| /* |
| * 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 "block/block_int-common.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 non-zeroes parts of @blk into @buf |
| * Reading all of the @blk is expensive if the zeroes parts of @blk |
| * is large enough. Therefore check the block status and only write |
| * the non-zeroes block into @buf. |
| * |
| * Return 0 on success, non-zero on error. |
| */ |
| static int blk_pread_nonzeroes(BlockBackend *blk, hwaddr size, void *buf) |
| { |
| int ret; |
| int64_t bytes, offset = 0; |
| BlockDriverState *bs = blk_bs(blk); |
| |
| for (;;) { |
| bytes = MIN(size - offset, BDRV_REQUEST_MAX_SECTORS); |
| if (bytes <= 0) { |
| return 0; |
| } |
| ret = bdrv_block_status(bs, offset, bytes, &bytes, NULL, NULL); |
| if (ret < 0) { |
| return ret; |
| } |
| if (!(ret & BDRV_BLOCK_ZERO)) { |
| ret = bdrv_pread(bs->file, offset, bytes, |
| (uint8_t *) buf + offset, 0); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| offset += bytes; |
| } |
| } |
| |
| /* |
| * 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_nonzeroes(blk, size, buf); |
| 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); |
| |
| block_acct_setup(blk_get_stats(blk), conf->account_invalid, |
| conf->account_failed); |
| 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; |
| } |
