[Intel-gfx] [RFC-v4 09/26] drm/i915/pxp: Implement ioctl action to reserve session slot

["Huang, Sean Z" <sean.z.huang@intel.com>]

With this ioctl action, user space driver can reserve a specific
session slot/id assigned by PXP, as the first step of PXP session
establishment flow. The session info is stored in the session list
structure.

Signed-off-by: Huang, Sean Z <sean.z.huang@intel.com>
---
 drivers/gpu/drm/i915/pxp/intel_pxp.c    |  20 ++++
 drivers/gpu/drm/i915/pxp/intel_pxp.h    |  24 +++-
 drivers/gpu/drm/i915/pxp/intel_pxp_sm.c | 149 +++++++++++++++++++++++-
 drivers/gpu/drm/i915/pxp/intel_pxp_sm.h |   3 +
 4 files changed, 193 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
index ba473e1f4dde..d0d126205b12 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp.c
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
@@ -39,6 +39,26 @@ int i915_pxp_ops_ioctl(struct drm_device *dev, void *data, struct drm_file *drmf
 	}
 
 	switch (pxp_info.action) {
+	case PXP_ACTION_SET_SESSION_STATUS:
+	{
+		struct pxp_sm_set_session_status_params *params = &pxp_info.set_session_status;
+
+		if (params->req_session_state == PXP_SM_REQ_SESSION_ID_INIT) {
+			ret = intel_pxp_sm_reserve_session(i915, drmfile, 0,
+							   params->session_type,
+							   params->session_mode,
+							   &params->pxp_tag);
+			if (ret == PXP_SM_STATUS_RETRY_REQUIRED ||
+			    ret == PXP_SM_STATUS_SESSION_NOT_AVAILABLE) {
+				pxp_info.sm_status = ret;
+				ret = 0;
+			}
+		} else {
+			ret = -EINVAL;
+			goto end;
+		}
+		break;
+	}
 	case PXP_ACTION_SET_USER_CONTEXT:
 	{
 		ret = intel_pxp_set_user_ctx(i915, pxp_info.set_user_ctx);
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
index c781a07bb7d5..ed77630bb7c4 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp.h
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
@@ -15,6 +15,9 @@
 #define pxp_session_list(i915, session_type) (((session_type) == SESSION_TYPE_TYPE0) ? \
 	&(i915)->pxp.ctx->active_pxp_type0_sessions : &(i915)->pxp.ctx->active_pxp_type1_sessions)
 
+#define pxp_session_max(session_type) (((session_type) == SESSION_TYPE_TYPE0) ? \
+	MAX_TYPE0_SESSIONS : MAX_TYPE1_SESSIONS)
+
 #define MAX_TYPE0_SESSIONS 16
 #define MAX_TYPE1_SESSIONS 6
 
@@ -27,7 +30,10 @@ enum pxp_sm_session_req {
 	PXP_SM_REQ_SESSION_TERMINATE
 };
 
-#define PXP_ACTION_SET_USER_CONTEXT 5
+enum pxp_ioctl_action {
+	PXP_ACTION_SET_SESSION_STATUS = 1,
+	PXP_ACTION_SET_USER_CONTEXT = 5,
+};
 
 enum pxp_sm_status {
 	PXP_SM_STATUS_SUCCESS,
@@ -36,10 +42,24 @@ enum pxp_sm_status {
 	PXP_SM_STATUS_ERROR_UNKNOWN
 };
 
+struct pxp_sm_set_session_status_params {
+	/** @pxp_tag: in [optional], for Arbitrator session, out pxp tag */
+	u32 pxp_tag;
+	/** @session_type: in, session type */
+	u32 session_type;
+	/** @session_mode: in, session mode */
+	u32 session_mode;
+	/** @req_session_state: in, new session state */
+	u32 req_session_state;
+};
+
 struct pxp_info {
 	u32 action;
 	u32 sm_status;
-	u32 set_user_ctx;
+	union {
+		struct pxp_sm_set_session_status_params set_session_status;
+		u32 set_user_ctx;
+	};
 } __attribute__((packed));
 
 struct drm_i915_pxp_ops {
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_sm.c b/drivers/gpu/drm/i915/pxp/intel_pxp_sm.c
index 469810390c9b..e4218083f7ec 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_sm.c
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_sm.c
@@ -145,7 +145,7 @@ static int pxp_set_pxp_tag(struct drm_i915_private *i915, int session_type,
 	}
 
 	pxp_tag->session_id = pxp_get_session_id(session_idx, session_type);
-end:
+
 	return 0;
 }
 
@@ -298,6 +298,153 @@ static bool check_if_protected_type0_sessions_are_attacked(struct drm_i915_priva
 	return false;
 }
 
