6.12-stable review patch. If anyone has any objections, please let me know.
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From: Sohil Mehta sohil.mehta@intel.com
[ Upstream commit 7e6b0a2e4152f4046af95eeb46f8b4f9b2a7398d ]
The Family model check to read the processor flag MSR is misleading and potentially incorrect. It doesn't consider Family while comparing the model number. The original check did have a Family number but it got lost/moved during refactoring.
intel_collect_cpu_info() is called through multiple paths such as early initialization, CPU hotplug as well as IFS image load. Some of these flows would be error prone due to the ambiguous check.
Correct the processor flag scan check to use a Family number and update it to a VFM based one to make it more readable.
Signed-off-by: Sohil Mehta sohil.mehta@intel.com Signed-off-by: Ingo Molnar mingo@kernel.org Acked-by: Dave Hansen dave.hansen@linux.intel.com Link: https://lore.kernel.org/r/20250219184133.816753-4-sohil.mehta@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/include/asm/intel-family.h | 1 + arch/x86/kernel/cpu/microcode/intel.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h index 62d8b9448dc5c..c6198fbcc1d77 100644 --- a/arch/x86/include/asm/intel-family.h +++ b/arch/x86/include/asm/intel-family.h @@ -46,6 +46,7 @@ #define INTEL_ANY IFM(X86_FAMILY_ANY, X86_MODEL_ANY)
#define INTEL_PENTIUM_PRO IFM(6, 0x01) +#define INTEL_PENTIUM_III_DESCHUTES IFM(6, 0x05)
#define INTEL_CORE_YONAH IFM(6, 0x0E)
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index df5650eb3f088..362cc71bbc866 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -74,7 +74,7 @@ void intel_collect_cpu_info(struct cpu_signature *sig) sig->pf = 0; sig->rev = intel_get_microcode_revision();
- if (x86_model(sig->sig) >= 5 || x86_family(sig->sig) > 6) { + if (IFM(x86_family(sig->sig), x86_model(sig->sig)) >= INTEL_PENTIUM_III_DESCHUTES) { unsigned int val[2];
/* get processor flags from MSR 0x17 */