[PATCH v2 1/4] iommu/arm-smmu-v3: Add feature detection for HTTU

[Ryan Roberts]

On 24/04/2024 13:23, Jason Gunthorpe wrote:
> On Wed, Apr 24, 2024 at 11:04:43AM +0100, Ryan Roberts wrote:
>> On 23/04/2024 15:52, Jason Gunthorpe wrote:
>>> On Tue, Apr 23, 2024 at 03:41:30PM +0100, Ryan Roberts wrote:
>>>> Hi,
>>>>
>>>> I'm aiming to (slowly) get more involved with SMMU activities, although I'm sure
>>>> it will take a while to get up to speed and provide useful input. It was
>>>> suggested that this series would be a useful starting point to dip my toe in.
>>>> Please bear with me while I ask stupid questions...
>>>
>>> Nice!
>>>
>>> I would like to see this merged as it was part of the original three
>>> implementations for iommufd dirty tracking. The other two have been
>>> merged for a long time now..
>>
>> My understanding is that this series should pretty much apply on top of
>> mainline, is that correct? (in practice there are some conflicts, but I think
>> they are trivial).
> 
> It was originally based on my part 2, but I suspect it could apply
> easially on top of part 2a. I don't think it is worth rebasing to
> v6.9-rc since I expect Will to take 2a.
> 
>> I don't think it depends on anything new in your smmuv3_newapi branch?
> 
> I feel part 2a is done, hopefully Will will take it soon:
> 
>   https://lore.kernel.org/linux-iommu/0-v8-4c4298c63951+13484-smmuv3_newapi_p2_jgg@nvidia.com/
> 
> There are quite a few distros waiting on this:
> 
>   https://lore.kernel.org/linux-iommu/cover.1712977210.git.nicolinc@nvidia.com/

Great thanks for the links. I'll aim to start working through from this one
onwards as an when I can.

> 
> The cmdq area is not something I've studied deeply
> 
> I will be reposting the latter half of this as a part 2b:
> 
>   https://lore.kernel.org/linux-iommu/0-v6-228e7adf25eb+4155-smmuv3_newapi_p2_jgg@nvidia.com/
> 
> Which is the prerequisite for the part 3 series to enable nested
> translation an vSMMUv3 for iommufd.
> 
> Nested translation and a few more bits is prerequisite to finally enable BTM:
> 
>   https://lore.kernel.org/linux-iommu/20240208151837.35068-1-shameerali.kolothum.thodi@huawei.com/
> 
> Thanks,
> Jason