Re: [PATCH v3 11/11] hw/arm/smmuv3: Advertise SMMUv3.2 range invalidation

[Auger Eric]

Hi Peter,

On 7/10/20 11:47 AM, Peter Maydell wrote:
> On Wed, 8 Jul 2020 at 15:20, Eric Auger <eric.auger@redhat.com> wrote:
>>
>> Expose the RIL bit so that the guest driver uses range
>> invalidation. Range invalidation being an SMMU3.2 feature,
>> let AIDR advertise SMMUv3.2 support.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> 
> I think that to advertise SMMUv3.2 we would also need to
> set the IDR3.BBML field to something non-zero. That means
> we need to analyze our implementation of the caching of page
> table structures to see if we need to do anything different
> (per the behaviours and guarantees described in section 3.21.1
> of the spec).
> 
> Alternatively, we could take advantage of the language
> in section 2.5 that says that a v3.x implementation is
> allowed to implement features from v3.(x+1), and just
> set the RIL bit while leaving AIDR advertising us as v3.1.
So I eventually lazily chose this solution. I will address BBML support
in a separate patch series.

Thanks

Eric
> 
> thanks
> -- PMM
>