Re: [Qemu-devel] [PATCH v9 3/6] s390x/kvm: enable AP instruction interpretation for guest

[Pierre Morel <pmorel@linux.ibm.com>]

On 27/09/2018 09:52, David Hildenbrand wrote:
> On 27/09/2018 00:54, Tony Krowiak wrote:
>> From: Tony Krowiak <akrowiak@linux.ibm.com>
>>
>> Let's use the KVM_SET_DEVICE_ATTR ioctl to enable hardware
>> interpretation of AP instructions executed on the guest.
>> If the S390_FEAT_AP feature is switched on for the guest,
>> AP instructions must be interpreted by default; otherwise,
>> they will be intercepted.
>>
>> This attribute setting may be overridden by a device. For example,
>> a device may want to provide AP instructions to the guest (i.e.,
>> S390_FEAT_AP turned on), but it may want to emulate them. In this
>> case, the AP instructions executed on the guest must be
>> intercepted; so when the device is realized, it must disable
>> interpretation.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>> ---
>>   target/s390x/kvm.c | 14 ++++++++++++++
>>   1 file changed, 14 insertions(+)
>>
>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>> index 5277acd79a2c..d55d24abfd78 100644
>> --- a/target/s390x/kvm.c
>> +++ b/target/s390x/kvm.c
>> @@ -2301,6 +2301,16 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
>>                  S390_FEAT_MAX);
>>   }
>>   
>> +static void kvm_s390_configure_apie(bool interpret)
>> +{
>> +    uint64_t attr = interpret ? KVM_S390_VM_CRYPTO_ENABLE_APIE :
>> +                                KVM_S390_VM_CRYPTO_DISABLE_APIE;
>> +
>> +    if (kvm_vm_check_attr(kvm_state, KVM_S390_VM_CRYPTO, attr)) {
>> +            kvm_s390_set_attr(attr);
> 
> Wrong indentation, apart from that
> 
> Reviewed-by: David Hildenbrand <david@redhat.com>
> 
>> +    }
>> +}
>> +
>>   void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
>>   {
>>       struct kvm_s390_vm_cpu_processor prop  = {
>> @@ -2350,6 +2360,10 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
>>       if (test_bit(S390_FEAT_CMM, model->features)) {
>>           kvm_s390_enable_cmma();
>>       }
>> +
>> +    if (test_bit(S390_FEAT_AP, model->features)) {
>> +        kvm_s390_configure_apie(true);
>> +    }
>>   }
>>   
>>   void kvm_s390_restart_interrupt(S390CPU *cpu)
>>
> 
> 


Tested-by: Pierre Morel<pmorel@linux.ibm.com>


-- 
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany