[Intel-gfx] [PATCH 1/2] drm/i915/hdcp: Allocate a multipage object to hdcp_gsc_message

Ceraolo Spurio, Daniele daniele.ceraolospurio at intel.com
Thu Jun 1 22:39:04 UTC 2023



On 5/29/2023 4:49 AM, Suraj Kandpal wrote:
> Allocate a multipage object that can be used for input
> and output for intel_hdcp_gsc_message so that corruption of
> output message can be avoided by the current overwriting method.
>
> --v2
> -Change approach from allocating two objects to just one multipage
> object [Daniele]
>
> Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> Cc: Alan Previn <alan.previn.teres.alexis at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_hdcp_gsc.c | 55 +++++++++++--------
>   drivers/gpu/drm/i915/display/intel_hdcp_gsc.h |  3 +-
>   2 files changed, 34 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> index 7e52aea6aa17..72d1e261d0a9 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> @@ -621,24 +621,26 @@ static int intel_hdcp_gsc_initialize_message(struct drm_i915_private *i915,
>   	struct intel_gt *gt = i915->media_gt;
>   	struct drm_i915_gem_object *obj = NULL;
>   	struct i915_vma *vma = NULL;
> -	void *cmd;
> +	void *cmd_in, *cmd_out;
>   	int err;
>   
> -	/* allocate object of one page for HDCP command memory and store it */
> -	obj = i915_gem_object_create_shmem(i915, PAGE_SIZE);
> +	/* allocate object of two page for HDCP command memory and store it */
> +	obj = i915_gem_object_create_shmem(i915, 2 * PAGE_SIZE);
>   
>   	if (IS_ERR(obj)) {
>   		drm_err(&i915->drm, "Failed to allocate HDCP streaming command!\n");
>   		return PTR_ERR(obj);
>   	}
>   
> -	cmd = i915_gem_object_pin_map_unlocked(obj, i915_coherent_map_type(i915, obj, true));
> -	if (IS_ERR(cmd)) {
> +	cmd_in = i915_gem_object_pin_map_unlocked(obj, i915_coherent_map_type(i915, obj, true));
> +	if (IS_ERR(cmd_in)) {
>   		drm_err(&i915->drm, "Failed to map gsc message page!\n");
> -		err = PTR_ERR(cmd);
> +		err = PTR_ERR(cmd_in);
>   		goto out_unpin;
>   	}
>   
> +	cmd_out = cmd_in + PAGE_SIZE;
> +
>   	vma = i915_vma_instance(obj, &gt->ggtt->vm, NULL);
>   	if (IS_ERR(vma)) {
>   		err = PTR_ERR(vma);
> @@ -649,9 +651,10 @@ static int intel_hdcp_gsc_initialize_message(struct drm_i915_private *i915,
>   	if (err)
>   		goto out_unmap;
>   
> -	memset(cmd, 0, obj->base.size);
> +	memset(cmd_in, 0, obj->base.size);
>   
> -	hdcp_message->hdcp_cmd = cmd;
> +	hdcp_message->hdcp_cmd_in = cmd_in;
> +	hdcp_message->hdcp_cmd_out = cmd_out;
>   	hdcp_message->vma = vma;
>   
>   	return 0;
> @@ -668,7 +671,7 @@ static int intel_hdcp_gsc_hdcp2_init(struct drm_i915_private *i915)
>   	struct intel_hdcp_gsc_message *hdcp_message;
>   	int ret;
>   
> -	hdcp_message = kzalloc(sizeof(*hdcp_message), GFP_KERNEL);
> +	hdcp_message = kzalloc(2 * sizeof(*hdcp_message), GFP_KERNEL);

As far as I can see you only need 1 hdcp_message structure, so no need 
to double the alloc size here.
With this fixed:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

