Re: [PATCH v1 5/7] docs: mark intention to deprecate TCG tracing functionality

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(a)linaro.org&gt; Cc: Luis Vilanova <vilanova(a)imperial.ac.uk&gt; Cc: Stefan Hajnoczi <stefanha(a)redhat.com&gt; --- 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. +