Re: [PATCH] x86/gen-cpuid: Fix debugging for cycle detection

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.08.2025 21:29, Andrew Cooper wrote:
> Jan reports the following exception when using the cycle debugging:
> 
>   Feature IBRSB, seen [IBRSB, STIBP, INTEL_PSFD, EIBRS, IPRED_CTRL, 
> RRSBA_CTRL, RRSBA, BHI_CTRL], to_process [SSBD]
>   Traceback (most recent call last):
>     File "/local/xen.git/xen/../xen/tools/gen-cpuid.py", line 594, in <module>
>       sys.exit(main())
>                ^^^^^^
>     File "/local/xen.git/xen/../xen/tools/gen-cpuid.py", line 588, in main
>       crunch_numbers(state)
>     File "/local/xen.git/xen/../xen/tools/gen-cpuid.py", line 366, in 
> crunch_numbers
>       (state.names[feat], repl(seen), repl(to_process)))
>                                       ^^^^^^^^^^^^^^^^
>     File "/local/xen.git/xen/../xen/tools/gen-cpuid.py", line 364, in repl
>       return "[" + ", ".join((state.names[x] for x in l)) + "]"
>                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>     File "/local/xen.git/xen/../xen/tools/gen-cpuid.py", line 364, in 
> <genexpr>
>       return "[" + ", ".join((state.names[x] for x in l)) + "]"
>                               ~~~~~~~~~~~^^^
>   KeyError: 534
>   make[2]: *** [/local/xen.git/xen/include/xen/lib/x86/Makefile:9: 
> cpuid-autogen.h] Error 1
> 
> This is caused by commit ce8c930851a5 ("x86/cpu-policy: MSR_ARCH_CAPS feature
> names") being rather lazy and marking dependenices on unknown features.
> 
> Introduce a helper to pick the known features in a range, and use it for
> ARCH_CAPS.
> 
> Additionally, remove trailing whitepsace from the debug print.
> 
> Reported-by: Jan Beulich <jbeulich@xxxxxxxx>
> Fixes: ce8c930851a5 ("x86/cpu-policy: MSR_ARCH_CAPS feature names")
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>