Currently attempts to add a new TCG trace events results in failures
to build. Previous discussions have suggested maybe it's time to mark
the feature as deprecated and push people towards using plugins.
Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
Cc: Luis Vilanova <vilanova@xxxxxxxxxxxxxx>
Cc: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
---
docs/devel/tcg-plugins.rst | 2 ++
docs/devel/tracing.rst | 7 +++++++
docs/system/deprecated.rst | 13 +++++++++++++
3 files changed, 22 insertions(+)
diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst
index 18c6581d85..edf04e3091 100644
--- a/docs/devel/tcg-plugins.rst
+++ b/docs/devel/tcg-plugins.rst
@@ -3,6 +3,8 @@
Copyright (c) 2019, Linaro Limited
Written by Emilio Cota and Alex Bennée
+.. _tcgplugin-ref:
+
================
QEMU TCG Plugins
================
diff --git a/docs/devel/tracing.rst b/docs/devel/tracing.rst
index ba83954899..6b0f46cd54 100644
--- a/docs/devel/tracing.rst
+++ b/docs/devel/tracing.rst
@@ -414,6 +414,13 @@ disabled, this check will have no performance impact.
"tcg"
-----
+.. warning::
+ The ability to add new TCG trace points relies on a having a good
+ understanding of the TCG internals. In the meantime TCG plugins
+ have been introduced which solve many of the same problems with
+ more of a focus on analysing guest code. See :ref:`tcgplugin-ref`
+ for more details.
+
Guest code generated by TCG can be traced by defining an event with the "tcg"
event property. Internally, this property generates two events:
"<eventname>_trans" to trace the event at translation time, and
diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
index 80cae86252..0c9d3c1e1e 100644
--- a/docs/system/deprecated.rst
+++ b/docs/system/deprecated.rst
@@ -312,6 +312,19 @@ 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.
+TCG introspection features
+--------------------------
+
+TCG trace-events (since 6.1)
+''''''''''''''''''''''''''''
+
+The ability to add new TCG trace points has bit rotted and as the
+feature can be replicated with TCG plugins it will be deprecated. If
+any user is currently using this feature and needs help with
+converting to using TCG plugins they should contact the qemu-devel
+mailing list.
+
+
Related binaries
----------------
--
2.20.1
