Archipelago » qemu

/*

 * QEMU host block devices

 *

 * Copyright (c) 2003-2008 Fabrice Bellard

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or

 * later.  See the COPYING file in the top-level directory.

 *

 * This file incorporates work covered by the following copyright and

 * permission notice:

 *

 * Copyright (c) 2003-2008 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "sysemu/blockdev.h"

#include "hw/block/block.h"

#include "block/blockjob.h"

#include "monitor/monitor.h"

#include "qapi/qmp/qerror.h"

#include "qemu/option.h"

#include "qemu/config-file.h"

#include "qapi/qmp/types.h"

#include "qapi-visit.h"

#include "qapi/qmp-output-visitor.h"

#include "sysemu/sysemu.h"

#include "block/block_int.h"

#include "qmp-commands.h"

#include "trace.h"

#include "sysemu/arch_init.h"

static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);

static const char *const if_name[IF_COUNT] = {

    [IF_NONE] = "none",

    [IF_IDE] = "ide",

    [IF_SCSI] = "scsi",

    [IF_FLOPPY] = "floppy",

    [IF_PFLASH] = "pflash",

    [IF_MTD] = "mtd",

    [IF_SD] = "sd",

    [IF_VIRTIO] = "virtio",

    [IF_XEN] = "xen",

};

static const int if_max_devs[IF_COUNT] = {

    /*

     * Do not change these numbers!  They govern how drive option

     * index maps to unit and bus.  That mapping is ABI.

     *

     * All controllers used to imlement if=T drives need to support

     * if_max_devs[T] units, for any T with if_max_devs[T] != 0.

     * Otherwise, some index values map to "impossible" bus, unit

     * values.

     *

     * For instance, if you change [IF_SCSI] to 255, -drive

     * if=scsi,index=12 no longer means bus=1,unit=5, but

     * bus=0,unit=12.  With an lsi53c895a controller (7 units max),

     * the drive can't be set up.  Regression.

     */

    [IF_IDE] = 2,

    [IF_SCSI] = 7,

};

/*

 * We automatically delete the drive when a device using it gets

 * unplugged.  Questionable feature, but we can't just drop it.

 * Device models call blockdev_mark_auto_del() to schedule the

 * automatic deletion, and generic qdev code calls blockdev_auto_del()

 * when deletion is actually safe.

 */

void blockdev_mark_auto_del(BlockDriverState *bs)

{

    DriveInfo *dinfo = drive_get_by_blockdev(bs);

    if (dinfo && !dinfo->enable_auto_del) {

        return;

    }

    if (bs->job) {

        block_job_cancel(bs->job);

    }

    if (dinfo) {

        dinfo->auto_del = 1;

    }

}

void blockdev_auto_del(BlockDriverState *bs)

{

    DriveInfo *dinfo = drive_get_by_blockdev(bs);

    if (dinfo && dinfo->auto_del) {

        drive_put_ref(dinfo);

    }

}

static int drive_index_to_bus_id(BlockInterfaceType type, int index)

{

    int max_devs = if_max_devs[type];

    return max_devs ? index / max_devs : 0;

}

static int drive_index_to_unit_id(BlockInterfaceType type, int index)

{

    int max_devs = if_max_devs[type];

    return max_devs ? index % max_devs : index;

}

QemuOpts *drive_def(const char *optstr)

{

    return qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);

}

QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,

                    const char *optstr)

{

    QemuOpts *opts;

    char buf[32];

    opts = drive_def(optstr);

    if (!opts) {

        return NULL;

    }

    if (type != IF_DEFAULT) {

        qemu_opt_set(opts, "if", if_name[type]);

    }

    if (index >= 0) {

        snprintf(buf, sizeof(buf), "%d", index);

        qemu_opt_set(opts, "index", buf);

    }

    if (file)

        qemu_opt_set(opts, "file", file);

    return opts;

}

DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)

{

    DriveInfo *dinfo;

    /* seek interface, bus and unit */

    QTAILQ_FOREACH(dinfo, &drives, next) {

        if (dinfo->type == type &&

            dinfo->bus == bus &&

            dinfo->unit == unit)

            return dinfo;

    }

    return NULL;

}

DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)

{

    return drive_get(type,

                     drive_index_to_bus_id(type, index),

                     drive_index_to_unit_id(type, index));

}

int drive_get_max_bus(BlockInterfaceType type)

{

    int max_bus;

    DriveInfo *dinfo;

    max_bus = -1;

