Re: [PATCH v7 2/8] ethdev: add telemetry cmd for registers

[fengchengwen <fengchengwen@huawei.com>]

On 2024/9/14 15:13, Jie Hai wrote:
> This patch adds a telemetry command for registers dump,
> and supports obtaining the registers of a specified module.
> 
> In one way, the number of registers that can be exported
> is limited by the number of elements carried by dict and
> container. In another way, the length of the string
> exported by telemetry is limited by MAX_OUTPUT_LEN.
> Therefore, when the number of registers to be exported
> exceeds, some information will be lost. Warn on the former
> case.
> 
> An example usage is shown below:
> --> /ethdev/regs,0,ring
> {
>   "/ethdev/regs": {
>     "registers_length": 318,
>     "registers_width": 4,
>     "register_offset": "0x0",
>     "version": "0x1140011",
>     "group_0": {
>       "Q0_ring_rx_bd_num": "0x0",
>       "Q0_ring_rx_bd_len": "0x0",
>       ...
>       },
>     "group_1": {
>         ...
>     },
>     ...
> }
> 
> Signed-off-by: Jie Hai <haijie1@huawei.com>
> ---
>  lib/ethdev/rte_ethdev_telemetry.c | 128 ++++++++++++++++++++++++++++++
>  1 file changed, 128 insertions(+)
> 
> diff --git a/lib/ethdev/rte_ethdev_telemetry.c b/lib/ethdev/rte_ethdev_telemetry.c
> index 6b873e7abe68..1d59c693883e 100644
> --- a/lib/ethdev/rte_ethdev_telemetry.c
> +++ b/lib/ethdev/rte_ethdev_telemetry.c
> @@ -1395,6 +1395,132 @@ eth_dev_handle_port_tm_node_caps(const char *cmd __rte_unused,
>  	return ret;
>  }
>  
> +static void
> +eth_dev_add_reg_data(struct rte_tel_data *d, struct rte_dev_reg_info *reg_info,
> +		     uint32_t idx)
> +{
> +	if (reg_info->width == sizeof(uint32_t))
> +		rte_tel_data_add_dict_uint_hex(d, reg_info->names[idx].name,
> +			*((uint32_t *)reg_info->data + idx), 0);
> +	else
> +		rte_tel_data_add_dict_uint_hex(d, reg_info->names[idx].name,
> +			*((uint64_t *)reg_info->data + idx), 0);
> +}
> +
> +static int
> +eth_dev_store_regs(struct rte_tel_data *d, struct rte_dev_reg_info *reg_info)
> +{
> +	struct rte_tel_data *groups[RTE_TEL_MAX_DICT_ENTRIES];
> +	char group_name[RTE_TEL_MAX_STRING_LEN] = {0};
> +	struct rte_tel_data *group = NULL;
> +	uint32_t grp_num = 0;
> +	uint32_t i;
> +	int ret;
> +
> +	rte_tel_data_start_dict(d);
> +	rte_tel_data_add_dict_uint(d, "register_length", reg_info->length);
> +	rte_tel_data_add_dict_uint(d, "register_width", reg_info->width);
> +	rte_tel_data_add_dict_uint_hex(d, "register_offset", reg_info->offset, 0);
> +	rte_tel_data_add_dict_uint_hex(d, "version", reg_info->version, 0);
> +
> +	for (i = 0; i < reg_info->length; i++) {
> +		if (i % RTE_TEL_MAX_DICT_ENTRIES != 0) {
> +			eth_dev_add_reg_data(group, reg_info, i);
> +			continue;
> +		}
> +
> +		group = rte_tel_data_alloc();
> +		if (group == NULL) {
> +			ret = -ENOMEM;
> +			RTE_ETHDEV_LOG_LINE(WARNING, "No enough memory for group data");
> +			goto out;
> +		}
> +		groups[grp_num++] = group;

Although the probability is very small, the groups array may overflow if the length is very large.

