Re: [PATCH 1/2] iommu: Pass domain to remove_dev_pasid() op

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Mar 27, 2024 at 05:54:32AM -0700, Yi Liu wrote:
> Existing remove_dev_pasid() callbacks of the underlying iommu drivers get
> the attached domain from the group->pasid_array. However, the domains
> stored in group->pasid_array are not always correct. For example, the
> set_dev_pasid() path updates group->pasid_array first and then invoke
> remove_dev_pasid() callback when error happened. The remove_dev_pasid()
> callback would get the updated domain. This is not correct for the
> devices that are still attached with an old domain or just no attached
> domain.
> 
> To avoid the above problem, passing the attached domain to the
> remove_dev_pasid() callback is more reliable.

I've relaized we have the same issue with set_dev_pasid, there is no
way for the driver to get the old domain since the xarray was updated
before calling set_dev_pasid. This is unlike the RID path. Meaning
drivers can't implement PASID replace.

So we need another patch to pass the old domain into set_dev_pasid
too...

This looks fine

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

Jason