[Qemu-devel] [PATCH v7 0/3] DEVICE_DELETED event

[Qemu-devel] [PATCH v7 0/3] 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.

First patch only adds the event with ID, second patch adds a path field.
Split this way for ease of backport (stable downstreams without QOM
would want to only take the first patch).
Event without fields is still useful as management can use it to
poll device list to figure out which device was removed.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Changes from v6:
    - make empty event use data: {}, Markus prefers this

Changes from v5:
    - Emit an empty event on unnamed devices in patch 1/3, as suggested by Markus

Changes from v4:
    - Add extra triggers and extra fields as requested by Markus

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


-- 
Anthony Liguori


Michael S. Tsirkin (2):
  qdev: DEVICE_DELETED event
  qom: pass original path to unparent method

Stefan Hajnoczi (1):
  exec: assert that RAMBlock size is non-zero

 QMP/qmp-events.txt        | 18 ++++++++++++++++++
 exec.c                    |  2 ++
 hw/qdev.c                 | 15 +++++++++++++--
 include/monitor/monitor.h |  1 +
 include/qom/object.h      |  3 ++-
 monitor.c                 |  1 +
 qapi-schema.json          |  4 +++-
 qom/object.c              |  4 +++-
 8 files changed, 43 insertions(+), 5 deletions(-)

-- 
MST

[Qemu-devel] [PATCH v7 2/3] 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>
---
 QMP/qmp-events.txt        | 16 ++++++++++++++++
 hw/qdev.c                 | 10 ++++++++++
 include/monitor/monitor.h |  1 +
 monitor.c                 |  1 +
 qapi-schema.json          |  4 +++-
 5 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
index b2698e4..24cf3e8 100644
--- a/QMP/qmp-events.txt
+++ b/QMP/qmp-events.txt
@@ -136,6 +136,22 @@ 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, optional)
+
+{ "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..741af96 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;
@@ -760,6 +761,7 @@ static void device_unparent(Object *obj)
     DeviceState *dev = DEVICE(obj);
     DeviceClass *dc = DEVICE_GET_CLASS(dev);
     BusState *bus;
+    QObject *event_data;
 
     while (dev->num_child_bus) {
         bus = QLIST_FIRST(&dev->child_bus);
@@ -778,6 +780,14 @@ static void device_unparent(Object *obj)
         object_unref(OBJECT(dev->parent_bus));
         dev->parent_bus = NULL;
     }
+
+    if (dev->id) {
+        event_data = qobject_from_jsonf("{ 'device': %s }", dev->id);
+    } else {
+        event_data = qobject_from_jsonf("{ }");
+    }
+    monitor_protocol_event(QEVENT_DEVICE_DELETED, event_data);
+    qobject_decref(event_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