[PATCH] drm/xe/guc: Ratelimit diagnostic messages from the relay

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

There might be some malicious VFs that by sending an invalid VF2PF
relay messages will flood PF's dmesg with our diagnostics messages.

Rate limit all relay messages, unless running in DEBUG_SRIOV mode.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
---
 drivers/gpu/drm/xe/xe_guc_relay.c       | 17 +++++++++++++++--
 drivers/gpu/drm/xe/xe_guc_relay_types.h |  4 ++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_relay.c b/drivers/gpu/drm/xe/xe_guc_relay.c
index e5dc94f3e618..0c0ff24ba62a 100644
--- a/drivers/gpu/drm/xe/xe_guc_relay.c
+++ b/drivers/gpu/drm/xe/xe_guc_relay.c
@@ -56,9 +56,19 @@ static struct xe_device *relay_to_xe(struct xe_guc_relay *relay)
 	return gt_to_xe(relay_to_gt(relay));
 }
 
+#define XE_RELAY_DIAG_RATELIMIT_INTERVAL	(10 * HZ)
+#define XE_RELAY_DIAG_RATELIMIT_BURST		10
+
+#define relay_ratelimit_printk(relay, _level, fmt...) ({			\
+	typeof(relay) _r = (relay);						\
+	if (IS_ENABLED(CONFIG_DRM_XE_DEBUG_SRIOV) ||				\
+	    ___ratelimit(&_r->diag_ratelimit, "xe_guc_relay"))			\
+		xe_gt_sriov_##_level(relay_to_gt(_r), "relay: " fmt);		\
+})
+
 #define relay_assert(relay, condition)	xe_gt_assert(relay_to_gt(relay), condition)
-#define relay_notice(relay, msg...)	xe_gt_sriov_notice(relay_to_gt(relay), "relay: " msg)
-#define relay_debug(relay, msg...)	xe_gt_sriov_dbg_verbose(relay_to_gt(relay), "relay: " msg)
+#define relay_notice(relay, msg...)	relay_ratelimit_printk((relay), notice, msg)
+#define relay_debug(relay, msg...)	relay_ratelimit_printk((relay), dbg_verbose, msg)
 
 static int relay_get_totalvfs(struct xe_guc_relay *relay)
 {
@@ -345,6 +355,9 @@ int xe_guc_relay_init(struct xe_guc_relay *relay)
 	INIT_WORK(&relay->worker, relays_worker_fn);
 	INIT_LIST_HEAD(&relay->pending_relays);
 	INIT_LIST_HEAD(&relay->incoming_actions);
+	ratelimit_state_init(&relay->diag_ratelimit,
+			     XE_RELAY_DIAG_RATELIMIT_INTERVAL,
+			     XE_RELAY_DIAG_RATELIMIT_BURST);
 
 	err = mempool_init_kmalloc_pool(&relay->pool, XE_RELAY_MEMPOOL_MIN_NUM +
 					relay_get_totalvfs(relay),
diff --git a/drivers/gpu/drm/xe/xe_guc_relay_types.h b/drivers/gpu/drm/xe/xe_guc_relay_types.h
index 5999fcb77e96..20eee10856b2 100644
--- a/drivers/gpu/drm/xe/xe_guc_relay_types.h
+++ b/drivers/gpu/drm/xe/xe_guc_relay_types.h
@@ -7,6 +7,7 @@
 #define _XE_GUC_RELAY_TYPES_H_
 
 #include <linux/mempool.h>
+#include <linux/ratelimit_types.h>
 #include <linux/spinlock.h>
 #include <linux/workqueue.h>
 
@@ -31,6 +32,9 @@ struct xe_guc_relay {
 
 	/** @last_rid: last Relay-ID used while sending a message. */
 	u32 last_rid;
+
+	/** @diag_ratelimit: ratelimit state used to throttle diagnostics messages. */
+	struct ratelimit_state diag_ratelimit;
 };
 
 #endif
-- 
2.47.1