Re: [PATCH v4 14/32] iommu: introduce iommu_domain_alloc_type and the KVM type

[Jason Gunthorpe]

On Mon, Mar 14, 2022 at 03:44:33PM -0400, Matthew Rosato wrote:
> s390x will introduce an additional domain type that is used for
> managing IOMMU owned by KVM.  Define the type here and add an
> interface for allocating a specified type vs the default type.
> 
> Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
> ---
>  drivers/iommu/iommu.c |  7 +++++++
>  include/linux/iommu.h | 12 ++++++++++++
>  2 files changed, 19 insertions(+)

I think the general idea is right, but I'm not keen on this as an
interface at all.

We are trying to build in iommufd a generic interface for an IOMMU
driver to expose IOMMU-device-specific domains such as this in a
general purpose way so all the platforms can get what they need.

Jason