diff options
Diffstat (limited to 'include/uapi/linux/ublk_cmd.h')
| -rw-r--r-- | include/uapi/linux/ublk_cmd.h | 597 |
1 files changed, 597 insertions, 0 deletions
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h new file mode 100644 index 000000000000..77d9d6af46da --- /dev/null +++ b/include/uapi/linux/ublk_cmd.h @@ -0,0 +1,597 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef USER_BLK_DRV_CMD_INC_H +#define USER_BLK_DRV_CMD_INC_H + +#include <linux/types.h> + +/* ublk server command definition */ + +/* + * Admin commands, issued by ublk server, and handled by ublk driver. + * + * Legacy command definition, don't use in new application, and don't + * add new such definition any more + */ +#define UBLK_CMD_GET_QUEUE_AFFINITY 0x01 +#define UBLK_CMD_GET_DEV_INFO 0x02 +#define UBLK_CMD_ADD_DEV 0x04 +#define UBLK_CMD_DEL_DEV 0x05 +#define UBLK_CMD_START_DEV 0x06 +#define UBLK_CMD_STOP_DEV 0x07 +#define UBLK_CMD_SET_PARAMS 0x08 +#define UBLK_CMD_GET_PARAMS 0x09 +#define UBLK_CMD_START_USER_RECOVERY 0x10 +#define UBLK_CMD_END_USER_RECOVERY 0x11 +#define UBLK_CMD_GET_DEV_INFO2 0x12 + +/* Any new ctrl command should encode by __IO*() */ +#define UBLK_U_CMD_GET_QUEUE_AFFINITY \ + _IOR('u', UBLK_CMD_GET_QUEUE_AFFINITY, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_GET_DEV_INFO \ + _IOR('u', UBLK_CMD_GET_DEV_INFO, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_ADD_DEV \ + _IOWR('u', UBLK_CMD_ADD_DEV, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_DEL_DEV \ + _IOWR('u', UBLK_CMD_DEL_DEV, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_START_DEV \ + _IOWR('u', UBLK_CMD_START_DEV, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_STOP_DEV \ + _IOWR('u', UBLK_CMD_STOP_DEV, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_SET_PARAMS \ + _IOWR('u', UBLK_CMD_SET_PARAMS, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_GET_PARAMS \ + _IOR('u', UBLK_CMD_GET_PARAMS, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_START_USER_RECOVERY \ + _IOWR('u', UBLK_CMD_START_USER_RECOVERY, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_END_USER_RECOVERY \ + _IOWR('u', UBLK_CMD_END_USER_RECOVERY, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_GET_DEV_INFO2 \ + _IOR('u', UBLK_CMD_GET_DEV_INFO2, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_GET_FEATURES \ + _IOR('u', 0x13, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_DEL_DEV_ASYNC \ + _IOR('u', 0x14, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_UPDATE_SIZE \ + _IOWR('u', 0x15, struct ublksrv_ctrl_cmd) +#define UBLK_U_CMD_QUIESCE_DEV \ + _IOWR('u', 0x16, struct ublksrv_ctrl_cmd) + +/* + * 64bits are enough now, and it should be easy to extend in case of + * running out of feature flags + */ +#define UBLK_FEATURES_LEN 8 + +/* + * IO commands, issued by ublk server, and handled by ublk driver. + * + * FETCH_REQ: issued via sqe(URING_CMD) beforehand for fetching IO request + * from ublk driver, should be issued only when starting device. After + * the associated cqe is returned, request's tag can be retrieved via + * cqe->userdata. + * + * COMMIT_AND_FETCH_REQ: issued via sqe(URING_CMD) after ublkserver handled + * this IO request, request's handling