Re: [dpdk-dev] [PATCH 1/1] net/mlx5: add support for PF representor

[Shahaf Shuler <shahafs@mellanox.com>]

Hi Slava,

Friday, April 12, 2019 6:48 PM, Viacheslav Ovsiienko:
> Subject: [dpdk-dev] [PATCH 1/1] net/mlx5: add support for PF representor
> 
> On BlueField platform we have the new entity - PF representor.
> This one represents the PCI PF attached to external host on the side of ARM.
> The traffic sent by the external host to the NIC via PF will be seem by ARM on
> this PF representor.
> 
> This patch extends port recognizing capability on the base of physical port
> name. The following naming formats are supported:
> 
>   - missing physical port name (no sysfs/netlink key) at all,
>     this is old style (before kernel 5.0) format, master assumed
>   - 1 (decimal digits) - old style (before kernel 5.0) format,
>     exists only for representors, master does not have physical
>     port name at all (see above)
>   - p0 ("p" followed by decimal digits), new style (kernel version
>     is 5.0 or higher, Mellanox OFED 4.6 or higher) name format
>     for uplink representor, plays the role of master
>   - pf0vf0 ("pf" followed by PF index concatenated with "vf"
>     followed by VF index),  new style (kernel version  is 5.0
>     or higher, Mellanox OFED 4.6 or higher) name format for
>     VF representor. If index of VF is "-1" it is a special case
>     of host PF representor, this representor must be indexed in
>     devargs as 65535, for example representor=[0-3,65535] will
>     allow representors for VF0, VF1, VF2, VF3 and host PF.
>     Note: do not specify representor=[0-65535] it causes devargs
>     processing error, because number of ports (rte_eth_dev) is
>     limited.
> 

The above is a bit complex to understand and in fact we have 2 modes:
1. legacy - phys_port_name are numbers. Master doesn't have phys_port_name
2. modern - phys_port_name are strings. 
uplink representor is p%d
representors are (including PF representor) pf%dvf%d. the vf index for the PF representor is 65535. 

> Applications should distinguish representors and master devices exclusively
> by device flag RTE_ETH_DEV_REPRESENTOR and do not rely on switch
> port_id (mlx5 PMD deduces ones from representor_id) values returned by
> dev_infos_get() API.
> 

Please also reference the kernel commit which introduce the name change. 

> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5.h        | 11 ++++++-
>  drivers/net/mlx5/mlx5_ethdev.c | 68 +++++++++++++++++++++++++++----
> -----------
>  drivers/net/mlx5/mlx5_nl.c     | 42 +++++++++++++++++---------
>  3 files changed, 82 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h index
> 8eb1019..81c02ce 100644
> --- a/drivers/net/mlx5/mlx5.h
> +++ b/drivers/net/mlx5/mlx5.h
> @@ -80,11 +80,20 @@ struct mlx5_mp_param {
>  /** Key string for IPC. */
>  #define MLX5_MP_NAME "net_mlx5_mp"
> 
> +/* Recognized Infiniband device physical port name types. */ enum
> +mlx5_phys_port_name_type {
> +	MLX5_PHYS_PORT_NAME_TYPE_UNKNOWN = 0, /* Unrecognized.
> */
> +	MLX5_PHYS_PORT_NAME_TYPE_LEGACY, /* before kernel ver < 5.0
> */
> +	MLX5_PHYS_PORT_NAME_TYPE_UPLINK, /* p0, kernel ver >= 5.0 */
> +	MLX5_PHYS_PORT_NAME_TYPE_PFVF, /* pf0vf0, kernel ver >= 5.0
> */ };
> +
>  /** Switch information returned by mlx5_nl_switch_info(). */  struct
> mlx5_switch_info {
>  	uint32_t master:1; /**< Master device. */
>  	uint32_t representor:1; /**< Representor device. */
> -	uint32_t port_name_new:1; /**< Rep. port name is in new format.
> */
> +	enum mlx5_phys_port_name_type name_type; /** < Port name
> type. */
> +	int32_t pf_num; /**< PF number (valid for pfxvfx format only). */
>  	int32_t port_name; /**< Representor port name. */
>  	uint64_t switch_id; /**< Switch identifier. */  }; diff --git
> a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c index
> 3992918..371989f 100644
> --- a/drivers/net/mlx5/mlx5_ethdev.c
> +++ b/drivers/net/mlx5/mlx5_ethdev.c
> @@ -1395,12 +1395,11 @@ int mlx5_fw_version_get(struct rte_eth_dev
> *dev, char *fw_ver, size_t fw_size)
>  	struct mlx5_switch_info data = {
>  		.master = 0,
>  		.representor = 0,
> -		.port_name_new = 0,
> +		.name_type = MLX5_PHYS_PORT_NAME_TYPE_UNKNOWN,
>  		.port_name = 0,
>  		.switch_id = 0,
>  	};
>  	DIR *dir;
> -	bool port_name_set = false;
>  	bool port_switch_id_set = false;
>  	bool device_dir = false;
>  	char c;
> @@ -1423,8 +1422,7 @@ int mlx5_fw_version_get(struct rte_eth_dev *dev,
> char *fw_ver, size_t fw_size)
>  		ret = fscanf(file, "%s", port_name);
>  		fclose(file);
>  		if (ret == 1)
> -			port_name_set =
> mlx5_translate_port_name(port_name,
> -								 &data);
> +			mlx5_translate_port_name(port_name, &data);
>  	}
>  	file = fopen(phys_switch_id, "rb");
>  	if (file == NULL) {
> @@ -1440,8 +1438,15 @@ int mlx5_fw_version_get(struct rte_eth_dev
> *dev, char *fw_ver, size_t fw_size)
>  		closedir(dir);
>  		device_dir = true;
>  	}
> -	data.master = port_switch_id_set && (!port_name_set ||
> device_dir);
> -	data.representor = port_switch_id_set && port_name_set &&
> !device_dir;
> +	if (port_switch_id_set) {
> +		data.master =
> +			device_dir ||
> +			data.name_type ==
> MLX5_PHYS_PORT_NAME_TYPE_UNKNOWN ||
> +			data.name_type ==
> MLX5_PHYS_PORT_NAME_TYPE_UPLINK;
> +		data.representor = !device_dir &&
> +			(data.name_type ==
> MLX5_PHYS_PORT_NAME_TYPE_LEGACY ||
> +			 data.name_type ==
> MLX5_PHYS_PORT_NAME_TYPE_PFVF);


