Re: [PATCH v7 0/4] iommufd: Add iommu hardware info reporting

[Jason Gunthorpe]

On Fri, Aug 11, 2023 at 12:14:57AM -0700, Yi Liu wrote:
> iommufd gives userspace the capability to manipulate iommu subsytem.
> e.g. DMA map/unmap etc. In the near future, it will support iommu nested
> translation. Different platform vendors have different implementation for
> the nested translation. For example, Intel VT-d supports using guest I/O
> page table as the stage-1 translation table. This requires guest I/O page
> table be compatible with hardware IOMMU. So before set up nested translation,
> userspace needs to know the hardware iommu information to understand the
> nested translation requirements.
> 
> This series reports the iommu hardware information for a given device
> which has been bound to iommufd. It is preparation work for userspace to
> allocate hwpt for given device. Like the nested translation support[1].
> 
> This series introduces an iommu op to report the iommu hardware info,
> and an ioctl IOMMU_GET_HW_INFO is added to report such hardware info to
> user. enum iommu_hw_info_type is defined to differentiate the iommu hardware
> info reported to user hence user can decode them. This series only adds the
> framework for iommu hw info reporting, the complete reporting path needs vendor
> specific definition and driver support. The full code is available in [1]
> as well.
> 
> [1] https://github.com/yiliu1765/iommufd/tree/wip/iommufd_nesting_08112023-yi
> (only the hw_info report path is the latest, other parts is wip)

I made the changes I noted and pull these plus the single vt-d patch
into iommufd for-next

Let me know if it is not OK and we can back it out

Thanks,
Jason