qemu-e2k/hw/ide/qdev.c
Markus Armbruster b69c3c21a5 qdev: Unrealize must not fail
Devices may have component devices and buses.

Device realization may fail.  Realization is recursive: a device's
realize() method realizes its components, and device_set_realized()
realizes its buses (which should in turn realize the devices on that
bus, except bus_set_realized() doesn't implement that, yet).

When realization of a component or bus fails, we need to roll back:
unrealize everything we realized so far.  If any of these unrealizes
failed, the device would be left in an inconsistent state.  Must not
happen.

device_set_realized() lets it happen: it ignores errors in the roll
back code starting at label child_realize_fail.

Since realization is recursive, unrealization must be recursive, too.
But how could a partly failed unrealize be rolled back?  We'd have to
re-realize, which can fail.  This design is fundamentally broken.

device_set_realized() does not roll back at all.  Instead, it keeps
unrealizing, ignoring further errors.

It can screw up even for a device with no buses: if the lone
dc->unrealize() fails, it still unregisters vmstate, and calls
listeners' unrealize() callback.

bus_set_realized() does not roll back either.  Instead, it stops
unrealizing.

Fortunately, no unrealize method can fail, as we'll see below.

To fix the design error, drop parameter @errp from all the unrealize
methods.

Any unrealize method that uses @errp now needs an update.  This leads
us to unrealize() methods that can fail.  Merely passing it to another
unrealize method cannot cause failure, though.  Here are the ones that
do other things with @errp:

* virtio_serial_device_unrealize()

  Fails when qbus_set_hotplug_handler() fails, but still does all the
  other work.  On failure, the device would stay realized with its
  resources completely gone.  Oops.  Can't happen, because
  qbus_set_hotplug_handler() can't actually fail here.  Pass
  &error_abort to qbus_set_hotplug_handler() instead.

* hw/ppc/spapr_drc.c's unrealize()

  Fails when object_property_del() fails, but all the other work is
  already done.  On failure, the device would stay realized with its
  vmstate registration gone.  Oops.  Can't happen, because
  object_property_del() can't actually fail here.  Pass &error_abort
  to object_property_del() instead.

* spapr_phb_unrealize()

  Fails and bails out when remove_drcs() fails, but other work is
  already done.  On failure, the device would stay realized with some
  of its resources gone.  Oops.  remove_drcs() fails only when
  chassis_from_bus()'s object_property_get_uint() fails, and it can't
  here.  Pass &error_abort to remove_drcs() instead.

Therefore, no unrealize method can fail before this patch.

device_set_realized()'s recursive unrealization via bus uses
object_property_set_bool().  Can't drop @errp there, so pass
&error_abort.

We similarly unrealize with object_property_set_bool() elsewhere,
always ignoring errors.  Pass &error_abort instead.

Several unrealize methods no longer handle errors from other unrealize
methods: virtio_9p_device_unrealize(),
virtio_input_device_unrealize(), scsi_qdev_unrealize(), ...
Much of the deleted error handling looks wrong anyway.

One unrealize methods no longer ignore such errors:
usb_ehci_pci_exit().

Several realize methods no longer ignore errors when rolling back:
v9fs_device_realize_common(), pci_qdev_unrealize(),
spapr_phb_realize(), usb_qdev_realize(), vfio_ccw_realize(),
virtio_device_realize().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-17-armbru@redhat.com>
2020-05-15 07:08:14 +02:00

