On Thu, 2 Jun 2016, Andi Kleen wrote: Sorry for answering late. This got stuck in my backlog forever.
> diff --git a/arch/x86/kernel/cpu/microcode/intel.c > b/arch/x86/kernel/cpu/microcode/intel.c > index ee81c54..bcd3f59 100644 > --- a/arch/x86/kernel/cpu/microcode/intel.c > +++ b/arch/x86/kernel/cpu/microcode/intel.c > @@ -812,6 +812,8 @@ static int collect_cpu_info(int cpu_num, struct > cpu_signature *csig) > /* get processor flags from MSR 0x17 */ > rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]); > csig->pf = 1 << ((val[1] >> 18) & 7); > + cpu_data(cpu_num).platform_id = (val[1] >> 18) & 7; > + cpu_data(cpu_num).has_platform_id = true; Please move that evaluation to arch/x86/kernel/cpu/intel.c and let the micro code driver use the information from cpu_data. Thanks, tglx