> From: Baolu Lu <[email protected]> > Sent: Wednesday, September 27, 2023 10:49 AM > > On 9/26/23 5:26 PM, Yi Liu wrote: > > From: Kevin Tian<[email protected]> > > > > This introduces three APIs for device drivers to manage pasid attach/ > > replace/detach. > > > > int iommufd_device_pasid_attach(struct iommufd_device *idev, > > u32 pasid, u32 *pt_id); > > int iommufd_device_pasid_replace(struct iommufd_device *idev, > > u32 pasid, u32 *pt_id); > > void iommufd_device_pasid_detach(struct iommufd_device *idev, > > u32 pasid); > > I am a bit puzzled. Do we really need both attach and replace interfaces > to install a hwpt onto a pasid on device? The IOMMUFD already tracks the > connections between hwpt and {device, pasid}, so it could easily call > the right iommu interfaces (attach vs. replace). Perhaps I overlooked > previous discussion on this. >
attach means a transition from non-present to present. replace can support changing a present entry atomically if iommu driver support it. the necessity of supporting both applies to both RID and RID+PASID.
