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 #define UBLK_CMD_GET_QUEUE_AFFINITY 0x01
13 #define UBLK_CMD_GET_DEV_INFO 0x02
14 #define UBLK_CMD_ADD_DEV 0x04
15 #define UBLK_CMD_DEL_DEV 0x05
16 #define UBLK_CMD_START_DEV 0x06
17 #define UBLK_CMD_STOP_DEV 0x07
18 #define UBLK_CMD_SET_PARAMS 0x08
19 #define UBLK_CMD_GET_PARAMS 0x09
20 #define UBLK_CMD_START_USER_RECOVERY 0x10
21 #define UBLK_CMD_END_USER_RECOVERY 0x11
22 #define UBLK_CMD_GET_DEV_INFO2 0x12
23
24 /*
25 * IO commands, issued by ublk server, and handled by ublk driver.
26 *
27 * FETCH_REQ: issued via sqe(URING_CMD) beforehand for fetching IO request
28 * from ublk driver, should be issued only when starting device. After
29 * the associated cqe is returned, request's tag can be retrieved via
30 * cqe->userdata.
31 *
32 * COMMIT_AND_FETCH_REQ: issued via sqe(URING_CMD) after ublkserver handled
33 * this IO request, request's handling result is committed to ublk
34 * driver, meantime FETCH_REQ is piggyback, and FETCH_REQ has to be
35 * handled before completing io request.
36 *
37 * NEED_GET_DATA: only used for write requests to set io addr and copy data
38 * When NEED_GET_DATA is set, ublksrv has to issue UBLK_IO_NEED_GET_DATA
39 * command after ublk driver returns UBLK_IO_RES_NEED_GET_DATA.
40 *
41 * It is only used if ublksrv set UBLK_F_NEED_GET_DATA flag
42 * while starting a ublk device.
43 */
44 #define UBLK_IO_FETCH_REQ 0x20
45 #define UBLK_IO_COMMIT_AND_FETCH_REQ 0x21
46 #define UBLK_IO_NEED_GET_DATA 0x22
47
48 /* only ABORT means that no re-fetch */
49 #define UBLK_IO_RES_OK 0
50 #define UBLK_IO_RES_NEED_GET_DATA 1
51 #define UBLK_IO_RES_ABORT (-ENODEV)
52
53 #define UBLKSRV_CMD_BUF_OFFSET 0
54 #define UBLKSRV_IO_BUF_OFFSET 0x80000000
55
56 /* tag bit is 12bit, so at most 4096 IOs for each queue */
57 #define UBLK_MAX_QUEUE_DEPTH 4096
58
59 /*
60 * zero copy requires 4k block size, and can remap ublk driver's io
61 * request into ublksrv's vm space
62 */
63 #define UBLK_F_SUPPORT_ZERO_COPY (1ULL << 0)
64
65 /*
66 * Force to complete io cmd via io_uring_cmd_complete_in_task so that
67 * performance comparison is done easily with using task_work_add
68 */
69 #define UBLK_F_URING_CMD_COMP_IN_TASK (1ULL << 1)
70
71 /*
72 * User should issue io cmd again for write requests to
73 * set io buffer address and copy data from bio vectors
74 * to the userspace io buffer.
75 *
76 * In this mode, task_work is not used.
77 */
78 #define UBLK_F_NEED_GET_DATA (1UL << 2)
79
80 #define UBLK_F_USER_RECOVERY (1UL << 3)
81
82 #define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4)
83
84 /*
85 * Unprivileged user can create /dev/ublkcN and /dev/ublkbN.
86 *
87 * /dev/ublk-control needs to be available for unprivileged user, and it
88 * can be done via udev rule to make all control commands available to
89 * unprivileged user. Except for the command of UBLK_CMD_ADD_DEV, all
90 * other commands are only allowed for the owner of the specified device.
91 *
92 * When userspace sends UBLK_CMD_ADD_DEV, the device pair's owner_uid and
93 * owner_gid are stored to ublksrv_ctrl_dev_info by kernel, so far only
94 * the current user's uid/gid is stored, that said owner of the created
95 * device is always the current user.
96 *
97 * We still need udev rule to apply OWNER/GROUP with the stored owner_uid
98 * and owner_gid.
99 *
100 * Then ublk server can be run as unprivileged user, and /dev/ublkbN can
101 * be accessed and managed by its owner represented by owner_uid/owner_gid.
102 */
103 #define UBLK_F_UNPRIVILEGED_DEV (1UL << 5)
104
105 /* device state */
106 #define UBLK_S_DEV_DEAD 0
107 #define UBLK_S_DEV_LIVE 1
108 #define UBLK_S_DEV_QUIESCED 2
109
110 /* shipped via sqe->cmd of io_uring command */
111 struct ublksrv_ctrl_cmd {
112 /* sent to which device, must be valid */
113 __u32 dev_id;
114
115 /* sent to which queue, must be -1 if the cmd isn't for queue */
116 __u16 queue_id;
117 /*
118 * cmd specific buffer, can be IN or OUT.
