hw/virtio-blk.h

   1 /*
   2  * Virtio Block Device
   3  *
   4  * Copyright IBM, Corp. 2007
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #ifndef _QEMU_VIRTIO_BLK_H
  15 #define _QEMU_VIRTIO_BLK_H
  16
  17 #include "virtio.h"
  18 #include "block.h"
  19 #include "pci.h"
  20
  21 /* from Linux's linux/virtio_blk.h */
  22
  23 /* The ID for virtio_block */
  24 #define VIRTIO_ID_BLOCK 2
  25
  26 /* Feature bits */
  27 #define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
  28 #define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
  29 #define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
  30 #define VIRTIO_BLK_F_GEOMETRY   4       /* Indicates support of legacy geometry */
  31 #define VIRTIO_BLK_F_RO         5       /* Disk is read-only */
  32 #define VIRTIO_BLK_F_BLK_SIZE   6       /* Block size of disk is available*/
  33 #define VIRTIO_BLK_F_SCSI       7       /* Supports scsi command passthru */
  34
  35 struct virtio_blk_config
  36 {
  37     uint64_t capacity;
  38     uint32_t size_max;
  39     uint32_t seg_max;
  40     uint16_t cylinders;
  41     uint8_t heads;
  42     uint8_t sectors;
  43 } __attribute__((packed));
  44
  45 /* These two define direction. */
  46 #define VIRTIO_BLK_T_IN         0
  47 #define VIRTIO_BLK_T_OUT        1
  48
  49 /* This bit says it's a scsi command, not an actual read or write. */
  50 #define VIRTIO_BLK_T_SCSI_CMD   2
  51
  52 /* Barrier before this op. */
  53 #define VIRTIO_BLK_T_BARRIER    0x80000000
  54
  55 /* This is the first element of the read scatter-gather list. */
  56 struct virtio_blk_outhdr
  57 {
  58     /* VIRTIO_BLK_T* */
  59     uint32_t type;
  60     /* io priority. */
  61     uint32_t ioprio;
  62     /* Sector (ie. 512 byte offset) */
  63     uint64_t sector;
  64 };
  65
  66 #define VIRTIO_BLK_S_OK         0
  67 #define VIRTIO_BLK_S_IOERR      1
  68 #define VIRTIO_BLK_S_UNSUPP     2
  69
  70 /* This is the last element of the write scatter-gather list */
  71 struct virtio_blk_inhdr
  72 {
  73     unsigned char status;
  74 };
  75
  76 /* SCSI pass-through header */
  77 struct virtio_scsi_inhdr
  78 {
  79     uint32_t errors;
  80     uint32_t data_len;
  81     uint32_t sense_len;
  82     uint32_t residual;
  83 };
  84
  85 void *virtio_blk_init(PCIBus *bus, BlockDriverState *bs);
  86
  87 #endif