Why we need to split the logic of the master/representor detection between the mlx5_translate_port_name and the caller function?

The way I envision it is mlx5_tranlate_port_name receives the phys_port_name and maybe more metadata and return the port classification (master/representor) and the representor/pf number. 
No need for data.master = some_logic(translate_port_name_info). 

Inside the translate function I would expect to have 2 smaller function:
1. to handle the modern format (strings)
2. to handle the legacy format (integers) 

> +	}
>  	*info = data;
>  	assert(!(data.master && data.representor));
>  	if (data.master && data.representor) { @@ -1459,10 +1464,11 @@ int
> mlx5_fw_version_get(struct rte_eth_dev *dev, char *fw_ver, size_t
> fw_size)
>   * @param[in] port_name_in
>   *   String representing the port name.
>   * @param[out] port_info_out
> - *   Port information, including port name as a number.
> + *   Port information, including port name as a number and port name
> + *   type if recognized
>   *
>   * @return
> - *   true on success, false otherwise.
> + *   true on success (if name format recognized), false otherwise.
>   */
>  bool
>  mlx5_translate_port_name(const char *port_name_in, @@ -1470,25
> +1476,39 @@ int mlx5_fw_version_get(struct rte_eth_dev *dev, char
> *fw_ver, size_t fw_size)  {
>  	char pf_c1, pf_c2, vf_c1, vf_c2;
>  	char *end;
> -	int32_t pf_num;
> -	bool port_name_set = false;
> +	int sc_items;
> 
>  	/*
>  	 * Check for port-name as a string of the form pf0vf0
> -	 * (support kernel ver >= 5.0)
> +	 * (support kernel ver >= 5.0 or OFED ver >= 4.6).
>  	 */
> -	port_name_set =	(sscanf(port_name_in, "%c%c%d%c%c%d",
> &pf_c1, &pf_c2,
> -				&pf_num, &vf_c1, &vf_c2,
> -				&port_info_out->port_name) == 6);
> -	if (port_name_set) {
> -		port_info_out->port_name_new = 1;
> -	} else {
> -		/* Check for port-name as a number (support kernel ver <
> 5.0 */
> -		errno = 0;
> -		port_info_out->port_name = strtol(port_name_in, &end, 0);
> -		if (!errno &&
> -		    (size_t)(end - port_name_in) == strlen(port_name_in))
> -			port_name_set = true;
> +	sc_items = sscanf(port_name_in, "%c%c%d%c%c%d",
> +			  &pf_c1, &pf_c2, &port_info_out->pf_num,
> +			  &vf_c1, &vf_c2, &port_info_out->port_name);
> +	if (sc_items == 6 &&
> +	    pf_c1 == 'p' && pf_c2 == 'f' &&
> +	    vf_c1 == 'v' && vf_c2 == 'f') {
> +		port_info_out->name_type =
> MLX5_PHYS_PORT_NAME_TYPE_PFVF;
> +		return true;
> +	}
> +	/*
> +	 * Check for port-name as a string of the form p0
> +	 * (support kernel ver >= 5.0, or OFED ver >= 4.6).
> +	 */
> +	sc_items = sscanf(port_name_in, "%c%d",
> +			  &pf_c1, &port_info_out->port_name);
> +	if (sc_items == 2 && pf_c1 == 'p') {
> +		port_info_out->name_type =
> MLX5_PHYS_PORT_NAME_TYPE_UPLINK;
> +		return true;
> +	}