119 */
120 __u16 len;
121 __u64 addr;
122
123 /* inline data */
124 __u64 data[1];
125
126 /*
127 * Used for UBLK_F_UNPRIVILEGED_DEV and UBLK_CMD_GET_DEV_INFO2
128 * only, include null char
129 */
130 __u16 dev_path_len;
131 __u16 pad;
132 __u32 reserved;
133 };
134
135 struct ublksrv_ctrl_dev_info {
136 __u16 nr_hw_queues;
137 __u16 queue_depth;
138 __u16 state;
139 __u16 pad0;
140
141 __u32 max_io_buf_bytes;
142 __u32 dev_id;
143
144 __s32 ublksrv_pid;
145 __u32 pad1;
146
147 __u64 flags;
148
149 /* For ublksrv internal use, invisible to ublk driver */
150 __u64 ublksrv_flags;
151
152 __u32 owner_uid; /* store by kernel */
153 __u32 owner_gid; /* store by kernel */
154 __u64 reserved1;
155 __u64 reserved2;
156 };
157
158 #define UBLK_IO_OP_READ 0
159 #define UBLK_IO_OP_WRITE 1
160 #define UBLK_IO_OP_FLUSH 2
161 #define UBLK_IO_OP_DISCARD 3
162 #define UBLK_IO_OP_WRITE_SAME 4
163 #define UBLK_IO_OP_WRITE_ZEROES 5
164
165 #define UBLK_IO_F_FAILFAST_DEV (1U << 8)
166 #define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9)
167 #define UBLK_IO_F_FAILFAST_DRIVER (1U << 10)
168 #define UBLK_IO_F_META (1U << 11)
169 #define UBLK_IO_F_FUA (1U << 13)
170 #define UBLK_IO_F_NOUNMAP (1U << 15)
171 #define UBLK_IO_F_SWAP (1U << 16)
172
173 /*
174 * io cmd is described by this structure, and stored in share memory, indexed
175 * by request tag.
176 *
177 * The data is stored by ublk driver, and read by ublksrv after one fetch command
178 * returns.
179 */
180 struct ublksrv_io_desc {
181 /* op: bit 0-7, flags: bit 8-31 */
182 __u32 op_flags;
183
184 __u32 nr_sectors;
185
186 /* start sector for this io */
187 __u64 start_sector;
188
189 /* buffer address in ublksrv daemon vm space, from ublk driver */
190 __u64 addr;
191 };
192
ublksrv_get_op(const struct ublksrv_io_desc * iod)193 static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod)
194 {
195 return iod->op_flags & 0xff;
196 }
197
ublksrv_get_flags(const struct ublksrv_io_desc * iod)198 static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod)
199 {
200 return iod->op_flags >> 8;
201 }
202
203 /* issued to ublk driver via /dev/ublkcN */
204 struct ublksrv_io_cmd {
205 __u16 q_id;
206
207 /* for fetch/commit which result */
208 __u16 tag;
209
210 /* io result, it is valid for COMMIT* command only */
211 __s32 result;
212
213 /*
214 * userspace buffer address in ublksrv daemon process, valid for
215 * FETCH* command only
216 */
217 __u64 addr;
218 };
219
220 struct ublk_param_basic {
221 #define UBLK_ATTR_READ_ONLY (1 << 0)
222 #define UBLK_ATTR_ROTATIONAL (1 << 1)
223 #define UBLK_ATTR_VOLATILE_CACHE (1 << 2)
224 #define UBLK_ATTR_FUA (1 << 3)
225 __u32 attrs;
226 __u8 logical_bs_shift;
227 __u8 physical_bs_shift;
228 __u8 io_opt_shift;
229 __u8 io_min_shift;
230
231 __u32 max_sectors;
232 __u32 chunk_sectors;
233
234 __u64 dev_sectors;
235 __u64 virt_boundary_mask;
236 };
237
238 struct ublk_param_discard {
239 __u32 discard_alignment;
240
241 __u32 discard_granularity;
242 __u32 max_discard_sectors;
243
244 __u32 max_write_zeroes_sectors;
245 __u16 max_discard_segments;
246 __u16 reserved0;
247 };
248
249 /*
250 * read-only, can't set via UBLK_CMD_SET_PARAMS, disk_devt is available
251 * after device is started
252 */
253 struct ublk_param_devt {
254 __u32 char_major;
255 __u32 char_minor;
256 __u32 disk_major;
257 __u32 disk_minor;
258 };
259
260 struct ublk_params {
261 /*
262 * Total length of parameters, userspace has to set 'len' for both
263 * SET_PARAMS and GET_PARAMS command, and driver may update len
264 * if two sides use different version of 'ublk_params', same with
265 * 'types' fields.
266 */
267 __u32 len;
268 #define UBLK_PARAM_TYPE_BASIC (1 << 0)
269 #define UBLK_PARAM_TYPE_DISCARD (1 << 1)
270 #define UBLK_PARAM_TYPE_DEVT (1 << 2)
271 __u32 types; /* types of parameter included */
272
273 struct ublk_param_basic basic;
274 struct ublk_param_discard discard;
275 struct ublk_param_devt devt;
276 };
277
278 #endif
279