diff --git a/include/linux/mem-buf-exporter.h b/include/linux/mem-buf-exporter.h new file mode 100644 index 000000000000..d1b86d36691d --- /dev/null +++ b/include/linux/mem-buf-exporter.h @@ -0,0 +1,111 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2020-2021, The Linux Foundation. All rights reserved. + */ + +#ifndef _MEM_BUF_EXPORTER_H +#define _MEM_BUF_EXPORTER_H + +#include +#include + +int mem_buf_dma_buf_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment); + +/* Private data for managing a dmabuf's Virtual Machine permissions. */ +struct mem_buf_vmperm; + +/* + * @lookup: Returns the mem_buf_vmperm data structure contained somewhere + * in the exporter's private_data, or a negative number on error. + * @attach: The exporter's normal dma_buf_attach callback + * @dma_ops: The exporter's standard dma_buf callbacks, except for + * attach which must be NULL. + */ +struct mem_buf_dma_buf_ops { + struct mem_buf_vmperm *(*lookup)(struct dma_buf *dmabuf); + int (*attach)(struct dma_buf *dmabuf, struct dma_buf_attachment *a); + struct dma_buf_ops dma_ops; +}; + +struct dma_buf * +mem_buf_dma_buf_export(struct dma_buf_export_info *exp_info, + struct mem_buf_dma_buf_ops *ops); + + +#define MEM_BUF_WRAPPER_FLAG_STATIC_VM BIT(0) +#define MEM_BUF_WRAPPER_FLAG_LENDSHARE BIT(1) +#define MEM_BUF_WRAPPER_FLAG_ACCEPT BIT(2) +#define MEM_BUF_WRAPPER_FLAG_ERR BIT(3) + +/* + * A dmabuf owned by the current VM with RWX permissions. + * All variants should be free'd via mem_buf_vmperm_free(). + * + * @dmabuf: value returned from dma_buf_export() + * @sgt: Reference to the exporter's internal memory descriptor. + * Will not be freed by mem_buf_vmperm_free(). + */ +struct mem_buf_vmperm *mem_buf_vmperm_alloc(struct sg_table *sgt); + +/* + * A dmabuf which permantently belongs to the given VMs & permissions. + */ +struct mem_buf_vmperm *mem_buf_vmperm_alloc_staticvm(struct sg_table *sgt, int *vmids, int *perms, + u32 nr_acl_entries); + +/* + * Performs the expected close step based on whether the dmabuf + * is of the "STATICVM" "MEMACCEPT" or "DEFAULT" type. + * Exporters should call this from dma_buf_release. If this function + * Returns an error, exporters should consider the underlying memory + * to have undefined permissions. + */ +int mem_buf_vmperm_release(struct mem_buf_vmperm *vmperm); + +/* + * Pins ths permissions of the dmabuf. + * The exporter should call this from dma_buf_mmap, vm_ops->open(), and + * dma_buf_map_attachment. It must not be called from + * dma_buf_begin_cpu_access as userspace may call this function unsafely + * via DMA_BUF_IOCTL_SYNC. + */ +void mem_buf_vmperm_pin(struct mem_buf_vmperm *vmperm); + +/* + * Unpins ths permissions of the dmabuf. + * The exporter should call this from vm_ops->close(), and + * dma_buf_unmap_attachment. It must not be called from + * dma_buf_end_cpu_access as userspace may call this function unsafely + * via DMA_BUF_IOCTL_SYNC. + */ +void mem_buf_vmperm_unpin(struct mem_buf_vmperm *vmperm); + +/* + * Check whether the current permissions of the dmabuf allow CMO. + * Requires RW. + * + * The exporter should call this during dma_buf_map/unmap_attachment, + * and dma_buf_begin/end_cpu_access. + */ +bool mem_buf_vmperm_can_cmo(struct mem_buf_vmperm *vmperm); + +/* + * Check whether the current permissions of the dmabuf allow mmap. + * Requires at minimum the permissions specified in vma. + * + * The exporter should call mem_buf_vmperm_pin() from mmap. + * The exporter should implement the open() and close() operations of + * vma->vm_ops, and call mem_buf_vmperm_pin()/unpin() respectively. + */ +bool mem_buf_vmperm_can_mmap(struct mem_buf_vmperm *vmperm, struct vm_area_struct *vma); + +/* + * Check whether the current permissions of the dmabuf allow vmap. + * Requires RW. + * + * The exporter should call this during dma_buf_vmap, + */ +bool mem_buf_vmperm_can_vmap(struct mem_buf_vmperm *vmperm); + +#endif /*_MEM_BUF_EXPORTER_H */