Re: [PATCH v9 14/21] iommufd: Support pasid attach/replace

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Mar 13, 2025 at 05:35:25AM -0700, Yi Liu wrote:
> This extends the below APIs to support PASID. Device drivers to manage pasid
> attach/replace/detach.
> 
>     int iommufd_device_attach(struct iommufd_device *idev,
> 			      ioasid_t pasid, u32 *pt_id);
>     int iommufd_device_replace(struct iommufd_device *idev,
> 			       ioasid_t pasid, u32 *pt_id);
>     void iommufd_device_detach(struct iommufd_device *idev,
> 			       ioasid_t pasid);
> 
> The pasid operations share underlying attach/replace/detach infrastructure
> with the device operations, but still have some different implications:
> 
>  - no reserved region per pasid otherwise SVA architecture is already
>    broken (CPU address space doesn't count device reserved regions);
> 
>  - accordingly no sw_msi trick;
> 
> Cache coherency enforcement is still applied to pasid operations since
> it is about memory accesses post page table walking (no matter the walk
> is per RID or per PASID).
> 
> Signed-off-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>  drivers/iommu/iommufd/device.c   | 57 ++++++++++++++++++++------------
>  drivers/iommu/iommufd/selftest.c |  8 ++---
>  drivers/vfio/iommufd.c           | 10 +++---
>  include/linux/iommufd.h          |  9 +++--
>  4 files changed, 52 insertions(+), 32 deletions(-)

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

Jason