net/mlx5: Don't handle VF func change if host PF is disabled

When ECPF eswitch manager is at offloads mode, it monitors functions
changed event from host PF side and acts according to the number of
VFs enabled/disabled.

As ECPF and host PF work in two independent hosts, it's possible that
host PF OS reboots but ECPF system is still kept on and continues
monitoring events from host PF. When kernel from host PF side is
booting, PCI iov driver does sriov_init and compute_max_vf_buses by
iterating over all valid num of VFs. This triggers FLR and generates
functions changed events, even though host PF HCA is not enabled at
this time. However, ECPF is not aware of this information, and still
handles these events as usual. ECPF system will see massive number of
reps are created, but destroyed immediately once creation finished.

To eliminate this noise, a bit is added to host parameter context to
indicate host PF is disabled. ECPF will not handle the VF changed
event if this bit is set.
Signed-off-by: Bodong Wang <bodong@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c

@@ -2026,6 +2026,7 @@ static void esw_functions_changed_event_handler(struct work_struct *work)
 	u32 out[MLX5_ST_SZ_DW(query_esw_functions_out)] = {};
 	struct mlx5_host_work *host_work;
 	struct mlx5_eswitch *esw;
+	bool host_pf_disabled;
 	u16 num_vfs = 0;
 	int err;
 
@@ -2035,7 +2036,9 @@ static void esw_functions_changed_event_handler(struct work_struct *work)
 	err = mlx5_esw_query_functions(esw->dev, out, sizeof(out));
 	num_vfs = MLX5_GET(query_esw_functions_out, out,
 			   host_params_context.host_num_of_vfs);
-	if (err || num_vfs == esw->esw_funcs.num_vfs)
+	host_pf_disabled = MLX5_GET(query_esw_functions_out, out,
+				    host_params_context.host_pf_disabled);
+	if (err || host_pf_disabled || num_vfs == esw->esw_funcs.num_vfs)
 		goto out;
 
 	/* Number of VFs can only change from "0 to x" or "x to 0". */

include/linux/mlx5/mlx5_ifc.h

@@ -9823,7 +9823,8 @@ struct mlx5_ifc_mtrc_ctrl_bits {
 
 struct mlx5_ifc_host_params_context_bits {
 	u8         host_number[0x8];
-	u8         reserved_at_8[0x8];
+	u8         reserved_at_8[0x7];
+	u8         host_pf_disabled[0x1];
 	u8         host_num_of_vfs[0x10];
 
 	u8         host_total_vfs[0x10];