NVME-ID-CTRL(1) NVMe Manual NVME-ID-CTRL(1)

nvme-id-ctrl - Send NVMe Identify Controller, return result and structure

nvme id-ctrl <device> [--vendor-specific | -V] [--raw-binary | -b]
                        [--output-format=<fmt> | -o <fmt>] [--verbose | -v]

For the NVMe device given, sends an identify controller command and provides the result and returned structure.

The <device> parameter is mandatory and may be either the NVMe character device (ex: /dev/nvme0), or a namespace block device (ex: /dev/nvme0n1).

On success, the structure may be returned in one of several ways depending on the option flags; the structure may be parsed by the program or the raw buffer may be printed to stdout.

-b, --raw-binary

Print the raw buffer to stdout. Structure is not parsed by program. This overrides the vendor specific and human readable options.

-V, --vendor-specific

In addition to parsing known fields, this option will dump the vendor specific region of the structure in hex with ascii interpretation.

-H, --human-readable

This option will parse and format many of the bit fields into human-readable formats.

-o <fmt>, --output-format=<fmt>

Set the reporting format to normal, json or binary. Only one output format can be used at a time.

-v, --verbose

Increase the information detail in the output.

•Has the program interpret the returned buffer and display the known fields in a human readable format: 
# nvme id-ctrl /dev/nvme0
•In addition to showing the known fields, has the program to display the vendor unique field: 
# nvme id-ctrl /dev/nvme0 --vendor-specific
# nvme id-ctrl /dev/nvme0 -V

The above will dump the vs buffer in hex since it doesn’t know how to interpret it.

•Have the program return the raw structure in binary: 
# nvme id-ctrl /dev/nvme0 --raw-binary > id_ctrl.raw
# nvme id-ctrl /dev/nvme0 -b > id_ctrl.raw

It is probably a bad idea to not redirect stdout when using this mode.

•Alternatively you may want to send the data to another program that can parse the raw buffer. 
# nvme id-ctrl /dev/nvme0 --raw-binary | nvme_parse_id_ctrl

The parse program in the above example can be a program that shows the structure in a way you like. The following program is such an example that will parse it and can accept the output through a pipe, '|', as shown in the above example, or you can 'cat' a saved output buffer to it.

/* File: nvme_parse_id_ctrl.c */
#include <linux/nvme.h>
#include <stdio.h>
#include <unistd.h>
int main(int argc, char **argv)
{
        unsigned char buf[sizeof(struct nvme_id_ctrl)];
        struct nvme_id_ctrl *ctrl = (struct nvme_id_ctrl *)buf;
        if (read(STDIN_FILENO, buf, sizeof(buf)))
                return 1;
        printf("vid   : %#x\n", ctrl->vid);
        printf("ssvid : %#x\n", ctrl->ssvid);
        return 0;
}

Part of the nvme-user suite

08/07/2024 NVMe