Daniele

>   
>   	if (!hdcp_message)
>   		return -ENOMEM;
> @@ -691,6 +694,8 @@ static void intel_hdcp_gsc_free_message(struct drm_i915_private *i915)
>   	struct intel_hdcp_gsc_message *hdcp_message =
>   					i915->display.hdcp.hdcp_message;
>   
> +	hdcp_message->hdcp_cmd_in = NULL;
> +	hdcp_message->hdcp_cmd_out = NULL;
>   	i915_vma_unpin_and_release(&hdcp_message->vma, I915_VMA_RELEASE_MAP);
>   	kfree(hdcp_message);
>   }
> @@ -769,11 +774,11 @@ ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private *i915, u8 *msg_in,
>   				size_t msg_out_len)
>   {
>   	struct intel_gt *gt = i915->media_gt;
> -	struct intel_gsc_mtl_header *header;
> -	const size_t max_msg_size = PAGE_SIZE - sizeof(*header);
> +	struct intel_gsc_mtl_header *header_in, *header_out;
> +	const size_t max_msg_size = PAGE_SIZE - sizeof(*header_in);
>   	struct intel_hdcp_gsc_message *hdcp_message;
> -	u64 addr, host_session_id;
> -	u32 reply_size, msg_size;
> +	u64 addr_in, addr_out, host_session_id;
> +	u32 reply_size, msg_size_in, msg_size_out;
>   	int ret, tries = 0;
>   
>   	if (!intel_uc_uses_gsc_uc(&gt->uc))
> @@ -782,16 +787,20 @@ ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private *i915, u8 *msg_in,
>   	if (msg_in_len > max_msg_size || msg_out_len > max_msg_size)
>   		return -ENOSPC;
>   
> +	msg_size_in = msg_in_len + sizeof(*header_in);
> +	msg_size_out = msg_out_len + sizeof(*header_out);
>   	hdcp_message = i915->display.hdcp.hdcp_message;
> -	header = hdcp_message->hdcp_cmd;
> -	addr = i915_ggtt_offset(hdcp_message->vma);
> +	header_in = hdcp_message->hdcp_cmd_in;
> +	header_out = hdcp_message->hdcp_cmd_out;
> +	addr_in = i915_ggtt_offset(hdcp_message->vma);
> +	addr_out = addr_in + PAGE_SIZE;
>   
> -	msg_size = msg_in_len + sizeof(*header);
> -	memset(header, 0, msg_size);
> +	memset(header_in, 0, msg_size_in);
> +	memset(header_out, 0, msg_size_out);
>   	get_random_bytes(&host_session_id, sizeof(u64));
> -	intel_gsc_uc_heci_cmd_emit_mtl_header(header, HECI_MEADDRESS_HDCP,
> -					      msg_size, host_session_id);
> -	memcpy(hdcp_message->hdcp_cmd + sizeof(*header), msg_in, msg_in_len);
> +	intel_gsc_uc_heci_cmd_emit_mtl_header(header_in, HECI_MEADDRESS_HDCP,
> +					      msg_size_in, host_session_id);
> +	memcpy(hdcp_message->hdcp_cmd_in + sizeof(*header_in), msg_in, msg_in_len);
>   
>   	/*
>   	 * Keep sending request in case the pending bit is set no need to add
> @@ -800,7 +809,7 @@ ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private *i915, u8 *msg_in,
>   	 * 20 times each message 50 ms apart
>   	 */
>   	do {
> -		ret = intel_gsc_send_sync(i915, header, addr, msg_out_len);
> +		ret = intel_gsc_send_sync(i915, header_in, addr_in, msg_out_len);
>   
>   		/* Only try again if gsc says so */
>   		if (ret != -EAGAIN)
> @@ -814,7 +823,7 @@ ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private *i915, u8 *msg_in,
>   		goto err;
>   
>   	/* we use the same mem for the reply, so header is in the same loc */
> -	reply_size = header->message_size - sizeof(*header);
> +	reply_size = header_out->message_size - sizeof(*header_out);
>   	if (reply_size > msg_out_len) {
>   		drm_warn(&i915->drm, "caller with insufficient HDCP reply size %u (%d)\n",
>   			 reply_size, (u32)msg_out_len);
> @@ -824,7 +833,7 @@ ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private *i915, u8 *msg_in,
>   			    reply_size, (u32)msg_out_len);
>   	}
>   
> -	memcpy(msg_out, hdcp_message->hdcp_cmd + sizeof(*header), msg_out_len);
> +	memcpy(msg_out, hdcp_message->hdcp_cmd_out + sizeof(*header_out), msg_out_len);
>   
>   err:
>   	return ret;
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.h b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.h
> index 5cc9fd2e88f6..cbf96551e534 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.h
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.h
> @@ -13,7 +13,8 @@ struct drm_i915_private;
>   
>   struct intel_hdcp_gsc_message {
>   	struct i915_vma *vma;
> -	void *hdcp_cmd;
> +	void *hdcp_cmd_in;
> +	void *hdcp_cmd_out;
>   };
>   
>   bool intel_hdcp_gsc_cs_required(struct drm_i915_private *i915);



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