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Re: [PATCH v2 2/2] docs/devel: tvg-plugins: add execlog plugin descripti
From: |
Alexandre IOOSS |
Subject: |
Re: [PATCH v2 2/2] docs/devel: tvg-plugins: add execlog plugin description |
Date: |
Tue, 22 Jun 2021 11:27:22 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 |
On 6/22/21 10:48 AM, Alex Bennée wrote:
Alexandre Iooss<erdnaxe@crans.org> writes:
[...]
+
+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.
Yes! In my downstream version I am triggering the beginning and the end
of trace acquisition by matching two virtual addresses of GPIO device
access. This works in my case because I'm also using the same GPIO for
triggering an oscilloscope, but maybe we would like to upstream
something more generic.
I'm still thinking about this (maybe for a later patch) but I believe it
would be nice to have the following:
- If no argument is given to the plugin, log everything.
- Allow the user to specify either a memory address, an instruction
virtual address or an opcode that would start the acquisition.
- Same to stop the acquisition.
This would look like this to start/stop acquisition using GPIO PA8 on
STM32VLDISCOVERY:
./arm-softmmu/qemu-system-arm -M stm32vldiscovery \
-kernel ./firmware.elf -d plugin \
-plugin libexeclog.so,arg=mem:1073809424,arg=mem:1073809424
I would like to hear other users opinion on this, because I fear I might
implement something too specific.
Thanks,
-- Alexandre
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Re: [PATCH v2 2/2] docs/devel: tvg-plugins: add execlog plugin description, Alex Bennée, 2021/06/22
Re: [PATCH v2 0/2] execlog TCG plugin to log instructions, Alexandre IOOSS, 2021/06/18