Re: [PATCH V2] accel/amdxdna: Remove mmap and export support for ubuf

["Christian König" <christian.koenig@amd.com>]

On 5/18/26 17:57, Lizhi Hou wrote:
> Ubuf pages should not be mmaped or exported. Remove the ubuf mmap callback
> and return -EOPNOTSUPP when exporting ubuf objects.
> 
> ubuf vmap is also removed for there is not a real use case yet.
> 
> Fixes: bd72d4acda10 ("accel/amdxdna: Support user space allocated buffer")
> Cc: Christian Koenig <christian.koenig@amd.com>
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
> v2:
>   Remove dead code amdxdna_ubuf_vm_ops structure and amdxdna_ubuf_vm_fault
>   function.
>   Rename Non-exportable buffer flag from 'pri' to 'private_buffer'
> 
>  drivers/accel/amdxdna/amdxdna_gem.c  |  9 ++++-
>  drivers/accel/amdxdna/amdxdna_gem.h  |  2 ++
>  drivers/accel/amdxdna/amdxdna_ubuf.c | 50 ----------------------------
>  3 files changed, 10 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/accel/amdxdna/amdxdna_gem.c b/drivers/accel/amdxdna/amdxdna_gem.c
> index 319d2064fafa..6b9b556de555 100644
> --- a/drivers/accel/amdxdna/amdxdna_gem.c
> +++ b/drivers/accel/amdxdna/amdxdna_gem.c
> @@ -492,6 +492,9 @@ static struct dma_buf *amdxdna_gem_prime_export(struct drm_gem_object *gobj, int
>  	struct amdxdna_gem_obj *abo = to_xdna_obj(gobj);
>  	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
>  
> +	if (abo->private_buffer)
> +		return ERR_PTR(-EOPNOTSUPP);
> +
>  	if (abo->dma_buf) {
>  		get_dma_buf(abo->dma_buf);
>  		return abo->dma_buf;
> @@ -716,6 +719,7 @@ amdxdna_gem_create_ubuf_object(struct drm_device *dev, struct amdxdna_drm_create
>  {
>  	struct amdxdna_dev *xdna = to_xdna_dev(dev);
>  	struct amdxdna_drm_va_tbl va_tbl;
> +	struct amdxdna_gem_obj *abo;
>  	struct drm_gem_object *gobj;
>  	struct dma_buf *dma_buf;
>  
> @@ -742,7 +746,10 @@ amdxdna_gem_create_ubuf_object(struct drm_device *dev, struct amdxdna_drm_create
>  
>  	dma_buf_put(dma_buf);
>  
> -	return to_xdna_obj(gobj);
> +	abo = to_xdna_obj(gobj);
> +	abo->private_buffer = true;
> +
> +	return abo;
>  }
>  
>  static struct amdxdna_gem_obj *
> diff --git a/drivers/accel/amdxdna/amdxdna_gem.h b/drivers/accel/amdxdna/amdxdna_gem.h
> index 4fc48a1189d2..957305ccb485 100644
> --- a/drivers/accel/amdxdna/amdxdna_gem.h
> +++ b/drivers/accel/amdxdna/amdxdna_gem.h
> @@ -54,6 +54,8 @@ struct amdxdna_gem_obj {
>  
>  	/* True, if BO is managed by XRT, not application */
>  	bool				internal;
> +	/* True, if BO is not exportable */
> +	bool				private_buffer;
>  };
>  
>  #define to_gobj(obj)    (&(obj)->base.base)
> diff --git a/drivers/accel/amdxdna/amdxdna_ubuf.c b/drivers/accel/amdxdna/amdxdna_ubuf.c
> index 3769210c55cc..bb60fb80467e 100644
> --- a/drivers/accel/amdxdna/amdxdna_ubuf.c
> +++ b/drivers/accel/amdxdna/amdxdna_ubuf.c
> @@ -69,60 +69,10 @@ static void amdxdna_ubuf_release(struct dma_buf *dbuf)
>  	kfree(ubuf);
>  }
>  
> -static vm_fault_t amdxdna_ubuf_vm_fault(struct vm_fault *vmf)
> -{
> -	struct vm_area_struct *vma = vmf->vma;
> -	struct amdxdna_ubuf_priv *ubuf;
> -	unsigned long pfn;
> -	pgoff_t pgoff;
> -
> -	ubuf = vma->vm_private_data;
> -	pgoff = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
> -
> -	pfn = page_to_pfn(ubuf->pages[pgoff]);
> -	return vmf_insert_pfn(vma, vmf->address, pfn);
> -}
> -
> -static const struct vm_operations_struct amdxdna_ubuf_vm_ops = {
> -	.fault = amdxdna_ubuf_vm_fault,
> -};
> -
> -static int amdxdna_ubuf_mmap(struct dma_buf *dbuf, struct vm_area_struct *vma)
> -{
> -	struct amdxdna_ubuf_priv *ubuf = dbuf->priv;
> -
> -	vma->vm_ops = &amdxdna_ubuf_vm_ops;
> -	vma->vm_private_data = ubuf;
> -	vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
> -
> -	return 0;
> -}
> -
> -static int amdxdna_ubuf_vmap(struct dma_buf *dbuf, struct iosys_map *map)
> -{
> -	struct amdxdna_ubuf_priv *ubuf = dbuf->priv;
> -	void *kva;
> -
> -	kva = vmap(ubuf->pages, ubuf->nr_pages, VM_MAP, PAGE_KERNEL);
> -	if (!kva)
> -		return -EINVAL;
> -
> -	iosys_map_set_vaddr(map, kva);
> -	return 0;
> -}
> -
> -static void amdxdna_ubuf_vunmap(struct dma_buf *dbuf, struct iosys_map *map)
> -{
> -	vunmap(map->vaddr);
> -}
> -
>  static const struct dma_buf_ops amdxdna_ubuf_dmabuf_ops = {
>  	.map_dma_buf = amdxdna_ubuf_map,
>  	.unmap_dma_buf = amdxdna_ubuf_unmap,
>  	.release = amdxdna_ubuf_release,
> -	.mmap = amdxdna_ubuf_mmap,
> -	.vmap = amdxdna_ubuf_vmap,
> -	.vunmap = amdxdna_ubuf_vunmap,
>  };
>  
>  static int readonly_va_entry(struct amdxdna_drm_va_entry *va_ent)