Inspect vDPA Management Devices Before Creating a Device

Use vdpa mgmtdev show to discover the vDPA management devices available to the kernel, then query one by its name. This is a read-only check: it does not create, remove or reconfigure a vDPA device.

Before you start

You need the vdpa utility from the iproute2 package. The examples here were checked with Ubuntu's iproute2 package version 6.1.0-1ubuntu6.4. You also need a running kernel and driver that expose the vDPA Netlink interface, plus a management device supplied by a vDPA provider if you expect a non-empty result.

Allow about five minutes. No elevated privileges are required for these inspection commands in the usual configuration. If your system restricts Netlink access, retry the same command with sudo only after checking your local policy.

Checkpoint 1: confirm the command version

Start by checking which implementation is installed. This catches a missing command and makes later differences easier to explain.

vdpa -V

On the reference system, the result identifies vdpa utility, iproute2-6.1.0. The package revision and the utility's reported upstream version are separate pieces of information, so record both when troubleshooting.

Checkpoint 2: list every management device

Run the command without a device name. The argument is optional; when omitted, vdpa mgmtdev show asks for all management devices.

vdpa mgmtdev show

Read the returned names and attributes as discovery data. A name such as bar is only an example from the installed manual, not a device that should exist on every host. Do not copy a name from a different server without first confirming it appears in this list.

If the command completes without listing anything, there may simply be no provider currently registered. That is different from the command failing to contact the vDPA Netlink family. Preserve the exact exit status and error text before changing drivers, modules or services.

Checkpoint 3: inspect one named device

Choose a name from the previous result and pass it as the optional MGMTDEV argument.

vdpa mgmtdev show <MGMTDEV>

For example, if the discovery output really contained bar, the command would be:

vdpa mgmtdev show bar

This narrows the response to the selected management device and is useful when several providers are installed. It still only displays attributes. The mgmtdev command has no add, delete or change operation, so there is no undo step for this guide.

Checkpoint 4: diagnose a failed query

On the reference host, each query returned Failed to connect to vdpa Netlink because the required interface was not available. Treat that message as a host capability or kernel integration problem, not as evidence that a management device called bar exists or is missing.

Collect the basics without modifying the system:

command -v vdpa
vdpa -V
vdpa mgmtdev show
uname -r

Check that vdpa resolves to the expected iproute2 installation, compare the reported utility version with the package you administer, and save the kernel release alongside the exact error. Then check your distribution's vDPA driver and kernel documentation. Loading a driver, changing module configuration or restarting a service is outside this read-only inspection and may affect workloads.

A named query can also fail because the name is wrong or has disappeared since discovery. Re-run the all-devices query and use a currently returned name. Do not guess names, and do not move on to vdpa dev add until management-device discovery works.

How this fits the next step

A management device is the control point used by a vDPA provider. This command shows which control points are visible; it does not show every vDPA data-path device and does not create one. Once a provider is visible, consult vdpa-dev(8) for device operations and verify its prerequisites before making a change. Keep discovery and mutation separate so an incorrect provider name cannot become an accidental provisioning attempt.