[Qemu-devel] [PATCHv3] qdev: DEVICE_DELETED event

[Qemu-devel] [PATCHv3] qdev: DEVICE_DELETED event

[Michael S. Tsirkin]

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 <mst@redhat.com>
---

Changes from v2:
    - move event toward the end of device_unparent,
      so that parents are reported after their children,
      as suggested by Paolo
Changes from v1:
    - move to device_unparent
    - address comments by Andreas and Eric


 QMP/qmp-events.txt        | 15 +++++++++++++++
 hw/qdev.c                 |  6 ++++++
 include/monitor/monitor.h |  1 +
 monitor.c                 |  1 +
 qapi-schema.json          |  4 +++-
 5 files changed, 26 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..393e83e 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;
@@ -778,6 +779,11 @@ static void device_unparent(Object *obj)
         object_unref(OBJECT(dev->parent_bus));
         dev->parent_bus = NULL;
     }
+    if (dev->id) {
+        QObject *data = qobject_from_jsonf("{ 'device': %s }", dev->id);
+        monitor_protocol_event(QEVENT_DEVICE_DELETED, data);
+        qobject_decref(data);
+    }
 }
 
 static void device_class_init(ObjectClass *class, void *data)
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
 ##
-- 
MST

Re: [Qemu-devel] [PATCHv3] qdev: DEVICE_DELETED event

[Andreas Färber]

Am 07.03.2013 10:49, schrieb Michael S. Tsirkin:
> 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 <mst@redhat.com>
> ---
> 
> Changes from v2:
>     - move event toward the end of device_unparent,
>       so that parents are reported after their children,
>       as suggested by Paolo
> Changes from v1:
>     - move to device_unparent
>     - address comments by Andreas and Eric

Reviewed-by: Andreas Färber <afaerber@suse.de>

Thanks,
Andreas

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg

[Qemu-devel] [PATCHv3] qdev: DEVICE_DELETED event

[Michael S. Tsirkin]

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 <mst@redhat.com>
---

Changes from v3:
    - Document that we only emit events for devices with
      and ID, as suggested by Markus
Changes from v2:
    - move event toward the end of device_unparent,
      so that parents are reported after their children,
      as suggested by Paolo
Changes from v1:
    - move to device_unparent
    - address comments by Andreas and Eric


 QMP/qmp-events.txt        | 17 +++++++++++++++++
 hw/qdev.c                 |  6 ++++++
 include/monitor/monitor.h |  1 +
 monitor.c                 |  1 +
 qapi-schema.json          |  4 +++-
 5 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
index b2698e4..0ab5017 100644
--- a/QMP/qmp-events.txt
+++ b/QMP/qmp-events.txt
@@ -136,6 +136,23 @@ 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. This event is only emitted for devices with
+a user-specified ID.
+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..393e83e 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;
@@ -778,6 +779,11 @@ static void device_unparent(Object *obj)
         object_unref(OBJECT(dev->parent_bus));
         dev->parent_bus = NULL;
     }
+    if (dev->id) {
+        QObject *data = qobject_from_jsonf("{ 'device': %s }", dev->id);
+        monitor_protocol_event(QEVENT_DEVICE_DELETED, data);
+        qobject_decref(data);
+    }
 }
 
 static void device_class_init(ObjectClass *class, void *data)
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
 ##
-- 
MST

Re: [Qemu-devel] [PATCHv3] qdev: DEVICE_DELETED event

[Markus Armbruster]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> 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.

This is *v4*.  I think you should respin to avoid confusing Anthony's
tools.  Recommend to delay the respin until the discussion we're having
in the v1 thread has run its course.

Re: [Qemu-devel] [PATCHv3] qdev: DEVICE_DELETED event

[Anthony Liguori]

Markus Armbruster <armbru@redhat.com> writes:

> "Michael S. Tsirkin" <mst@redhat.com> writes:
>
>> 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.
>
> This is *v4*.  I think you should respin to avoid confusing Anthony's
> tools.

Ack and thanks for pointing this out.  Please put a space before the v3
too.

Regards,

Anthony Liguori

  Recommend to delay the respin until the discussion we're having
> in the v1 thread has run its course.

Re: [Qemu-devel] [PATCHv3] qdev: DEVICE_DELETED event

[Michael S. Tsirkin]

On Thu, Mar 07, 2013 at 11:39:21AM -0600, Anthony Liguori wrote:
> Markus Armbruster <armbru@redhat.com> writes:
> 
> > "Michael S. Tsirkin" <mst@redhat.com> writes:
> >
> >> 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.
> >
> > This is *v4*.  I think you should respin to avoid confusing Anthony's
> > tools.
> 
> Ack and thanks for pointing this out.  Please put a space before the v3
> too.
> 
> Regards,
> 
> Anthony Liguori

Do you need me to respin or can you apply this for now?

>   Recommend to delay the respin until the discussion we're having
> > in the v1 thread has run its course.