root/drivers/accel/ivpu/ivpu_gem_userptr.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2020-2025 Intel Corporation
 */

#include <linux/dma-buf.h>
#include <linux/err.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/capability.h>

#include <drm/drm_device.h>
#include <drm/drm_file.h>
#include <drm/drm_gem.h>

#include "ivpu_drv.h"
#include "ivpu_gem.h"

static struct sg_table *
ivpu_gem_userptr_dmabuf_map(struct dma_buf_attachment *attachment,
                            enum dma_data_direction direction)
{
        struct sg_table *sgt = attachment->dmabuf->priv;
        int ret;

        ret = dma_map_sgtable(attachment->dev, sgt, direction, DMA_ATTR_SKIP_CPU_SYNC);
        if (ret)
                return ERR_PTR(ret);

        return sgt;
}

static void ivpu_gem_userptr_dmabuf_unmap(struct dma_buf_attachment *attachment,
                                          struct sg_table *sgt,
                                          enum dma_data_direction direction)
{
        dma_unmap_sgtable(attachment->dev, sgt, direction, DMA_ATTR_SKIP_CPU_SYNC);
}

static void ivpu_gem_userptr_dmabuf_release(struct dma_buf *dma_buf)
{
        struct sg_table *sgt = dma_buf->priv;
        struct sg_page_iter page_iter;
        struct page *page;

        for_each_sgtable_page(sgt, &page_iter, 0) {
                page = sg_page_iter_page(&page_iter);
                unpin_user_page(page);
        }

        sg_free_table(sgt);
        kfree(sgt);
}

static const struct dma_buf_ops ivpu_gem_userptr_dmabuf_ops = {
        .map_dma_buf = ivpu_gem_userptr_dmabuf_map,
        .unmap_dma_buf = ivpu_gem_userptr_dmabuf_unmap,
        .release = ivpu_gem_userptr_dmabuf_release,
};

static struct dma_buf *
ivpu_create_userptr_dmabuf(struct ivpu_device *vdev, void __user *user_ptr,
                           size_t size, uint32_t flags)
{
        struct dma_buf_export_info exp_info = {};
        struct dma_buf *dma_buf;
        struct sg_table *sgt;
        struct page **pages;
        unsigned long nr_pages = size >> PAGE_SHIFT;
        unsigned int gup_flags = FOLL_LONGTERM;
        int ret, i, pinned;

        /* Add FOLL_WRITE only if the BO is not read-only */
        if (!(flags & DRM_IVPU_BO_READ_ONLY))
                gup_flags |= FOLL_WRITE;

        pages = kvmalloc_objs(*pages, nr_pages);
        if (!pages)
                return ERR_PTR(-ENOMEM);

        pinned = pin_user_pages_fast((unsigned long)user_ptr, nr_pages, gup_flags, pages);
        if (pinned < 0) {
                ret = pinned;
                ivpu_dbg(vdev, IOCTL, "Failed to pin user pages: %d\n", ret);
                goto free_pages_array;
        }

        if (pinned != nr_pages) {
                ivpu_dbg(vdev, IOCTL, "Pinned %d pages, expected %lu\n", pinned, nr_pages);
                ret = -EFAULT;
                goto unpin_pages;
        }

        sgt = kmalloc_obj(*sgt);
        if (!sgt) {
                ret = -ENOMEM;
                goto unpin_pages;
        }

        ret = sg_alloc_table_from_pages(sgt, pages, nr_pages, 0, size, GFP_KERNEL);
        if (ret) {
                ivpu_dbg(vdev, IOCTL, "Failed to create sg table: %d\n", ret);
                goto free_sgt;
        }

        exp_info.exp_name = "ivpu_userptr_dmabuf";
        exp_info.owner = THIS_MODULE;
        exp_info.ops = &ivpu_gem_userptr_dmabuf_ops;
        exp_info.size = size;
        exp_info.flags = O_RDWR | O_CLOEXEC;
        exp_info.priv = sgt;

        dma_buf = dma_buf_export(&exp_info);
        if (IS_ERR(dma_buf)) {
                ret = PTR_ERR(dma_buf);
                ivpu_dbg(vdev, IOCTL, "Failed to export userptr dma-buf: %d\n", ret);
                goto free_sg_table;
        }

        kvfree(pages);
        return dma_buf;

free_sg_table:
        sg_free_table(sgt);
free_sgt:
        kfree(sgt);
unpin_pages:
        for (i = 0; i < pinned; i++)
                unpin_user_page(pages[i]);
free_pages_array:
        kvfree(pages);
        return ERR_PTR(ret);
}

static struct ivpu_bo *
ivpu_bo_create_from_userptr(struct ivpu_device *vdev, void __user *user_ptr,
                            size_t size, uint32_t flags)
{
        struct dma_buf *dma_buf;
        struct drm_gem_object *obj;
        struct ivpu_bo *bo;

        dma_buf = ivpu_create_userptr_dmabuf(vdev, user_ptr, size, flags);
        if (IS_ERR(dma_buf))
                return ERR_CAST(dma_buf);

        obj = ivpu_gem_prime_import(&vdev->drm, dma_buf);
        if (IS_ERR(obj)) {
                dma_buf_put(dma_buf);
                return ERR_CAST(obj);
        }

        dma_buf_put(dma_buf);

        bo = to_ivpu_bo(obj);
        bo->flags = flags;

        return bo;
}

int ivpu_bo_create_from_userptr_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
{
        struct drm_ivpu_bo_create_from_userptr *args = data;
        struct ivpu_file_priv *file_priv = file->driver_priv;
        struct ivpu_device *vdev = to_ivpu_device(dev);
        void __user *user_ptr = u64_to_user_ptr(args->user_ptr);
        struct ivpu_bo *bo;
        int ret;

        if (args->flags & ~(DRM_IVPU_BO_HIGH_MEM | DRM_IVPU_BO_DMA_MEM | DRM_IVPU_BO_READ_ONLY)) {
                ivpu_dbg(vdev, IOCTL, "Invalid BO flags: 0x%x\n", args->flags);
                return -EINVAL;
        }

        if (!args->user_ptr || !args->size) {
                ivpu_dbg(vdev, IOCTL, "Userptr or size are zero: ptr %llx size %llu\n",
                         args->user_ptr, args->size);
                return -EINVAL;
        }

        if (!PAGE_ALIGNED(args->user_ptr) || !PAGE_ALIGNED(args->size)) {
                ivpu_dbg(vdev, IOCTL, "Userptr or size not page aligned: ptr %llx size %llu\n",
                         args->user_ptr, args->size);
                return -EINVAL;
        }

        if (!access_ok(user_ptr, args->size)) {
                ivpu_dbg(vdev, IOCTL, "Userptr is not accessible: ptr %llx size %llu\n",
                         args->user_ptr, args->size);
                return -EFAULT;
        }

        bo = ivpu_bo_create_from_userptr(vdev, user_ptr, args->size, args->flags);
        if (IS_ERR(bo))
                return PTR_ERR(bo);

        ret = drm_gem_handle_create(file, &bo->base.base, &args->handle);
        if (ret) {
                ivpu_dbg(vdev, IOCTL, "Failed to create handle for BO: %pe ctx %u size %llu flags 0x%x\n",
                         bo, file_priv->ctx.id, args->size, args->flags);
        } else {
                ivpu_dbg(vdev, BO, "Created userptr BO: handle=%u vpu_addr=0x%llx size=%llu flags=0x%x\n",
                         args->handle, bo->vpu_addr, args->size, bo->flags);
                args->vpu_addr = bo->vpu_addr;
        }

        drm_gem_object_put(&bo->base.base);

        return ret;
}