> +	/* Check for port-name as a number (support kernel ver < 5.0 */
> +	errno = 0;
> +	port_info_out->port_name = strtol(port_name_in, &end, 0);
> +	if (!errno &&
> +	    (size_t)(end - port_name_in) == strlen(port_name_in)) {
> +		port_info_out->name_type =
> MLX5_PHYS_PORT_NAME_TYPE_LEGACY;
> +		return  true;
>  	}
> -	return port_name_set;
> +	port_info_out->name_type =
> MLX5_PHYS_PORT_NAME_TYPE_UNKNOWN;
> +	return false;
>  }
> diff --git a/drivers/net/mlx5/mlx5_nl.c b/drivers/net/mlx5/mlx5_nl.c index
> fd9226b..669de76 100644
> --- a/drivers/net/mlx5/mlx5_nl.c
> +++ b/drivers/net/mlx5/mlx5_nl.c
> @@ -887,12 +887,11 @@ struct mlx5_nl_ifindex_data {
>  	struct mlx5_switch_info info = {
>  		.master = 0,
>  		.representor = 0,
> -		.port_name_new = 0,
> +		.name_type = MLX5_PHYS_PORT_NAME_TYPE_UNKNOWN,
>  		.port_name = 0,
>  		.switch_id = 0,
>  	};
>  	size_t off = NLMSG_LENGTH(sizeof(struct ifinfomsg));
> -	bool port_name_set = false;
>  	bool switch_id_set = false;
>  	bool num_vf_set = false;
> 
> @@ -910,9 +909,7 @@ struct mlx5_nl_ifindex_data {
>  			num_vf_set = true;
>  			break;
>  		case IFLA_PHYS_PORT_NAME:
> -			port_name_set =
> -				mlx5_translate_port_name((char *)payload,
> -							 &info);
> +			mlx5_translate_port_name((char *)payload, &info);
>  			break;
>  		case IFLA_PHYS_SWITCH_ID:
>  			info.switch_id = 0;
> @@ -926,16 +923,33 @@ struct mlx5_nl_ifindex_data {
>  		off += RTA_ALIGN(ra->rta_len);
>  	}
>  	if (switch_id_set) {
> -		if (info.port_name_new) {
> -			/* New representors naming schema. */
> -			if (port_name_set) {
> -				info.master = (info.port_name == -1);
> -				info.representor = (info.port_name != -1);
> -			}
> -		} else {
> +		/* We have some E-Switch configuration. */
> +		switch (info.name_type) {
> +		case MLX5_PHYS_PORT_NAME_TYPE_UNKNOWN:
> +			/*
> +			 * Name is not recognized or not set,
> +			 * it can not be representor, check
> +			 * VF number to see if it is a master.
> +			 */
> +			info.master = num_vf_set;
> +			break;
> +		case MLX5_PHYS_PORT_NAME_TYPE_LEGACY:
>  			/* Legacy representors naming schema. */
> -			info.master = (!port_name_set || num_vf_set);
> -			info.representor = port_name_set && !num_vf_set;
> +			info.representor = !num_vf_set;
> +			break;
> +		case MLX5_PHYS_PORT_NAME_TYPE_UPLINK:
> +			/* New uplink naming schema. */
> +			info.master = 1;
> +			break;
> +		case MLX5_PHYS_PORT_NAME_TYPE_PFVF:
> +			/* New representors naming schema. */
> +			info.representor = 1;
> +			break;
> +		}
> +		if (!info.master && !info.representor) {
> +			DRV_LOG(INFO,
> +				"unable to recognize master/representors"
> +				" on the device in switch domain");

Same comment as above. Would like to avoid this switch case outside of the translate function .

>  		}
>  	}
>  	assert(!(info.master && info.representor));
> --
> 1.8.3.1