    QTAILQ_FOREACH(dinfo, &drives, next) {

        if(dinfo->type == type &&

           dinfo->bus > max_bus)

            max_bus = dinfo->bus;

    }

    return max_bus;

}

/* Get a block device.  This should only be used for single-drive devices

   (e.g. SD/Floppy/MTD).  Multi-disk devices (scsi/ide) should use the

   appropriate bus.  */

DriveInfo *drive_get_next(BlockInterfaceType type)

{

    static int next_block_unit[IF_COUNT];

    return drive_get(type, 0, next_block_unit[type]++);

}

DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)

{

    DriveInfo *dinfo;

    QTAILQ_FOREACH(dinfo, &drives, next) {

        if (dinfo->bdrv == bs) {

            return dinfo;

        }

    }

    return NULL;

}

static void bdrv_format_print(void *opaque, const char *name)

{

    error_printf(" %s", name);

}

static void drive_uninit(DriveInfo *dinfo)

{

    if (dinfo->opts) {

        qemu_opts_del(dinfo->opts);

    }

    bdrv_unref(dinfo->bdrv);

    g_free(dinfo->id);

    QTAILQ_REMOVE(&drives, dinfo, next);

    g_free(dinfo->serial);

    g_free(dinfo);

}

void drive_put_ref(DriveInfo *dinfo)

{

    assert(dinfo->refcount);

    if (--dinfo->refcount == 0) {

        drive_uninit(dinfo);

    }

}

void drive_get_ref(DriveInfo *dinfo)

{

    dinfo->refcount++;

}

typedef struct {

    QEMUBH *bh;

    BlockDriverState *bs;

} BDRVPutRefBH;

static void bdrv_put_ref_bh(void *opaque)

{

    BDRVPutRefBH *s = opaque;

    bdrv_unref(s->bs);

    qemu_bh_delete(s->bh);

    g_free(s);

}

/*

 * Release a BDS reference in a BH

 *

 * It is not safe to use bdrv_unref() from a callback function when the callers

 * still need the BlockDriverState.  In such cases we schedule a BH to release

 * the reference.

 */

static void bdrv_put_ref_bh_schedule(BlockDriverState *bs)

{

    BDRVPutRefBH *s;

    s = g_new(BDRVPutRefBH, 1);

    s->bh = qemu_bh_new(bdrv_put_ref_bh, s);

    s->bs = bs;

    qemu_bh_schedule(s->bh);

}

static int parse_block_error_action(const char *buf, bool is_read, Error **errp)

{

    if (!strcmp(buf, "ignore")) {

        return BLOCKDEV_ON_ERROR_IGNORE;

    } else if (!is_read && !strcmp(buf, "enospc")) {

        return BLOCKDEV_ON_ERROR_ENOSPC;

    } else if (!strcmp(buf, "stop")) {

        return BLOCKDEV_ON_ERROR_STOP;

    } else if (!strcmp(buf, "report")) {

        return BLOCKDEV_ON_ERROR_REPORT;

    } else {

        error_setg(errp, "'%s' invalid %s error action",

                   buf, is_read ? "read" : "write");

        return -1;

    }

}

static bool check_throttle_config(ThrottleConfig *cfg, Error **errp)

{

    if (throttle_conflicting(cfg)) {

        error_setg(errp, "bps/iops/max total values and read/write values"

                         " cannot be used at the same time");

        return false;

    }

    if (!throttle_is_valid(cfg)) {

        error_setg(errp, "bps/iops/maxs values must be 0 or greater");

        return false;

    }

    return true;

}

typedef enum { MEDIA_DISK, MEDIA_CDROM } DriveMediaType;

/* Takes the ownership of bs_opts */

static DriveInfo *blockdev_init(const char *file, QDict *bs_opts,

                                BlockInterfaceType type,

                                Error **errp)

{

    const char *buf;

    const char *serial;

    int ro = 0;

    int bdrv_flags = 0;

    int on_read_error, on_write_error;

    DriveInfo *dinfo;

    ThrottleConfig cfg;

    int snapshot = 0;

    bool copy_on_read;

    int ret;

    Error *error = NULL;

    QemuOpts *opts;

    const char *id;

    bool has_driver_specific_opts;

    BlockDriver *drv = NULL;

    /* Check common options by copying from bs_opts to opts, all other options

     * stay in bs_opts for processing by bdrv_open(). */

    id = qdict_get_try_str(bs_opts, "id");

    opts = qemu_opts_create(&qemu_common_drive_opts, id, 1, &error);

    if (error_is_set(&error)) {

        error_propagate(errp, error);

        return NULL;

