Re: [Qemu-ppc] [RFC PATCH] booke206: fix MAS update on tlb miss

[Thomas Huth]

On 03.08.2017 14:08, KONRAD Frederic wrote:
> 
> 
> On 08/03/2017 01:37 PM, Thomas Huth wrote:
>> On 01.08.2017 10:44, KONRAD Frederic wrote:
>>> When a tlb instruction miss happen, rw is set to 0 at the bottom
>>> of cpu_ppc_handle_mmu_fault which cause the MAS update function to miss
>>> the SAS and TS bit in MAS6, MAS1 in booke206_update_mas_tlb_miss.
>>>
>>> Just calling booke206_update_mas_tlb_miss with rw = 2 solve the issue.
>>>
>>> Signed-off-by: KONRAD Frederic <address@hidden>
>>> ---
>>>   target/ppc/mmu_helper.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c
>>> index b7b9088..f06b938 100644
>>> --- a/target/ppc/mmu_helper.c
>>> +++ b/target/ppc/mmu_helper.c
>>> @@ -1551,7 +1551,7 @@ static int cpu_ppc_handle_mmu_fault(CPUPPCState
>>> *env, target_ulong address,
>>>                       env->spr[SPR_40x_ESR] = 0x00000000;
>>>                       break;
>>>                   case POWERPC_MMU_BOOKE206:
>>> -                    booke206_update_mas_tlb_miss(env, address, rw);
>>> +                    booke206_update_mas_tlb_miss(env, address, 2);
>>
> Hi Thomas,
> 
>> Couldn't that code path be called for normal data read miss (instead of
>> instruction miss), too?
>>
> 
> I don't think so because we have access_type == ACCESS_CODE and
> the code in cpu_ppc_handle_mmu_fault explicitely split the CODE
> and DATA cases.

Ah, right, I missed that if-statement. So never mind about my comment!

>> Anyway, could we please use MMU_INST_FETCH instead of magic values like
>> 2 here?
> 
> I agree it's not nice to have a magic value like this.. But it's
> used all over the code there and david took the patch.
> 
> So I suggest I send a second patch to fix all the instances of
> that magic value.

Sounds like a good idea!

 Thanks,
  Thomas