Generated banner for Doca Devemu
Generated logo for Doca Devemu

Doca Devemu

NVIDIAOfficialCreated by NVIDIA

  • Skill
  • Tool integration
  • Software development
  • Apache-2.0
  • Medium risk

From the author

Use this skill when the user is doing hands-on DOCA Device Emulation on a BlueField DPU — exposing a custom emulated PCIe device the host sees as a real peripheral while DPU-side code runs the backend, picking the sub-library (PCI Generic, virtio-net, virtio-fs), wiring the per-sub-library Core context plus doorbell / DMA primitives, querying `doca_devemu_*_cap_*`, or debugging DOCA_ERROR_* from a `doca_devemu_*` call. Trigger even when the user does not say "devemu" — typical implicit phrasings include "expose a custom PCIe device from BlueField to the host", "host should see a virtio NIC backed by my DPU code", "lspci does not show my emulated device", "device enumerated but no driver binds", "DPU sees nothing when host kicks the queue", or "virtio feature negotiation failed at bind". Refuse and route elsewhere for the packaged DOCA SNAP / Virtio-net Services, host-side virtio kernel drivers, backend body design, or standard BlueField NIC behavior — those belong to other skills.
— the description by NVIDIA

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

The doca-devemu skill assists developers in building custom PCIe devices that appear as real peripherals to a host system, while the backend logic runs on a BlueField DPU. It covers the three primary sub-libraries: PCI Generic, virtio-net, and virtio-fs. The skill helps users navigate the lifecycle of emulated devices, including sub-library selection, capability discovery, context initialization, and debugging errors returned by the DOCA Device Emulation API. It is designed for developers writing their own DPU-side backends, rather than those using pre-packaged services like DOCA SNAP.

What it does

  • Guides sub-library selection between PCI Generic, virtio-net, and virtio-fs.
  • Assists with initializing DOCA Core contexts and configuring doorbell/DMA primitives.
  • Provides methods for querying device capabilities via doca_devemu_*_cap_* functions.
  • Helps debug DOCA_ERROR_* codes specific to device emulation.
  • Clarifies the distinction between custom library development and packaged DOCA services.
  • Supports developers working in C/C++ or other languages via FFI.

When to use it

  • When you need to expose a custom PCIe device from a BlueField DPU to a host.
  • When you are writing a DPU-side backend for a virtio-net or virtio-fs device.
  • When you need to verify if your BlueField firmware and DOCA version support a specific emulation class.
  • When you encounter errors during device emulation initialization or feature negotiation.
  • When you need to determine if a custom backend is required or if a packaged DOCA service suffices.

Advantages

  • Provides a clear path for selecting the correct emulation sub-library.
  • Simplifies the complex process of bridging host-side PCIe drivers with DPU-side logic.
  • Offers structured debugging steps for firmware and driver-level issues.
  • Ensures developers follow correct capability discovery patterns before implementation.

Usage examples

“Expose a custom PCIe device from BlueField to the host.”
The agent will guide you through selecting the appropriate sub-library (PCI Generic, virtio-net, or virtio-fs) and initializing the corresponding DOCA Core context.
“lspci does not show my emulated device.”
The agent will help you verify the firmware-level emulation configuration and ensure the host-side kernel driver is correctly bound to the emulated device.
“Why does my virtio-net emulation create call return DOCA_ERROR_NOT_PERMITTED?”
The agent will check if the virtio-net emulation slot is enabled in the BlueField firmware and verify DPU-side process privileges.

Install

  1. Download the skill as a ZIP:

    https://autogineer.com/agent-skills/nvidia/doca-devemu/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip doca-devemu.zip -d .agents/skills

Documentation by NVIDIA

DOCA Device Emulation

Examples

  • "Expose a custom PCIe device from BlueField to the host." — this is in scope. Pick PCI Generic / virtio-net / virtio-fs; do not stand up SNAP or Virtio-net Service here.

  • "lspci does not show my emulated device." — confirm the firmware emulation type and host driver before changing DPU-side code.

Instructions

Follow Loading order below. Open the tasks companion for configure / emulate / debug. Open the capabilities companion for sub-libraries and cap queries. Do not open every companion file.

