Re: [PATCH v3 11/15] crypto: x86/aes-kl - Support AES algorithm using Key Locker instructions

[Bae, Chang Seok]

On Dec 2, 2021, at 06:21, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Wed, Nov 24, 2021 at 12:06:56PM -0800, Chang S. Bae wrote:
>> +	encodekey256 %eax, %eax
> 
> So this thing uses the fancy new keylocker instructions, however:
> 
>> diff --git a/crypto/Kconfig b/crypto/Kconfig
>> index 285f82647d2b..784a04433549 100644
>> --- a/crypto/Kconfig
>> +++ b/crypto/Kconfig
>> @@ -1113,6 +1113,50 @@ config CRYPTO_AES_NI_INTEL
>> 	  ECB, CBC, LRW, XTS. The 64 bit version has additional
>> 	  acceleration for CTR.
>> 
>> +config CRYPTO_AES_KL
>> +	tristate "AES cipher algorithms (AES-KL)"
>> +	depends on (LD_VERSION >= 23600) || (LLD_VERSION >= 120000)
>> +	depends on DM_CRYPT
>> +	select X86_KEYLOCKER
>> +	select CRYPTO_AES_NI_INTEL
> 
> 
> There is no dependency on the compiler actually supporting them..
> 
> config AS_HAS_KEYLOCKER
> 	def_bool $(as-instr,encodekey256)
> 
> 	depends on AS_HAS_KEYLOCKER
> 
> Hmm?

Well, LD_VERSION reflects the binutils version.

But yes, the as-instr macro looks to be useful here:

+config AS_HAS_KEYLOCKER
+       def_bool $(as-instr,encodekey256 %eax$(comma)%eax)
+       help
+         Supported by binutils >=2.36 and LLVM integrated assembler >= V12
+
 config CRYPTO_AES_KL
        tristate "AES cipher algorithms (AES-KL)"
-       depends on (LD_VERSION >= 23600) || (LLD_VERSION >= 120000)
+       depends on AS_HAS_KEYLOCKER

Thanks,
Chang