Re: [PATCH v1 1/5] s390x/mmu: Add EDAT2 translation support

[David Hildenbrand <david@redhat.com>]

On 01.10.19 10:55, Thomas Huth wrote:
> On 01/10/2019 10.51, David Hildenbrand wrote:
>> On 01.10.19 10:41, Thomas Huth wrote:
>>> On 26/09/2019 12.18, David Hildenbrand wrote:
>>>> On 26.09.19 12:16, David Hildenbrand wrote:
>>>>> This only adds basic support to the DAT translation, but no EDAT2 support
>>>>> for TCG. E.g., the gdbstub under kvm uses this function, too, to
>>>>> translate virtual addresses.
>>>>>
>>>>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>>>>> Signed-off-by: David Hildenbrand <david@redhat.com>
>>>>> ---
>>>>>  target/s390x/mmu_helper.c | 9 +++++++++
>>>>>  1 file changed, 9 insertions(+)
>>>>>
>>>>> diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c
>>>>> index 6b34c4c7b4..54f54137ec 100644
>>>>> --- a/target/s390x/mmu_helper.c
>>>>> +++ b/target/s390x/mmu_helper.c
>>>>> @@ -120,6 +120,7 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
>>>>>  {
>>>>>      const bool edat1 = (env->cregs[0] & CR0_EDAT) &&
>>>>>                         s390_has_feat(S390_FEAT_EDAT);
>>>>> +    const bool edat2 = edat1 && s390_has_feat(S390_FEAT_EDAT_2);
>>>>>      const int asce_tl = asce & ASCE_TABLE_LENGTH;
>>>>>      const int asce_p = asce & ASCE_PRIVATE_SPACE;
>>>>>      hwaddr gaddr = asce & ASCE_ORIGIN;
>>>>> @@ -219,9 +220,17 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
>>>>>          if ((entry & REGION_ENTRY_TT) != REGION_ENTRY_TT_REGION3) {
>>>>>              return PGM_TRANS_SPEC;
>>>>>          }
>>>>> +        if (edat2 && (entry & REGION3_ENTRY_CR) && asce_p) {
>>>>> +            return PGM_TRANS_SPEC;
>>>>> +        }
>>>>>          if (edat1 && (entry & REGION_ENTRY_P)) {
>>>>>              *flags &= ~PAGE_WRITE;
>>>>>          }
>>>>> +        if (edat2 && (entry & REGION3_ENTRY_FC)) {
>>>>> +            *raddr = (entry & REGION3_ENTRY_RFAA) |
>>>>> +                     (vaddr & REGION3_ENTRY_RFAA);
>>>>
>>>> Messed up
>>>>
>>>> (vaddr & ~REGION3_ENTRY_RFAA)
>>>>
>>>> it is.
>>>
>>> With that fix:
>>>
>>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>>>
>>
>> BTW, this change explains the different order of checks you mentioned. I now have here:
>>
>> diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c
>> index dc33c63b1d..dcbffb682f 100644
>> --- a/target/s390x/mmu_helper.c
>> +++ b/target/s390x/mmu_helper.c
>> @@ -120,6 +120,7 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
>>  {
>>      const bool edat1 = (env->cregs[0] & CR0_EDAT) &&
>>                         s390_has_feat(S390_FEAT_EDAT);
>> +    const bool edat2 = edat1 && s390_has_feat(S390_FEAT_EDAT_2);
>>      const int asce_tl = asce & ASCE_TABLE_LENGTH;
>>      const int asce_p = asce & ASCE_PRIVATE_SPACE;
>>      hwaddr gaddr = asce & ASCE_ORIGIN;
>> @@ -217,6 +218,17 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
>>          if ((entry & REGION_ENTRY_TT) != REGION_ENTRY_TT_REGION3) {
>>              return PGM_TRANS_SPEC;
>>          }
>> +        if (edat2 && (entry & REGION3_ENTRY_CR) && asce_p) {
>> +            return PGM_TRANS_SPEC;
>> +        }
>> +        if (edat2 && (entry & REGION3_ENTRY_FC)) {
>> +            if (entry & REGION_ENTRY_P) {
>> +                *flags &= ~PAGE_WRITE;
>> +            }
>> +            *raddr = (entry & REGION3_ENTRY_RFAA) |
>> +                     (vaddr & ~REGION3_ENTRY_RFAA);
>> +            return 0;
>> +        }
>>          if (VADDR_SEGMENT_TL(vaddr) < (entry & REGION_ENTRY_TF) >> 6 ||
>>              VADDR_SEGMENT_TL(vaddr) > (entry & REGION_ENTRY_TL)) {
>>              return PGM_SEGMENT_TRANS;
> 
> Ah, ok, and the *flags have to be set first, of course. So better keep
> it the original way round in your other patch.

I can just move it in this patch, then it's clearer why a different
order is needed.

-- 

Thanks,

David / dhildenb