> From: Liu, Yi L <[email protected]> > Sent: Monday, February 13, 2023 11:14 PM > > This adds three vfio device ioctls for userspace using iommufd to set up > secure DMA context for device access. > > VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain > DMA > control provided by the iommufd. open_device > op is called after bind_iommufd op. > VFIO no iommu mode is indicated by passing > a negative iommufd value. > VFIO_DEVICE_ATTACH_IOMMUFD_PT: attach device to IOAS, > hw_pagetable > managed by iommufd. Attach can be > undo by > VFIO_DEVICE_DETACH_IOMMUFD_PT > or device fd close. > VFIO_DEVICE_DETACH_IOMMUFD_PT: detach device from the current > attached > IOAS or hw_pagetable managed by > iommufd.
let's split into two patches: bind and attach/detach. > > +int vfio_device_claim_group(struct vfio_device *device) > +void vfio_device_release_group(struct vfio_device *device) vfio_device_block_group() vfio_device_unblock_group() > > + /* > + * For group/container path, iommufd pointer is NULL when comes > + * into this helper. Its noiommu support is in container.c. "Its noiommu support is handled by vfio_device_group_use_iommu()" > + * > + * For iommufd compat mode, iommufd pointer here is a valid value. > + * Its noiommu support is in vfio_iommufd_bind(). > + * > + * For device cdev path, iommufd pointer here is a valid value for > + * normal cases, but it is NULL if it's noiommu. To differentiate > + * the noiommu from the group/container path which also passes > NULL > + * iommufd pointer in, check df->noiommu which is set only in the > + * cdev path. "Check df->noiommu to differentiate cdev noiommu from the group/ container path which also passes NULL iommufd pointer in. If set then do nothing."
