LXR qemu/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 */
  30bool 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
  64void blkconf_blocksizes(BlockConf *conf)
  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
  88bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
  89                                   bool resizable, Error **errp)
  90{
  91    BlockBackend *blk = conf->blk;
  92    BlockdevOnError rerror, werror;
  93    uint64_t perm, shared_perm;
  94    bool wce;
  95    int ret;
  96
  97    perm = BLK_PERM_CONSISTENT_READ;
  98    if (!readonly) {
  99        perm |= BLK_PERM_WRITE;
 100    }
 101
 102    shared_perm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
 103                  BLK_PERM_GRAPH_MOD;
 104    if (resizable) {
 105        shared_perm |= BLK_PERM_RESIZE;
 106    }
 107    if (conf->share_rw) {
 108        shared_perm |= BLK_PERM_WRITE;
 109    }
 110
 111    ret = blk_set_perm(blk, perm, shared_perm, errp);
 112    if (ret < 0) {
 113        return false;
 114    }
 115
 116    switch (conf->wce) {
 117    case ON_OFF_AUTO_ON:    wce = true; break;
 118    case ON_OFF_AUTO_OFF:   wce = false; break;
 119    case ON_OFF_AUTO_AUTO:  wce = blk_enable_write_cache(blk); break;
 120    default:
 121        abort();
 122    }
 123
 124    rerror = conf->rerror;
 125    if (rerror == BLOCKDEV_ON_ERROR_AUTO) {
 126        rerror = blk_get_on_error(blk, true);
 127    }
 128
 129    werror = conf->werror;
 130    if (werror == BLOCKDEV_ON_ERROR_AUTO) {
 131        werror = blk_get_on_error(blk, false);
 132    }
 133
 134    blk_set_enable_write_cache(blk, wce);
 135    blk_set_on_error(blk, rerror, werror);
 136
 137    return true;
 138}
 139
 140bool blkconf_geometry(BlockConf *conf, int *ptrans,
 141                      unsigned cyls_max, unsigned heads_max, unsigned secs_max,
 142                      Error **errp)
 143{
 144    if (!conf->cyls && !conf->heads && !conf->secs) {
 145        hd_geometry_guess(conf->blk,
 146                          &conf->cyls, &conf->heads, &conf->secs,
 147                          ptrans);
 148    } else if (ptrans && *ptrans == BIOS_ATA_TRANSLATION_AUTO) {
 149        *ptrans = hd_bios_chs_auto_trans(conf->cyls, conf->heads, conf->secs);
 150    }
 151    if (conf->cyls || conf->heads || conf->secs) {
 152        if (conf->cyls < 1 || conf->cyls > cyls_max) {
 153            error_setg(errp, "cyls must be between 1 and %u", cyls_max);
 154            return false;
 155        }
 156        if (conf->heads < 1 || conf->heads > heads_max) {
 157            error_setg(errp, "heads must be between 1 and %u", heads_max);
 158            return false;
 159        }
 160        if (conf->secs < 1 || conf->secs > secs_max) {
 161            error_setg(errp, "secs must be between 1 and %u", secs_max);
 162            return false;
 163        }
 164    }
 165    return true;
 166}
 167