hw/block/block.c

   1 /*
   2  * Common code for block device models
   3  *
   4  * Copyright (C) 2012 Red Hat, Inc.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or
   7  * later.  See the COPYING file in the top-level directory.
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "sysemu/blockdev.h"
  12 #include "sysemu/block-backend.h"
  13 #include "hw/block/block.h"
  14 #include "qapi/error.h"
  15 #include "qapi/qapi-types-block.h"
  16
  17 /*
  18  * Read the entire contents of @blk into @buf.
  19  * @blk's contents must be @size bytes, and @size must be at most
  20  * BDRV_REQUEST_MAX_BYTES.
  21  * On success, return true.
  22  * On failure, store an error through @errp and return false.
  23  * Note that the error messages do not identify the block backend.
  24  * TODO Since callers don't either, this can result in confusing
  25  * errors.
  26  * This function not intended for actual block devices, which read on
  27  * demand.  It's for things like memory devices that (ab)use a block
  28  * backend to provide persistence.
  29  */
  30 bool blk_check_size_and_read_all(BlockBackend *blk, void *buf, hwaddr size,
  31                                  Error **errp)
  32 {
  33     int64_t blk_len;
  34     int ret;
  35
  36     blk_len = blk_getlength(blk);
  37     if (blk_len < 0) {
  38         error_setg_errno(errp, -blk_len,
  39                          "can't get size of block backend");
  40         return false;
  41     }
  42     if (blk_len != size) {
  43         error_setg(errp, "device requires %" HWADDR_PRIu " bytes, "
  44                    "block backend provides %" PRIu64 " bytes",
  45                    size, blk_len);
  46         return false;
  47     }
  48
  49     /*
  50      * We could loop for @size > BDRV_REQUEST_MAX_BYTES, but if we
  51      * ever get to the point we want to read *gigabytes* here, we
  52      * should probably rework the device to be more like an actual
  53      * block device and read only on demand.
  54      */
  55     assert(size <= BDRV_REQUEST_MAX_BYTES);
  56     ret = blk_pread(blk, 0, buf, size);
  57     if (ret < 0) {
  58         error_setg_errno(errp, -ret, "can't read block backend");
  59         return false;
  60     }
  61     return true;
  62 }
  63
  64 bool blkconf_blocksizes(BlockConf *conf, Error **errp)
  65 {
  66     BlockBackend *blk = conf->blk;
  67     BlockSizes blocksizes;
  68     int backend_ret;
  69
  70     backend_ret = blk_probe_blocksizes(blk, &blocksizes);
  71     /* fill in detected values if they are not defined via qemu command line */
  72     if (!conf->physical_block_size) {
  73         if (!backend_ret) {
  74            conf->physical_block_size = blocksizes.phys;
  75         } else {
  76             conf->physical_block_size = BDRV_SECTOR_SIZE;
  77         }
  78     }
  79     if (!conf->logical_block_size) {
  80         if (!backend_ret) {
  81             conf->logical_block_size = blocksizes.log;
  82         } else {
  83             conf->logical_block_size = BDRV_SECTOR_SIZE;
  84         }
  85     }
  86
  87     if (conf->logical_block_size > conf->physical_block_size) {
  88         error_setg(errp,
  89                    "logical_block_size > physical_block_size not supported");
  90         return false;
  91     }
  92
  93     if (!QEMU_IS_ALIGNED(conf->min_io_size, conf->logical_block_size)) {
  94         error_setg(errp,
  95                    "min_io_size must be a multiple of logical_block_size");
  96         return false;
  97     }
  98
  99     /*
 100      * all devices which support min_io_size (scsi and virtio-blk) expose it to
 101      * the guest as a uint16_t in units of logical blocks
 102      */
 103     if (conf->min_io_size / conf->logical_block_size > UINT16_MAX) {
 104         error_setg(errp, "min_io_size must not exceed %u logical blocks",
 105                    UINT16_MAX);
 106         return false;
 107     }
 108
 109     if (!QEMU_IS_ALIGNED(conf->opt_io_size, conf->logical_block_size)) {
 110         error_setg(errp,
 111                    "opt_io_size must be a multiple of logical_block_size");
 112         return false;
 113     }
 114
 115     if (conf->discard_granularity != -1 &&
 116         !QEMU_IS_ALIGNED(conf->discard_granularity,
 117                          conf->logical_block_size)) {
 118         error_setg(errp, "discard_granularity must be "
 119                    "a multiple of logical_block_size");
 120         return false;
 121     }
 122
 123     return true;
 124 }
 125
 126 bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
 127                                    bool resizable, Error **errp)
 128 {
 129     BlockBackend *blk = conf->blk;
 130     BlockdevOnError rerror, werror;
 131     uint64_t perm, shared_perm;
 132     bool wce;
 133     int ret;
 134
 135     perm = BLK_PERM_CONSISTENT_READ;
 136     if (!readonly) {
 137         perm |= BLK_PERM_WRITE;
 138     }
 139
 140     shared_perm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
 141                   BLK_PERM_GRAPH_MOD;
 142     if (resizable) {
 143         shared_perm |= BLK_PERM_RESIZE;
 144     }
 145     if (conf->share_rw) {
 146         shared_perm |= BLK_PERM_WRITE;
 147     }
 148
 149     ret = blk_set_perm(blk, perm, shared_perm, errp);
 150     if (ret < 0) {
 151         return false;
 152     }
 153
 154     switch (conf->wce) {
 155     case ON_OFF_AUTO_ON:    wce = true; break;
 156     case ON_OFF_AUTO_OFF:   wce = false; break;
 157     case ON_OFF_AUTO_AUTO:  wce = blk_enable_write_cache(blk); break;
 158     default:
 159         abort();
 160     }
 161
 162     rerror = conf->rerror;
 163     if (rerror == BLOCKDEV_ON_ERROR_AUTO) {
 164         rerror = blk_get_on_error(blk, true);
 165     }
 166
 167     werror = conf->werror;
 168     if (werror == BLOCKDEV_ON_ERROR_AUTO) {
 169         werror = blk_get_on_error(blk, false);
 170     }
 171
 172     blk_set_enable_write_cache(blk, wce);
 173     blk_set_on_error(blk, rerror, werror);
 174
 175     return true;
 176 }
 177
 178 bool blkconf_geometry(BlockConf *conf, int *ptrans,
 179                       unsigned cyls_max, unsigned heads_max, unsigned secs_max,
 180                       Error **errp)
 181 {
 182     if (!conf->cyls && !conf->heads && !conf->secs) {
 183         hd_geometry_guess(conf->blk,
 184                           &conf->cyls, &conf->heads, &conf->secs,
 185                           ptrans);
 186     } else if (ptrans && *ptrans == BIOS_ATA_TRANSLATION_AUTO) {
 187         *ptrans = hd_bios_chs_auto_trans(conf->cyls, conf->heads, conf->secs);
 188     }
 189     if (conf->cyls || conf->heads || conf->secs) {
 190         if (conf->cyls < 1 || conf->cyls > cyls_max) {
 191             error_setg(errp, "cyls must be between 1 and %u", cyls_max);
 192             return false;
 193         }
 194         if (conf->heads < 1 || conf->heads > heads_max) {
 195             error_setg(errp, "heads must be between 1 and %u", heads_max);
 196             return false;
 197         }
 198         if (conf->secs < 1 || conf->secs > secs_max) {
 199             error_setg(errp, "secs must be between 1 and %u", secs_max);
 200             return false;
 201         }
 202     }
 203     return true;
 204 }