result is committed to ublk + * driver, meantime FETCH_REQ is piggyback, and FETCH_REQ has to be + * handled before completing io request. + * + * NEED_GET_DATA: only used for write requests to set io addr and copy data + * When NEED_GET_DATA is set, ublksrv has to issue UBLK_IO_NEED_GET_DATA + * command after ublk driver returns UBLK_IO_RES_NEED_GET_DATA. + * + * It is only used if ublksrv set UBLK_F_NEED_GET_DATA flag + * while starting a ublk device. + */ + +/* + * Legacy IO command definition, don't use in new application, and don't + * add new such definition any more + */ +#define UBLK_IO_FETCH_REQ 0x20 +#define UBLK_IO_COMMIT_AND_FETCH_REQ 0x21 +#define UBLK_IO_NEED_GET_DATA 0x22 + +/* Any new IO command should encode by __IOWR() */ +#define UBLK_U_IO_FETCH_REQ \ + _IOWR('u', UBLK_IO_FETCH_REQ, struct ublksrv_io_cmd) +#define UBLK_U_IO_COMMIT_AND_FETCH_REQ \ + _IOWR('u', UBLK_IO_COMMIT_AND_FETCH_REQ, struct ublksrv_io_cmd) +#define UBLK_U_IO_NEED_GET_DATA \ + _IOWR('u', UBLK_IO_NEED_GET_DATA, struct ublksrv_io_cmd) +#define UBLK_U_IO_REGISTER_IO_BUF \ + _IOWR('u', 0x23, struct ublksrv_io_cmd) +#define UBLK_U_IO_UNREGISTER_IO_BUF \ + _IOWR('u', 0x24, struct ublksrv_io_cmd) + +/* only ABORT means that no re-fetch */ +#define UBLK_IO_RES_OK 0 +#define UBLK_IO_RES_NEED_GET_DATA 1 +#define UBLK_IO_RES_ABORT (-ENODEV) + +#define UBLKSRV_CMD_BUF_OFFSET 0 +#define UBLKSRV_IO_BUF_OFFSET 0x80000000 + +/* tag bit is 16bit, so far limit at most 4096 IOs for each queue */ +#define UBLK_MAX_QUEUE_DEPTH 4096 + +/* single IO buffer max size is 32MB */ +#define UBLK_IO_BUF_OFF 0 +#define UBLK_IO_BUF_BITS 25 +#define UBLK_IO_BUF_BITS_MASK ((1ULL << UBLK_IO_BUF_BITS) - 1) + +/* so at most 64K IOs for each queue */ +#define UBLK_TAG_OFF UBLK_IO_BUF_BITS +#define UBLK_TAG_BITS 16 +#define UBLK_TAG_BITS_MASK ((1ULL << UBLK_TAG_BITS) - 1) + +/* max 4096 queues */ +#define UBLK_QID_OFF (UBLK_TAG_OFF + UBLK_TAG_BITS) +#define UBLK_QID_BITS 12 +#define UBLK_QID_BITS_MASK ((1ULL << UBLK_QID_BITS) - 1) + +#define UBLK_MAX_NR_QUEUES (1U << UBLK_QID_BITS) + +#define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_QID_OFF + UBLK_QID_BITS) +#define UBLKSRV_IO_BUF_TOTAL_SIZE (1ULL << UBLKSRV_IO_BUF_TOTAL_BITS) + +/* + * zero copy requires 4k block size, and can remap ublk driver's io + * request into ublksrv's vm space + */ +#define UBLK_F_SUPPORT_ZERO_COPY (1ULL << 0) + +/* + * Force to complete io cmd via io_uring_cmd_complete_in_task so that + * performance comparison is done easily with using task_work_add + */ +#define UBLK_F_URING_CMD_COMP_IN_TASK (1ULL << 1) + +/* + * User should issue io cmd again for write requests to + * set io buffer address and copy data from bio vectors + * to the userspace io buffer. + * + * In this mode, task_work is not used. + */ +#define UBLK_F_NEED_GET_DATA (1UL << 2) + +/* + * - Block devices are recoverable if ublk server exits and restarts + * - Outstanding I/O when ublk server exits is met with errors + * - I/O issued while there is no ublk server queues + */ +#define UBLK_F_USER_RECOVERY (1UL << 3) + +/* + * - Block devices are recoverable if ublk server exits and restarts + * - Outstanding I/O when ublk server exits is reissued + * - I/O issued while there is no ublk server queues + */ +#define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4) + +/* + * Unprivileged user can create /dev/ublkcN and /dev/ublkbN. + * + * /dev/ublk-control needs to be available for unprivileged user, and it + * can be done via udev rule to make all control commands available to + * unprivileged user. Except for the command of UBLK_CMD_ADD_DEV, all + * other commands are only allowed for the owner of the specified device. + * + * When userspace sends UBLK_CMD_ADD_DEV, the device pair's owner_uid and + * owner_gid are stored to ublksrv_ctrl_dev_info by kernel, so far only + * the current user's uid/gid is stored, that said owner of the created + * device is always the current user. + * + * We still need udev rule to apply OWNER/GROUP with the stored owner_uid + * and owner_gid. + * + * Then ublk server can be run as unprivileged user, and /dev/ublkbN can + * be accessed and managed by its owner represented by owner_uid/owner_gid. + */ +#define UBLK_F_UNPRIVILEGED_DEV (1UL << 5) + +/* use ioctl encoding for uring command */ +#define UBLK_F_CMD_IOCTL_ENCODE (1UL << 6) + +/* + * Copy between request and user buffer by pread()/pwrite() + * + * Not available for UBLK_F_UNPRIVILEGED_DEV, otherwise userspace may + * deceive us by not filling request buffer, then kernel uninitialized + * data may be leaked. + */ +#define UBLK_F_USER_COPY (1UL << 7) + +/* + * User space sets this flag when setting up the device to request zoned storage support. Kernel may + * deny the request by returning an error. + */ +#define UBLK_F_ZONED (1ULL << 8) + +/* + * - Block devices are recoverable if ublk server exits and restarts + * - Outstanding I/O when ublk server exits is met with errors + * - I/O issued while there is no ublk server is met with errors + */ +#define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9) + +/* + * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE + * New size is passed in cmd->data[0] and is in units of sectors + */ +#define UBLK_F_UPDATE_SIZE (1ULL << 10) + +/* + * request buffer is registered automatically to uring_cmd's io_uring + * context before delivering this io command to ublk server, meantime + * it is un-registered automatically when completing this io command. + * + * For using this feature: + * + * - ublk server has to create sparse buffer table on the same `io_ring_ctx` + * for issuing `UBLK_IO_FETCH_REQ` and `UBLK_IO_COMMIT_AND_FETCH_REQ`. + * If uring_cmd isn't issued on same `io_ring_ctx`, it is ublk server's + * responsibility to unregister the buffer by issuing `IO_UNREGISTER_IO_BUF` + * manually, otherwise this ublk request won't complete. + * + * - ublk server passes auto buf register data via uring_cmd's sqe->addr, + * `struct ublk_auto_buf_reg` is populated from sqe->addr, please see + * the definition of ublk_sqe_addr_to_auto_buf_reg() + * + * - pass buffer index from `ublk_auto_buf_reg.index` + * + * - all reserved fields in `ublk_auto_buf_reg` need to be zeroed + * + * - pass flags from `ublk_auto_buf_reg.flags` if needed + * + * This way avoids extra cost from two uring_cmd, but also simplifies backend + * implementation, such as, the dependency on