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