[PATCH v4 05/10] qapi: make the vcpu parameters deprecated for 8.1

[Alex Bennée]

I don't think I can remove the parameters directly but certainly mark
them as deprecated.

Message-Id: <20230420150009.1675181-6-alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230503091756.1453057-6-alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230505155336.137393-6-alex.bennee@linaro.org>

---
v4
  - used @deprecated in json
  - added note to deprecated.rst
---
 docs/about/deprecated.rst |  9 +++++++++
 qapi/trace.json           | 38 ++++++++++++++++++--------------------
 2 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index e934e0a13a..e44cde057f 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -254,6 +254,15 @@ it. Since all recent x86 hardware from the past >10 years 
is capable of the
 QEMU API (QAPI) events
 ----------------------
 
+``vcpu`` trace events (since 8.1)
+'''''''''''''''''''''''''''''''''
+
+The ability to instrument QEMU helper functions with vcpu aware trace
+points was removed in 7.0. However the QAPI still exposed the vcpu
+parameter. This argument has now been deprecated and the remaining
+used trace points converted to plain trace points selected just by
+name.
+
 ``MEM_UNPLUG_ERROR`` (since 6.2)
 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
diff --git a/qapi/trace.json b/qapi/trace.json
index 6bf0af0946..aac58e875b 100644
--- a/qapi/trace.json
+++ b/qapi/trace.json
@@ -37,13 +37,14 @@
 #
 # @vcpu: Whether this is a per-vCPU event (since 2.7).
 #
-# An event is per-vCPU if it has the "vcpu" property in the
-# "trace-events" files.
+# Features:
+# @deprecated: Member @vcpu is deprecated, and always false.
 #
 # Since: 2.2
 ##
 { 'struct': 'TraceEventInfo',
-  'data': {'name': 'str', 'state': 'TraceEventState', 'vcpu': 'bool'} }
+  'data': {'name': 'str', 'state': 'TraceEventState',
+           'vcpu': { 'type': 'bool', 'features': ['deprecated'] } } }
 
 ##
 # @trace-event-get-state:
@@ -52,19 +53,17 @@
 #
 # @name: Event name pattern (case-sensitive glob).
 #
-# @vcpu: The vCPU to query (any by default; since 2.7).
+# @vcpu: The vCPU to query (since 2.7).
+#
+# Features:
+# @deprecated: Member @vcpu is deprecated, and always false.
 #
 # Returns: a list of @TraceEventInfo for the matching events
 #
 # An event is returned if:
 #
-# - its name matches the @name pattern, and
-# - if @vcpu is given, the event has the "vcpu" property.
-#
-# Therefore, if @vcpu is given, the operation will only match per-vCPU
-# events, returning their state on the specified vCPU. Special case:
-# if @name is an exact match, @vcpu is given and the event does not
-# have the "vcpu" property, an error is returned.
+# - its name matches the @name pattern
+#   There are no longer any per-vCPU events
 #
 # Since: 2.2
 #
@@ -75,7 +74,8 @@
 # <- { "return": [ { "name": "qemu_memalign", "state": "disabled", "vcpu": 
false } ] }
 ##
 { 'command': 'trace-event-get-state',
-  'data': {'name': 'str', '*vcpu': 'int'},
+  'data': {'name': 'str',
+           '*vcpu': {'type': 'int', 'features': ['deprecated'] } },
   'returns': ['TraceEventInfo'] }
 
 ##
@@ -91,15 +91,13 @@
 #
 # @vcpu: The vCPU to act upon (all by default; since 2.7).
 #
-# An event's state is modified if:
+# Features:
+# @deprecated: Member @vcpu is deprecated, and always false.
 #
-# - its name matches the @name pattern, and
-# - if @vcpu is given, the event has the "vcpu" property.
+# An event's state is modified if:
 #
-# Therefore, if @vcpu is given, the operation will only match per-vCPU
-# events, setting their state on the specified vCPU. Special case: if
-# @name is an exact match, @vcpu is given and the event does not have
-# the "vcpu" property, an error is returned.
+# - its name matches the @name pattern
+#   There are no longer any per-vCPU events
 #
 # Since: 2.2
 #
@@ -111,4 +109,4 @@
 ##
 { 'command': 'trace-event-set-state',
   'data': {'name': 'str', 'enable': 'bool', '*ignore-unavailable': 'bool',
-           '*vcpu': 'int'} }
+           '*vcpu': {'type': 'int', 'features': ['deprecated'] } } }
-- 
2.39.2