[Intel-gfx] [PATCH 1/2] drm/i915/hdcp: Create hdcp_gsc_message in and out

[Ceraolo Spurio, Daniele]

On 5/19/2023 2:49 AM, Suraj Kandpal wrote:
> Add hdcp_gsc_message_in and hdcp_gsc_message_out to help
> differenctiate the reply given by gsc to avoid any kind of
> message corruption due message structure reuse.
> hdcp_gsc_message_out will be filled in upcoming patches

Generic question on the approach: for both PXP and GSC proxy, we 
allocate a single multi-page object and use the first half for input and 
the second half output. This makes things simpler because we don't need 
to allocate, map and then cleanup 2 separate objects. Any reason not to 
follow a similar approach here?

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>
> ---
>   .../gpu/drm/i915/display/intel_display_core.h |  3 +-
>   drivers/gpu/drm/i915/display/intel_hdcp_gsc.c | 41 +++++++++++++------
>   2 files changed, 31 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h
> index e36f88a39b86..ead16d341f5c 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_core.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_core.h
> @@ -403,7 +403,8 @@ struct intel_display {
>   		 * reused when sending message to gsc cs.
>   		 * this is only populated post Meteorlake
>   		 */
> -		struct intel_hdcp_gsc_message *hdcp_message;
> +		struct intel_hdcp_gsc_message *hdcp_message_in;
> +		struct intel_hdcp_gsc_message *hdcp_message_out;
>   		/* Mutex to protect the above hdcp component related values. */
>   		struct mutex comp_mutex;
>   	} hdcp;
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> index 7e52aea6aa17..be505b2d679e 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> @@ -665,34 +665,51 @@ static int intel_hdcp_gsc_initialize_message(struct drm_i915_private *i915,
>   
>   static int intel_hdcp_gsc_hdcp2_init(struct drm_i915_private *i915)
>   {
> -	struct intel_hdcp_gsc_message *hdcp_message;
> +	struct intel_hdcp_gsc_message *hdcp_message_in, *hdcp_message_out;
>   	int ret;
>   
> -	hdcp_message = kzalloc(sizeof(*hdcp_message), GFP_KERNEL);
> +	hdcp_message_in = kzalloc(sizeof(*hdcp_message_in), GFP_KERNEL);
>   
> -	if (!hdcp_message)
> +	if (!hdcp_message_in)
>   		return -ENOMEM;
>   
> +	hdcp_message_out = kzalloc(sizeof(*hdcp_message_out), GFP_KERNEL);
> +
> +	if (!hdcp_message_out)
> +		return -ENOMEM;
>   	/*
>   	 * NOTE: No need to lock the comp mutex here as it is already
>   	 * going to be taken before this function called
>   	 */
> -	i915->display.hdcp.hdcp_message = hdcp_message;
> -	ret = intel_hdcp_gsc_initialize_message(i915, hdcp_message);
> +	i915->display.hdcp.hdcp_message_in = hdcp_message_in;
> +	ret = intel_hdcp_gsc_initialize_message(i915, hdcp_message_in);
> +
> +	if (ret) {
> +		drm_err(&i915->drm, "Could not initialize hdcp_message_in\n");
> +		goto out;
> +	}
> +
> +	i915->display.hdcp.hdcp_message_out = hdcp_message_out;
> +	ret = intel_hdcp_gsc_initialize_message(i915, hdcp_message_out);
>   
>   	if (ret)
> -		drm_err(&i915->drm, "Could not initialize hdcp_message\n");
> +		drm_err(&i915->drm, "Could not initialize hdcp_message_out\n");
>   
> +out:
>   	return ret;
>   }
>   
>   static void intel_hdcp_gsc_free_message(struct drm_i915_private *i915)
>   {
> -	struct intel_hdcp_gsc_message *hdcp_message =
> -					i915->display.hdcp.hdcp_message;
> -
> -	i915_vma_unpin_and_release(&hdcp_message->vma, I915_VMA_RELEASE_MAP);
> -	kfree(hdcp_message);
> +	struct intel_hdcp_gsc_message *hdcp_message_in =
> +					i915->display.hdcp.hdcp_message_in;
> +	struct intel_hdcp_gsc_message *hdcp_message_out =
> +					i915->display.hdcp.hdcp_message_out;
> +
> +	i915_vma_unpin_and_release(&hdcp_message_in->vma, I915_VMA_RELEASE_MAP);
> +	i915_vma_unpin_and_release(&hdcp_message_out->vma, I915_VMA_RELEASE_MAP);
> +	kfree(hdcp_message_in);
> +	kfree(hdcp_message_out);
>   }
>   
>   int intel_hdcp_gsc_init(struct drm_i915_private *i915)
> @@ -782,7 +799,7 @@ 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;
>   
> -	hdcp_message = i915->display.hdcp.hdcp_message;
> +	hdcp_message = i915->display.hdcp.hdcp_message_in;
>   	header = hdcp_message->hdcp_cmd;
>   	addr = i915_ggtt_offset(hdcp_message->vma);
>