Hi Jean, Have a question for you on whether we can have a fixed token type for ioasid_set.
Currently, ioasid_set has an arbitrary token. For VT-d vSVA usage, we choose mm as ioasid_set token to identify PASIDs within a guest. We have multiple in-kernel users of PASIDs such as VFIO, KVM, and VDCM. When an IOASID set is created, there is not a good way to communicate about the token choices. So we have to let VDCM and KVM *assume* mm is used as token, then retrieve ioasid_set based on the token. This assumption of "mm as token" is not a reliable SW architecture. So we are thinking if we can have an explicit ioasid_set token type where mm is used. After all, PASID and mm are closely related. The code change might be the following: 1. add a flag to indicate token type when ioasid_set is allocated, e.g. IOASID_SET_TYPE_MM IOASID_SET_TYPE_ANY 2. other users of the ioasid_set can query if an mm token exists based on the flag IOASID_SET_TYPE_MM, then retrieve the ioasid_set. Existing ioasid_set user can still use arbitrary token under the flag IOASID_SET_TYPE_ANY Would this be an issue for ARM usage? Thanks, Jacob _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
