Re: [PATCH v2 03/11] drm/mediatek: Add secure buffer control flow to mtk_drm_gem

["Jason-JH Lin (林睿祥)" <Jason-JH.Lin@mediatek.com>]

Hi Angelo,

Thanks for the reviews.

On Tue, 2023-10-24 at 10:37 +0200, AngeloGioacchino Del Regno wrote:
> Il 23/10/23 06:45, Jason-JH.Lin ha scritto:
> > Add secure buffer control flow to mtk_drm_gem.
> > 
> > When user space takes DRM_MTK_GEM_CREATE_ENCRYPTED flag and size
> > to create a mtk_drm_gem object, mtk_drm_gem will find a matched
> > size
> > dma buffer from secure dma-heap and bind it to mtk_drm_gem object.
> > 
> > Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> > ---
> >   drivers/gpu/drm/mediatek/mtk_drm_gem.c | 84
> > +++++++++++++++++++++++++-
> >   drivers/gpu/drm/mediatek/mtk_drm_gem.h |  4 ++
> >   2 files changed, 87 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > index bcce723f257d..2064ccd7dde0 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > @@ -4,6 +4,8 @@
> >    */
> >   
> >   #include <linux/dma-buf.h>
> > +#include <linux/dma-heap.h>
> > +#include <uapi/linux/dma-heap.h>
> >   #include <drm/mediatek_drm.h>
> >   
> >   #include <drm/drm.h>
> > @@ -55,6 +57,80 @@ static struct mtk_drm_gem_obj
> > *mtk_drm_gem_init(struct drm_device *dev,
> >   	return mtk_gem_obj;
> >   }
> >   
> > +struct mtk_drm_gem_obj *mtk_drm_gem_create_from_heap(struct
> > drm_device *dev,
> > +						     const char *heap,
> > size_t size)
> > +{
> > +	struct mtk_drm_private *priv = dev->dev_private;
> > +	struct mtk_drm_gem_obj *mtk_gem;
> > +	struct drm_gem_object *obj;
> > +	struct dma_heap *dma_heap;
> > +	struct dma_buf *dma_buf;
> > +	struct dma_buf_attachment *attach;
> > +	struct sg_table *sgt;
> > +	struct iosys_map map = {};
> > +	int ret;
> > +
> > +	mtk_gem = mtk_drm_gem_init(dev, size);
> > +	if (IS_ERR(mtk_gem))
> > +		return ERR_CAST(mtk_gem);
> > +
> > +	obj = &mtk_gem->base;
> > +
> > +	dma_heap = dma_heap_find(heap);
> > +	if (!dma_heap) {
> > +		DRM_ERROR("heap find fail\n");
> > +		goto err_gem_free;
> > +	}
> > +	dma_buf = dma_heap_buffer_alloc(dma_heap, size,
> > +					O_RDWR | O_CLOEXEC,
> > DMA_HEAP_VALID_HEAP_FLAGS);
> > +	if (IS_ERR(dma_buf)) {
> > +		DRM_ERROR("buffer alloc fail\n");
> > +		dma_heap_put(dma_heap);
> > +		goto err_gem_free;
> > +	}
> > +	dma_heap_put(dma_heap);
> > +
> > +	attach = dma_buf_attach(dma_buf, priv->dma_dev);
> > +	if (IS_ERR(attach)) {
> > +		DRM_ERROR("attach fail, return\n");
> > +		dma_buf_put(dma_buf);
> > +		goto err_gem_free;
> > +	}
> 
> blank line here please

OK, I'll add one blank.