IO_REGISTER_IO_BUF and + * IO_UNREGISTER_IO_BUF becomes not necessary. + * + * If wrong data or flags are provided, both IO_FETCH_REQ and + * IO_COMMIT_AND_FETCH_REQ are failed, for the latter, the ublk IO request + * won't be completed until new IO_COMMIT_AND_FETCH_REQ command is issued + * successfully + */ +#define UBLK_F_AUTO_BUF_REG (1ULL << 11) + +/* + * Control command `UBLK_U_CMD_QUIESCE_DEV` is added for quiescing device, + * which state can be transitioned to `UBLK_S_DEV_QUIESCED` or + * `UBLK_S_DEV_FAIL_IO` finally, and it needs ublk server cooperation for + * handling `UBLK_IO_RES_ABORT` correctly. + * + * Typical use case is for supporting to upgrade ublk server application, + * meantime keep ublk block device persistent during the period. + * + * This feature is only available when UBLK_F_USER_RECOVERY is enabled. + * + * Note, this command returns -EBUSY in case that all IO commands are being + * handled by ublk server and not completed in specified time period which + * is passed from the control command parameter. + */ +#define UBLK_F_QUIESCE (1ULL << 12) + +/* + * If this feature is set, ublk_drv supports each (qid,tag) pair having + * its own independent daemon task that is responsible for handling it. + * If it is not set, daemons are per-queue instead, so for two pairs + * (qid1,tag1) and (qid2,tag2), if qid1 == qid2, then the same task must + * be responsible for handling (qid1,tag1) and (qid2,tag2). + */ +#define UBLK_F_PER_IO_DAEMON (1ULL << 13) + +/* device state */ +#define UBLK_S_DEV_DEAD 0 +#define UBLK_S_DEV_LIVE 1 +#define UBLK_S_DEV_QUIESCED 2 +#define UBLK_S_DEV_FAIL_IO 3 + +/* shipped via sqe->cmd of io_uring command */ +struct ublksrv_ctrl_cmd { + /* sent to which device, must be valid */ + __u32 dev_id; + + /* sent to which queue, must be -1 if the cmd isn't for queue */ + __u16 queue_id; + /* + * cmd specific buffer, can be IN or OUT. + */ + __u16 len; + __u64 addr; + + /* inline data */ + __u64 data[1]; + + /* + * Used for UBLK_F_UNPRIVILEGED_DEV and UBLK_CMD_GET_DEV_INFO2 + * only, include null char + */ + __u16 dev_path_len; + __u16 pad; + __u32 reserved; +}; + +struct ublksrv_ctrl_dev_info { + __u16 nr_hw_queues; + __u16 queue_depth; + __u16 state; + __u16 pad0; + + __u32 max_io_buf_bytes; + __u32 dev_id; + + __s32 ublksrv_pid; + __u32 pad1; + + __u64 flags; + + /* For ublksrv internal use, invisible to ublk driver */ + __u64 ublksrv_flags; + + __u32 owner_uid; /* store by kernel */ + __u32 owner_gid; /* store by kernel */ + __u64 reserved1; + __u64 reserved2; +}; + +#define UBLK_IO_OP_READ 0 +#define UBLK_IO_OP_WRITE 1 +#define UBLK_IO_OP_FLUSH 2 +#define UBLK_IO_OP_DISCARD 3 +#define UBLK_IO_OP_WRITE_SAME 4 +#define UBLK_IO_OP_WRITE_ZEROES 5 +#define UBLK_IO_OP_ZONE_OPEN 10 +#define UBLK_IO_OP_ZONE_CLOSE 11 +#define UBLK_IO_OP_ZONE_FINISH 12 +#define UBLK_IO_OP_ZONE_APPEND 13 +#define UBLK_IO_OP_ZONE_RESET_ALL 14 +#define UBLK_IO_OP_ZONE_RESET 15 +/* + * Construct a zone report. The report request is carried in `struct + * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone + * and shall indicate the first zone of the report. The `nr_zones` shall + * indicate how many zones should be reported at most. The report