include/hw/virtio/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 "hw/virtio/virtio.h"
  18 #include "hw/block/block.h"
  19 #include "sysemu/iothread.h"
  20 #include "sysemu/block-backend.h"
  21
  22 #define TYPE_VIRTIO_BLK "virtio-blk-device"
  23 #define VIRTIO_BLK(obj) \
  24         OBJECT_CHECK(VirtIOBlock, (obj), TYPE_VIRTIO_BLK)
  25
  26 /* from Linux's linux/virtio_blk.h */
  27
  28 /* The ID for virtio_block */
  29 #define VIRTIO_ID_BLOCK 2
  30
  31 /* Feature bits */
  32 #define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
  33 #define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
  34 #define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
  35 #define VIRTIO_BLK_F_GEOMETRY   4       /* Indicates support of legacy geometry */
  36 #define VIRTIO_BLK_F_RO         5       /* Disk is read-only */
  37 #define VIRTIO_BLK_F_BLK_SIZE   6       /* Block size of disk is available*/
  38 #define VIRTIO_BLK_F_SCSI       7       /* Supports scsi command passthru */
  39 /* #define VIRTIO_BLK_F_IDENTIFY   8       ATA IDENTIFY supported, DEPRECATED */
  40 #define VIRTIO_BLK_F_WCE        9       /* write cache enabled */
  41 #define VIRTIO_BLK_F_TOPOLOGY   10      /* Topology information is available */
  42 #define VIRTIO_BLK_F_CONFIG_WCE 11      /* write cache configurable */
  43
  44 #define VIRTIO_BLK_ID_BYTES     20      /* ID string length */
  45
  46 struct virtio_blk_config
  47 {
  48     uint64_t capacity;
  49     uint32_t size_max;
  50     uint32_t seg_max;
  51     uint16_t cylinders;
  52     uint8_t heads;
  53     uint8_t sectors;
  54     uint32_t blk_size;
  55     uint8_t physical_block_exp;
  56     uint8_t alignment_offset;
  57     uint16_t min_io_size;
  58     uint32_t opt_io_size;
  59     uint8_t wce;
  60 } QEMU_PACKED;
  61
  62 /* These two define direction. */
  63 #define VIRTIO_BLK_T_IN         0
  64 #define VIRTIO_BLK_T_OUT        1
  65
  66 /* This bit says it's a scsi command, not an actual read or write. */
  67 #define VIRTIO_BLK_T_SCSI_CMD   2
  68
  69 /* Flush the volatile write cache */
  70 #define VIRTIO_BLK_T_FLUSH      4
  71
  72 /* return the device ID string */
  73 #define VIRTIO_BLK_T_GET_ID     8
  74
  75 /* Barrier before this op. */
  76 #define VIRTIO_BLK_T_BARRIER    0x80000000
  77
  78 /* This is the first element of the read scatter-gather list. */
  79 struct virtio_blk_outhdr
  80 {
  81     /* VIRTIO_BLK_T* */
  82     uint32_t type;
  83     /* io priority. */
  84     uint32_t ioprio;
  85     /* Sector (ie. 512 byte offset) */
  86     uint64_t sector;
  87 };
  88
  89 #define VIRTIO_BLK_S_OK         0
  90 #define VIRTIO_BLK_S_IOERR      1
  91 #define VIRTIO_BLK_S_UNSUPP     2
  92
  93 /* This is the last element of the write scatter-gather list */
  94 struct virtio_blk_inhdr
  95 {
  96     unsigned char status;
  97 };
  98
  99 /* SCSI pass-through header */
 100 struct virtio_scsi_inhdr
 101 {
 102     uint32_t errors;
 103     uint32_t data_len;
 104     uint32_t sense_len;
 105     uint32_t residual;
 106 };
 107
 108 struct VirtIOBlkConf
 109 {
 110     BlockConf conf;
 111     IOThread *iothread;
 112     char *serial;
 113     uint32_t scsi;
 114     uint32_t config_wce;
 115     uint32_t data_plane;
 116     uint32_t request_merging;
 117 };
 118
 119 struct VirtIOBlockDataPlane;
 120
 121 struct VirtIOBlockReq;
 122 typedef struct VirtIOBlock {
 123     VirtIODevice parent_obj;
 124     BlockBackend *blk;
 125     VirtQueue *vq;
 126     void *rq;
 127     QEMUBH *bh;
 128     VirtIOBlkConf conf;
 129     unsigned short sector_mask;
 130     bool original_wce;
 131     VMChangeStateEntry *change;
 132     /* Function to push to vq and notify guest */
 133     void (*complete_request)(struct VirtIOBlockReq *req, unsigned char status);
 134     Notifier migration_state_notifier;
 135     struct VirtIOBlockDataPlane *dataplane;
 136 } VirtIOBlock;
 137
 138 typedef struct VirtIOBlockReq {
 139     int64_t sector_num;
 140     VirtIOBlock *dev;
 141     VirtQueueElement elem;
 142     struct virtio_blk_inhdr *in;
 143     struct virtio_blk_outhdr out;
 144     QEMUIOVector qiov;
 145     struct VirtIOBlockReq *next;
 146     struct VirtIOBlockReq *mr_next;
 147     BlockAcctCookie acct;
 148 } VirtIOBlockReq;
 149
 150 #define VIRTIO_BLK_MAX_MERGE_REQS 32
 151
 152 typedef struct MultiReqBuffer {
 153     VirtIOBlockReq *reqs[VIRTIO_BLK_MAX_MERGE_REQS];
 154     unsigned int num_reqs;
 155     bool is_write;
 156 } MultiReqBuffer;
 157
 158 VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s);
 159
 160 void virtio_blk_free_request(VirtIOBlockReq *req);
 161
 162 void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb);
 163
 164 void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb);
 165
 166 #endif