Re: [PATCH 2/2] iommu/arm-smmu-v3: Override for Inst/Data attribute

[Robin Murphy <robin.murphy@arm.com>]

On 10/08/2026 3:15 pm, Jason Gunthorpe wrote:
> On Fri, Aug 07, 2026 at 03:37:37PM +0100, Peter Griffin wrote:
> 
>>>> @@ -1222,7 +1224,8 @@ void arm_smmu_get_ste_used(const __le64 *ent, __le64 *used_bits)
>>>>        if (cfg & BIT(1)) {
>>>>                used_bits[1] |=
>>>>                        cpu_to_le64(STRTAB_STE_1_S2FWB | STRTAB_STE_1_EATS |
>>>> -                                 STRTAB_STE_1_SHCFG | STRTAB_STE_1_MEV);
>>>> +                                 STRTAB_STE_1_SHCFG | STRTAB_STE_1_MEV |
>>>> +                                 STRTAB_STE_1_INSTCFG);
>>>>                used_bits[2] |=
>>>>                        cpu_to_le64(STRTAB_STE_2_S2VMID | STRTAB_STE_2_VTCR |
>>>>                                    STRTAB_STE_2_S2AA64 | STRTAB_STE_2_S2ENDI |
>>>
>>> This adds for "stage-1" and "stage-2", while missing "bypass"?
>>
>> I need to follow up again on this point, but I don't believe currently
>> we require the override for Laguna when it's in bypass.
> 
> Oh? Why not?
> 
> Is the issue the IOPTEs are set to no-exec or something like that?

In general, there isn't expected to be anything in the memory system 
downstream of the SMMU that makes use of the Privileged or 
Instruction/Data attributes, so I would assume that is the case on this 
SoC. FWIW, hardware folks would be quite keen on relaxing the 
architecture to say that an SMMU isn't even required to propagate those 
attributes at all.

Thanks,
Robin.