Re: [PATCH 4/7] KVM: s390/CPACF: Choose crypto control block format

[Christian Borntraeger <borntraeger@de.ibm.com>]

Am 04.02.2015 um 14:00 schrieb Paolo Bonzini:
> 
> 
> On 04/02/2015 10:44, Christian Borntraeger wrote:
>> +static void kvm_s390_set_crycb_format(struct kvm *kvm)
>> +{
>> +	kvm->arch.crypto.crycbd = (__u32)(unsigned long) kvm->arch.crypto.crycb;
>> +
>> +	if (kvm_s390_apxa_installed())
>> +		kvm->arch.crypto.crycbd |= CRYCB_FORMAT2;
>> +	else
>> +		kvm->arch.crypto.crycbd |= CRYCB_FORMAT1;
>> +}
>> +
>>  static int kvm_s390_crypto_init(struct kvm *kvm)
>>  {
>>  	if (!test_vfacility(76))
>> @@ -663,8 +709,7 @@ static int kvm_s390_crypto_init(struct kvm *kvm)
>>  	if (!kvm->arch.crypto.crycb)
>>  		return -ENOMEM;
>>  
>> -	kvm->arch.crypto.crycbd = (__u32) (unsigned long) kvm->arch.crypto.crycb |
>> -				  CRYCB_FORMAT1;
>> +	kvm_s390_set_crycb_format(kvm);
> 
> Could this also be part of the "things" that KVM can choose to enable,
> even though it's not a facility?

Can you re-ask that question? Not sure what you want to know. 

This is mostly a fixup for z13, which wants to have a bigger control block. but
this block is not guest visible.
Talking about key wrapping, this is actually masked via a facility bit (for MSA-3
and MSA-4), therefore we have the test_vfacility thing in that function.

Christian