When unplugging a device, at one point the device will be destroyed
via object_unparent(). This will, one the one hand, unrealize the
removed device hierarchy, and on the other hand, destroy/free the
device hierarchy.
When chaining hotplug handlers, we want to overwrite a bus hotplug
handler by the machine hotplug handler, to be able to perform
some part of the plug/unplug and to forward the calls to the bus hotplug
handler.
For now, the bus hotplug handler would trigger an object_unparent(), not
allowing us to perform some unplug action on a device after we forwarded
the call to the bus hotplug handler. The device would be gone at that
point.
machine_unplug_handler(dev)
/* eventually do unplug stuff */
bus_unplug_handler(dev)
/* dev is gone, we can't do more unplug stuff */
So move the object_unparent() to the original caller of the unplug. For
now, keep the unrealize() at the original places of the
object_unparent(). For implicitly chained hotplug handlers (e.g. pc
code calling acpi hotplug handlers), the object_unparent() has to be
done by the outermost caller. So when calling hotplug_handler_unplug()
from inside an unplug handler, nothing is to be done.
hotplug_handler_unplug(dev) -> calls machine_unplug_handler()
machine_unplug_handler(dev) {
/* eventually do unplug stuff */
bus_unplug_handler(dev) -> calls unrealize(dev)
/* we can do more unplug stuff but device already unrealized */
}
object_unparent(dev)
In the long run, every unplug action should be factored out of the
unrealize() function into the unplug handler (especially for PCI). Then
we can get rid of the additonal unrealize() calls and object_unparent()
will properly unrealize the device hierarchy after the device has been
unplugged.
hotplug_handler_unplug(dev) -> calls machine_unplug_handler()
machine_unplug_handler(dev) {
/* eventually do unplug stuff */
bus_unplug_handler(dev) -> only unplugs, does not unrealize
/* we can do more unplug stuff */
}
object_unparent(dev) -> will unrealize
The original approach was suggested by Igor Mammedov for the PCI
part, but I extended it to all hotplug handlers. I consider this one
step into the right direction.
To summarize:
- object_unparent() on synchronous unplugs is done by common code
-- "Caller of hotplug_handler_unplug"
- object_unparent() on asynchronous unplugs ("unplug requests") has to
be done manually
-- "Caller of hotplug_handler_unplug"
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190228122849.4296-2-david@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Certain devices types, like memory/CPU, are now being handled using a
hotplug interface provided by a top-level MachineClass. Hotpluggable
host bridges are another such device where it makes sense to use a
machine-level hotplug handler. However, unlike those devices,
host-bridges have a parent bus (the main system bus), and devices with
a parent bus use a different mechanism for registering their hotplug
handlers: qbus_set_hotplug_handler(). This interface currently expects
a handler to be a subclass of DeviceClass, but this is not the case
for MachineClass, which derives directly from ObjectClass.
Internally, the interface only requires an ObjectClass, so expose that
in qbus_set_hotplug_handler().
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <154999589921.690774.3640149277362188566.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This option has been deprecated for two releases; remove it.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Logically, the css bridge should be attached to the machine.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
The default css 0xfe is currently restricted to virtual subchannel
devices. The hope when the decision was made was, that non-virtual
subchannel devices will come around when guest can exploit multiple
channel subsystems. Since the guests generally don't do, the pain
of the partitioned (cssid) namespace outweighs the gain.
Let us remove the corresponding restrictions (virtual devices
can be put only in 0xfe and non-virtual devices in any css except
the 0xfe -- while s390-squash-mcss then remaps everything to cssid 0).
At the same time, change our schema for generating css bus ids to put
both virtual and non-virtual devices into the default css (spilling over
into other css images, if needed). The intention is to deprecate
s390-squash-mcss. With this change devices without a specified devno
won't end up hidden to guests not supporting multiple channel subsystems,
unless this can not be avoided (default css full).
Let us also advertise the changes to the management software (so it can
tell are cssids unrestricted or restricted).
The adverse effect of getting rid of the restriction on migration should
not be too severe. Vfio-ccw devices are not live-migratable yet, and for
virtual devices using the extra freedom would only make sense with the
aforementioned guest support in place.