    }

    qemu_opts_absorb_qdict(opts, bs_opts, &error);

    if (error_is_set(&error)) {

        error_propagate(errp, error);

        goto early_err;

    }

    if (id) {

        qdict_del(bs_opts, "id");

    }

    has_driver_specific_opts = !!qdict_size(bs_opts);

    /* extract parameters */

    snapshot = qemu_opt_get_bool(opts, "snapshot", 0);

    ro = qemu_opt_get_bool(opts, "read-only", 0);

    copy_on_read = qemu_opt_get_bool(opts, "copy-on-read", false);

    serial = qemu_opt_get(opts, "serial");

    if ((buf = qemu_opt_get(opts, "discard")) != NULL) {

        if (bdrv_parse_discard_flags(buf, &bdrv_flags) != 0) {

            error_setg(errp, "invalid discard option");

            goto early_err;

        }

    }

    if (qemu_opt_get_bool(opts, "cache.writeback", true)) {

        bdrv_flags |= BDRV_O_CACHE_WB;

    }

    if (qemu_opt_get_bool(opts, "cache.direct", false)) {

        bdrv_flags |= BDRV_O_NOCACHE;

    }

    if (qemu_opt_get_bool(opts, "cache.no-flush", false)) {

        bdrv_flags |= BDRV_O_NO_FLUSH;

    }

#ifdef CONFIG_LINUX_AIO

    if ((buf = qemu_opt_get(opts, "aio")) != NULL) {

        if (!strcmp(buf, "native")) {

            bdrv_flags |= BDRV_O_NATIVE_AIO;

        } else if (!strcmp(buf, "threads")) {

            /* this is the default */

        } else {

           error_setg(errp, "invalid aio option");

           goto early_err;

        }

    }

#endif

    if ((buf = qemu_opt_get(opts, "format")) != NULL) {

        if (is_help_option(buf)) {

            error_printf("Supported formats:");

            bdrv_iterate_format(bdrv_format_print, NULL);

            error_printf("\n");

            goto early_err;

        }

        drv = bdrv_find_format(buf);

        if (!drv) {

            error_setg(errp, "'%s' invalid format", buf);

            goto early_err;

        }

    }

    /* disk I/O throttling */

    memset(&cfg, 0, sizeof(cfg));

    cfg.buckets[THROTTLE_BPS_TOTAL].avg =

        qemu_opt_get_number(opts, "throttling.bps-total", 0);

    cfg.buckets[THROTTLE_BPS_READ].avg  =

        qemu_opt_get_number(opts, "throttling.bps-read", 0);

    cfg.buckets[THROTTLE_BPS_WRITE].avg =

        qemu_opt_get_number(opts, "throttling.bps-write", 0);

    cfg.buckets[THROTTLE_OPS_TOTAL].avg =

        qemu_opt_get_number(opts, "throttling.iops-total", 0);

    cfg.buckets[THROTTLE_OPS_READ].avg =

        qemu_opt_get_number(opts, "throttling.iops-read", 0);

    cfg.buckets[THROTTLE_OPS_WRITE].avg =

        qemu_opt_get_number(opts, "throttling.iops-write", 0);

    cfg.buckets[THROTTLE_BPS_TOTAL].max =

        qemu_opt_get_number(opts, "throttling.bps-total-max", 0);

    cfg.buckets[THROTTLE_BPS_READ].max  =

        qemu_opt_get_number(opts, "throttling.bps-read-max", 0);

    cfg.buckets[THROTTLE_BPS_WRITE].max =

        qemu_opt_get_number(opts, "throttling.bps-write-max", 0);

    cfg.buckets[THROTTLE_OPS_TOTAL].max =

        qemu_opt_get_number(opts, "throttling.iops-total-max", 0);

    cfg.buckets[THROTTLE_OPS_READ].max =

        qemu_opt_get_number(opts, "throttling.iops-read-max", 0);

    cfg.buckets[THROTTLE_OPS_WRITE].max =

        qemu_opt_get_number(opts, "throttling.iops-write-max", 0);

    cfg.op_size = qemu_opt_get_number(opts, "throttling.iops-size", 0);

    if (!check_throttle_config(&cfg, &error)) {

        error_propagate(errp, error);

        goto early_err;

