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authorSohil Mehta <sohil.mehta@intel.com>2025-02-19 18:41:21 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-05-29 11:12:34 +0200
commit0c16728fea580cf8f1699bce166c0b0e431f9fb8 (patch)
tree6a6c9635ebbf0b149add861ffca062e97d221405
parent87c618316ef5a349355d7ae483e3c6dc11103aa3 (diff)
x86/microcode: Update the Intel processor flag scan check
[ 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>
-rw-r--r--arch/x86/include/asm/intel-family.h1
-rw-r--r--arch/x86/kernel/cpu/microcode/intel.c2
2 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h
index ef5a06ddf0287..44fe88d6cf5c0 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 9309468c8d2c1..2a397da43923b 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 */