[PATCH v2 0/5] Convert riscv to use the generic iommu page table

[Robin Murphy]

On 2026-01-23 1:52 pm, Jason Gunthorpe wrote:
> On Fri, Jan 23, 2026 at 08:29:01PM +0800, Vincent Chen wrote:
> 
>> With this codebase, the IOMMU group type is now correctly configured as
>> DMA:
>>
>>    # cat /sys/kernel/iommu_groups/0/type
>>    DMA
>>    # cat /sys/kernel/iommu_groups/1/type
>>    DMA
>>
>> I re-ran the iperf3 test in this environment, and the test passed
>> successfully.
> 
> OK great thanks alot!
> 
> I'm surprised it doesn't say DMA-FQ, someone from RISCV may want to
> investigate that, it is probably reducing performance..

The driver does not advertise IOMMU_CAP_DEFERRED_FLUSH, as the existing 
pagetable code has never implemented the conditional TLB maintenance 
optimisation that makes it meaningful. Mind you, I don't see any 
reference to iommu_iotlb_gather_queued() in generic_pt either, so I have 
no idea how that's trying to do it :/

Thanks,
Robin.