Re: [Intel-gfx] [PATCH v5 4/6] drm/i915/pxp: Invalidate all PXP fw sessions during teardown

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, Jan 12, 2023 at 05:18:48PM -0800, Alan Previn wrote:
> A gap was recently discovered where if an application did not
> invalidate all of the stream keys (intentionally or not), and the
> driver did a full PXP global teardown on the GT subsystem, we
> find that future session creation would fail on the security
> firmware's side of the equation. i915 is the entity that needs
> ensure the sessions' state across both iGT and security firmware
> are at a known clean point when performing a full global teardown.
> 
> Architecturally speaking, i915 should inspect all active sessions
> and submit the invalidate-stream-key PXP command to the security
> firmware for each of them. However, for the upstream i915 driver
> we only support the arbitration session that can be created
> so that will be the only session we will cleanup.
> 
> Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
> Reviewed-by: Juston Li <justonli@chromium.org>

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/pxp/intel_pxp.h          |  1 +
>  .../drm/i915/pxp/intel_pxp_cmd_interface_42.h | 15 ++++++++
>  .../i915/pxp/intel_pxp_cmd_interface_cmn.h    |  3 ++
>  drivers/gpu/drm/i915/pxp/intel_pxp_session.c  |  2 ++
>  drivers/gpu/drm/i915/pxp/intel_pxp_tee.c      | 35 +++++++++++++++++++
>  5 files changed, 56 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> index 04440fada711..9658d3005222 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> @@ -24,6 +24,7 @@ void intel_pxp_init_hw(struct intel_pxp *pxp);
>  void intel_pxp_fini_hw(struct intel_pxp *pxp);
>  
>  void intel_pxp_mark_termination_in_progress(struct intel_pxp *pxp);
> +void intel_pxp_tee_end_arb_fw_session(struct intel_pxp *pxp, u32 arb_session_id);
>  
>  int intel_pxp_start(struct intel_pxp *pxp);
>  
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_42.h b/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_42.h
> index 739f9072fa5f..26f7d9f01bf3 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_42.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_42.h
> @@ -12,6 +12,9 @@
>  /* PXP-Opcode for Init Session */
>  #define PXP42_CMDID_INIT_SESSION 0x1e
>  
> +/* PXP-Opcode for Invalidate Stream Key */
> +#define PXP42_CMDID_INVALIDATE_STREAM_KEY 0x00000007
> +
>  /* PXP-Input-Packet: Init Session (Arb-Session) */
>  struct pxp42_create_arb_in {
>  	struct pxp_cmd_header header;
> @@ -25,4 +28,16 @@ struct pxp42_create_arb_out {
>  	struct pxp_cmd_header header;
>  } __packed;
>  
> +/* PXP-Input-Packet: Invalidate Stream Key */
> +struct pxp42_inv_stream_key_in {
> +	struct pxp_cmd_header header;
> +	u32 rsvd[3];
> +} __packed;
> +
> +/* PXP-Output-Packet: Invalidate Stream Key */
> +struct pxp42_inv_stream_key_out {
> +	struct pxp_cmd_header header;
> +	u32 rsvd;
> +} __packed;
> +
>  #endif /* __INTEL_PXP_FW_INTERFACE_42_H__ */
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_cmn.h b/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_cmn.h
> index c2f23394f9b8..69e34ec49e78 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_cmn.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_cmd_interface_cmn.h
> @@ -27,6 +27,9 @@ struct pxp_cmd_header {
>  	union {
>  		u32 status; /* out */
>  		u32 stream_id; /* in */
> +#define PXP_CMDHDR_EXTDATA_SESSION_VALID GENMASK(0, 0)
> +#define PXP_CMDHDR_EXTDATA_APP_TYPE GENMASK(1, 1)
> +#define PXP_CMDHDR_EXTDATA_SESSION_ID GENMASK(17, 2)
>  	};
>  	/* Length of the message (excluding the header) */
>  	u32 buffer_len;
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> index ae413580b81a..74ed7e16e481 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> @@ -110,6 +110,8 @@ static int pxp_terminate_arb_session_and_global(struct intel_pxp *pxp)
>  
>  	intel_uncore_write(gt->uncore, PXP_GLOBAL_TERMINATE, 1);
>  
> +	intel_pxp_tee_end_arb_fw_session(pxp, ARB_SESSION);
> +
>  	return ret;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
> index bef6d7f8ac55..9e247f38f3bd 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
> @@ -311,3 +311,38 @@ int intel_pxp_tee_cmd_create_arb_session(struct intel_pxp *pxp,
>  
>  	return ret;
>  }
> +
> +void intel_pxp_tee_end_arb_fw_session(struct intel_pxp *pxp, u32 session_id)
> +{
> +	struct drm_i915_private *i915 = pxp->ctrl_gt->i915;
> +	struct pxp42_inv_stream_key_in msg_in = {0};
> +	struct pxp42_inv_stream_key_out msg_out = {0};
> +	int ret, trials = 0;
> +
> +try_again:
> +	memset(&msg_in, 0, sizeof(msg_in));
> +	memset(&msg_out, 0, sizeof(msg_out));
> +	msg_in.header.api_version = PXP_APIVER(4, 2);
> +	msg_in.header.command_id = PXP42_CMDID_INVALIDATE_STREAM_KEY;
> +	msg_in.header.buffer_len = sizeof(msg_in) - sizeof(msg_in.header);
> +
> +	msg_in.header.stream_id = FIELD_PREP(PXP_CMDHDR_EXTDATA_SESSION_VALID, 1);
> +	msg_in.header.stream_id |= FIELD_PREP(PXP_CMDHDR_EXTDATA_APP_TYPE, 0);
> +	msg_in.header.stream_id |= FIELD_PREP(PXP_CMDHDR_EXTDATA_SESSION_ID, session_id);
> +
> +	ret = intel_pxp_tee_io_message(pxp,
> +				       &msg_in, sizeof(msg_in),
> +				       &msg_out, sizeof(msg_out),
> +				       NULL);
> +
> +	/* Cleanup coherency between GT and Firmware is critical, so try again if it fails */
> +	if ((ret || msg_out.header.status != 0x0) && ++trials < 3)
> +		goto try_again;
> +
> +	if (ret)
> +		drm_err(&i915->drm, "Failed to send tee msg for inv-stream-key-%d, ret=[%d]\n",
> +			session_id, ret);
> +	else if (msg_out.header.status != 0x0)
> +		drm_warn(&i915->drm, "PXP firmware failed inv-stream-key-%d with status 0x%08x\n",
> +			 session_id, msg_out.header.status);
> +}
> -- 
> 2.39.0
>