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Tue, 10 Mar 2026 22:00:32 +0000 Message-ID: <5701aca3-5ca7-4cf3-a2d9-18bc570b150c@intel.com> Date: Tue, 10 Mar 2026 15:00:30 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 1/3] x86/cpu: Clear feature bits disabled at compile-time Content-Language: en-US To: Maciej Wieczor-Retman , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , "H. 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Examples of such feature flags are lam, fred, sgx, ibrs_enhanced, > split_lock_detect, user_shstk, avx_vnni and enqcmd. > Do all of these features have compile time options today? For example, I couldn't find X86_DISABLED_FEATURE_* equivalent for ibrs_enhanced, split_lock_detect or avx_vnni. Maybe I am missing some obvious connection. But, if these can't be disabled using config options, it would be better to avoid any mention of them here. > Once the cpu_caps_cleared[] is initialized with the autogenerated > disabled bitmask apply_forced_caps() will clear the corresponding bits > in boot_cpu_data.x86_capability[] and other secondary CPUs' This sentence was a bit hard to read for me. How about? Initialize cpu_caps_cleared[] with an autogenerated disabled bitmask. During CPU init, apply_forced_caps() will clear the corresponding bits in struct cpuinfo_x86 for each CPU. Thus features disabled at... > cpu_data.x86_capability[]. Thus features disabled at compile time won't > show up in /proc/cpuinfo. > > No BUGS are defined to be cleared at compile time, therefore only the > NCAPINTS part of cpu_caps_cleared[] is initialized. The NBUGINTS part is ..NCAPINTS part of cpu_caps_cleared[] is initialized using the macro. The NBUGINTS part is set to zero. > set initialized to zero. > You don't need the word 'initialized' here. > Reported-by: Farrah Chen > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220348 > Signed-off-by: Maciej Wieczor-Retman > --- > arch/x86/kernel/cpu/common.c | 3 ++- > arch/x86/tools/cpufeaturemasks.awk | 6 ++++++ > 2 files changed, 8 insertions(+), 1 deletion(-) > The code changes look good to me, Reviewed-by: Sohil Mehta