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 }; 192 193 static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod) 194 { 195 return iod->op_flags & 0xff; 196 } 197 198 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