Re: [PATCH v4 18/18] tests/functional/hexagon: enable more arch_tests cases

[Brian Cain <brian.cain@oss.qualcomm.com>]

On 7/31/2026 12:42 PM, Pierrick Bouvier wrote:
> On 7/29/2026 6:28 PM, Brian Cain wrote:
>> Add more tests from hexagon-arch-tests, enabled by QTimer device.
>>
>> These exercise cache maintenance ops, l2vic, thread start/stop, tlb/mmu
>> operations, and user-mode transitions.
>>
>> Signed-off-by: Brian Cain <brian.cain@oss.qualcomm.com>
>> ---
>>   tests/functional/hexagon/test_arch_tests.py | 32 +++++++++++++++++++++
>>   1 file changed, 32 insertions(+)
>>
>> diff --git a/tests/functional/hexagon/test_arch_tests.py b/tests/functional/hexagon/test_arch_tests.py
>> index 2bb34f9b8dc..0834398c3b1 100755
>> --- a/tests/functional/hexagon/test_arch_tests.py
>> +++ b/tests/functional/hexagon/test_arch_tests.py
>> @@ -58,6 +58,38 @@ def test_int_steering(self) -> None:
>>           """
>>           self.run_uart_test("test_int_steering")
>>   
>> +    def test_cache(self) -> None:
>> +        """Tests cache operations: dckill/ickill, l2kill, dczeroa,
>> +        dccleaninva, cache disable/enable, barriers, and dcinva/dccleana.
>> +        """
>> +        self.run_uart_test("test_cache")
>> +
>> +    def test_l2vic(self) -> None:
>> +        """Tests the L2VIC interrupt controller: enable readback,
>> +        interrupt type readback, VID capture, and the fast interface.
>> +        """
>> +        self.run_uart_test("test_l2vic")
>> +
>> +    def test_threads(self) -> None:
>> +        """Tests hardware thread management: start/stop, MODECTL state,
>> +        per-thread HTID, shared memory, wait/resume, STID priority, and
>> +        SCHEDCFG/BESTWAIT readback.
>> +        """
>> +        self.run_uart_test("test_threads")
>> +
>> +    def test_tlb_mmu(self) -> None:
>> +        """Tests TLB/MMU operations: write/read/probe/invalidate,
>> +        global entries, multiple entries, overwrite, ASID matching,
>> +        and permission checks.
>> +        """
>> +        self.run_uart_test("test_tlb_mmu")
>> +
>> +    def test_user_mode(self) -> None:
>> +        """Tests user mode / privilege transitions: supervisor mode,
>> +        SSR UM/IE/XE/CE/PE bits, and the trap0 user-mode exit handler.
>> +        """
>> +        self.run_uart_test("test_user_mode")
>> +
>>   
>>   if __name__ == "__main__":
>>       QemuSystemTest.main()
> A general question on the pattern we have here.
>
> If those tests can be compiled with hexagon-cross container, would it
> make sense to add them to tcg/tests/hexagon/system directly in the future?
> Hopefully will be more easy once we have meson tcg-tests, so you don't
> need to add all dependencies by hand.


Glad you asked -- in a downstream fork, we originally did have several 
tests like these (not these particular ones but ~similar scope) running 
in check-tcg.  But we pivoted away from that because:

1. they're not testing merely translation: they depend on several sysemu 
devices.  More like integration/functional testing.

2. sometimes it's useful to verify not merely the exit code but also 
some output text to semihost/uart console.  This *can* be done with 
shell programs in make/meson, but it feels like "coloring outside of the 
lines."

3. most other architectures seem to have fairly ~light system emu 
check-tcg tests, perhaps because of #1/2?


We did this change with the assumption that these sysemu check-tcg tests 
wouldn't be welcomed by community because it diverges from what other 
targets do.  But maybe that was an overreaction?

It's certainly convenient to have test cases in-project so that changes 
to the tests don't require an indirect step to update a test code repo.  
So, we can do whatever best conforms to the project idioms in this 
regard.  Note that these particular tests in this patch are written in 
Rust and would introduce a new dependency (in the existing container, I 
suppose) beyond the C/C++ toolchain.  Fine w/me but food for thought.


>
> Regards,
> Pierrick