Re: [PATCH v2 0/9] Add MTE stubs for aarch64 user mode

[Gustavo Romero <gustavo.romero@linaro.org>]

Hi Alex,

On 6/14/24 12:49 PM, Alex Bennée wrote:
> Gustavo Romero <gustavo.romero@linaro.org> writes:
> 
>> This patchset adds the stubs necessary to support GDB memory tagging
>> commands on QEMU aarch64 user mode.
>>
>> These new stubs handle the qIsAddressTagged, qMemTag, and QMemTag
>> packets, which allow GDB memory tagging subcommands 'check',
>> 'print-allocation-tag', and 'set-allocation-tag' to work. The remaining
>> memory tagging commands ('print-logical-tag' and 'with-logical-tag')
>> will also work, but they don't rely on any stub because they perform
>> local operations.
>>
>> Since the memory tagging stubs are not common to all architectures, this
>> patchset also introduces three functions: gdb_extend_qsupported_features,
>> gdb_extend_query_table, and gdb_extend_set_table. These functions can be
>> used to extend the target-specific 'qSupported' feature string and the
>> handlers for the 'q' (query) and 'Q' (set) packets. These new functions
>> are used to add the MTE stubs for the aarch64 gdbstub.
>>   
>> Note that this patchset requires a GDB that supports the
>> qIsAddressTagged packet (recently added to GDB), so the gdbstub MTE
>> tests introduced by it must be run using GDB's master branch, since the
>> GDB in the distros hasn't picked up the change yet.
>>
>> Once GDB is built and installed locally, the tests can be exercised, for
>> example, this way:
>>
>> make GDB=~/.local/bin/gdb run-tcg-tests-aarch64-linux-user -j 32
> 
> It looks like there might be some BSD build failures as well:
> 
>    https://gitlab.com/stsquad/qemu/-/pipelines/1332635371/failures

I fixed the build for the BSD target in v3, however I think that the GDB in
the test containers need to be bumped to GDB 15 so the MTE tests can pass,
because support for IsAddressTagged packet is necessary. GDB 15 branch
is created by it's not released yet, so I don't know to proceed..


Cheers,
Gustavo