    }

    on_write_error = BLOCKDEV_ON_ERROR_ENOSPC;

    if ((buf = qemu_opt_get(opts, "werror")) != NULL) {

        if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {

            error_setg(errp, "werror is not supported by this bus type");

            goto early_err;

        }

        on_write_error = parse_block_error_action(buf, 0, &error);

        if (error_is_set(&error)) {

            error_propagate(errp, error);

            goto early_err;

        }

    }

    on_read_error = BLOCKDEV_ON_ERROR_REPORT;

    if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {

        if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {

            error_report("rerror is not supported by this bus type");

            goto early_err;

        }

        on_read_error = parse_block_error_action(buf, 1, &error);

        if (error_is_set(&error)) {

            error_propagate(errp, error);

            goto early_err;

        }

    }

    /* init */

    dinfo = g_malloc0(sizeof(*dinfo));

    dinfo->id = g_strdup(qemu_opts_id(opts));

    dinfo->bdrv = bdrv_new(dinfo->id);

    dinfo->bdrv->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0;

    dinfo->bdrv->read_only = ro;

    dinfo->type = type;

    dinfo->refcount = 1;

    if (serial != NULL) {

        dinfo->serial = g_strdup(serial);

    }

    QTAILQ_INSERT_TAIL(&drives, dinfo, next);

    bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);

    /* disk I/O throttling */

    if (throttle_enabled(&cfg)) {

        bdrv_io_limits_enable(dinfo->bdrv);

        bdrv_set_io_limits(dinfo->bdrv, &cfg);

    }

    if (!file || !*file) {

        if (has_driver_specific_opts) {

            file = NULL;

        } else {

            QDECREF(bs_opts);

            qemu_opts_del(opts);

            return dinfo;

        }

    }

    if (snapshot) {

        /* always use cache=unsafe with snapshot */

        bdrv_flags &= ~BDRV_O_CACHE_MASK;

        bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);

    }

    if (copy_on_read) {

        bdrv_flags |= BDRV_O_COPY_ON_READ;

    }

    if (runstate_check(RUN_STATE_INMIGRATE)) {

        bdrv_flags |= BDRV_O_INCOMING;

    }

    bdrv_flags |= ro ? 0 : BDRV_O_RDWR;

    QINCREF(bs_opts);

    ret = bdrv_open(dinfo->bdrv, file, bs_opts, bdrv_flags, drv, &error);

    if (ret < 0) {

        error_setg(errp, "could not open disk image %s: %s",

                   file ?: dinfo->id, error_get_pretty(error));

        error_free(error);

        goto err;

    }

    if (bdrv_key_required(dinfo->bdrv))

        autostart = 0;

    QDECREF(bs_opts);

    qemu_opts_del(opts);

    return dinfo;

err:

    bdrv_unref(dinfo->bdrv);

    g_free(dinfo->id);

    QTAILQ_REMOVE(&drives, dinfo, next);

    g_free(dinfo);

early_err:

    QDECREF(bs_opts);

    qemu_opts_del(opts);

    return NULL;

}

static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to)

{

    const char *value;

    value = qemu_opt_get(opts, from);

    if (value) {

        qemu_opt_set(opts, to, value);

        qemu_opt_unset(opts, from);

