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  */
  28 void 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 }