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x86/microcode: Update the Intel processor flag scan check

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[ 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>
This commit is contained in:
Sohil Mehta
2025-02-19 18:41:21 +00:00
committed by Greg Kroah-Hartman
parent 8973fb71c9
commit d0f9875257
2 changed files with 2 additions and 1 deletions
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1
arch/x86/include/asm/intel-family.h
View File

@@ -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)

2
arch/x86/kernel/cpu/microcode/intel.c
View File

@@ -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 */