    }

}

QemuOptsList qemu_legacy_drive_opts = {

    .name = "drive",

    .head = QTAILQ_HEAD_INITIALIZER(qemu_legacy_drive_opts.head),

    .desc = {

        {

            .name = "bus",

            .type = QEMU_OPT_NUMBER,

            .help = "bus number",

        },{

            .name = "unit",

            .type = QEMU_OPT_NUMBER,

            .help = "unit number (i.e. lun for scsi)",

        },{

            .name = "index",

            .type = QEMU_OPT_NUMBER,

            .help = "index number",

        },{

            .name = "media",

            .type = QEMU_OPT_STRING,

            .help = "media type (disk, cdrom)",

        },{

            .name = "if",

            .type = QEMU_OPT_STRING,

            .help = "interface (ide, scsi, sd, mtd, floppy, pflash, virtio)",

        },{

            .name = "cyls",

            .type = QEMU_OPT_NUMBER,

            .help = "number of cylinders (ide disk geometry)",

        },{

            .name = "heads",

            .type = QEMU_OPT_NUMBER,

            .help = "number of heads (ide disk geometry)",

        },{

            .name = "secs",

            .type = QEMU_OPT_NUMBER,

            .help = "number of sectors (ide disk geometry)",

        },{

            .name = "trans",

            .type = QEMU_OPT_STRING,

            .help = "chs translation (auto, lba, none)",

        },{

            .name = "boot",

            .type = QEMU_OPT_BOOL,

            .help = "(deprecated, ignored)",

        },{

            .name = "addr",

            .type = QEMU_OPT_STRING,

            .help = "pci address (virtio only)",

        },{

            .name = "file",

            .type = QEMU_OPT_STRING,

            .help = "file name",

        },

        /* Options that are passed on, but have special semantics with -drive */

        {

            .name = "read-only",

            .type = QEMU_OPT_BOOL,

            .help = "open drive file as read-only",

        },{

            .name = "copy-on-read",

            .type = QEMU_OPT_BOOL,

            .help = "copy read data from backing file into image file",

        },

        { /* end of list */ }

    },

};

DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)

{

    const char *value;

    DriveInfo *dinfo = NULL;

    QDict *bs_opts;

    QemuOpts *legacy_opts;

    DriveMediaType media = MEDIA_DISK;

    BlockInterfaceType type;

    int cyls, heads, secs, translation;

    int max_devs, bus_id, unit_id, index;

    const char *devaddr;

    bool read_only = false;

    bool copy_on_read;

    const char *filename;

    Error *local_err = NULL;

    /* Change legacy command line options into QMP ones */

    qemu_opt_rename(all_opts, "iops", "throttling.iops-total");

    qemu_opt_rename(all_opts, "iops_rd", "throttling.iops-read");

    qemu_opt_rename(all_opts, "iops_wr", "throttling.iops-write");

    qemu_opt_rename(all_opts, "bps", "throttling.bps-total");

    qemu_opt_rename(all_opts, "bps_rd", "throttling.bps-read");

    qemu_opt_rename(all_opts, "bps_wr", "throttling.bps-write");

    qemu_opt_rename(all_opts, "iops_max", "throttling.iops-total-max");

    qemu_opt_rename(all_opts, "iops_rd_max", "throttling.iops-read-max");

    qemu_opt_rename(all_opts, "iops_wr_max", "throttling.iops-write-max");

    qemu_opt_rename(all_opts, "bps_max", "throttling.bps-total-max");

    qemu_opt_rename(all_opts, "bps_rd_max", "throttling.bps-read-max");

    qemu_opt_rename(all_opts, "bps_wr_max", "throttling.bps-write-max");

    qemu_opt_rename(all_opts,

                    "iops_size", "throttling.iops-size");

    qemu_opt_rename(all_opts, "readonly", "read-only");

    value = qemu_opt_get(all_opts, "cache");

    if (value) {

        int flags = 0;

        if (bdrv_parse_cache_flags(value, &flags) != 0) {

            error_report("invalid cache option");

            return NULL;

        }

        /* Specific options take precedence */

        if (!qemu_opt_get(all_opts, "cache.writeback")) {

            qemu_opt_set_bool(all_opts, "cache.writeback",

                              !!(flags & BDRV_O_CACHE_WB));

        }

        if (!qemu_opt_get(all_opts, "cache.direct")) {

            qemu_opt_set_bool(all_opts, "cache.direct",

                              !!(flags & BDRV_O_NOCACHE));

        }

        if (!qemu_opt_get(all_opts, "cache.no-flush")) {

            qemu_opt_set_bool(all_opts, "cache.no-flush",

                              !!(flags & BDRV_O_NO_FLUSH));

        }

        qemu_opt_unset(all_opts, "cache");

    }

    /* Get a QDict for processing the options */

    bs_opts = qdict_new();

    qemu_opts_to_qdict(all_opts, bs_opts);

    legacy_opts = qemu_opts_create(&qemu_legacy_drive_opts, NULL, 0,

                                   &error_abort);

    qemu_opts_absorb_qdict(legacy_opts, bs_opts, &local_err);

    if (error_is_set(&local_err)) {

        qerror_report_err(local_err);

        error_free(local_err);

        goto fail;

    }

    /* Deprecated option boot=[on|off] */

    if (qemu_opt_get(legacy_opts, "boot") != NULL) {

        fprintf(stderr, "qemu-kvm: boot=on|off is deprecated and will be "

                "ignored. Future versions will reject this parameter. Please "

                "update your scripts.\n");

    }

    /* Media type */

    value = qemu_opt_get(legacy_opts, "media");

    if (value) {

        if (!strcmp(value, "disk")) {

            media = MEDIA_DISK;

