Re: [PATCH v9 15/15] s390x: Add unpack facility feature to GA1

[Janosch Frank]

On 3/17/20 7:06 PM, Cornelia Huck wrote:
> On Wed, 11 Mar 2020 09:21:51 -0400
> Janosch Frank <address@hidden> wrote:
> 
>> From: Christian Borntraeger <address@hidden>
>>
>> The unpack facility is an indication that diagnose 308 subcodes 8-10
>> are available to the guest. That means, that the guest can put itself
>> into protected mode.
>>
>> Once it is in protected mode, the hardware stops any attempt of VM
>> introspection by the hypervisor.
>>
>> Some features are currently not supported in protected mode:
>>      * Passthrough devices
> 
> s/Passthrough/vfio/ ?

Ack

> 
>>      * Migration
>>      * Huge page backings
>>
>> Signed-off-by: Christian Borntraeger <address@hidden>
>> Reviewed-by: David Hildenbrand <address@hidden>
> 
> Btw: please add your s-o-b if you're passing on patches from others.

Ack

> 
>> ---
>>  target/s390x/gen-features.c | 1 +
>>  target/s390x/kvm.c          | 5 +++++
>>  2 files changed, 6 insertions(+)
>>
>> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
>> index 6278845b12b8dee8..8ddeebc54419a3e2 100644
>> --- a/target/s390x/gen-features.c
>> +++ b/target/s390x/gen-features.c
>> @@ -562,6 +562,7 @@ static uint16_t full_GEN15_GA1[] = {
>>      S390_FEAT_GROUP_MSA_EXT_9,
>>      S390_FEAT_GROUP_MSA_EXT_9_PCKMO,
>>      S390_FEAT_ETOKEN,
>> +    S390_FEAT_UNPACK,
>>  };
>>  
>>  /* Default features (in order of release)
>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>> index ff6027036ec2f14a..e11e895a3d9038bb 100644
>> --- a/target/s390x/kvm.c
>> +++ b/target/s390x/kvm.c
>> @@ -2403,6 +2403,11 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
>> Error **errp)
>>          clear_bit(S390_FEAT_BPB, model->features);
>>      }
>>  
>> +    /* we do have the IPL enhancements */
> 
> I'm more confused by that comment than educated :) Not sure what 'IPL
> enhancements' means in this context.

/* We do have the protected virtualization ipl unpack facility */
?

> 
>> +    if (cap_protected) {
>> +        set_bit(S390_FEAT_UNPACK, model->features);
>> +    }
>> +
>>      /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
>>      set_bit(S390_FEAT_ZPCI, model->features);
>>      set_bit(S390_FEAT_ADAPTER_EVENT_NOTIFICATION, model->features);
>

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