1a42b19ed0
Tested on Qemu/KVM, VirtualBox, and BHyVe. Currently built as modules-only on i386/amd64. Man pages not yet hooked up, pending review. Submitted by: Bryan Venteicher bryanv at daemoninthecloset dot org Reviewed by: bz MFC after: 4 weeks or so
107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/*
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* This header is BSD licensed so anyone can use the definitions to implement
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* compatible drivers/servers.
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*
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* $FreeBSD$
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*/
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#ifndef _VIRTIO_BLK_H
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#define _VIRTIO_BLK_H
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#include <sys/types.h>
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/* Feature bits */
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#define VIRTIO_BLK_F_BARRIER 0x0001 /* Does host support barriers? */
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#define VIRTIO_BLK_F_SIZE_MAX 0x0002 /* Indicates maximum segment size */
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#define VIRTIO_BLK_F_SEG_MAX 0x0004 /* Indicates maximum # of segments */
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#define VIRTIO_BLK_F_GEOMETRY 0x0010 /* Legacy geometry available */
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#define VIRTIO_BLK_F_RO 0x0020 /* Disk is read-only */
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#define VIRTIO_BLK_F_BLK_SIZE 0x0040 /* Block size of disk is available*/
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#define VIRTIO_BLK_F_SCSI 0x0080 /* Supports scsi command passthru */
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#define VIRTIO_BLK_F_FLUSH 0x0200 /* Cache flush command support */
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#define VIRTIO_BLK_F_TOPOLOGY 0x0400 /* Topology information is available */
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#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
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struct virtio_blk_config {
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/* The capacity (in 512-byte sectors). */
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uint64_t capacity;
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/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
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uint32_t size_max;
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/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
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uint32_t seg_max;
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/* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
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struct virtio_blk_geometry {
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uint16_t cylinders;
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uint8_t heads;
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uint8_t sectors;
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} geometry;
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/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
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uint32_t blk_size;
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/* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */
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/* exponent for physical block per logical block. */
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uint8_t physical_block_exp;
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/* alignment offset in logical blocks. */
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uint8_t alignment_offset;
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/* minimum I/O size without performance penalty in logical blocks. */
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uint16_t min_io_size;
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/* optimal sustained I/O size in logical blocks. */
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uint32_t opt_io_size;
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} __packed;
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/*
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* Command types
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*
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* Usage is a bit tricky as some bits are used as flags and some are not.
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*
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* Rules:
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* VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
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* VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
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* and may not be combined with any of the other flags.
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*/
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/* These two define direction. */
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#define VIRTIO_BLK_T_IN 0
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#define VIRTIO_BLK_T_OUT 1
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/* This bit says it's a scsi command, not an actual read or write. */
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#define VIRTIO_BLK_T_SCSI_CMD 2
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/* Cache flush command */
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#define VIRTIO_BLK_T_FLUSH 4
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/* Get device ID command */
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#define VIRTIO_BLK_T_GET_ID 8
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/* Barrier before this op. */
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#define VIRTIO_BLK_T_BARRIER 0x80000000
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/* ID string length */
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#define VIRTIO_BLK_ID_BYTES 20
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/* This is the first element of the read scatter-gather list. */
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struct virtio_blk_outhdr {
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/* VIRTIO_BLK_T* */
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uint32_t type;
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/* io priority. */
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uint32_t ioprio;
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/* Sector (ie. 512 byte offset) */
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uint64_t sector;
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};
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struct virtio_scsi_inhdr {
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uint32_t errors;
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uint32_t data_len;
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uint32_t sense_len;
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uint32_t residual;
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};
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/* And this is the final byte of the write scatter-gather list. */
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#define VIRTIO_BLK_S_OK 0
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#define VIRTIO_BLK_S_IOERR 1
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#define VIRTIO_BLK_S_UNSUPP 2
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#endif /* _VIRTIO_BLK_H */
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