407 lines
11 KiB
C

/*
* ide bus support for qdev.
*
* Copyright (c) 2009 Gerd Hoffmann <kraxel@redhat.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "sysemu/dma.h"
#include "qapi/error.h"
#include "qapi/qapi-types-block.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "hw/ide/internal.h"
#include "hw/qdev-properties.h"
#include "sysemu/block-backend.h"
#include "sysemu/blockdev.h"
#include "hw/block/block.h"
#include "sysemu/sysemu.h"
#include "sysemu/runstate.h"
#include "qapi/visitor.h"
/* --------------------------------- */
static char *idebus_get_fw_dev_path(DeviceState *dev);
static void idebus_unrealize(BusState *qdev);
static Property ide_props[] = {
DEFINE_PROP_UINT32("unit", IDEDevice, unit, -1),
DEFINE_PROP_END_OF_LIST(),
};
static void ide_bus_class_init(ObjectClass *klass, void *data)
{
BusClass *k = BUS_CLASS(klass);
k->get_fw_dev_path = idebus_get_fw_dev_path;
k->unrealize = idebus_unrealize;
}
static void idebus_unrealize(BusState *bus)
{
IDEBus *ibus = IDE_BUS(bus);
if (ibus->vmstate) {
qemu_del_vm_change_state_handler(ibus->vmstate);
}
}
static const TypeInfo ide_bus_info = {
.name = TYPE_IDE_BUS,
.parent = TYPE_BUS,
.instance_size = sizeof(IDEBus),
.class_init = ide_bus_class_init,
};
void ide_bus_new(IDEBus *idebus, size_t idebus_size, DeviceState *dev,
int bus_id, int max_units)
{
qbus_create_inplace(idebus, idebus_size, TYPE_IDE_BUS, dev, NULL);
idebus->bus_id = bus_id;
idebus->max_units = max_units;
}
static char *idebus_get_fw_dev_path(DeviceState *dev)
{
char path[30];
snprintf(path, sizeof(path), "%s@%x", qdev_fw_name(dev),
((IDEBus*)dev->parent_bus)->bus_id);
return g_strdup(path);
}
static void ide_qdev_realize(DeviceState *qdev, Error **errp)
{
IDEDevice *dev = IDE_DEVICE(qdev);
IDEDeviceClass *dc = IDE_DEVICE_GET_CLASS(dev);
IDEBus *bus = DO_UPCAST(IDEBus, qbus, qdev->parent_bus);
if (dev->unit == -1) {
dev->unit = bus->master ? 1 : 0;
}
if (dev->unit >= bus->max_units) {
error_setg(errp, "Can't create IDE unit %d, bus supports only %d units",
dev->unit, bus->max_units);
return;
}
switch (dev->unit) {
case 0:
if (bus->master) {
error_setg(errp, "IDE unit %d is in use", dev->unit);
return;
}
bus->master = dev;
break;
case 1:
if (bus->slave) {
error_setg(errp, "IDE unit %d is in use", dev->unit);
return;
}
bus->slave = dev;
break;
default:
error_setg(errp, "Invalid IDE unit %d", dev->unit);
return;
}
dc->realize(dev, errp);
}
IDEDevice *ide_create_drive(IDEBus *bus, int unit, DriveInfo *drive)
{
DeviceState *dev;
dev = qdev_create(&bus->qbus, drive->media_cd ? "ide-cd" : "ide-hd");
qdev_prop_set_uint32(dev, "unit", unit);
qdev_prop_set_drive(dev, "drive", blk_by_legacy_dinfo(drive),
&error_fatal);
qdev_init_nofail(dev);
return DO_UPCAST(IDEDevice, qdev, dev);
}
int ide_get_geometry(BusState *bus, int unit,
int16_t *cyls, int8_t *heads, int8_t *secs)
{
IDEState *s = &DO_UPCAST(IDEBus, qbus, bus)->ifs[unit];
if (s->drive_kind != IDE_HD || !s->blk) {
return -1;
}
*cyls = s->cylinders;
*heads = s->heads;
*secs = s->sectors;
return 0;
}
int ide_get_bios_chs_trans(BusState *bus, int unit)
