root/include/uapi/linux/virtio_blk.h
#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 */
#define VIRTIO_BLK_F_SECURE_ERASE       16 /* Secure Erase is supported */
#define VIRTIO_BLK_F_ZONED              17      /* Zoned block device */

/* 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 */
#ifndef __KERNEL__
/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
#endif
#endif /* !VIRTIO_BLK_NO_LEGACY */

#define VIRTIO_BLK_ID_BYTES     20      /* ID string length */

struct virtio_blk_config {
        /* The capacity (in 512-byte sectors). */
        __virtio64 capacity;
        /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
        __virtio32 size_max;
        /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
        __virtio32 seg_max;
        /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
        struct virtio_blk_geometry {
                __virtio16 cylinders;
                __u8 heads;
                __u8 sectors;
        } geometry;

        /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
        __virtio32 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. */
        __virtio16 min_io_size;
        /* optimal sustained I/O size in logical blocks. */
        __virtio32 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 */
        __virtio16 num_queues;

        /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
        /*
         * The maximum discard sectors (in 512-byte sectors) for
         * one segment.
         */
        __virtio32 max_discard_sectors;
        /*
         * The maximum number of discard segments in a
         * discard command.
         */
        __virtio32 max_discard_seg;
        /* Discard commands must be aligned to this number of sectors. */
        __virtio32 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.
         */
        __virtio32 max_write_zeroes_sectors;
        /*
         * The maximum number of segments in a write zeroes
         * command.
         */
        __virtio32 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];

        /* the next 3 entries are guarded by VIRTIO_BLK_F_SECURE_ERASE */
        /*
         * The maximum secure erase sectors (in 512-byte sectors) for
         * one segment.
         */
        __virtio32 max_secure_erase_sectors;
        /*
         * The maximum number of secure erase segments in a
         * secure erase command.
         */
        __virtio32 max_secure_erase_seg;
        /* Secure erase commands must be aligned to this number of sectors. */
        __virtio32 secure_erase_sector_alignment;

        /* Zoned block device characteristics (if VIRTIO_BLK_F_ZONED) */
        struct virtio_blk_zoned_characteristics {
                __virtio32 zone_sectors;
                __virtio32 max_open_zones;
                __virtio32 max_active_zones;
                __virtio32 max_append_sectors;
                __virtio32 write_granularity;
                __u8 model;
                __u8 unused2[3];
        } zoned;
} __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

/* Secure erase command */
#define VIRTIO_BLK_T_SECURE_ERASE       14

/* Zone append command */
#define VIRTIO_BLK_T_ZONE_APPEND    15

/* Report zones command */
#define VIRTIO_BLK_T_ZONE_REPORT    16

/* Open zone command */
#define VIRTIO_BLK_T_ZONE_OPEN      18

/* Close zone command */
#define VIRTIO_BLK_T_ZONE_CLOSE     20

/* Finish zone command */
#define VIRTIO_BLK_T_ZONE_FINISH    22

/* Reset zone command */
#define VIRTIO_BLK_T_ZONE_RESET     24

/* Reset All zones command */
#define VIRTIO_BLK_T_ZONE_RESET_ALL 26

#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;
};

/*
 * Supported zoned device models.
 */

/* Regular block device */
#define VIRTIO_BLK_Z_NONE      0
/* Host-managed zoned device */
#define VIRTIO_BLK_Z_HM        1
/* Host-aware zoned device */
#define VIRTIO_BLK_Z_HA        2

/*
 * Zone descriptor. A part of VIRTIO_BLK_T_ZONE_REPORT command reply.
 */
struct virtio_blk_zone_descriptor {
        /* Zone capacity */
        __virtio64 z_cap;
        /* The starting sector of the zone */
        __virtio64 z_start;
        /* Zone write pointer position in sectors */
        __virtio64 z_wp;
        /* Zone type */
        __u8 z_type;
        /* Zone state */
        __u8 z_state;
        __u8 reserved[38];
};

struct virtio_blk_zone_report {
        __virtio64 nr_zones;
        __u8 reserved[56];
        struct virtio_blk_zone_descriptor zones[];
};

/*
 * Supported zone types.
 */

/* Conventional zone */
#define VIRTIO_BLK_ZT_CONV         1
/* Sequential Write Required zone */
#define VIRTIO_BLK_ZT_SWR          2
/* Sequential Write Preferred zone */
#define VIRTIO_BLK_ZT_SWP          3

/*
 * Zone states that are available for zones of all types.
 */

/* Not a write pointer (conventional zones only) */
#define VIRTIO_BLK_ZS_NOT_WP       0
/* Empty */
#define VIRTIO_BLK_ZS_EMPTY        1
/* Implicitly Open */
#define VIRTIO_BLK_ZS_IOPEN        2
/* Explicitly Open */
#define VIRTIO_BLK_ZS_EOPEN        3
/* Closed */
#define VIRTIO_BLK_ZS_CLOSED       4
/* Read-Only */
#define VIRTIO_BLK_ZS_RDONLY       13
/* Full */
#define VIRTIO_BLK_ZS_FULL         14
/* Offline */
#define VIRTIO_BLK_ZS_OFFLINE      15

/* 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

/* Error codes that are specific to zoned block devices */
#define VIRTIO_BLK_S_ZONE_INVALID_CMD     3
#define VIRTIO_BLK_S_ZONE_UNALIGNED_WP    4
#define VIRTIO_BLK_S_ZONE_OPEN_RESOURCE   5
#define VIRTIO_BLK_S_ZONE_ACTIVE_RESOURCE 6

#endif /* _LINUX_VIRTIO_BLK_H */