| Current File : //usr/include/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 */
/* 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_WCE 9 /* Writeback mode enabled after reset */
#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
#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;
} __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
#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;
};
#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 */