Re: [PATCH v3 03/12] iommu: Add new flag to explictly request PASID capable domain

[Jason Gunthorpe <jgg@ziepe.ca>]

On Thu, Oct 17, 2024 at 02:01:28PM +0000, Vasant Hegde wrote:
> From: Jason Gunthorpe <jgg@ziepe.ca>
> 
> Introduce new flag (IOMMU_HWPT_ALLOC_PASID) to domain_alloc_users() ops.
> If both IOMMU and device supports PASID it will allocate domain.
> Otherwise return error.

Do we want the "and device" language here?

I guess we need to decide and make it consistent.

This is if the iommu driver/core code should fail the flag if the
device doesn't have a PCI PASID cap.

> @@ -359,11 +359,17 @@ struct iommu_vfio_ioas {
>   *                                   enforced on device attachment
>   * @IOMMU_HWPT_FAULT_ID_VALID: The fault_id field of hwpt allocation data is
>   *                             valid.
> + * @IOMMU_HWPT_ALLOC_PASID: Requests a domain that can be used with PASID. The
> + *                          domain can be attached to any PASID on the device.
> + *                          Any domain attached to the non-PASID part of the
> + *                          device must also be flaged, otherwise attaching a
> + *                          PASID will blocked.
>   */

And the choice needs to be documented here

Jason