gve: Add flow steering adminq commands

Add new adminq commands for the driver to configure and query flow rules
that are stored in the device. Flow steering rules are assigned with a
location that determines the relative order of the rules.

Flow rules can run up to an order of millions. In such cases, storing
a full copy of the rules in the driver to prepare for the ethtool query
is infeasible while querying them from the device is better. That needs
to be optimized too so that we don't send a lot of adminq commands. The
solution here is to store a limited number of rules/rule ids in the
driver in a cache. Use dma_pool to allocate 4k bytes which lets device
write at most 46 flow rules(4096/88) or 1024 rule ids(4096/4) at a time.

For configuring flow rules, there are 3 sub-commands:
- ADD which adds a rule at the location supplied
- DEL which deletes the rule at the location supplied
- RESET which clears all currently active rules in the device

For querying flow rules, there are also 3 sub-commands:
- QUERY_RULES corresponds to ETHTOOL_GRXCLSRULE. It fills the rules in
  the allocated cache after querying the device
- QUERY_RULES_IDS corresponds to ETHTOOL_GRXCLSRLALL. It fills the
  rule_ids in the allocated cache after querying the device
- QUERY_RULES_STATS corresponds to ETHTOOL_GRXCLSRLCNT. It queries the
  device's current flow rule number and the supported max flow rule
  limit

Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@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/20240625001232.1476315-5-ziweixiao@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
index 58213c15e084..b9e9dd958f3c 100644
--- a/drivers/net/ethernet/google/gve/gve.h
+++ b/drivers/net/ethernet/google/gve/gve.h
@@ -60,6 +60,11 @@
 
 #define GVE_DEFAULT_RX_BUFFER_OFFSET 2048
 
+#define GVE_FLOW_RULES_CACHE_SIZE \
+	(GVE_ADMINQ_BUFFER_SIZE / sizeof(struct gve_adminq_queried_flow_rule))
+#define GVE_FLOW_RULE_IDS_CACHE_SIZE \
+	(GVE_ADMINQ_BUFFER_SIZE / sizeof(((struct gve_adminq_queried_flow_rule *)0)->location))
+
 #define GVE_XDP_ACTIONS 5
 
 #define GVE_GQ_TX_MIN_PKT_DESC_BYTES 182
@@ -678,6 +683,39 @@ enum gve_queue_format {
 	GVE_DQO_QPL_FORMAT		= 0x4,
 };
 
+struct gve_flow_spec {
+	__be32 src_ip[4];
+	__be32 dst_ip[4];
+	union {
+		struct {
+			__be16 src_port;
+			__be16 dst_port;
+		};
+		__be32 spi;
+	};
+	union {
+		u8 tos;
+		u8 tclass;
+	};
+};
+
+struct gve_flow_rule {
+	u32 location;
+	u16 flow_type;
+	u16 action;
+	struct gve_flow_spec key;
+	struct gve_flow_spec mask;
+};
+
+struct gve_flow_rules_cache {
+	bool rules_cache_synced; /* False if the driver's rules_cache is outdated */
+	struct gve_adminq_queried_flow_rule *rules_cache;
+	__be32 *rule_ids_cache;
+	/* The total number of queried rules that stored in the caches */
+	u32 rules_cache_num;
+	u32 rule_ids_cache_num;
+};
+
 struct gve_priv {
 	struct net_device *dev;
 	struct gve_tx_ring *tx; /* array of tx_cfg.num_queues */
@@ -744,6 +782,8 @@ struct gve_priv {
 	u32 adminq_report_link_speed_cnt;
 	u32 adminq_get_ptype_map_cnt;
 	u32 adminq_verify_driver_compatibility_cnt;
+	u32 adminq_query_flow_rules_cnt;
+	u32 adminq_cfg_flow_rule_cnt;
 
 	/* Global stats */
 	u32 interface_up_cnt; /* count of times interface turned up since last reset */
@@ -788,6 +828,9 @@ struct gve_priv {
 	bool header_split_enabled; /* True if the header split is enabled by the user */
 
 	u32 max_flow_rules;
+	u32 num_flow_rules;
+
+	struct gve_flow_rules_cache flow_rules_cache;
 };
 
 enum gve_service_task_flags_bit {