These are useful functions for when you want proper inheritance of
functionality across realize/unrealize calls.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230710153522.3469097-3-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
I'm still not sure how I achieve by use case of the parent class
defining the following properties:
static Property vud_properties[] = {
DEFINE_PROP_CHR("chardev", VHostUserDevice, chardev),
DEFINE_PROP_UINT16("id", VHostUserDevice, id, 0),
DEFINE_PROP_UINT32("num_vqs", VHostUserDevice, num_vqs, 1),
DEFINE_PROP_END_OF_LIST(),
};
But for the specialisation of the class I want the id to default to
the actual device id, e.g.:
static Property vu_rng_properties[] = {
DEFINE_PROP_UINT16("id", VHostUserDevice, id, VIRTIO_ID_RNG),
DEFINE_PROP_UINT32("num_vqs", VHostUserDevice, num_vqs, 1),
DEFINE_PROP_END_OF_LIST(),
};
And so far the API for doing that isn't super clear.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230710153522.3469097-2-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fix up the kerneldoc markup and start documenting the various fields
in QDEV related structures. This involved:
- moving overall description to a DOC: comment at top
- fixing various markup issues for types and structures
- adding missing Return: statements
- adding some typedefs to hide QLIST macros in headers
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230630180423.558337-25-alex.bennee@linaro.org>
Add a helper function to check whether the device is realized without
requiring the Big QEMU Lock. The next patch adds a second caller. The
goal is to avoid spreading DeviceState field accesses throughout the
code.
Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-3-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Currently the property may flip its state
during VM bring up or just doesn't work as
the name implies.
In particular with PCIE root port that has
'hotplug={on|off}' property, and when it's
turned off, one would expect
'hotpluggable' == false
for any devices attached to it.
Which is not the case since qbus_is_hotpluggable()
used by the property just checks for presence
of any hotplug_handler set on bus.
The problem is that name BusState::hotplug_handler
from its inception is misnomer, as it handles
not only hotplug but also in many cases coldplug
as well (i.e. generic wiring interface), and
it's fine to have hotplug_handler set on bus
while it doesn't support hotplug (ex. pcie-slot
with hotplug=off).
Another case of root port flipping 'hotpluggable'
state when ACPI PCI hotplug is enabled in this
case root port with 'hotplug=off' starts as
hotpluggable and then later on, pcihp
hotplug_handler clears hotplug_handler
explicitly after checking root port's 'hotplug'
property.
So root-port hotpluggablity check sort of works
if pcihp is enabled but is broken if pcihp is
disabled.
One way to deal with the issue is to ask
hotplug_handler if bus it controls is hotpluggable
or not. To do that add is_hotpluggable_bus()
hook to HotplugHandler interface and use it in
'hotpluggable' property + teach pcie-slot to
actually look into 'hotplug' property state
before deciding if bus is hotpluggable.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20230302161543.286002-13-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The structure is accessed read-only by qdev_get_parent_bus().
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230212224730.51438-2-philmd@linaro.org>
The device_legacy_reset() function is now not used anywhere, so we
can remove the implementation.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Remove the qdev_reset_all() and qbus_reset_all() functions, now we
have moved all the callers over to the new device_cold_reset() and
bus_cold_reset() functions.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220707163720.1421716-5-berrange@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Add blocker to prevent hot-unplug of devices
TYPE_VFIO_USER_SERVER, which is introduced shortly, attaches itself to a
PCIDevice on which it depends. If the attached PCIDevice gets removed
while the server in use, it could cause it crash. To prevent this,
TYPE_VFIO_USER_SERVER adds an unplug blocker for the PCIDevice.
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: c41ef80b7cc063314d629737bed2159e5713f2e0.1655151679.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Fix a comment in qdev-core.h where we incorrectly referred
to TYPE_IRQ_SPLIT when we meant TYPE_SPLIT_IRQ.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20220111172655.3546766-1-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
@pin is an input where we connect a device output.
Rename it @input_pin to simplify the documentation.
Reviewed-by: Yanan Wang <wangyanan55@huawei.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20211218130437.1516929-5-f4bug@amsat.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
qdev_connect_gpio_out_named() is described as qdev_connect_gpio_out(),
and referring to itself in an endless loop, which is confusing. Fix.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Yanan Wang <wangyanan55@huawei.com>
Message-Id: <20211218130437.1516929-4-f4bug@amsat.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
qdev_init_gpio_out_named() is described as qdev_init_gpio_out(),
and referring to itself in an endless loop, which is confusing. Fix.
