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28 * $FreeBSD: src/sys/dev/virtio/block/virtio_blk.h,v 1.2 2011/12/06 06:28:32 grehan Exp $
34 #include <sys/types.h>
37 #define VIRTIO_BLK_F_BARRIER 0x0001 /* Does host support barriers? */
38 #define VIRTIO_BLK_F_SIZE_MAX 0x0002 /* Indicates maximum segment size */
39 #define VIRTIO_BLK_F_SEG_MAX 0x0004 /* Indicates maximum # of segments */
40 #define VIRTIO_BLK_F_GEOMETRY 0x0010 /* Legacy geometry available */
41 #define VIRTIO_BLK_F_RO 0x0020 /* Disk is read-only */
42 #define VIRTIO_BLK_F_BLK_SIZE 0x0040 /* Block size of disk is available*/
43 #define VIRTIO_BLK_F_SCSI 0x0080 /* Supports scsi command passthru */
44 #define VIRTIO_BLK_F_FLUSH 0x0200 /* Cache flush command support */
45 #define VIRTIO_BLK_F_TOPOLOGY 0x0400 /* Topology information is available */
47 #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
49 struct virtio_blk_config {
50 /* The capacity (in 512-byte sectors). */
52 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
54 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
56 /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
57 struct virtio_blk_geometry {
63 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
70 * Usage is a bit tricky as some bits are used as flags and some are not.
73 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
74 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
75 * and may not be combined with any of the other flags.
78 /* These two define direction. */
79 #define VIRTIO_BLK_T_IN 0
80 #define VIRTIO_BLK_T_OUT 1
82 /* This bit says it's a scsi command, not an actual read or write. */
83 #define VIRTIO_BLK_T_SCSI_CMD 2
85 /* Cache flush command */
86 #define VIRTIO_BLK_T_FLUSH 4
88 /* Get device ID command */
89 #define VIRTIO_BLK_T_GET_ID 8
91 /* Barrier before this op. */
92 #define VIRTIO_BLK_T_BARRIER 0x80000000
94 /* ID string length */
95 #define VIRTIO_BLK_ID_BYTES 20
97 /* This is the first element of the read scatter-gather list. */
98 struct virtio_blk_outhdr {
103 /* Sector (ie. 512 byte offset) */
107 struct virtio_scsi_inhdr {
114 /* And this is the final byte of the write scatter-gather list. */
115 #define VIRTIO_BLK_S_OK 0
116 #define VIRTIO_BLK_S_IOERR 1
117 #define VIRTIO_BLK_S_UNSUPP 2
119 #endif /* _VIRTIO_BLK_H */