gve: Add RSS device option

Add a device option to inform the driver about the hash key size and
hash table size used by the device. This information will be stored and
made available for RSS ethtool operations.
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240812222013.1503584-2-pkaligineedi@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/google/gve/gve.h

@@ -831,6 +831,9 @@ struct gve_priv {
 	u32 num_flow_rules;
 
 	struct gve_flow_rules_cache flow_rules_cache;
+
+	u16 rss_key_size;
+	u16 rss_lut_size;
 };
 
 enum gve_service_task_flags_bit {

drivers/net/ethernet/google/gve/gve_adminq.c

@@ -45,6 +45,7 @@ void gve_parse_device_option(struct gve_priv *priv,
 			     struct gve_device_option_dqo_qpl **dev_op_dqo_qpl,
 			     struct gve_device_option_buffer_sizes **dev_op_buffer_sizes,
 			     struct gve_device_option_flow_steering **dev_op_flow_steering,
+			     struct gve_device_option_rss_config **dev_op_rss_config,
 			     struct gve_device_option_modify_ring **dev_op_modify_ring)
 {
 	u32 req_feat_mask = be32_to_cpu(option->required_features_mask);
@@ -207,6 +208,23 @@ void gve_parse_device_option(struct gve_priv *priv,
 				 "Flow Steering");
 		*dev_op_flow_steering = (void *)(option + 1);
 		break;
+	case GVE_DEV_OPT_ID_RSS_CONFIG:
+		if (option_length < sizeof(**dev_op_rss_config) ||
+		    req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_RSS_CONFIG) {
+			dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
+				 "RSS config",
+				 (int)sizeof(**dev_op_rss_config),
+				 GVE_DEV_OPT_REQ_FEAT_MASK_RSS_CONFIG,
+				 option_length, req_feat_mask);
+			break;
+		}
+
+		if (option_length > sizeof(**dev_op_rss_config))
+			dev_warn(&priv->pdev->dev,
+				 GVE_DEVICE_OPTION_TOO_BIG_FMT,
+				 "RSS config");
+		*dev_op_rss_config = (void *)(option + 1);
+		break;
 	default:
 		/* If we don't recognize the option just continue
 		 * without doing anything.
@@ -227,6 +245,7 @@ gve_process_device_options(struct gve_priv *priv,
 			   struct gve_device_option_dqo_qpl **dev_op_dqo_qpl,
 			   struct gve_device_option_buffer_sizes **dev_op_buffer_sizes,
 			   struct gve_device_option_flow_steering **dev_op_flow_steering,
+			   struct gve_device_option_rss_config **dev_op_rss_config,
 			   struct gve_device_option_modify_ring **dev_op_modify_ring)
 {
 	const int num_options = be16_to_cpu(descriptor->num_device_options);
@@ -249,7 +268,8 @@ gve_process_device_options(struct gve_priv *priv,
 					dev_op_gqi_rda, dev_op_gqi_qpl,
 					dev_op_dqo_rda, dev_op_jumbo_frames,
 					dev_op_dqo_qpl, dev_op_buffer_sizes,
-					dev_op_flow_steering, dev_op_modify_ring);
+					dev_op_flow_steering, dev_op_rss_config,
+					dev_op_modify_ring);
 		dev_opt = next_opt;
 	}
 
@@ -867,6 +887,8 @@ static void gve_enable_supported_features(struct gve_priv *priv,
 					  *dev_op_buffer_sizes,
 					  const struct gve_device_option_flow_steering
 					  *dev_op_flow_steering,
+					  const struct gve_device_option_rss_config
+					  *dev_op_rss_config,
 					  const struct gve_device_option_modify_ring
 					  *dev_op_modify_ring)
 {
@@ -931,6 +953,14 @@ static void gve_enable_supported_features(struct gve_priv *priv,
 				 priv->max_flow_rules);
 		}
 	}
+
+	if (dev_op_rss_config &&
+	    (supported_features_mask & GVE_SUP_RSS_CONFIG_MASK)) {
+		priv->rss_key_size =
+			be16_to_cpu(dev_op_rss_config->hash_key_size);
+		priv->rss_lut_size =
+			be16_to_cpu(dev_op_rss_config->hash_lut_size);
+	}
 }
 
