On Mon, Sep 16, 2024 at 01:31:01PM +0200, James Gowans wrote: > +#ifdef CONFIG_GUESTMEMFS_FS > + struct vm_area_struct *vma; > + struct mm_struct *mm = current->mm; > + > + mmap_read_lock(mm); > + vma = find_vma_intersection(current->mm, > + cmd->user_va, cmd->user_va + cmd->length); > + if (!vma || !is_guestmemfs_file(vma->vm_file)) { > + mmap_read_unlock(mm); > + return -EFAULT; > + } > + mmap_read_unlock(mm); > +#else Any kind of FD interaction needs to go through the new FD path that Steve is building: https://lore.kernel.org/linux-iommu/1727190338-385692-1-git-send-email-steven.sistare@xxxxxxxxxx I'm expecting multiple kinds of fds to fall into that pattern, including memfs, guestmemfd, and dmabuf. guestmemfd can just be one more.. Jason