minor;
371};
372
373struct ublk_param_zoned {
374 __u32 max_open_zones;
375 __u32 max_active_zones;
376 __u32 max_zone_append_sectors;
377 __u8 reserved[20];
378};
379
380struct ublk_params {
381 /*
382 * Total length of parameters, userspace has to set 'len' for both
383 * SET_PARAMS and GET_PARAMS command, and driver may update len
384 * if two sides use different version of 'ublk_params', same with
385 * 'types' fields.
386 */
387 __u32 len;
388#define UBLK_PARAM_TYPE_BASIC (1 << 0)
389#define UBLK_PARAM_TYPE_DISCARD (1 << 1)
390#define UBLK_PARAM_TYPE_DEVT (1 << 2)
391#define UBLK_PARAM_TYPE_ZONED (1 << 3)
392 __u32 types; /* types of parameter included */
393
394 struct ublk_param_basic basic;
395 struct ublk_param_discard discard;
396 struct ublk_param_devt devt;
397 struct ublk_param_zoned zoned;
398};
399
400#endif
401

source code of linux/include/uapi/linux/ublk_cmd.h