Re: [PATCH] target/ppc: powerpc_excp: Guard ALIGNMENT interrupt with CONFIG_TCG

[Fabiano Rosas <farosas@linux.ibm.com>]

Fabiano Rosas <farosas@linux.ibm.com> writes:

> Cédric Le Goater <clg@kaod.org> writes:
>
>> Richard,
>>
>> On 12/9/21 16:05, Fabiano Rosas wrote:
>>> Cédric Le Goater <clg@kaod.org> writes:
>>> 
>>>> On 12/9/21 00:06, Fabiano Rosas wrote:
>>>>> We cannot have TCG code in powerpc_excp because the function is called
>>>>> from kvm-only code via ppc_cpu_do_interrupt:
>>>>>
>>>>>    ../target/ppc/excp_helper.c:463:29: error: implicit declaration of
>>>>>    function ‘cpu_ldl_code’ [-Werror=implicit-function-declaration]
>>>>>
>>>>> Fortunately, the Alignment interrupt is not among the ones dispatched
>>>>> from kvm-only code, so we can keep it out of the disable-tcg build for
>>>>> now.
>>>>>
>>>>> Fixes: 336e91f853 ("target/ppc: Move SPR_DSISR setting to powerpc_excp")
>>>>> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
>>>>>
>>>>> ---
>>>>>
>>>>> Perhaps we could make powerpc_excp TCG only and have a separate
>>>>> function that only knows the two interrupts that we use with KVM
>>>>> (Program, Machine check). But for now this fix will do, I think.
>>>>> ---
>>>>>    target/ppc/excp_helper.c | 2 ++
>>>>>    1 file changed, 2 insertions(+)
>>>>>
>>>>> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
>>>>> index 17607adbe4..dcf22440cc 100644
>>>>> --- a/target/ppc/excp_helper.c
>>>>> +++ b/target/ppc/excp_helper.c
>>>>> @@ -453,6 +453,7 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>>>>>            }
>>>>>            break;
>>>>>        }
>>>>> +#ifdef CONFIG_TCG
>>>>>        case POWERPC_EXCP_ALIGN:     /* Alignment exception                      */
>>>>>            /*
>>>>>             * Get rS/rD and rA from faulting opcode.
>>>>> @@ -464,6 +465,7 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>>>>>                env->spr[SPR_DSISR] |= (insn & 0x03FF0000) >> 16;
>>>>>            }
>>>>>            break;
>>>>> +#endif
>>>>>        case POWERPC_EXCP_PROGRAM:   /* Program exception                        */
>>>>>            switch (env->error_code & ~0xF) {
>>>>>            case POWERPC_EXCP_FP:
>>>>>
>>>>
>>>> Shouldn't we move that code under ppc_cpu_do_unaligned_access ?
>>> 
>>> Well, it came from there initially. We could revert 336e91f853 and that
>>> would fix the issue as well.
>>
>> What would you prefer ?
>
> Well none of this interfere with the work I'm doing, so it really makes
> no difference. I guess reverting the patch is cleaner than having an
> ifdef loose in the middle of the code. I'll send a v2 with the revert.
>

Ah I missed that you were talking to Richard! That first line got kind of
hidden.

I already sent a v2, but as I said, I have no preference either
way. Let's hear from Richard.

Sorry for the confusion =)

>>
>> Thanks,
>>
>> C.