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virtio_blk.h
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#ifndef _LINUX_VIRTIO_BLK_H #define _LINUX_VIRTIO_BLK_H /* This header is BSD licensed so anyone can use the definitions to implement * compatible drivers/servers. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of IBM nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <linux/types.h> #include <linux/virtio_ids.h> #include <linux/virtio_config.h> #include <linux/virtio_types.h> /* Feature bits */ #define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */ #define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */ #define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */ #define VIRTIO_BLK_F_RO 5 /* Disk is read-only */ #define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/ #define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */ #define VIRTIO_BLK_F_MQ 12 /* support more than one vq */ #define VIRTIO_BLK_F_DISCARD 13 /* DISCARD is supported */ #define VIRTIO_BLK_F_WRITE_ZEROES 14 /* WRITE ZEROES is supported */ /* Legacy feature bits */ #ifndef VIRTIO_BLK_NO_LEGACY #define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */ #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ #define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */ #define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */ /* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */ #define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH #endif /* !VIRTIO_BLK_NO_LEGACY */ #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */ struct virtio_blk_config { /* The capacity (in 512-byte sectors). */ __u64 capacity; /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */ __u32 size_max; /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */ __u32 seg_max; /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */ struct virtio_blk_geometry { __u16 cylinders; __u8 heads; __u8 sectors; } geometry; /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */ __u32 blk_size; /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */ /* exponent for physical block per logical block. */ __u8 physical_block_exp; /* alignment offset in logical blocks. */ __u8 alignment_offset; /* minimum I/O size without performance penalty in logical blocks. */ __u16 min_io_size; /* optimal sustained I/O size in logical blocks. */ __u32 opt_io_size; /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */ __u8 wce; __u8 unused; /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */ __u16 num_queues; /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */ /* * The maximum discard sectors (in 512-byte sectors) for * one segment. */ __u32 max_discard_sectors; /* * The maximum number of discard segments in a * discard command. */ __u32 max_discard_seg; /* Discard commands must be aligned to this number of sectors. */ __u32 discard_sector_alignment; /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */ /* * The maximum number of write zeroes sectors (in 512-byte sectors) in * one segment. */ __u32 max_write_zeroes_sectors; /* * The maximum number of segments in a write zeroes * command. */ __u32 max_write_zeroes_seg; /* * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the * deallocation of one or more of the sectors. */ __u8 write_zeroes_may_unmap; __u8 unused1[3]; } __attribute__((packed)); /* * Command types * * Usage is a bit tricky as some bits are used as flags and some are not. * * Rules: * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own * and may not be combined with any of the other flags. */ /* These two define direction. */ #define VIRTIO_BLK_T_IN 0 #define VIRTIO_BLK_T_OUT 1 #ifndef VIRTIO_BLK_NO_LEGACY /* This bit says it's a scsi command, not an actual read or write. */ #define VIRTIO_BLK_T_SCSI_CMD 2 #endif /* VIRTIO_BLK_NO_LEGACY */ /* Cache flush command */ #define VIRTIO_BLK_T_FLUSH 4 /* Get device ID command */ #define VIRTIO_BLK_T_GET_ID 8 /* Discard command */ #define VIRTIO_BLK_T_DISCARD 11 /* Write zeroes command */ #define VIRTIO_BLK_T_WRITE_ZEROES 13 #ifndef VIRTIO_BLK_NO_LEGACY /* Barrier before this op. */ #define VIRTIO_BLK_T_BARRIER 0x80000000 #endif /* !VIRTIO_BLK_NO_LEGACY */ /* * This comes first in the read scatter-gather list. * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, * this is the first element of the read scatter-gather list. */ struct virtio_blk_outhdr { /* VIRTIO_BLK_T* */ __virtio32 type; /* io priority. */ __virtio32 ioprio; /* Sector (ie. 512 byte offset) */ __virtio64 sector; }; /* Unmap this range (only valid for write zeroes command) */ #define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001 /* Discard/write zeroes range for each request. */ struct virtio_blk_discard_write_zeroes { /* discard/write zeroes start sector */ __le64 sector; /* number of discard/write zeroes sectors */ __le32 num_sectors; /* flags for this range */ __le32 flags; }; #ifndef VIRTIO_BLK_NO_LEGACY struct virtio_scsi_inhdr { __virtio32 errors; __virtio32 data_len; __virtio32 sense_len; __virtio32 residual; }; #endif /* !VIRTIO_BLK_NO_LEGACY */ /* And this is the final byte of the write scatter-gather list. */ #define VIRTIO_BLK_S_OK 0 #define VIRTIO_BLK_S_IOERR 1 #define VIRTIO_BLK_S_UNSUPP 2 #endif /* _LINUX_VIRTIO_BLK_H */