Re: [RFC 01/10] x86/microcode/intel: expose collect_cpu_info_early() for IFS

["Joseph, Jithu" <jithu.joseph@intel.com>]

On 3/2/2022 2:30 AM, Borislav Petkov wrote:
> On Tue, Mar 01, 2022 at 11:54:48AM -0800, Jithu Joseph wrote:
>> @@ -58,6 +58,7 @@ static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
>>  	/* ... or they intersect. */
>>  	return p1 & p2;
>>  }
>> +EXPORT_SYMBOL_GPL(cpu_signatures_match);
...
> 
> Hell, even your function signatures don't match.
> 
> And then, with that fixed it would build but then one would wonder a
> long time why that ifs thing doesn't work. Well:
> 
> # CONFIG_MICROCODE is not set

Thanks for reviewing the patch and pointing out the mistakes of not setting the module build dependency(on CONFIG_MICROCODE) and that of signature mismatch

> 
> So the proper thing to do is to extract the generic functionality for
> comparing microcode patch signatures and for gathering the information
> collect_cpu_info_early() collects, into intel-generic functions, like
> I've done with intel_get_microcode_revision(), move that functionality
> to arch/x86/kernel/cpu/intel.c and then use it *both* in the microcode
> loader *and* your driver.
> 

Will move these two function definitions from arch/x86/kernel/cpu/microcode/intel.c to arch/x86/kernel/cpu/intel.c in the next revision as you suggest above.
Need to find an appropriate header for these moved functions too.


Jithu