 int gve_adminq_describe_device(struct gve_priv *priv)
@@ -939,6 +969,7 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 	struct gve_device_option_buffer_sizes *dev_op_buffer_sizes = NULL;
 	struct gve_device_option_jumbo_frames *dev_op_jumbo_frames = NULL;
 	struct gve_device_option_modify_ring *dev_op_modify_ring = NULL;
+	struct gve_device_option_rss_config *dev_op_rss_config = NULL;
 	struct gve_device_option_gqi_rda *dev_op_gqi_rda = NULL;
 	struct gve_device_option_gqi_qpl *dev_op_gqi_qpl = NULL;
 	struct gve_device_option_dqo_rda *dev_op_dqo_rda = NULL;
@@ -973,6 +1004,7 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 					 &dev_op_jumbo_frames, &dev_op_dqo_qpl,
 					 &dev_op_buffer_sizes,
 					 &dev_op_flow_steering,
+					 &dev_op_rss_config,
 					 &dev_op_modify_ring);
 	if (err)
 		goto free_device_descriptor;
@@ -1035,7 +1067,7 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 	gve_enable_supported_features(priv, supported_features_mask,
 				      dev_op_jumbo_frames, dev_op_dqo_qpl,
 				      dev_op_buffer_sizes, dev_op_flow_steering,
-				      dev_op_modify_ring);
+				      dev_op_rss_config, dev_op_modify_ring);
 
 free_device_descriptor:
 	dma_pool_free(priv->adminq_pool, descriptor, descriptor_bus);

drivers/net/ethernet/google/gve/gve_adminq.h

@@ -164,6 +164,14 @@ struct gve_device_option_flow_steering {
 
 static_assert(sizeof(struct gve_device_option_flow_steering) == 12);
 
+struct gve_device_option_rss_config {
+	__be32 supported_features_mask;
+	__be16 hash_key_size;
+	__be16 hash_lut_size;
+};
+
+static_assert(sizeof(struct gve_device_option_rss_config) == 8);
+
 /* Terminology:
  *
  * RDA - Raw DMA Addressing - Buffers associated with SKBs are directly DMA
@@ -182,6 +190,7 @@ enum gve_dev_opt_id {
 	GVE_DEV_OPT_ID_JUMBO_FRAMES		= 0x8,
 	GVE_DEV_OPT_ID_BUFFER_SIZES		= 0xa,
 	GVE_DEV_OPT_ID_FLOW_STEERING		= 0xb,
+	GVE_DEV_OPT_ID_RSS_CONFIG		= 0xe,
 };
 
 enum gve_dev_opt_req_feat_mask {
@@ -194,6 +203,7 @@ enum gve_dev_opt_req_feat_mask {
 	GVE_DEV_OPT_REQ_FEAT_MASK_BUFFER_SIZES		= 0x0,
 	GVE_DEV_OPT_REQ_FEAT_MASK_MODIFY_RING		= 0x0,
 	GVE_DEV_OPT_REQ_FEAT_MASK_FLOW_STEERING		= 0x0,
+	GVE_DEV_OPT_REQ_FEAT_MASK_RSS_CONFIG		= 0x0,
 };
 
 enum gve_sup_feature_mask {
@@ -201,6 +211,7 @@ enum gve_sup_feature_mask {
 	GVE_SUP_JUMBO_FRAMES_MASK	= 1 << 2,
 	GVE_SUP_BUFFER_SIZES_MASK	= 1 << 4,
 	GVE_SUP_FLOW_STEERING_MASK	= 1 << 5,
+	GVE_SUP_RSS_CONFIG_MASK		= 1 << 7,
 };
 
 #define GVE_DEV_OPT_LEN_GQI_RAW_ADDRESSING 0x0
@@ -214,6 +225,7 @@ enum gve_driver_capbility {
 	gve_driver_capability_dqo_rda = 3,
 	gve_driver_capability_alt_miss_compl = 4,
 	gve_driver_capability_flexible_buffer_size = 5,
+	gve_driver_capability_flexible_rss_size = 6,
 };
 
 #define GVE_CAP1(a) BIT((int)a)
@@ -226,7 +238,8 @@ enum gve_driver_capbility {
 	 GVE_CAP1(gve_driver_capability_gqi_rda) | \
 	 GVE_CAP1(gve_driver_capability_dqo_rda) | \
 	 GVE_CAP1(gve_driver_capability_alt_miss_compl) | \
-	 GVE_CAP1(gve_driver_capability_flexible_buffer_size))
+	 GVE_CAP1(gve_driver_capability_flexible_buffer_size) | \
+	 GVE_CAP1(gve_driver_capability_flexible_rss_size))
 
 #define GVE_DRIVER_CAPABILITY_FLAGS2 0x0
 #define GVE_DRIVER_CAPABILITY_FLAGS3 0x0