ceefa0b746
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>
100 lines
3.0 KiB
C
100 lines
3.0 KiB
C
/*
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* Hotplug handler interface.
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*
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* Copyright (c) 2014 Red Hat Inc.
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*
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* Authors:
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* Igor Mammedov <imammedo@redhat.com>,
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#ifndef HOTPLUG_H
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#define HOTPLUG_H
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#include "qom/object.h"
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#define TYPE_HOTPLUG_HANDLER "hotplug-handler"
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typedef struct HotplugHandlerClass HotplugHandlerClass;
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DECLARE_CLASS_CHECKERS(HotplugHandlerClass, HOTPLUG_HANDLER,
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TYPE_HOTPLUG_HANDLER)
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#define HOTPLUG_HANDLER(obj) \
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INTERFACE_CHECK(HotplugHandler, (obj), TYPE_HOTPLUG_HANDLER)
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typedef struct HotplugHandler HotplugHandler;
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/**
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* hotplug_fn:
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* @plug_handler: a device performing plug/uplug action
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* @plugged_dev: a device that has been (un)plugged
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* @errp: returns an error if this function fails
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*/
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typedef void (*hotplug_fn)(HotplugHandler *plug_handler,
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DeviceState *plugged_dev, Error **errp);
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/**
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* HotplugDeviceClass:
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*
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* Interface to be implemented by a device performing
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* hardware (un)plug functions.
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*
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* @parent: Opaque parent interface.
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* @pre_plug: pre plug callback called at start of device.realize(true)
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* @plug: plug callback called at end of device.realize(true).
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* @unplug_request: unplug request callback.
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* Used as a means to initiate device unplug for devices that
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* require asynchronous unplug handling.
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* @unplug: unplug callback.
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* Used for device removal with devices that implement
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* asynchronous and synchronous (surprise) removal.
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* @is_hotpluggable_bus: called to check if bus/its parent allow hotplug on bus
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*/
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struct HotplugHandlerClass {
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/* <private> */
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InterfaceClass parent;
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/* <public> */
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hotplug_fn pre_plug;
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hotplug_fn plug;
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hotplug_fn unplug_request;
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hotplug_fn unplug;
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bool (*is_hotpluggable_bus)(HotplugHandler *plug_handler, BusState *bus);
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};
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/**
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* hotplug_handler_plug:
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*
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* Call #HotplugHandlerClass.plug callback of @plug_handler.
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*/
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void hotplug_handler_plug(HotplugHandler *plug_handler,
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DeviceState *plugged_dev,
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Error **errp);
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/**
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* hotplug_handler_pre_plug:
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*
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* Call #HotplugHandlerClass.pre_plug callback of @plug_handler.
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*/
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void hotplug_handler_pre_plug(HotplugHandler *plug_handler,
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DeviceState *plugged_dev,
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Error **errp);
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/**
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* hotplug_handler_unplug_request:
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*
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* Calls #HotplugHandlerClass.unplug_request callback of @plug_handler.
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*/
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void hotplug_handler_unplug_request(HotplugHandler *plug_handler,
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DeviceState *plugged_dev,
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Error **errp);
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/**
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* hotplug_handler_unplug:
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*
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* Calls #HotplugHandlerClass.unplug callback of @plug_handler.
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*/
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void hotplug_handler_unplug(HotplugHandler *plug_handler,
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DeviceState *plugged_dev,
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Error **errp);
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#endif
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