> 
> > +	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
> > +	if (IS_ERR(sgt)) {
> > +		DRM_ERROR("map failed, detach and return\n");
> > +		dma_buf_detach(dma_buf, attach);
> > +		dma_buf_put(dma_buf);
> > +		goto err_gem_free;
> > +	}
> > +	obj->import_attach = attach;
> > +	mtk_gem->dma_addr = sg_dma_address(sgt->sgl);
> > +	mtk_gem->sg = sgt;
> > +	mtk_gem->size = dma_buf->size;
> > +
> > +	if (!strcmp(heap, "mtk_svp") || !strcmp(heap, "mtk_svp_cma")) {
> > +		/* secure buffer can not be mapped */
> > +		mtk_gem->sec = true;
> > +	} else {
> > +		ret = dma_buf_vmap(dma_buf, &map);
> > +		mtk_gem->kvaddr = map.vaddr;
> > +		if (ret) {
> > +			DRM_ERROR("map failed, ret=%d\n", ret);
> > +			dma_buf_unmap_attachment(attach, sgt,
> > DMA_BIDIRECTIONAL);
> > +			dma_buf_detach(dma_buf, attach);
> > +			dma_buf_put(dma_buf);
> > +			mtk_gem->kvaddr = NULL;
> > +		}
> > +	}
> > +
> > +	return mtk_gem;
> > +
> > +err_gem_free:
> > +	drm_gem_object_release(obj);
> > +	kfree(mtk_gem);
> > +	return ERR_PTR(-ENOMEM);
> > +}
> > +
> >   struct mtk_drm_gem_obj *mtk_drm_gem_create(struct drm_device
> > *dev,
> >   					   size_t size, bool
> > alloc_kmap)
> >   {
> > @@ -218,7 +294,9 @@ struct drm_gem_object
> > *mtk_gem_prime_import_sg_table(struct drm_device *dev,
> >   	if (IS_ERR(mtk_gem))
> >   		return ERR_CAST(mtk_gem);
> >   
> > +	mtk_gem->sec = !sg_page(sg->sgl);
> >   	mtk_gem->dma_addr = sg_dma_address(sg->sgl);
> > +	mtk_gem->size = attach->dmabuf->size;
> >   	mtk_gem->sg = sg;
> >   
> >   	return &mtk_gem->base;
> > @@ -290,7 +368,11 @@ int mtk_gem_create_ioctl(struct drm_device
> > *dev, void *data,
> >   	struct drm_mtk_gem_create *args = data;
> >   	int ret;
> >   
> > -	mtk_gem = mtk_drm_gem_create(dev, args->size, false);
> > +	if (args->flags & DRM_MTK_GEM_CREATE_ENCRYPTED)
> > +		mtk_gem = mtk_drm_gem_create_from_heap(dev,
> > "mtk_svp_cma", args->size);
> > +	else
> > +		mtk_gem = mtk_drm_gem_create(dev, args->size, false);
> > +
> >   	if (IS_ERR(mtk_gem))
> >   		return PTR_ERR(mtk_gem);
> >   
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.h
> > b/drivers/gpu/drm/mediatek/mtk_drm_gem.h
> > index 90f3d2916ec5..ed4d23e252e9 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_gem.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.h
> > @@ -27,9 +27,11 @@ struct mtk_drm_gem_obj {
> >   	void			*cookie;
> >   	void			*kvaddr;
> >   	dma_addr_t		dma_addr;
> > +	size_t			size;
> >   	unsigned long		dma_attrs;
> >   	struct sg_table		*sg;
> >   	struct page		**pages;
> > +	bool			sec;
> 
> `sec` may be ambiguous. You can call that `secure` or
> `is_secure_buf`.
> 
OK, I'll change it to `secure`.

Regards,
Jason-JH.Lin

> >   };
> >   
> >   #define to_mtk_gem_obj(x)	container_of(x, struct mtk_drm_gem_obj,
> > base)
> > @@ -37,6 +39,8 @@ struct mtk_drm_gem_obj {
> >   void mtk_drm_gem_free_object(struct drm_gem_object *gem);
> >   struct mtk_drm_gem_obj *mtk_drm_gem_create(struct drm_device
> > *dev, size_t size,
> >   					   bool alloc_kmap);
> > +struct mtk_drm_gem_obj *mtk_drm_gem_create_from_heap(struct
> > drm_device *dev,
> > +						     const char *heap,
> > size_t size);
> >   int mtk_drm_gem_dumb_create(struct drm_file *file_priv, struct
> > drm_device *dev,
> >   			    struct drm_mode_create_dumb *args);
> >   struct sg_table *mtk_gem_prime_get_sg_table(struct drm_gem_object
> > *obj);
> 
> 
> 
>