The following commit has been merged into the x86/urgent branch of tip: Commit-ID: d9bb40544653cf039fe79225ec1d742183e2339a Gitweb: https://git.kernel.org/tip/d9bb40544653cf039fe79225ec1d742183e2339a Author: Tony Luck <tony.luck@xxxxxxxxx> AuthorDate: Fri, 22 Nov 2024 15:42:12 -08:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Mon, 25 Nov 2024 10:11:33 +01:00 x86/cpu: Fix PPIN initialization On systems that enumerate PPIN (protected processor inventory number) using CPUID, but where the BIOS locked the MSR to prevent access /proc/cpuinfo reports "intel_ppin" feature as present on all logical CPUs except for CPU 0. This happens because ppin_init() uses x86_match_cpu() to determine whether PPIN is supported. When called on CPU 0 the test for locked PPIN MSR results in: clear_cpu_cap(c, info->feature); This clears the X86 FEATURE bit in boot_cpu_data. When other CPUs are brought online the x86_match_cpu() fails, and the PPIN FEATURE bit remains set for those other CPUs. Fix by using setup_clear_cpu_cap() instead of clear_cpu_cap() which force clears the FEATURE bit for all CPUS. Reported-by: Adeel Ashad <adeel.arshad@xxxxxxxxx> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20241122234212.27451-1-tony.luck@xxxxxxxxx --- arch/x86/kernel/cpu/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 06a516f..d9d2d19 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -169,7 +169,7 @@ static void ppin_init(struct cpuinfo_x86 *c) } clear_ppin: - clear_cpu_cap(c, info->feature); + setup_clear_cpu_cap(info->feature); } static void default_init(struct cpuinfo_x86 *c)
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