net/mlx5: select driver by class device argument

There might be a case that one Mellanox device can be probed by
multiple mlx5 drivers.

One case is that any mlx5 vDPA device can be probed by both net/mlx5
and vdpa/mlx5.

Add a new mlx5 common API to get the requested driver by devargs:
class=[net/vdpa].

Skip net/mlx5 PMD probing while the device is selected to be probed by
the vDPA driver.

Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>

drivers/common/mlx5/Makefile

@@ -41,7 +41,7 @@ else
 LDLIBS += -libverbs -lmlx5
 endif
 
-LDLIBS += -lrte_eal -lrte_pci
+LDLIBS += -lrte_eal -lrte_pci -lrte_kvargs
 
 # A few warnings cannot be avoided in external headers.
 CFLAGS += -Wno-error=cast-qual -DNDEBUG -UPEDANTIC

drivers/common/mlx5/meson.build

@@ -37,7 +37,7 @@ endforeach
 
 if build
 	allow_experimental_apis = true
-	deps += ['hash', 'pci', 'net', 'eal']
+	deps += ['hash', 'pci', 'net', 'eal', 'kvargs']
 	ext_deps += libs
 	sources = files(
 		'mlx5_devx_cmds.c',

drivers/common/mlx5/mlx5_common.c

@@ -69,6 +69,42 @@ mlx5_dev_to_pci_addr(const char *dev_path,
 	return 0;
 }
 
+static int
+mlx5_class_check_handler(__rte_unused const char *key, const char *value,
+			 void *opaque)
+{
+	enum mlx5_class *ret = opaque;
+
+	if (strcmp(value, "vdpa") == 0) {
+		*ret = MLX5_CLASS_VDPA;
+	} else if (strcmp(value, "net") == 0) {
+		*ret = MLX5_CLASS_NET;
+	} else {
+		DRV_LOG(ERR, "Invalid mlx5 class %s. Maybe typo in device"
+			" class argument setting?", value);
+		*ret = MLX5_CLASS_INVALID;
+	}
+	return 0;
+}
+
+enum mlx5_class
+mlx5_class_get(struct rte_devargs *devargs)
+{
+	struct rte_kvargs *kvlist;
+	const char *key = MLX5_CLASS_ARG_NAME;
+	enum mlx5_class ret = MLX5_CLASS_NET;
+
+	if (devargs == NULL)
+		return ret;
+	kvlist = rte_kvargs_parse(devargs->args, NULL);
+	if (kvlist == NULL)
+		return ret;
+	if (rte_kvargs_count(kvlist, key))
+		rte_kvargs_process(kvlist, key, mlx5_class_check_handler, &ret);
+	rte_kvargs_free(kvlist);
+	return ret;
+}
+
 #ifdef RTE_IBVERBS_LINK_DLOPEN
 
 /**

drivers/common/mlx5/mlx5_common.h

@@ -11,6 +11,8 @@
 #include <rte_pci.h>
 #include <rte_atomic.h>
 #include <rte_log.h>
+#include <rte_kvargs.h>
+#include <rte_devargs.h>
 
 #include "mlx5_prm.h"
 
@@ -150,4 +152,13 @@ check_cqe(volatile struct mlx5_cqe *cqe, const uint16_t cqes_n,
 
 int mlx5_dev_to_pci_addr(const char *dev_path, struct rte_pci_addr *pci_addr);
 
+#define MLX5_CLASS_ARG_NAME "class"
+
+enum mlx5_class {
+	MLX5_CLASS_NET,
+	MLX5_CLASS_VDPA,
+	MLX5_CLASS_INVALID,
+};
+enum mlx5_class mlx5_class_get(struct rte_devargs *devargs);
+
 #endif /* RTE_PMD_MLX5_COMMON_H_ */

drivers/common/mlx5/rte_common_mlx5_version.map

@@ -1,6 +1,8 @@
 DPDK_20.02 {
 	global:
 
+	mlx5_class_get;
+
 	mlx5_devx_cmd_create_cq;
 	mlx5_devx_cmd_create_qp;
 	mlx5_devx_cmd_create_rq;

drivers/net/mlx5/mlx5.c

@@ -1565,6 +1565,8 @@ mlx5_args_check(const char *key, const char *val, void *opaque)
 		config->max_dump_files_num = tmp;
 	} else if (strcmp(MLX5_LRO_TIMEOUT_USEC, key) == 0) {
 		config->lro.timeout = tmp;
+	} else if (strcmp(MLX5_CLASS_ARG_NAME, key) == 0) {
+		DRV_LOG(DEBUG, "class argument is %s.", val);
 	} else {
 		DRV_LOG(WARNING, "%s: unknown parameter", key);
 		rte_errno = EINVAL;
@@ -1616,6 +1618,7 @@ mlx5_args(struct mlx5_dev_config *config, struct rte_devargs *devargs)
 		MLX5_REPRESENTOR,
 		MLX5_MAX_DUMP_FILES_NUM,
 		MLX5_LRO_TIMEOUT_USEC,
+		MLX5_CLASS_ARG_NAME,
 		NULL,
 	};
 	struct rte_kvargs *kvlist;
@@ -2967,6 +2970,11 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
 	struct mlx5_dev_config dev_config;
 	int ret;
 
+	if (mlx5_class_get(pci_dev->device.devargs) != MLX5_CLASS_NET) {
+		DRV_LOG(DEBUG, "Skip probing - should be probed by other mlx5"
+			" driver.");
+		return 1;
+	}
 	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
 		mlx5_pmd_socket_init();
 	ret = mlx5_init_once();