Re: [PATCH v4 6/7] iommu/arm-smmu-v3: Add arm_smmu_invs based arm_smmu_domain_inv_range()

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Oct 27, 2025 at 11:54:20AM -0700, Nicolin Chen wrote:
> Each smmu_domain now has an arm_smmu_invs that specifies the invalidation
> steps to perform after any change the IOPTEs. This includes supports for
> basic ASID/VMID, the special case for nesting, and ATC invalidations.
> 
> Introduce a new arm_smmu_domain_inv helper iterating smmu_domain->invs to
> convert the invalidation array to commands. Any invalidation request with
> no size specified means an entire flush over a range based one.
> 
> Take advantage of the sorted array to compatible batch operations together
> to the same SMMU. For instance, ATC invaliations for multiple SIDs can be
> pushed as a batch.
> 
> ATC invalidations must be completed before the driver disables ATS. Or the
> device is permitted to ignore any racing invalidation that would cause an
> SMMU timeout. The sequencing is done with a rwlock where holding the write
> side of the rwlock means that there are no outstanding ATC invalidations.
> If ATS is not used the rwlock is ignored, similar to the existing code.
> 
> Co-developed-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |   9 +
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 225 ++++++++++++++++++--
>  2 files changed, 221 insertions(+), 13 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason