Alexandre Iooss <erdn...@crans.org> writes:
> This adds description of the execlog TCG plugin with an example.
>
> Signed-off-by: Alexandre Iooss <erdn...@crans.org>
> ---
> docs/devel/tcg-plugins.rst | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst
> index 18c6581d85..02818a3327 100644
> --- a/docs/devel/tcg-plugins.rst
> +++ b/docs/devel/tcg-plugins.rst
> @@ -319,3 +319,25 @@ the user to see what hardware is accessed how often. It
> has a number of options:
> off:0000001c, 1, 2
> off:00000020, 1, 2
> ...
> +
> +- contrib/plugins/execlog.c
> +
> +The execlog tool traces executed instructions with memory access. It can be
> used
> +for debugging and security analysis purposes.
We should probably mention that this will generate a lot of output.
Running the admittedly memory heavy softmmu memory test:
./aarch64-softmmu/qemu-system-aarch64 -D test.out -d plugin \
-plugin contrib/plugins/libexeclog.so \
-cpu max -serial mon:stdio -M virt \
-display none -semihosting-config chardev=serial0 \
-kernel ./tests/tcg/aarch64-softmmu/memory
generates a 8.6Gb text file. I suspect once this is merged you might
want to look at options to target the instrumentation at areas of
specific interest or abbreviate information.
> +The plugin takes no argument::
> +
> + qemu-system-arm $(QEMU_ARGS) \
> + -plugin ./contrib/plugins/libexeclog.so -d plugin
> +
> +which will output an execution trace following this structure::
> +
> + # vCPU, vAddr, opcode, disassembly[, load/store, memory addr, device]...
> + 0, 0xa12, 0xf8012400, "movs r4, #0"
> + 0, 0xa14, 0xf87f42b4, "cmp r4, r6"
> + 0, 0xa16, 0xd206, "bhs #0xa26"
> + 0, 0xa18, 0xfff94803, "ldr r0, [pc, #0xc]", load, 0x00010a28, RAM
> + 0, 0xa1a, 0xf989f000, "bl #0xd30"
> + 0, 0xd30, 0xfff9b510, "push {r4, lr}", store, 0x20003ee0, RAM, store,
> 0x20003ee4, RAM
> + 0, 0xd32, 0xf9893014, "adds r0, #0x14"
> + 0, 0xd34, 0xf9c8f000, "bl #0x10c8"
> + 0, 0x10c8, 0xfff96c43, "ldr r3, [r0, #0x44]", load, 0x200000e4, RAM
--
Alex Bennée