shall be + * delivered as a `struct blk_zone` array. To report fewer zones than requested, + * zero the last entry of the returned array. + * + * Related definitions(blk_zone, blk_zone_cond, blk_zone_type, ...) in + * include/uapi/linux/blkzoned.h are part of ublk UAPI. + */ +#define UBLK_IO_OP_REPORT_ZONES 18 + +#define UBLK_IO_F_FAILFAST_DEV (1U << 8) +#define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9) +#define UBLK_IO_F_FAILFAST_DRIVER (1U << 10) +#define UBLK_IO_F_META (1U << 11) +#define UBLK_IO_F_FUA (1U << 13) +#define UBLK_IO_F_NOUNMAP (1U << 15) +#define UBLK_IO_F_SWAP (1U << 16) +/* + * For UBLK_F_AUTO_BUF_REG & UBLK_AUTO_BUF_REG_FALLBACK only. + * + * This flag is set if auto buffer register is failed & ublk server passes + * UBLK_AUTO_BUF_REG_FALLBACK, and ublk server need to register buffer + * manually for handling the delivered IO command if this flag is observed + * + * ublk server has to check this flag if UBLK_AUTO_BUF_REG_FALLBACK is + * passed in. + */ +#define UBLK_IO_F_NEED_REG_BUF (1U << 17) + +/* + * io cmd is described by this structure, and stored in share memory, indexed + * by request tag. + * + * The data is stored by ublk driver, and read by ublksrv after one fetch command + * returns. + */ +struct ublksrv_io_desc { + /* op: bit 0-7, flags: bit 8-31 */ + __u32 op_flags; + + union { + __u32 nr_sectors; + __u32 nr_zones; /* for UBLK_IO_OP_REPORT_ZONES */ + }; + + /* start sector for this io */ + __u64 start_sector; + + /* buffer address in ublksrv daemon vm space, from ublk driver */ + __u64 addr; +}; + +static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod) +{ + return iod->op_flags & 0xff; +} + +static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod) +{ + return iod->op_flags >> 8; +} + +/* + * If this flag is set, fallback by completing the uring_cmd and setting + * `UBLK_IO_F_NEED_REG_BUF` in case of auto-buf-register failure; + * otherwise the client ublk request is failed silently + * + * If ublk server passes this flag, it has to check if UBLK_IO_F_NEED_REG_BUF + * is set in `ublksrv_io_desc.op_flags`. If UBLK_IO_F_NEED_REG_BUF is set, + * ublk server needs to register io buffer manually for handling IO command. + */ +#define UBLK_AUTO_BUF_REG_FALLBACK (1 << 0) +#define UBLK_AUTO_BUF_REG_F_MASK UBLK_AUTO_BUF_REG_FALLBACK + +struct ublk_auto_buf_reg { + /* index for registering the delivered request buffer */ + __u16 index; + __u8 flags; + __u8 reserved0; + + /* + * io_ring FD can be passed via the reserve field in future for + * supporting to register io buffer to external io_uring + */ + __u32 reserved1; +}; + +/* + * For UBLK_F_AUTO_BUF_REG, auto buffer register data is carried via + * uring_cmd's sqe->addr: + * + * - bit0 ~ bit15: buffer index + * - bit16 ~ bit23: flags + * - bit24 ~ bit31: reserved0 + * - bit32 ~ bit63: reserved1 + */ +static inline struct ublk_auto_buf_reg ublk_sqe_addr_to_auto_buf_reg( + __u64 sqe_addr) +{ + struct ublk_auto_buf_reg reg = { + .index = sqe_addr & 0xffff, + .flags = (sqe_addr >> 16) & 0xff, + .reserved0 = (sqe_addr >> 24) & 0xff, + .reserved1 = sqe_addr >> 32, + }; + + return reg; +} + +static inline __u64 +ublk_auto_buf_reg_to_sqe_addr(const struct