LXR qemu/util/block-helpers.c

   1/*
   2 * Block utility functions
   3 *
   4 * Copyright IBM, Corp. 2011
   5 * Copyright (c) 2020 Coiby Xu <coiby.xu@gmail.com>
   6 *
   7 * This work is licensed under the terms of the GNU GPL, version 2 or later.
   8 * See the COPYING file in the top-level directory.
   9 */
  10
  11#include "qemu/osdep.h"
  12#include "qapi/error.h"
  13#include "qapi/qmp/qerror.h"
  14#include "block-helpers.h"
  15
  16/**
  17 * check_block_size:
  18 * @id: The unique ID of the object
  19 * @name: The name of the property being validated
  20 * @value: The block size in bytes
  21 * @errp: A pointer to an area to store an error
  22 *
  23 * This function checks that the block size meets the following conditions:
  24 * 1. At least MIN_BLOCK_SIZE
  25 * 2. No larger than MAX_BLOCK_SIZE
  26 * 3. A power of 2
  27 */
  28void check_block_size(const char *id, const char *name, int64_t value,
  29                      Error **errp)
  30{
  31    /* value of 0 means "unset" */
  32    if (value && (value < MIN_BLOCK_SIZE || value > MAX_BLOCK_SIZE)) {
  33        error_setg(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE,
  34                   id, name, value, MIN_BLOCK_SIZE, MAX_BLOCK_SIZE);
  35        return;
  36    }
  37
  38    /* We rely on power-of-2 blocksizes for bitmasks */
  39    if ((value & (value - 1)) != 0) {
  40        error_setg(errp,
  41                   "Property %s.%s doesn't take value '%" PRId64
  42                   "', it's not a power of 2",
  43                   id, name, value);
  44        return;
  45    }
  46}
  47