{
return DO_UPCAST(IDEBus, qbus, bus)->ifs[unit].chs_trans;
}
/* --------------------------------- */
typedef struct IDEDrive {
IDEDevice dev;
} IDEDrive;
static void ide_dev_initfn(IDEDevice *dev, IDEDriveKind kind, Error **errp)
{
IDEBus *bus = DO_UPCAST(IDEBus, qbus, dev->qdev.parent_bus);
IDEState *s = bus->ifs + dev->unit;
int ret;
if (!dev->conf.blk) {
if (kind != IDE_CD) {
error_setg(errp, "No drive specified");
return;
} else {
/* Anonymous BlockBackend for an empty drive */
dev->conf.blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
ret = blk_attach_dev(dev->conf.blk, &dev->qdev);
assert(ret == 0);
}
}
if (dev->conf.discard_granularity == -1) {
dev->conf.discard_granularity = 512;
} else if (dev->conf.discard_granularity &&
dev->conf.discard_granularity != 512) {
error_setg(errp, "discard_granularity must be 512 for ide");
return;
}
blkconf_blocksizes(&dev->conf);
if (dev->conf.logical_block_size != 512) {
error_setg(errp, "logical_block_size must be 512 for IDE");
return;
}
if (kind != IDE_CD) {
if (!blkconf_geometry(&dev->conf, &dev->chs_trans, 65535, 16, 255,
errp)) {
return;
}
}
if (!blkconf_apply_backend_options(&dev->conf, kind == IDE_CD,
kind != IDE_CD, errp)) {
return;
}
if (ide_init_drive(s, dev->conf.blk, kind,
dev->version, dev->serial, dev->model, dev->wwn,
dev->conf.cyls, dev->conf.heads, dev->conf.secs,
dev->chs_trans, errp) < 0) {
return;
}
if (!dev->version) {
dev->version = g_strdup(s->version);
}
if (!dev->serial) {
dev->serial = g_strdup(s->drive_serial_str);
}
add_boot_device_path(dev->conf.bootindex, &dev->qdev,
dev->unit ? "/disk@1" : "/disk@0");
add_boot_device_lchs(&dev->qdev, dev->unit ? "/disk@1" : "/disk@0",
dev->conf.lcyls,
dev->conf.lheads,
dev->conf.lsecs);
}
static void ide_dev_get_bootindex(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
IDEDevice *d = IDE_DEVICE(obj);
visit_type_int32(v, name, &d->conf.bootindex, errp);
}
static void ide_dev_set_bootindex(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
IDEDevice *d = IDE_DEVICE(obj);
int32_t boot_index;
Error *local_err = NULL;
visit_type_int32(v, name, &boot_index, &local_err);
if (local_err) {
goto out;
}
/* check whether bootindex is present in fw_boot_order list */
check_boot_index(boot_index, &local_err);
if (local_err) {
goto out;
}
/* change bootindex to a new one */
d->conf.bootindex = boot_index;
if (d->unit != -1) {
add_boot_device_path(d->conf.bootindex, &d->qdev,
d->unit ? "/disk@1" : "/disk@0");
}
out:
error_propagate(errp, local_err);
}
static void ide_dev_instance_init(Object *obj)
{
object_property_add(obj, "bootindex", "int32",
ide_dev_get_bootindex,
ide_dev_set_bootindex, NULL, NULL);
object_property_set_int(obj, -1, "bootindex", NULL);
}
static void ide_hd_realize(IDEDevice *dev, Error **errp)
{
ide_dev_initfn(dev, IDE_HD, errp);
}
static void ide_cd_realize(IDEDevice *dev, Error **errp)
{
ide_dev_initfn(dev, IDE_CD, errp);
}
static void ide_drive_realize(IDEDevice *dev, Error **errp)
{
DriveInfo *dinfo = NULL;
warn_report("'ide-drive' is deprecated, "