ublk_auto_buf_reg *buf) +{ + __u64 addr = buf->index | (__u64)buf->flags << 16 | (__u64)buf->reserved0 << 24 | + (__u64)buf->reserved1 << 32; + + return addr; +} + +/* issued to ublk driver via /dev/ublkcN */ +struct ublksrv_io_cmd { + __u16 q_id; + + /* for fetch/commit which result */ + __u16 tag; + + /* io result, it is valid for COMMIT* command only */ + __s32 result; + + union { + /* + * userspace buffer address in ublksrv daemon process, valid for + * FETCH* command only + * + * `addr` should not be used when UBLK_F_USER_COPY is enabled, + * because userspace handles data copy by pread()/pwrite() over + * /dev/ublkcN. But in case of UBLK_F_ZONED, this union is + * re-used to pass back the allocated LBA for + * UBLK_IO_OP_ZONE_APPEND which actually depends on + * UBLK_F_USER_COPY + */ + __u64 addr; + __u64 zone_append_lba; + }; +}; + +struct ublk_param_basic { +#define UBLK_ATTR_READ_ONLY (1 << 0) +#define UBLK_ATTR_ROTATIONAL (1 << 1) +#define UBLK_ATTR_VOLATILE_CACHE (1 << 2) +#define UBLK_ATTR_FUA (1 << 3) + __u32 attrs; + __u8 logical_bs_shift; + __u8 physical_bs_shift; + __u8 io_opt_shift; + __u8 io_min_shift; + + __u32 max_sectors; + __u32 chunk_sectors; + + __u64 dev_sectors; + __u64 virt_boundary_mask; +}; + +struct ublk_param_discard { + __u32 discard_alignment; + + __u32 discard_granularity; + __u32 max_discard_sectors; + + __u32 max_write_zeroes_sectors; + __u16 max_discard_segments; + __u16 reserved0; +}; + +/* + * read-only, can't set via UBLK_CMD_SET_PARAMS, disk_devt is available + * after device is started + */ +struct ublk_param_devt { + __u32 char_major; + __u32 char_minor; + __u32 disk_major; + __u32 disk_minor; +}; + +struct ublk_param_zoned { + __u32 max_open_zones; + __u32 max_active_zones; + __u32 max_zone_append_sectors; + __u8 reserved[20]; +}; + +struct ublk_param_dma_align { + __u32 alignment; + __u8 pad[4]; +}; + +#define UBLK_MIN_SEGMENT_SIZE 4096 +/* + * If any one of the three segment parameter is set as 0, the behavior is + * undefined. + */ +struct ublk_param_segment { + /* + * seg_boundary_mask + 1 needs to be power_of_2(), and the sum has + * to be >= UBLK_MIN_SEGMENT_SIZE(4096) + */ + __u64 seg_boundary_mask; + + /* + * max_segment_size could be override by virt_boundary_mask, so be + * careful when setting both. + * + * max_segment_size has to be >= UBLK_MIN_SEGMENT_SIZE(4096) + */ + __u32 max_segment_size; + __u16 max_segments; + __u8 pad[2]; +}; + +struct ublk_params { + /* + * Total length of parameters, userspace has to set 'len' for both + * SET_PARAMS and GET_PARAMS command, and driver may update len + * if two sides use different version of 'ublk_params', same with + * 'types' fields. + */ + __u32 len; +#define UBLK_PARAM_TYPE_BASIC (1 << 0) +#define UBLK_PARAM_TYPE_DISCARD (1 << 1) +#define UBLK_PARAM_TYPE_DEVT (1 << 2) +#define UBLK_PARAM_TYPE_ZONED (1 << 3) +#define UBLK_PARAM_TYPE_DMA_ALIGN (1 << 4) +#define UBLK_PARAM_TYPE_SEGMENT (1 << 5) + __u32 types; /* types of parameter included */ + + struct ublk_param_basic basic; + struct ublk_param_discard discard; + struct ublk_param_devt devt; + struct ublk_param_zoned zoned; + struct ublk_param_dma_align dma; + struct ublk_param_segment seg; +}; + +#endif |