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Re: [Qemu-devel] [PATCHv2] qdev: DEVICE_DELETED event
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCHv2] qdev: DEVICE_DELETED event |
Date: |
Wed, 06 Mar 2013 17:52:05 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130219 Thunderbird/17.0.3 |
Il 06/03/2013 17:49, Michael S. Tsirkin ha scritto:
> libvirt has a long-standing bug: when removing the device,
> it can request removal but does not know when the
> removal completes. Add an event so we can fix this in a robust way.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>
> Changes from v1:
> - move to device_unparent
> - address comments by Andreas and Eric
>
> Andreas also suggested a more generic object-deleted event,
> I'm not sure how useful that is so let's add what we already need, for
> devices with an id and wait and see what's necessary for non-device
> objects?
>
> QMP/qmp-events.txt | 15 +++++++++++++++
> hw/qdev.c | 7 +++++++
> include/monitor/monitor.h | 1 +
> monitor.c | 1 +
> qapi-schema.json | 4 +++-
> 5 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
> index b2698e4..f2f115a 100644
> --- a/QMP/qmp-events.txt
> +++ b/QMP/qmp-events.txt
> @@ -136,6 +136,21 @@ Example:
> Note: The "ready to complete" status is always reset by a BLOCK_JOB_ERROR
> event.
>
> +DEVICE_DELETED
> +-----------------
> +
> +Emitted whenever the device removal completion is acknowledged
> +by the guest. At this point, it's safe to reuse the specified device ID.
> +Device removal can be initiated by the guest or by HMP/QMP commands.
> +
> +Data:
> +
> +- "device": device name (json-string)
> +
> +{ "event": "DEVICE_DELETED",
> + "data": { "device": "virtio-net-pci-0" },
> + "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
> +
> DEVICE_TRAY_MOVED
> -----------------
>
> diff --git a/hw/qdev.c b/hw/qdev.c
> index 689cd54..d603f4f 100644
> --- a/hw/qdev.c
> +++ b/hw/qdev.c
> @@ -29,6 +29,7 @@
> #include "sysemu/sysemu.h"
> #include "qapi/error.h"
> #include "qapi/visitor.h"
> +#include "qapi/qmp/qjson.h"
>
> int qdev_hotplug = 0;
> static bool qdev_hot_added = false;
> @@ -761,6 +762,12 @@ static void device_unparent(Object *obj)
> DeviceClass *dc = DEVICE_GET_CLASS(dev);
> BusState *bus;
>
> + if (dev->id) {
> + QObject *data = qobject_from_jsonf("{ 'device': %s }", dev->id);
> + monitor_protocol_event(QEVENT_DEVICE_DELETED, data);
> + qobject_decref(data);
> + }
Do this at the end of device_unparent, so that parents are reported
after their children.
Paolo
> while (dev->num_child_bus) {
> bus = QLIST_FIRST(&dev->child_bus);
> qbus_free(bus);
> diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
> index 87fb49c..b868760 100644
> --- a/include/monitor/monitor.h
> +++ b/include/monitor/monitor.h
> @@ -39,6 +39,7 @@ typedef enum MonitorEvent {
> QEVENT_BLOCK_JOB_CANCELLED,
> QEVENT_BLOCK_JOB_ERROR,
> QEVENT_BLOCK_JOB_READY,
> + QEVENT_DEVICE_DELETED,
> QEVENT_DEVICE_TRAY_MOVED,
> QEVENT_SUSPEND,
> QEVENT_SUSPEND_DISK,
> diff --git a/monitor.c b/monitor.c
> index 32a6e74..2a5e7b6 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -457,6 +457,7 @@ static const char *monitor_event_names[] = {
> [QEVENT_BLOCK_JOB_CANCELLED] = "BLOCK_JOB_CANCELLED",
> [QEVENT_BLOCK_JOB_ERROR] = "BLOCK_JOB_ERROR",
> [QEVENT_BLOCK_JOB_READY] = "BLOCK_JOB_READY",
> + [QEVENT_DEVICE_DELETED] = "DEVICE_DELETED",
> [QEVENT_DEVICE_TRAY_MOVED] = "DEVICE_TRAY_MOVED",
> [QEVENT_SUSPEND] = "SUSPEND",
> [QEVENT_SUSPEND_DISK] = "SUSPEND_DISK",
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 28b070f..bb361e1 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -2354,7 +2354,9 @@
> # Notes: When this command completes, the device may not be removed from the
> # guest. Hot removal is an operation that requires guest cooperation.
> # This command merely requests that the guest begin the hot removal
> -# process.
> +# process. Completion of the device removal process is signaled with
> a
> +# DEVICE_DELETED event. Guest reset will automatically complete
> removal
> +# for all devices.
> #
> # Since: 0.14.0
> ##
>