diff options
Diffstat (limited to 'include/uapi/linux/ublk_cmd.h')
| -rw-r--r-- | include/uapi/linux/ublk_cmd.h | 223 |
1 files changed, 220 insertions, 3 deletions
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index c8dc5f8ea699..c9751bdfd937 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -51,6 +51,10 @@ _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 @@ -94,6 +98,10 @@ _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 @@ -127,8 +135,28 @@ #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 + * ublk server can register data buffers for incoming I/O requests with a sparse + * io_uring buffer table. The request buffer can then be used as the data buffer + * for io_uring operations via the fixed buffer index. + * Note that the ublk server can never directly access the request data memory. + * + * To use this feature, the ublk server must first register a sparse buffer + * table on an io_uring instance. + * When an incoming ublk request is received, the ublk server submits a + * UBLK_U_IO_REGISTER_IO_BUF command to that io_uring instance. The + * ublksrv_io_cmd's q_id and tag specify the request whose buffer to register + * and addr is the index in the io_uring's buffer table to install the buffer. + * SQEs can now be submitted to the io_uring to read/write the request's buffer + * by enabling fixed buffers (e.g. using IORING_OP_{READ,WRITE}_FIXED or + * IORING_URING_CMD_FIXED) and passing the registered buffer index in buf_index. + * Once the last io_uring operation using the request's buffer has completed, + * the ublk server submits a UBLK_U_IO_UNREGISTER_IO_BUF command with q_id, tag, + * and addr again specifying the request buffer to unregister. + * The ublk request is completed when its buffer is unregistered from all + * io_uring instances and the ublk server issues UBLK_U_IO_COMMIT_AND_FETCH_REQ. + * + * Not available for UBLK_F_UNPRIVILEGED_DEV, as a ublk server can leak + * uninitialized kernel memory by not reading into the full request buffer. */ #define UBLK_F_SUPPORT_ZERO_COPY (1ULL << 0) @@ -147,8 +175,18 @@ */ #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) /* @@ -175,7 +213,13 @@ /* use ioctl encoding for uring command */ #define UBLK_F_CMD_IOCTL_ENCODE (1UL << 6) -/* Copy between request and user buffer by pread()/pwrite() */ +/* + * 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) /* @@ -184,10 +228,84 @@ */ #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 { @@ -269,6 +387,17 @@ struct ublksrv_ctrl_dev_info { #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 @@ -303,6 +432,62 @@ 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 = (__u16)sqe_addr, + .flags = (__u8)(sqe_addr >> 16), + .reserved0 = (__u8)(sqe_addr >> 24), + .reserved1 = (__u32)(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; @@ -377,6 +562,34 @@ struct ublk_param_zoned { __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 @@ -389,12 +602,16 @@ struct ublk_params { #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 |