"please use 'ide-hd' or 'ide-cd' instead");
if (dev->conf.blk) {
dinfo = blk_legacy_dinfo(dev->conf.blk);
}
ide_dev_initfn(dev, dinfo && dinfo->media_cd ? IDE_CD : IDE_HD, errp);
}
#define DEFINE_IDE_DEV_PROPERTIES() \
DEFINE_BLOCK_PROPERTIES(IDEDrive, dev.conf), \
DEFINE_BLOCK_ERROR_PROPERTIES(IDEDrive, dev.conf), \
DEFINE_PROP_STRING("ver", IDEDrive, dev.version), \
DEFINE_PROP_UINT64("wwn", IDEDrive, dev.wwn, 0), \
DEFINE_PROP_STRING("serial", IDEDrive, dev.serial),\
DEFINE_PROP_STRING("model", IDEDrive, dev.model)
static Property ide_hd_properties[] = {
DEFINE_IDE_DEV_PROPERTIES(),
DEFINE_BLOCK_CHS_PROPERTIES(IDEDrive, dev.conf),
DEFINE_PROP_BIOS_CHS_TRANS("bios-chs-trans",
IDEDrive, dev.chs_trans, BIOS_ATA_TRANSLATION_AUTO),
DEFINE_PROP_UINT16("rotation_rate", IDEDrive, dev.rotation_rate, 0),
DEFINE_PROP_END_OF_LIST(),
};
static void ide_hd_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
IDEDeviceClass *k = IDE_DEVICE_CLASS(klass);
k->realize = ide_hd_realize;
dc->fw_name = "drive";
dc->desc = "virtual IDE disk";
device_class_set_props(dc, ide_hd_properties);
}
static const TypeInfo ide_hd_info = {
.name = "ide-hd",
.parent = TYPE_IDE_DEVICE,
.instance_size = sizeof(IDEDrive),
.class_init = ide_hd_class_init,
};
static Property ide_cd_properties[] = {
DEFINE_IDE_DEV_PROPERTIES(),
DEFINE_PROP_END_OF_LIST(),
};
static void ide_cd_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
IDEDeviceClass *k = IDE_DEVICE_CLASS(klass);
k->realize = ide_cd_realize;
dc->fw_name = "drive";
dc->desc = "virtual IDE CD-ROM";
device_class_set_props(dc, ide_cd_properties);
}
static const TypeInfo ide_cd_info = {
.name = "ide-cd",
.parent = TYPE_IDE_DEVICE,
.instance_size = sizeof(IDEDrive),
.class_init = ide_cd_class_init,
};
static Property ide_drive_properties[] = {
DEFINE_IDE_DEV_PROPERTIES(),
DEFINE_PROP_END_OF_LIST(),
};
static void ide_drive_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
IDEDeviceClass *k = IDE_DEVICE_CLASS(klass);
k->realize = ide_drive_realize;
dc->fw_name = "drive";
dc->desc = "virtual IDE disk or CD-ROM (legacy)";
device_class_set_props(dc, ide_drive_properties);
}
static const TypeInfo ide_drive_info = {
.name = "ide-drive",
.parent = TYPE_IDE_DEVICE,
.instance_size = sizeof(IDEDrive),
.class_init = ide_drive_class_init,
};
static void ide_device_class_init(ObjectClass *klass, void *data)
{
DeviceClass *k = DEVICE_CLASS(klass);
k->realize = ide_qdev_realize;
set_bit(DEVICE_CATEGORY_STORAGE, k->categories);
k->bus_type = TYPE_IDE_BUS;
device_class_set_props(k, ide_props);
}
static const TypeInfo ide_device_type_info = {
.name = TYPE_IDE_DEVICE,
.parent = TYPE_DEVICE,
.instance_size = sizeof(IDEDevice),
.abstract = true,
.class_size = sizeof(IDEDeviceClass),
.class_init = ide_device_class_init,
.instance_init = ide_dev_instance_init,
};
static void ide_register_types(void)
{
type_register_static(&ide_bus_info);
type_register_static(&ide_hd_info);
type_register_static(&ide_cd_info);
type_register_static(&ide_drive_info);
type_register_static(&ide_device_type_info);
}
type_init(ide_register_types)