Hi Bagas, On Wed, Sep 11, 2024 at 09:13:10AM +0700, Bagas Sanjaya wrote: > ---- >8 --- > diff --git a/Documentation/userspace-api/iommufd.rst b/Documentation/userspace-api/iommufd.rst > index 3b0e46017dce22..e3ff476aba097e 100644 > --- a/Documentation/userspace-api/iommufd.rst > +++ b/Documentation/userspace-api/iommufd.rst > @@ -115,21 +115,21 @@ creating the objects and links:: > > 3. IOMMUFD_OBJ_HWPT_PAGING can be created in two ways: > > - IOMMUFD_OBJ_HWPT_PAGING is created when an external driver calls the IOMMUFD > - kAPI to attach a bound device to an IOAS. Similarly the external driver uAPI > - allows userspace to initiate the attaching operation. If a compatible > - pagetable already exists then it is reused for the attachment. Otherwise a > - new pagetable object and iommu_domain is created. Successful completion of > - this operation sets up the linkages among IOAS, device and iommu_domain. Once > - this completes the device could do DMA. Note that every iommu_domain inside > - the IOAS is also represented to userspace as an IOMMUFD_OBJ_HWPT_PAGING. > + * IOMMUFD_OBJ_HWPT_PAGING is created when an external driver calls the IOMMUFD > + kAPI to attach a bound device to an IOAS. Similarly the external driver uAPI > + allows userspace to initiate the attaching operation. If a compatible > + pagetable already exists then it is reused for the attachment. Otherwise a > + new pagetable object and iommu_domain is created. Successful completion of > + this operation sets up the linkages among IOAS, device and iommu_domain. Once > + this completes the device could do DMA. Note that every iommu_domain inside > + the IOAS is also represented to userspace as an IOMMUFD_OBJ_HWPT_PAGING. > > - IOMMUFD_OBJ_HWPT_PAGING can be also manually created via the IOMMU_HWPT_ALLOC > - uAPI, provided an ioas_id via @pt_id to associate the new HWPT_PAGING object > - to the corresponding IOAS object. The benefit of this manual allocation is to > - provide allocation flags (defined in enum iommufd_hwpt_alloc_flags), e.g. it > - allocates a nesting parent HWPT_PAGING, if the IOMMU_HWPT_ALLOC_NEST_PARENT > - flag is set. > + * IOMMUFD_OBJ_HWPT_PAGING can be also manually created via the IOMMU_HWPT_ALLOC > + uAPI, provided an ioas_id via @pt_id to associate the new HWPT_PAGING object > + to the corresponding IOAS object. The benefit of this manual allocation is to > + provide allocation flags (defined in enum iommufd_hwpt_alloc_flags), e.g. it > + allocates a nesting parent HWPT_PAGING, if the IOMMU_HWPT_ALLOC_NEST_PARENT > + flag is set. > > 4. IOMMUFD_OBJ_HWPT_NESTED can be only manually created via the IOMMU_HWPT_ALLOC > uAPI, provided an hwpt_id via @pt_id to associate the new HWPT_NESTED object > > > <snipped>... > > + When @pt_id carries an ioas_id to an IOAS object, the IOMMU_HWPT_ALLOC > > + call is instructed to allocate an HWPT_PAGING object only. > > + When @pt_id carries an hwpt_id to an HWPT_PAGING object, the uAPI call > "If instead @pt_id ..." > > + is instructed to allocate an HWPT_NESTED object only. > > + If any other type of object is passed in via the @pt_id, the uAPI call > > + will fail. I've applied the diff to my local version and will respin another version after collecting remarks from others. Thanks! Nicolin