        } else if (!strcmp(value, "cdrom")) {

            media = MEDIA_CDROM;

            read_only = true;

        } else {

            error_report("'%s' invalid media", value);

            goto fail;

        }

    }

    /* copy-on-read is disabled with a warning for read-only devices */

    read_only |= qemu_opt_get_bool(legacy_opts, "read-only", false);

    copy_on_read = qemu_opt_get_bool(legacy_opts, "copy-on-read", false);

    if (read_only && copy_on_read) {

        error_report("warning: disabling copy-on-read on read-only drive");

        copy_on_read = false;

    }

    qdict_put(bs_opts, "read-only",

              qstring_from_str(read_only ? "on" : "off"));

    qdict_put(bs_opts, "copy-on-read",

              qstring_from_str(copy_on_read ? "on" :"off"));

    /* Controller type */

    value = qemu_opt_get(legacy_opts, "if");

    if (value) {

        for (type = 0;

             type < IF_COUNT && strcmp(value, if_name[type]);

             type++) {

        }

        if (type == IF_COUNT) {

            error_report("unsupported bus type '%s'", value);

            goto fail;

        }

    } else {

        type = block_default_type;

    }

    /* Geometry */

    cyls  = qemu_opt_get_number(legacy_opts, "cyls", 0);

    heads = qemu_opt_get_number(legacy_opts, "heads", 0);

    secs  = qemu_opt_get_number(legacy_opts, "secs", 0);

    if (cyls || heads || secs) {

        if (cyls < 1) {

            error_report("invalid physical cyls number");

            goto fail;

        }

        if (heads < 1) {

            error_report("invalid physical heads number");

            goto fail;

        }

        if (secs < 1) {

            error_report("invalid physical secs number");

            goto fail;

        }

    }

    translation = BIOS_ATA_TRANSLATION_AUTO;

    value = qemu_opt_get(legacy_opts, "trans");

    if (value != NULL) {

        if (!cyls) {

            error_report("'%s' trans must be used with cyls, heads and secs",

                         value);

            goto fail;

        }

        if (!strcmp(value, "none")) {

            translation = BIOS_ATA_TRANSLATION_NONE;

        } else if (!strcmp(value, "lba")) {

            translation = BIOS_ATA_TRANSLATION_LBA;

        } else if (!strcmp(value, "auto")) {

            translation = BIOS_ATA_TRANSLATION_AUTO;

        } else {

            error_report("'%s' invalid translation type", value);

            goto fail;

        }

    }

    if (media == MEDIA_CDROM) {

        if (cyls || secs || heads) {

            error_report("CHS can't be set with media=cdrom");

            goto fail;

        }

    }

    /* Device address specified by bus/unit or index.

     * If none was specified, try to find the first free one. */

    bus_id  = qemu_opt_get_number(legacy_opts, "bus", 0);

    unit_id = qemu_opt_get_number(legacy_opts, "unit", -1);

    index   = qemu_opt_get_number(legacy_opts, "index", -1);

    max_devs = if_max_devs[type];

    if (index != -1) {

        if (bus_id != 0 || unit_id != -1) {

            error_report("index cannot be used with bus and unit");

            goto fail;

        }

        bus_id = drive_index_to_bus_id(type, index);

        unit_id = drive_index_to_unit_id(type, index);

    }

    if (unit_id == -1) {

       unit_id = 0;

       while (drive_get(type, bus_id, unit_id) != NULL) {

           unit_id++;

           if (max_devs && unit_id >= max_devs) {

               unit_id -= max_devs;

               bus_id++;

           }

       }

    }

    if (max_devs && unit_id >= max_devs) {

        error_report("unit %d too big (max is %d)", unit_id, max_devs - 1);

        goto fail;

    }

    if (drive_get(type, bus_id, unit_id) != NULL) {

        error_report("drive with bus=%d, unit=%d (index=%d) exists",

                     bus_id, unit_id, index);

        goto fail;

    }

    /* no id supplied -> create one */

    if (qemu_opts_id(all_opts) == NULL) {

        char *new_id;

        const char *mediastr = "";

        if (type == IF_IDE || type == IF_SCSI) {

            mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";

        }

        if (max_devs) {

            new_id = g_strdup_printf("%s%i%s%i", if_name[type], bus_id,

                                     mediastr, unit_id);

        } else {

            new_id = g_strdup_printf("%s%s%i", if_name[type],

                                     mediastr, unit_id);

        }

        qdict_put(bs_opts, "id", qstring_from_str(new_id));