> From: Nicolin Chen <nicolinc@xxxxxxxxxx> > Sent: Saturday, May 20, 2023 2:45 AM > > On Fri, May 19, 2023 at 08:47:45AM +0000, Tian, Kevin wrote: > > > From: Liu, Yi L <yi.l.liu@xxxxxxxxx> > > > Sent: Thursday, May 11, 2023 10:39 PM > > > @@ -229,6 +238,15 @@ struct iommu_iotlb_gather { > > > * after use. Return the data buffer if success, or ERR_PTR on > > > * failure. > > > * @domain_alloc: allocate iommu domain > > > + * @domain_alloc_user: allocate user iommu domain > > > + * @domain_alloc_user_data_len: return the required length of the user > > > data > > > + * to allocate a specific type user iommu domain. > > > + * @hwpt_type is defined as enum iommu_hwpt_type > > > + * in include/uapi/linux/iommufd.h. The returned > > > + * length is the corresponding sizeof driver data > > > + * structures in include/uapi/linux/iommufd.h. > > > + * -EOPNOTSUPP would be returned if the input > > > + * @hwpt_type is not supported by the driver. > > > > Can this be merged with earlier @hw_info callback? That will already > > report a list of supported hwpt types. is there a problem to further > > describe the data length for each type in that interface? > > Yi and I had a last minute talk before he sent this version > actually... This version of hw_info no longer reports a list > of supported hwpt types. We previously did that in a bitmap, > but we found that a bitmap will not be sufficient eventually > if there are more than 64 hwpt_types. > > And this domain_alloc_user_data_len might not be necessary, > because in this version the IOMMUFD core doesn't really care > about the actual data_len since it copies the data into the > ucmd_buffer, i.e. we would probably only need a bool op like > "hwpt_type_is_supported". > Or just pass to the @domain_alloc_user ops which should fail if the type is not supported?