diff options
author | Alex Bennée <alex.bennee@linaro.org> | 2022-02-04 20:43:26 +0000 |
---|---|---|
committer | Alex Bennée <alex.bennee@linaro.org> | 2022-02-09 12:08:42 +0000 |
commit | d9a6bad542cd796c785ff19793fa7ae24da6a97d (patch) | |
tree | df014b16e60c89eb608725817f546307e44e138a /docs/devel | |
parent | 3bdc19af00937191623fb0a2cacbc4ad54882072 (diff) | |
download | qemu-d9a6bad542cd796c785ff19793fa7ae24da6a97d.zip qemu-d9a6bad542cd796c785ff19793fa7ae24da6a97d.tar.gz qemu-d9a6bad542cd796c785ff19793fa7ae24da6a97d.tar.bz2 |
docs: remove references to TCG tracing
Users wanting this sort of functionality should turn to TCG plugins
instead.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Cc: Luis Vilanova <vilanova@imperial.ac.uk>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220204204335.1689602-18-alex.bennee@linaro.org>
Diffstat (limited to 'docs/devel')
-rw-r--r-- | docs/devel/tracing.rst | 85 |
1 files changed, 0 insertions, 85 deletions
diff --git a/docs/devel/tracing.rst b/docs/devel/tracing.rst index 4290ac4..ec9a687 100644 --- a/docs/devel/tracing.rst +++ b/docs/devel/tracing.rst @@ -413,88 +413,3 @@ disabled, this check will have no performance impact. return ptr; } -"tcg" ------ - -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 -"<eventname>_exec" to trace the event at execution time. - -Instead of using these two events, you should instead use the function -"trace_<eventname>_tcg" during translation (TCG code generation). This function -will automatically call "trace_<eventname>_trans", and will generate the -necessary TCG code to call "trace_<eventname>_exec" during guest code execution. - -Events with the "tcg" property can be declared in the "trace-events" file with a -mix of native and TCG types, and "trace_<eventname>_tcg" will gracefully forward -them to the "<eventname>_trans" and "<eventname>_exec" events. Since TCG values -are not known at translation time, these are ignored by the "<eventname>_trans" -event. Because of this, the entry in the "trace-events" file needs two printing -formats (separated by a comma):: - - tcg foo(uint8_t a1, TCGv_i32 a2) "a1=%d", "a1=%d a2=%d" - -For example:: - - #include "trace-tcg.h" - - void some_disassembly_func (...) - { - uint8_t a1 = ...; - TCGv_i32 a2 = ...; - trace_foo_tcg(a1, a2); - } - -This will immediately call:: - - void trace_foo_trans(uint8_t a1); - -and will generate the TCG code to call:: - - void trace_foo(uint8_t a1, uint32_t a2); - -"vcpu" ------- - -Identifies events that trace vCPU-specific information. It implicitly adds a -"CPUState*" argument, and extends the tracing print format to show the vCPU -information. If used together with the "tcg" property, it adds a second -"TCGv_env" argument that must point to the per-target global TCG register that -points to the vCPU when guest code is executed (usually the "cpu_env" variable). - -The "tcg" and "vcpu" properties are currently only honored in the root -./trace-events file. - -The following example events:: - - foo(uint32_t a) "a=%x" - vcpu bar(uint32_t a) "a=%x" - tcg vcpu baz(uint32_t a) "a=%x", "a=%x" - -Can be used as:: - - #include "trace-tcg.h" - - CPUArchState *env; - TCGv_ptr cpu_env; - - void some_disassembly_func(...) - { - /* trace emitted at this point */ - trace_foo(0xd1); - /* trace emitted at this point */ - trace_bar(env_cpu(env), 0xd2); - /* trace emitted at this point (env) and when guest code is executed (cpu_env) */ - trace_baz_tcg(env_cpu(env), cpu_env, 0xd3); - } - -If the translating vCPU has address 0xc1 and code is later executed by vCPU -0xc2, this would be an example output:: - - // at guest code translation - foo a=0xd1 - bar cpu=0xc1 a=0xd2 - baz_trans cpu=0xc1 a=0xd3 - // at guest code execution - baz_exec cpu=0xc2 a=0xd3 |