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/*
* Common code for block device models
*
* Copyright (C) 2012 Red Hat, Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "sysemu/blockdev.h"
#include "sysemu/block-backend.h"
#include "hw/block/block.h"
#include "qapi/error.h"
#include "qapi/qapi-types-block.h"
/*
* Read the entire contents of @blk into @buf.
* @blk's contents must be @size bytes, and @size must be at most
* BDRV_REQUEST_MAX_BYTES.
* On success, return true.
* On failure, store an error through @errp and return false.
* Note that the error messages do not identify the block backend.
* TODO Since callers don't either, this can result in confusing
* errors.
* This function not intended for actual block devices, which read on
* demand. It's for things like memory devices that (ab)use a block
* backend to provide persistence.
*/
bool blk_check_size_and_read_all(BlockBackend *blk, void *buf, hwaddr size,
Error **errp)
{
int64_t blk_len;
int ret;
blk_len = blk_getlength(blk);
if (blk_len < 0) {
error_setg_errno(errp, -blk_len,
"can't get size of block backend");
return false;
}
if (blk_len != size) {
error_setg(errp, "device requires %" HWADDR_PRIu " bytes, "
"block backend provides %" PRIu64 " bytes",
size, blk_len);
return false;
}
/*
* We could loop for @size > BDRV_REQUEST_MAX_BYTES, but if we
* ever get to the point we want to read *gigabytes* here, we
* should probably rework the device to be more like an actual
* block device and read only on demand.
*/
assert(size <= BDRV_REQUEST_MAX_BYTES);
ret = blk_pread(blk, 0, buf, size, 0);
if (ret < 0) {
error_setg_errno(errp, -ret, "can't read block backend");
return false;
}
return true;
}
bool blkconf_blocksizes(BlockConf *conf, Error **errp)
{
BlockBackend *blk = conf->blk;
BlockSizes blocksizes;
BlockDriverState *bs;
bool use_blocksizes;
bool use_bs;
switch (conf->backend_defaults) {
case ON_OFF_AUTO_AUTO:
use_blocksizes = !blk_probe_blocksizes(blk, &blocksizes);
use_bs = false;
break;
case ON_OFF_AUTO_ON:
use_blocksizes = !blk_probe_blocksizes(blk, &blocksizes);
bs = blk_bs(blk);
use_bs = bs;
break;
case ON_OFF_AUTO_OFF:
use_blocksizes = false;
use_bs = false;
break;
default:
abort();
}
/* fill in detected values if they are not defined via qemu command line */
if (!conf->physical_block_size) {
if (use_blocksizes) {
conf->physical_block_size = blocksizes.phys;
} else {
conf->physical_block_size = BDRV_SECTOR_SIZE;
}
}
if (!conf->logical_block_size) {
if (use_blocksizes) {
conf->logical_block_size = blocksizes.log;
} else {
conf->logical_block_size = BDRV_SECTOR_SIZE;
}
}
if (use_bs) {
if (!conf->opt_io_size) {
conf->opt_io_size = bs->bl.opt_transfer;
}
if (conf->discard_granularity == -1) {
if (bs->bl.pdiscard_alignment) {
conf->discard_granularity = bs->bl.pdiscard_alignment;
} else if (bs->bl.request_alignment != 1) {
conf->discard_granularity = bs->bl.request_alignment;
}
}
}
if (conf->logical_block_size > conf->physical_block_size) {
error_setg(errp,
"logical_block_size > physical_block_size not supported");
return false;
}
if (!QEMU_IS_ALIGNED(conf->min_io_size, conf->logical_block_size)) {
error_setg(errp,
"min_io_size must be a multiple of logical_block_size");
return false;
}
/*
* all devices which support min_io_size (scsi and virtio-blk) expose it to
* the guest as a uint16_t in units of logical blocks
*/
if (conf->min_io_size / conf->logical_block_size > UINT16_MAX) {
error_setg(errp, "min_io_size must not exceed %u logical blocks",
UINT16_MAX);
return false;
}
if (!QEMU_IS_ALIGNED(conf->opt_io_size, conf->logical_block_size)) {
error_setg(errp,
"opt_io_size must be a multiple of logical_block_size");
return false;
}
if (conf->discard_granularity != -1 &&
!QEMU_IS_ALIGNED(conf->discard_granularity,
conf->logical_block_size)) {
error_setg(errp, "discard_granularity must be "
"a multiple of logical_block_size");
return false;
}
return true;
}
bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
bool resizable, Error **errp)
{
BlockBackend *blk = conf->blk;
BlockdevOnError rerror, werror;
uint64_t perm, shared_perm;
bool wce;
int ret;
perm = BLK_PERM_CONSISTENT_READ;
if (!readonly) {
perm |= BLK_PERM_WRITE;
}
shared_perm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED;
if (resizable) {
shared_perm |= BLK_PERM_RESIZE;
}
if (conf->share_rw) {
shared_perm |= BLK_PERM_WRITE;
}
ret = blk_set_perm(blk, perm, shared_perm, errp);
if (ret < 0) {
return false;
}
switch (conf->wce) {
case ON_OFF_AUTO_ON: wce = true; break;
case ON_OFF_AUTO_OFF: wce = false; break;
case ON_OFF_AUTO_AUTO: wce = blk_enable_write_cache(blk); break;
default:
abort();
}
rerror = conf->rerror;
if (rerror == BLOCKDEV_ON_ERROR_AUTO) {
rerror = blk_get_on_error(blk, true);
}
werror = conf->werror;
if (werror == BLOCKDEV_ON_ERROR_AUTO) {
werror = blk_get_on_error(blk, false);
}
blk_set_enable_write_cache(blk, wce);
blk_set_on_error(blk, rerror, werror);
return true;
}
bool blkconf_geometry(BlockConf *conf, int *ptrans,
unsigned cyls_max, unsigned heads_max, unsigned secs_max,
Error **errp)
{
if (!conf->cyls && !conf->heads && !conf->secs) {
hd_geometry_guess(conf->blk,
&conf->cyls, &conf->heads, &conf->secs,
ptrans);
} else if (ptrans && *ptrans == BIOS_ATA_TRANSLATION_AUTO) {
*ptrans = hd_bios_chs_auto_trans(conf->cyls, conf->heads, conf->secs);
}
if (conf->cyls || conf->heads || conf->secs) {
if (conf->cyls < 1 || conf->cyls > cyls_max) {
error_setg(errp, "cyls must be between 1 and %u", cyls_max);
return false;
}
if (conf->heads < 1 || conf->heads > heads_max) {
error_setg(errp, "heads must be between 1 and %u", heads_max);
return false;
}
if (conf->secs < 1 || conf->secs > secs_max) {
error_setg(errp, "secs must be between 1 and %u", secs_max);
return false;
}
}
return true;
}
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