The auto-generated bus ids are affected by both changes. We hope to not
encounter any auto-generated bus ids in production as Libvirt is always
explicit about the bus id. Since 8ed179c937 ("s390x/css: catch section
mismatch on load", 2017-05-18) the worst that can happen because the same
device ended up having a different bus id is a cleanly failed migration.
I find it hard to reason about the impact of changed auto-generated bus
ids on migration for command line users as I don't know which rules is
such an user supposed to follow.
Another pain-point is down- or upgrade of QEMU for command line users.
The old way and the new way of doing vfio-ccw are mutually incompatible.
Libvirt is only going to support the new way, so for libvirt users, the
possible problems at QEMU downgrade are the following. If a domain
contains virtual devices placed into a css different than 0xfe the domain
will refuse to start with a QEMU not having this patch. Putting devices
into a css different that 0xfe however won't make much sense in the near
future (guest support). Libvirt will refuse to do vfio-ccw with a QEMU
not having this patch. This is business as usual.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-Id: <20171206144438.28908-2-pasic@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Introduce a new 'flags' field to IoAdapter to contain further
characteristics of the adapter, like whether the adapter is subject to
adapter-interruption suppression.
For the kvm case, pass this value in the 'flags' field when
registering an adapter.
Signed-off-by: Fei Li <sherrylf@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
The S390 virtual css support already has a mechanism to create a
virtual subchannel and provide it to the guest. However, to
pass-through subchannels to a guest, we need to introduce a new
mechanism to create the subchannel according to the real device
information. Thus we reconstruct css_create_virtual_sch to a new
css_create_sch function to handle all these cases and do allocation
and initialization of the subchannel according to the device type
and machine configuration.
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-Id: <20170517004813.58227-6-bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
The I/O adapters should exist as soon as the bus/infrastructure
exists, and not only when the guest is actually trying to do something
with them. While the lazy allocation was not wrong, allocating at init
time is cleaner, both for the architecture and the code. Let's adjust
this by having each device type (currently for PCI and virtio-ccw)
register the adapters for each ISC (as now we don't know which ISC the
guest will use) as soon as it initializes.
Use a two-dimensional array io_adapters[type][isc] to store adapters
in ChannelSubSys, so that we can conveniently get the adapter id by
the helper function css_get_adapter_id(type, isc).
Signed-off-by: Fei Li <sherrylf@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
We need to implement the get_dev_path method for the css bus, or
else we might end up with two different devices having the same
qdev_path.
This was noticed when adding two scsi_hd controllers: The SCSIBus
code will produce a non-unique dev_path for vmstate usage if the
parent bus does not provide the get_dev_path method.
We simply use the device's bus id, as this is unique and we won't
have any deeper hierarchy from a channel subsystem perspective
anyway.
Note that we need to disable this for older machine versions,
as this changes the migration format.
Reported-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Tested-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
The previous patch moved virtual css bridge and bus out from
virtio-ccw, but kept the direct reference of virtio-ccw specific
unplug function inside css-bridge.c.
To make the virtual css bus and bridge useful for non-virtio devices,
this introduces a common unplug function pointer "unplug" to call
specific virtio-ccw unplug parts. Thus, the tight coupling to
virtio-ccw can be removed.
This unplug pointer is a member of CCWDeviceClass, which is introduced
as an abstract device layer called "ccw-device". This layer is between
DeviceState and specific devices which are plugged in virtual css bus,
like virtio-ccw device. The specific unplug handlers should be assigned
to "unplug" during initialization.
Signed-off-by: Jing Liu <liujbjl@linux.vnet.ibm.com>
Reviewed-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Currently, common base layers virtual css bridge and bus are
defined in hw/s390x/virtio-ccw.c(h). In order to support
multiple types of devices in the virtual channel subsystem,
especially non virtio-ccw, refactoring work needs to be done.
This work is just a pure code move without any functional change
except dropping an empty function virtual_css_bridge_init() and
virtio_ccw_busdev_unplug() changing. virtio_ccw_busdev_unplug()
is specific to virtio-ccw but gets referenced from the common
virtual css bridge code. To keep the functional changes to a
minimum we export this function from virtio-ccw.c and continue
to reference it inside virtual_css_bridge_class_init()
(now living in hw/s390x/css-bridge.c). A follow-up patch will
clean this up.
Signed-off-by: Jing Liu <liujbjl@linux.vnet.ibm.com>
Reviewed-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
