Re: [PATCH] s390x: pv: Fence additional unavailable SCLP facilities for PV guests

[David Hildenbrand]

On 08.12.20 14:29, Christian Borntraeger wrote:
> 
> 
> On 04.12.20 09:36, Janosch Frank wrote:
>> There's no VSIE support for a protected guest, so let's better not
>> advertise it and its support facilities.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> 
> Looks sane. Assuming that all features that depend on SIE are named 
> S390_FEAT_SIE_*
> this should take care of everything. (i compared to gen-facilities.c)

We could add dependency checks to
target/s390x/cpu_models.c:check_consistency()

What about

DEF_FEAT(ESOP, "esop", SCLP_CONF_CHAR, 46,
"Enhanced-suppression-on-protection facility")
DEF_FEAT(HPMA2, "hpma2", SCLP_CONF_CHAR, 90, "Host page management
assist 2 Facility")

Although not related so SIE, do these features make sense for protected
guests?

> 
>> ---
>> CI:
>> https://gitlab.com/frankja/qemu/-/pipelines/224881703
>> ---
>>  target/s390x/cpu_features.c | 38 ++++++++++++++++++++++++++++++++++++-
>>  target/s390x/cpu_models.c   | 24 +++++++++++++++++++++--
>>  2 files changed, 59 insertions(+), 3 deletions(-)
>>
>> diff --git a/target/s390x/cpu_features.c b/target/s390x/cpu_features.c
>> index 42fe0bf4ca..7d7ea8e3b8 100644
>> --- a/target/s390x/cpu_features.c
>> +++ b/target/s390x/cpu_features.c
>> @@ -107,8 +107,44 @@ void s390_fill_feat_block(const S390FeatBitmap 
>> features, S390FeatType type,
>>          feat = find_next_bit(features, S390_FEAT_MAX, feat + 1);
>>      }
>>  
>> -    if (type == S390_FEAT_TYPE_SCLP_FAC134 && s390_is_pv()) {
>> +    if (!s390_is_pv()) {
>> +        return;
>> +    }
>> +
>> +    /*
>> +     * Some facilities are not available for CPUs in protected mode:
>> +     * - All SIE facilities because SIE is not available
>> +     * - DIAG318
>> +     *
>> +     * As VMs can move in and out of protected mode the CPU model
>> +     * doesn't protect us from that problem because it is only
>> +     * validated at the start of the VM.
>> +     */
>> +    switch (type) {
>> +    case S390_FEAT_TYPE_SCLP_CPU:
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_F2)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_SKEY)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_GPERE)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_SIIF)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_SIGPIF)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_IB)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_CEI)->bit, data);
>> +        break;
>> +    case S390_FEAT_TYPE_SCLP_CONF_CHAR:
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_KSS)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_GSLS)->bit, data);
>> +        break;
>> +    case S390_FEAT_TYPE_SCLP_CONF_CHAR_EXT:
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_64BSCAO)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_CMMA)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_PFMFI)->bit, data);
>> +        clear_be_bit(s390_feat_def(S390_FEAT_SIE_IBS)->bit, data);
>> +        break;
>> +    case S390_FEAT_TYPE_SCLP_FAC134:
>>          clear_be_bit(s390_feat_def(S390_FEAT_DIAG_318)->bit, data);
>> +        break;
>> +    default:
>> +        return;
>>      }
>>  }
>>  
>> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
>> index b5abff8bef..51feb71546 100644
>> --- a/target/s390x/cpu_models.c
>> +++ b/target/s390x/cpu_models.c
>> @@ -239,8 +239,28 @@ bool s390_has_feat(S390Feat feat)
>>          }
>>          return 0;
>>      }
>> -    if (feat == S390_FEAT_DIAG_318 && s390_is_pv()) {
>> -        return false;
>> +
>> +    if (s390_is_pv()) {
>> +        switch (feat) {
>> +        case S390_FEAT_DIAG_318:
>> +        case S390_FEAT_SIE_F2:
>> +        case S390_FEAT_SIE_SKEY:
>> +        case S390_FEAT_SIE_GPERE:
>> +        case S390_FEAT_SIE_SIIF:
>> +        case S390_FEAT_SIE_SIGPIF:
>> +        case S390_FEAT_SIE_IB:
>> +        case S390_FEAT_SIE_CEI:
>> +        case S390_FEAT_SIE_KSS:
>> +        case S390_FEAT_SIE_GSLS:
>> +        case S390_FEAT_SIE_64BSCAO:
>> +        case S390_FEAT_SIE_CMMA:
>> +        case S390_FEAT_SIE_PFMFI:
>> +        case S390_FEAT_SIE_IBS:
>> +            return false;
>> +            break;
>> +        default:
>> +            break;
>> +        }
>>      }
>>      return test_bit(feat, cpu->model->features);
>>  }
>>
> 


-- 
Thanks,

David / dhildenb