diff mbox series

[v5,2/9] drm/mediatek: Add secure buffer control flow to mtk_drm_gem

Message ID 20240403102701.369-3-shawn.sung@mediatek.com (mailing list archive)
State New, archived
Headers show
Series Add mediate-drm secure flow for SVP | expand

Commit Message

Shawn Sung (宋孝謙) April 3, 2024, 10:26 a.m. UTC
From: "Jason-JH.Lin" <jason-jh.lin@mediatek.com>

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>
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_gem.c | 85 +++++++++++++++++++++++++++++-
 drivers/gpu/drm/mediatek/mtk_gem.h |  4 ++
 2 files changed, 88 insertions(+), 1 deletion(-)

Comments

Maxime Ripard April 15, 2024, 9:37 a.m. UTC | #1
On Wed, Apr 03, 2024 at 06:26:54PM +0800, Shawn Sung wrote:
> From: "Jason-JH.Lin" <jason-jh.lin@mediatek.com>
> 
> 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>
> Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_gem.c | 85 +++++++++++++++++++++++++++++-
>  drivers/gpu/drm/mediatek/mtk_gem.h |  4 ++
>  2 files changed, 88 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_gem.c b/drivers/gpu/drm/mediatek/mtk_gem.c
> index e59e0727717b7..ec34d02c14377 100644
> --- a/drivers/gpu/drm/mediatek/mtk_gem.c
> +++ b/drivers/gpu/drm/mediatek/mtk_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>
> @@ -102,6 +104,81 @@ struct mtk_gem_obj *mtk_gem_create(struct drm_device *dev,
>  	return ERR_PTR(ret);
>  }
>  
> +struct mtk_gem_obj *mtk_gem_create_from_heap(struct drm_device *dev,
> +					     const char *heap, size_t size)
> +{
> +	struct mtk_drm_private *priv = dev->dev_private;
> +	struct mtk_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_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;
> +	}
> +
> +	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->secure = 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);
> +}
> +
>  void mtk_gem_free_object(struct drm_gem_object *obj)
>  {
>  	struct mtk_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
> @@ -229,7 +306,9 @@ 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->secure = !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;
> @@ -304,7 +383,11 @@ int mtk_gem_create_ioctl(struct drm_device *dev, void *data,
>  	struct drm_mtk_gem_create *args = data;
>  	int ret;
>  
> -	mtk_gem = mtk_gem_create(dev, args->size, false);
> +	if (args->flags & DRM_MTK_GEM_CREATE_ENCRYPTED)
> +		mtk_gem = mtk_gem_create_from_heap(dev, "mtk_svp_cma", args->size);

That heap doesn't exist upstream either. Also, I'm wondering if it's the
right solution there.

From what I can tell, you want to allow to create encrypted buffers from
the TEE. Why do we need this as a DRM ioctl at all? A heap seems like
the perfect solution to do so, and then you just have to import it into
DRM.

I'm also not entirely sure that not having a SG list is enough to
consider the buffer secure. Wouldn't a buffer allocated without a kernel
mapping also be in that situation?

Maxime
Jason-JH.Lin May 28, 2024, 7:06 a.m. UTC | #2
Hi Maxime,

[snip]

I'm sorry for losing your previous comment mail.
I finally found a way to import this mail back so I can reply to you.

> > -	mtk_gem = mtk_gem_create(dev, args->size, false);
> > +	if (args->flags & DRM_MTK_GEM_CREATE_ENCRYPTED)
> > +		mtk_gem = mtk_gem_create_from_heap(dev, "mtk_svp_cma",
> > args->size);
> 
> That heap doesn't exist upstream either. Also, I'm wondering if it's
> the
> right solution there.
> 

Yes, I found that its name changed to "restricted_mtk_cma" in the
latest patch: 
https://patchwork.kernel.org/project/linux-mediatek/patch/20240515112308.10171-10-yong.wu@mediatek.com/

> From what I can tell, you want to allow to create encrypted buffers
> from
> the TEE. Why do we need this as a DRM ioctl at all? A heap seems like
> the perfect solution to do so, and then you just have to import it
> into
> DRM.
> 

OK, I'll try to change the userspace's ioctl from
DRM_IOCTL_MTK_GEM_CREATE to DMA_HEAP_IOCTL_ALLOC to get the buffer fd,
then import to DRM.

> I'm also not entirely sure that not having a SG list is enough to
> consider the buffer secure. Wouldn't a buffer allocated without a
> kernel
> mapping also be in that situation?
> 

I have confirmed to Yong.Wu that secure buffer also have sg list, so
the secure checking method "!sg_page(sg->sgl)" will be deprecated.

Regards,
Jason-JH.Lin

> Maxime
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mediatek/mtk_gem.c b/drivers/gpu/drm/mediatek/mtk_gem.c
index e59e0727717b7..ec34d02c14377 100644
--- a/drivers/gpu/drm/mediatek/mtk_gem.c
+++ b/drivers/gpu/drm/mediatek/mtk_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>
@@ -102,6 +104,81 @@  struct mtk_gem_obj *mtk_gem_create(struct drm_device *dev,
 	return ERR_PTR(ret);
 }
 
+struct mtk_gem_obj *mtk_gem_create_from_heap(struct drm_device *dev,
+					     const char *heap, size_t size)
+{
+	struct mtk_drm_private *priv = dev->dev_private;
+	struct mtk_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_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;
+	}
+
+	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->secure = 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);
+}
+
 void mtk_gem_free_object(struct drm_gem_object *obj)
 {
 	struct mtk_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
@@ -229,7 +306,9 @@  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->secure = !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;
@@ -304,7 +383,11 @@  int mtk_gem_create_ioctl(struct drm_device *dev, void *data,
 	struct drm_mtk_gem_create *args = data;
 	int ret;
 
-	mtk_gem = mtk_gem_create(dev, args->size, false);
+	if (args->flags & DRM_MTK_GEM_CREATE_ENCRYPTED)
+		mtk_gem = mtk_gem_create_from_heap(dev, "mtk_svp_cma", args->size);
+	else
+		mtk_gem = mtk_gem_create(dev, args->size, false);
+
 	if (IS_ERR(mtk_gem))
 		return PTR_ERR(mtk_gem);
 
diff --git a/drivers/gpu/drm/mediatek/mtk_gem.h b/drivers/gpu/drm/mediatek/mtk_gem.h
index 4d7598220ca8f..75cf50495abe0 100644
--- a/drivers/gpu/drm/mediatek/mtk_gem.h
+++ b/drivers/gpu/drm/mediatek/mtk_gem.h
@@ -27,9 +27,11 @@  struct mtk_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			secure;
 };
 
 #define to_mtk_gem_obj(x) container_of(x, struct mtk_gem_obj, base)
@@ -37,6 +39,8 @@  struct mtk_gem_obj {
 void mtk_gem_free_object(struct drm_gem_object *gem);
 struct mtk_gem_obj *mtk_gem_create(struct drm_device *dev, size_t size,
 				   bool alloc_kmap);
+struct mtk_gem_obj *mtk_gem_create_from_heap(struct drm_device *dev,
+					     const char *heap, size_t size);
 int mtk_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);