Reported-by: Yanan Wang <wangyanan55@huawei.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Yanan Wang <wangyanan55@huawei.com>
Message-Id: <20211218130437.1516929-3-f4bug@amsat.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Add empty lines to have a clearer distinction between different
functions declarations.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Yanan Wang <wangyanan55@huawei.com>
Message-Id: <20211218130437.1516929-2-f4bug@amsat.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Add an expire time for pending delete, once the time is over allow
pressing the attention button again.
This makes pcie hotplug behave more like acpi hotplug, where one can
try sending an 'device_del' monitor command again in case the guest
didn't respond to the first attempt.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20211111130859.1171890-7-kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
QDicts are both what QMP natively uses and what the keyval parser
produces. Going through QemuOpts isn't useful for either one, so switch
the main device creation function to QDicts. By sharing more code with
the -object/object-add code path, we can even reduce the code size a
bit.
This commit doesn't remove the detour through QemuOpts from any code
path yet, but it allows the following commits to do so.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20211008133442.141332-15-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
hide_device() is used for virtio-net failover, where the standby virtio
device delays creation of the primary device. It only makes sense to
have a single primary device for each standby device. Adding a second
one should result in an error instead of hiding it and never using it
afterwards.
Prepare for this by adding an Error parameter to the hide_device()
callback where virtio-net is informed about adding a primary device.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20211008133442.141332-12-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
DeviceState.id is a pointer to a string that is stored in the QemuOpts
object DeviceState.opts and freed together with it. We want to create
devices without going through QemuOpts in the future, so make this a
separately allocated string.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211008133442.141332-9-kwolf@redhat.com>
Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Rename the "allocate and return" qbus creation function to
qbus_new(), to bring it into line with our _init vs _new convention.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Corey Minyard <cminyard@mvista.com>
Message-id: 20210923121153.23754-6-peter.maydell@linaro.org
Rename qbus_create_inplace() to qbus_init(); this is more in line
with our usual naming convention for functions that in-place
initialize objects.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 20210923121153.23754-5-peter.maydell@linaro.org
qdev_init_gpio_out() states it "creates an array of anonymous
output GPIO lines" but doesn't document how this array is
released. Add a note that it is automatically free'd in qdev
instance_finalize().
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20210819142731.2827912-1-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
By default, QEMU will allow devices to be plugged into a bus up to
the bus class's device count limit. If the user creates a device on
the command line or via the monitor and doesn't explicitly specify
the bus to plug it in, QEMU will plug it into the first non-full bus
that it finds.
This is fine in most cases, but some machines have multiple buses of
a given type, some of which are dedicated to on-board devices and
some of which have an externally exposed connector for user-pluggable
devices. One example is I2C buses.
Provide a new function qbus_mark_full() so that a machine model can
mark this kind of "internal only" bus as 'full' after it has created
all the devices that should be plugged into that bus. The "find a
non-full bus" algorithm will then skip the internal-only bus when
looking for a place to plug in user-created devices.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210903151435.22379-2-peter.maydell@linaro.org
Generalize the qdev_hotplug variable to the different phases of
machine initialization. We would like to allow different
monitor commands depending on the phase.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qdev_machine_creation_done is only setting a flag now. Extend it to
move more code out of vl.c. Leave only consistency checks and gdbserver
processing in qemu_machine_creation_done.
gdbserver_start can be moved after qdev_machine_creation_done because
it only does listen on the socket and creates some internal data
structures; it does not send any data (e.g. guest state) over the socket.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move everything related to Property and PropertyInfo to
qdev-properties.[ch] to make it easier to refactor that code.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20201211220529.2290218-4-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Some very simple initialization routines can be nested in existing
subsystem-level functions, do that to simplify qemu_init.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
You should not use pasive.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20201118083748.1328-17-quintela@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
We didn't use at all the -1 value, and we don't really care. It was
only used for the cases when this is not the device that we are
searching for. And in that case we should not hide the device.
Once there, simplify virtio-Snet_primary_should_be_hidden.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20201118083748.1328-16-quintela@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Some devices expose GPIO lines.
Add a GPIO qdev input to our LED device, so we can
connect a GPIO output using qdev_connect_gpio_out().
When used with GPIOs, the intensity can only be either
minium or maximum. This depends of the polarity of the
GPIO (which can be inverted).
Declare the GpioPolarity type to model the polarity.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Message-Id: <20200912134041.946260-3-f4bug@amsat.org>
Some code might race with placement of new devices on a bus.
We currently first place a (unrealized) device on the bus
and then realize it.
As a workaround, users that scan the child device list, can
check the realized property to see if it is safe to access such a device.
Use an atomic write here too to aid with this.
A separate discussion is what to do with devices that are unrealized:
It looks like for this case we only call the hotplug handler's unplug
callback and its up to it to unrealize the device.
An atomic operation doesn't cause harm for this code path though.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200913160259.32145-6-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20201006123904.610658-10-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This fixes the race between device emulation code that tries to find
a child device to dispatch the request to (e.g a scsi disk),
and hotplug of a new device to that bus.