+/**
+ * create_new_session_entry - Create a new session entry with provided info.
+ * @i915: i915 device handle.
+ * @drmfile: pointer to drm_file
+ * @context_id: Numeric identifier of the context created by the caller.
+ * @session_type: Type of the session requested. One of enum pxp_session_types.
+ * @protection_mode: Type of protection requested for the session.
+ *                   One of the enum pxp_protection_modes.
+ * @session_index: Numeric session identifier.
+ *
+ * Return: status. 0 means creation is successful.
+ */
+static int create_new_session_entry(struct drm_i915_private *i915, struct drm_file *drmfile,
+				    int context_id, int session_type, int protection_mode,
+				    int session_index)
+{
+	struct pxp_protected_session *new_session = NULL;
+	int pid = 0;
+
+	if (drmfile)
+		pid = pid_nr(drmfile->pid);
+
+	new_session = kzalloc(sizeof(*new_session), GFP_KERNEL);
+	if (!new_session)
+		return -ENOMEM;
+
+	new_session->context_id = context_id;
+	new_session->session_type = session_type;
+	new_session->protection_mode = protection_mode;
+	new_session->session_index = session_index;
+	new_session->session_is_in_play = false;
+	new_session->drmfile = drmfile;
+	new_session->pid = pid;
+
+	switch (session_type) {
+	case SESSION_TYPE_TYPE0:
+		/* check to make sure the session id is within allowed range */
+		if (session_index < 0 || session_index >= MAX_TYPE0_SESSIONS) {
+			/* session id out of range.. free the new entry and return error */
+			kfree(new_session);
+			drm_err(&i915->drm, "Failed to %s, bad params\n", __func__);
+			return -EINVAL;
+		}
+
+		list_add(&new_session->session_list, &i915->pxp.ctx->active_pxp_type0_sessions);
+		break;
+
+	case SESSION_TYPE_TYPE1:
+		/* check to make sure the session id is within allowed range */
+		if (session_index < 0 || session_index >= MAX_TYPE1_SESSIONS) {
+			/* session id out of range.. free the new entry and return error */
+			kfree(new_session);
+			drm_err(&i915->drm, "Failed to %s, bad params\n", __func__);
+			return -EINVAL;
+		}
+
+		list_add(&new_session->session_list, &i915->pxp.ctx->active_pxp_type1_sessions);
+		break;
+
+	default:
+		/* session type is invalid... free new entry and return error. */
+		kfree(new_session);
+		drm_err(&i915->drm, "Failed to %s, bad params\n", __func__);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * intel_pxp_sm_reserve_session - To reserve an available protected session.
+ * @i915: i915 device handle.
+ * @drmfile: pointer to drm_file.
+ * @context_id: Numeric identifier of the context created by the caller.
+ * @session_type: Type of the session requested. One of enum pxp_session_types.
+ * @protection_mode: Type of protection requested for the session. One of the
+ *                   enum pxp_protection_modes.
+ * @pxp_tag: Numeric session identifier returned back to caller.
+ *
+ * Return: status. 0 means reserve is successful.
+ */
+int intel_pxp_sm_reserve_session(struct drm_i915_private *i915, struct drm_file *drmfile,
+				 int context_id, int session_type, int protection_mode,
+				 u32 *pxp_tag)
+{
+	int ret;
+	int session_index = 0;
+
+	if (!pxp_tag || !i915)
+		return -EINVAL;
+
+	if (protection_mode != PROTECTION_MODE_LM && protection_mode != PROTECTION_MODE_HM &&
+	    protection_mode != PROTECTION_MODE_SM) {
+		drm_err(&i915->drm, "Failed to %s, invalid session mode=[%d]\n",
+			__func__, protection_mode);
+		return -EINVAL;
+	}
+
+	lockdep_assert_held(&i915->pxp.ctx->ctx_mutex);
+
+	if (session_type == SESSION_TYPE_TYPE0) {
+		/*
+		 * check if sessions are under attack. if so, don't allow creation of
+		 * new session entries
+		 */
+		if (check_if_protected_type0_sessions_are_attacked(i915))
+			/* protected sessions are under attack. return failure. */
+			return -EPERM;
+	}
+
+	/*
+	 * iterate over the active sessions list to find next available open session id
+	 * Cannot assume that the session entries will be sorted in the linked list
+	 * as terminates are allowed at any time without re-sorting the linked list.
+	 * So, the linked list should be walked start to finish to ensure a session is
+	 * not already active
+	 */
+	for (session_index = 0; session_index < pxp_session_max(session_type); session_index++) {
+		if (!is_sw_session_active(i915, session_type, session_index, false, NULL)) {
+			ret = sync_hw_sw_state(i915, session_index, session_type);
+			if (unlikely(ret)) {
+				ret = PXP_SM_STATUS_RETRY_REQUIRED;
+				goto end;
+			}
+
+			/*
+			 * found an available session... create a new session entry
+			 * with this identifier and return success
+			 */
+			ret = create_new_session_entry(i915, drmfile, context_id, session_type,
+						       protection_mode, session_index);
+			if (unlikely(ret))
+				goto end;
+
+			ret = pxp_set_pxp_tag(i915, session_type, session_index, protection_mode);
+			goto end;
+		}
+	}
+
+	ret = PXP_SM_STATUS_SESSION_NOT_AVAILABLE;
+end:
+	if (ret == 0)
+		*pxp_tag = intel_pxp_get_pxp_tag(i915, session_index, session_type, NULL);
+
+	return ret;
+}
+
 int pxp_sm_set_kcr_init_reg(struct drm_i915_private *i915)
 {
 	int ret;
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_sm.h b/drivers/gpu/drm/i915/pxp/intel_pxp_sm.h
index b5012948f971..5fcf63f804f8 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_sm.h
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_sm.h
@@ -84,6 +84,9 @@ struct pxp_protected_session {
 	bool session_is_in_play;
 };
 
+int intel_pxp_sm_reserve_session(struct drm_i915_private *i915, struct drm_file *drmfile,
+				 int context_id, int session_type, int protection_mode,
+				 u32 *pxp_tag);
 int pxp_sm_set_kcr_init_reg(struct drm_i915_private *i915);
 
 #endif /* __INTEL_PXP_SM_H__ */
-- 
2.17.1

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