[PATCH v3 4/7] drm/i915/pxp: Invalidate all PXP fw sessions during teardown
Juston Li
justonli at chromium.org
Wed Jan 4 23:34:29 UTC 2023
On Wed, 2022-12-21 at 15:06 -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 at intel.com>
Reviewed-by: Juston Li <justonli at chromium.org>
> ---
> 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);
> +}
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