[PATCH v4 1/3] qapi/qdev.json: add DEVICE_UNPLUG_ERROR QAPI event

[Daniel Henrique Barboza <danielhb413@gmail.com>]

At this moment we only provide one event to report a hotunplug error,
MEM_UNPLUG_ERROR. As of Linux kernel 5.12 and QEMU 6.0.0, the pseries
machine is now able to report unplug errors for other device types, such
as CPUs.

Instead of creating a (device_type)_UNPLUG_ERROR for each new device,
create a generic DEVICE_UNPLUG_ERROR event that can be used by all
unplug errors in the future.

With this new generic event, MEM_UNPLUG_ERROR is now marked as deprecated.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 docs/system/deprecated.rst | 10 ++++++++++
 qapi/machine.json          |  6 +++++-
 qapi/qdev.json             | 27 ++++++++++++++++++++++++++-
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
index 70e08baff6..ca6c7f9d43 100644
--- a/docs/system/deprecated.rst
+++ b/docs/system/deprecated.rst
@@ -204,6 +204,16 @@ The ``I7200`` guest CPU relies on the nanoMIPS ISA, which is deprecated
 (the ISA has never been upstreamed to a compiler toolchain). Therefore
 this CPU is also deprecated.
 
+
+QEMU API (QAPI) events
+----------------------
+
+``MEM_UNPLUG_ERROR`` (since 6.1)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Use the more generic event ``DEVICE_UNPLUG_ERROR`` instead.
+
+
 System emulator machines
 ------------------------
 
diff --git a/qapi/machine.json b/qapi/machine.json
index c3210ee1fb..a595c753d2 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -1271,6 +1271,9 @@
 #
 # @msg: Informative message
 #
+# Features:
+# @deprecated: This event is deprecated. Use @DEVICE_UNPLUG_ERROR instead.
+#
 # Since: 2.4
 #
 # Example:
@@ -1283,7 +1286,8 @@
 #
 ##
 { 'event': 'MEM_UNPLUG_ERROR',
-  'data': { 'device': 'str', 'msg': 'str' } }
+  'data': { 'device': 'str', 'msg': 'str' },
+  'features': ['deprecated'] }
 
 ##
 # @SMPConfiguration:
diff --git a/qapi/qdev.json b/qapi/qdev.json
index b83178220b..349d7439fa 100644
--- a/qapi/qdev.json
+++ b/qapi/qdev.json
@@ -84,7 +84,9 @@
 #        This command merely requests that the guest begin the hot removal
 #        process.  Completion of the device removal process is signaled with a
 #        DEVICE_DELETED event. Guest reset will automatically complete removal
-#        for all devices.
+#        for all devices. If an error in the hot removal process is detected,
+#        the device will not be removed and a DEVICE_UNPLUG_ERROR event is
+#        sent.
 #
 # Since: 0.14
 #
@@ -124,3 +126,26 @@
 ##
 { 'event': 'DEVICE_DELETED',
   'data': { '*device': 'str', 'path': 'str' } }
+
+##
+# @DEVICE_UNPLUG_ERROR:
+#
+# Emitted when a device hot unplug error occurs.
+#
+# @device: device name
+#
+# @msg: Informative message
+#
+# Since: 6.1
+#
+# Example:
+#
+# <- { "event": "DEVICE_UNPLUG_ERROR"
+#      "data": { "device": "dimm1",
+#                "msg": "Memory hotunplug rejected by the guest for device dimm1"
+#      },
+#      "timestamp": { "seconds": 1615570772, "microseconds": 202844 } }
+#
+##
+{ 'event': 'DEVICE_UNPLUG_ERROR',
+  'data': { 'device': 'str', 'msg': 'str' } }
-- 
2.31.1