Note that this doesn't convert all the readers of the list
but only these that might go over that list without BQL held.
This is a very small first step to make this code thread safe.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200913160259.32145-5-mlevitsk@redhat.com>
[Use RCU_READ_LOCK_GUARD in more places, adjust testcase now that
the delay in DEVICE_DELETED due to RCU is more consistent. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20201006123904.610658-9-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Check if an address is free on the bus before plugging in the
device. This makes it possible to do the check without any
side effects, and to detect the problem early without having
to do it in the realize callback.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20201006123904.610658-5-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some typedefs and macros are defined after the type check macros.
This makes it difficult to automatically replace their
definitions with OBJECT_DECLARE_TYPE.
Patch generated using:
$ ./scripts/codeconverter/converter.py -i \
--pattern=QOMStructTypedefSplit $(git grep -l '' -- '*.[ch]')
which will split "typdef struct { ... } TypedefName"
declarations.
Followed by:
$ ./scripts/codeconverter/converter.py -i --pattern=MoveSymbols \
$(git grep -l '' -- '*.[ch]')
which will:
- move the typedefs and #defines above the type check macros
- add missing #include "qom/object.h" lines if necessary
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20200831210740.126168-9-ehabkost@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20200831210740.126168-10-ehabkost@redhat.com>
Message-Id: <20200831210740.126168-11-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Add documentation comments for the various qdev functions
related to creating and connecting GPIO lines.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200711142425.16283-4-peter.maydell@linaro.org
Add a doc comment for qdev_unrealize(), to go with the new
documentation for the realize part of the qdev lifecycle.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200711142425.16283-3-peter.maydell@linaro.org
The doc-comments which document the qdev API are split between the
header file and the C source files, because as a project we haven't
been consistent about where we put them.
Move all the doc-comments in qdev.c to the header files, so that
users of the APIs don't have to look at the implementation files for
this information.
In the process, unify them into our doc-comment format and expand on
them in some cases to clarify expected use cases.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200711142425.16283-2-peter.maydell@linaro.org
qbus_set_hotplug_handler() is a simple wrapper around
object_property_set_link().
object_property_set_link() fails when the property doesn't exist, is
not settable, or its .check() method fails. These are all programming
errors here, so passing &error_abort to qbus_set_hotplug_handler() is
appropriate.
Most of its callers do. Exceptions:
* pcie_cap_slot_init(), shpc_init(), spapr_phb_realize() pass NULL,
i.e. they ignore errors.
* spapr_machine_init() passes &error_fatal.
* s390_pcihost_realize(), virtio_serial_device_realize(),
s390_pcihost_plug() pass the error to their callers. The latter two
keep going after the error, which looks wrong.
Drop the @errp parameter, and instead pass &error_abort to
object_property_set_link().
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200630090351.1247703-15-armbru@redhat.com>
All callers pass &error_abort. Drop the parameter.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200630090351.1247703-14-armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200610053247.1583243-58-armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200610053247.1583243-31-armbru@redhat.com>
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: <20200610053247.1583243-9-armbru@redhat.com>
We commonly plug devices into their bus right when we create them,
like this:
dev = qdev_create(bus, type_name);
Note that @dev is a weak reference. The reference from @bus to @dev
is the only strong one.
We realize at some later time, either with
object_property_set_bool(OBJECT(dev), true, "realized", errp);
or its convenience wrapper
qdev_init_nofail(dev);
If @dev still has no QOM parent then, realizing makes the
/machine/unattached/ orphanage its QOM parent.
Note that the device returned by qdev_create() is plugged into a bus,
but doesn't have a QOM parent, yet. Until it acquires one,
unrealizing the bus will hang in bus_unparent():
while ((kid = QTAILQ_FIRST(&bus->children)) != NULL) {
DeviceState *dev = kid->child;
object_unparent(OBJECT(dev));
}
object_unparent() does nothing when its argument has no QOM parent,
and the loop spins forever.
Device state "no QOM parent, but plugged into bus" is dangerous.
Paolo suggested to delay plugging into the bus until realize. We need
to plug into the parent bus before we call the device's realize
method, in case it uses the parent bus. So the dangerous state still
exists, but only within realization, where we can manage it safely.
This commit creates infrastructure to do this:
dev = qdev_new(type_name);
...
qdev_realize_and_unref(dev, bus, errp)
Note that @dev becomes a strong reference here.
qdev_realize_and_unref() drops it. There is also plain
qdev_realize(), which doesn't drop it.
The remainder of this series will convert all users to this new
interface.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: Alistair Francis <alistair@alistair23.me>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200610053247.1583243-5-armbru@redhat.com>
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>