Suggest add judgement at the begin of this function:

uint32_t max_cap = (RTE_TEL_MAX_DICT_ENTRIES - 4) * RTE_TEL_MAX_DICT_ENTRIES;   // it will be 65000+ register
if (reg_info->length > max_cap) {
    // just output error and exit
}

> +		rte_tel_data_start_dict(group);
> +		eth_dev_add_reg_data(group, reg_info, i);
> +	}
> +
> +	for (i = 0; i < grp_num; i++) {
> +		snprintf(group_name, RTE_TEL_MAX_STRING_LEN, "group_%u", i);
> +		ret = rte_tel_data_add_dict_container(d, group_name, groups[i], 0);
> +		if (ret == -ENOSPC) {
> +			RTE_ETHDEV_LOG_LINE(WARNING,
> +				"Reduce register number to be displayed from %u to %u due to limited capacity of telemetry",
> +				reg_info->length, i * RTE_TEL_MAX_DICT_ENTRIES);
> +			break;
> +		}

It may lead to memory leak when break. If we add such judgement before, there is no need to add such judgement here.

> +	}
> +	return 0;
> +out:
> +	for (i = 0; i < grp_num; i++)
> +		rte_tel_data_free(groups[i]);
> +
> +	return ret;
> +}
> +
> +static int
> +eth_dev_get_port_regs(int port_id, struct rte_tel_data *d, char *filter)
> +{
> +	struct rte_dev_reg_info reg_info;
> +	int ret;
> +
> +	memset(&reg_info, 0, sizeof(reg_info));
> +	reg_info.filter = filter;
> +
> +	ret = rte_eth_dev_get_reg_info_ext(port_id, &reg_info);
> +	if (ret != 0) {
> +		RTE_ETHDEV_LOG_LINE(ERR, "Error getting device reg info: %d", ret);

how about "Failed to get device reg info, ret = %d"

> +		return ret;
> +	}
> +
> +	reg_info.data = calloc(reg_info.length, reg_info.width);
> +	if (reg_info.data == NULL) {
> +		RTE_ETHDEV_LOG_LINE(ERR, "Fail to allocate memory for reg_info.data");
> +		return -ENOMEM;
> +	}
> +
> +	reg_info.names = calloc(reg_info.length, sizeof(struct rte_eth_reg_name));
> +	if (reg_info.names == NULL) {
> +		RTE_ETHDEV_LOG_LINE(ERR, "Fail to allocate memory for reg_info.names");
> +		free(reg_info.data);
> +		return -ENOMEM;
> +	}
> +
> +	ret = rte_eth_dev_get_reg_info_ext(port_id, &reg_info);
> +	if (ret != 0) {
> +		RTE_ETHDEV_LOG_LINE(ERR, "Error getting regs from device: %d", ret);

It seemed the ret is device id, how about "Failed to get device reg info, ret = %d"

> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	ret = eth_dev_store_regs(d, &reg_info);
> +out:
> +	free(reg_info.data);
> +	free(reg_info.names);
> +
> +	return ret;
> +}
> +
> +static int
> +eth_dev_handle_port_regs(const char *cmd __rte_unused,
> +		const char *params,
> +		struct rte_tel_data *d)
> +{
> +	char *filter, *end_param;
> +	uint16_t port_id;
> +	int ret;
> +
> +	ret = eth_dev_parse_port_params(params, &port_id, &end_param, true);
> +	if (ret != 0)
> +		return ret;
> +
> +	filter = strtok(end_param, ",");
> +	if (filter != NULL && strlen(filter) == 0)
> +		filter = NULL;
> +
> +	return eth_dev_get_port_regs(port_id, d, filter);
> +}
> +
>  RTE_INIT(ethdev_init_telemetry)
>  {
>  	rte_telemetry_register_cmd("/ethdev/list", eth_dev_handle_port_list,
> @@ -1436,4 +1562,6 @@ RTE_INIT(ethdev_init_telemetry)
>  			"Returns TM Level Capabilities info for a port. Parameters: int port_id, int level_id (see tm_capability for the max)");
>  	rte_telemetry_register_cmd("/ethdev/tm_node_capability", eth_dev_handle_port_tm_node_caps,
>  			"Returns TM Node Capabilities info for a port. Parameters: int port_id, int node_id (see tm_capability for the max)");
> +	rte_telemetry_register_cmd("/ethdev/regs", eth_dev_handle_port_regs,
> +			"Returns all or filtered registers info for a port. Parameters: int port_id, string module_name (Optional if show all)");
>  }