qemu/device-hotplug.c
Kevin Wolf abb21ac3e6 hmp: 'drive_add -n' for creating a node without BB
This patch adds an option to the drive_add HMP command to create only a
BlockDriverState without a BlockBackend on top.

The motivation for this is that libvirt needs to specify options to a
migration target (specifically, detect-zeroes). drive-mirror doesn't
allow specifying options, and the proper way to do this is to create the
target BDS separately with blockdev-add (where you can specify options)
and then use blockdev-mirror to that BDS.

However, libvirt can't use blockdev-add as long as it is still
experimental, and we're expecting that it will still take some time, so
we need to resort to drive_add.

The problem with drive_add is that so far it always created a BB, and
BDSes with a BB can't be used as a mirroring target as long as we don't
support multiple BBs per BDS - and while we're working towards that
goal, it's another thing that will still take some time.

So to achieve the goal, the simplest solution to provide the
functionality now without adding one-off options to the mirror QMP
commands is to extend drive_add to create nodes without BBs.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-03-14 16:46:43 +01:00

90 lines
2.5 KiB
C

/*
* QEMU device hotplug helpers
*
* Copyright (c) 2004 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 "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/boards.h"
#include "sysemu/block-backend.h"
#include "sysemu/blockdev.h"
#include "qemu/config-file.h"
#include "sysemu/sysemu.h"
#include "monitor/monitor.h"
#include "block/block_int.h"
static DriveInfo *add_init_drive(const char *optstr)
{
DriveInfo *dinfo;
QemuOpts *opts;
MachineClass *mc;
opts = drive_def(optstr);
if (!opts)
return NULL;
mc = MACHINE_GET_CLASS(current_machine);
dinfo = drive_new(opts, mc->block_default_type);
if (!dinfo) {
qemu_opts_del(opts);
return NULL;
}
return dinfo;
}
void hmp_drive_add(Monitor *mon, const QDict *qdict)
{
DriveInfo *dinfo = NULL;
const char *opts = qdict_get_str(qdict, "opts");
bool node = qdict_get_try_bool(qdict, "node", false);
if (node) {
hmp_drive_add_node(mon, opts);
return;
}
dinfo = add_init_drive(opts);
if (!dinfo) {
goto err;
}
if (dinfo->devaddr) {
monitor_printf(mon, "Parameter addr not supported\n");
goto err;
}
switch (dinfo->type) {
case IF_NONE:
monitor_printf(mon, "OK\n");
break;
default:
monitor_printf(mon, "Can't hot-add drive to type %d\n", dinfo->type);
goto err;
}
return;
err:
if (dinfo) {
blk_unref(blk_by_legacy_dinfo(dinfo));
}
}