Where to start: This skill assumes DOCA is already installed on the host AND on the BlueField, the user is doing hands-on emulated-PCIe-device work from the DPU side (writing the backend that the host's kernel driver will talk to over the emulated PCIe surface), and the user knows which CLASS of emulated device they want to build. Open the tasks companion if the user wants to do something (configure / build / modify / run / test / debug); open the capabilities companion when the question is what can Device Emulation express on this DOCA version + this BlueField generation + this firmware. If the user has not installed DOCA yet, route to doca-setup/SKILL.md first. Before anything else, the agent must route the user to the right sub-library — DOCA Device Emulation is an umbrella that covers PCI Generic (raw PCIe device emulation), virtio-net (emulated virtio network device), and virtio-fs (emulated virtio filesystem device); each sub-library has its own context, its own pkg-config module, and its own capability surface. The sub-library selection rule lives in the capabilities companion. If the user wants a packaged solution rather than a library (e.g. "I want NVMe SNAP on my host without writing the backend myself", or "I want a managed virtio-net daemon"), route via doca-public-knowledge-map/SKILL.md to the DOCA SNAP Service / DOCA Virtio-net Service guides — those services are built on top of this library and are a different artifact than what this skill covers.

Audience

This skill serves external developers building applications that consume the DOCA Device Emulation library — i.e., users whose DPU-side code calls doca_devemu_pci_*, doca_devemu_virtio_*, or doca_devemu_vfs_* (directly in C / C++, or through FFI / bindings from another language) to expose an emulated PCIe device to the host that the host's existing kernel drivers can drive as if it were a real PCIe peripheral. It is not for NVIDIA developers contributing to DOCA Device Emulation itself, and it is not the right artifact for users who want a packaged emulated-device daemon they do not have to write the backend for (the DOCA SNAP Service and the DOCA Virtio-net Service are the packaged options that build on top of this library).

Language scope. DOCA Device Emulation ships as a C library; this skill covers three sub-libraries end-to-end. Select the exact installed pkg-config module for the user's emulation class (see the sub-library selection table in the capabilities companion). The shipped samples under /opt/mellanox/doca/samples/doca_devemu/ are written in C. C and C++ consumers are the canonical case and the worked examples in the tasks companion assume that path. Other-language consumers (Rust, Go, Python, …) consume the same *.so files through FFI or language-specific bindings; the skill's contribution in that case is to keep the sub-library selection, umbrella lifecycle, capability-discovery, permission, and error-taxonomy guidance language-neutral, and to route the agent to the public C ABI as the authoritative surface that any wrapper will eventually call.

When to load this skill

Load this skill when the user is doing hands-on DOCA Device Emulation work from the DPU side, in any language. Concretely:

  • Deciding which Device Emulation sub-library (PCI Generic, virtio-net, virtio-fs) the user needs — the umbrella selection question is this skill's load-bearing first move.

  • Initializing the per-sub-library DOCA Core context on the DPU (one context per emulated device per sub-library) and configuring the doorbell / DMA primitives the host's PCIe driver will interact with.

  • Reading per-sub-library capability surface via the doca_devemu_pci_cap_*, doca_devemu_virtio_cap_*, or doca_devemu_vfs_cap_* query families against the active doca_devinfo BEFORE assuming a particular feature bit or device characteristic is available.

  • Choosing between writing the backend with doca-devemu yourself and adopting a packaged service (DOCA SNAP Service / DOCA Virtio-net Service) that already wraps this library.

  • Debugging a DOCA_ERROR_* returned from a doca_devemu_* call — in particular disambiguating firmware-level emulation type not enabled from BlueField generation does not support this sub-library at all from DPU-side process lacks privilege from host-side kernel driver did not bind.

  • Designing or extending non-C bindings (Rust, Go, Python, …) that wrap one of the device-emulation sub-libraries — for the sub-library selection, umbrella lifecycle, capability- discovery, permission, and error-taxonomy rules the wrapper must honor.

Do not load this skill for general DOCA orientation, install of DOCA itself, the host-side kernel driver for the emulated device class (virtio-net / virtio-blk / virtio-fs kernel drivers ship with the host kernel and are not part of DOCA), the packaged SNAP / Virtio-net services (they are separate artifacts with their own service guides), or for standard NIC behavior on the BlueField data path (use doca-flow/SKILL.md + doca-eth/SKILL.md instead — Device Emulation is for custom emulated devices, not for shaping the BlueField's built-in NIC personality).

What this skill provides

This is a thin loader. The body keeps only the orientation needed to pick the right next file. The substantive Device Emulation-specific material lives in two companion files:

  • the capabilities companion — what Device Emulation can express on this version + this BlueField generation + this firmware: the umbrella architecture (host sees an emulated PCIe device; DPU runs the backend), the sub-library selection rule (PCI Generic vs virtio-net vs virtio-fs), the per- sub-library Core context shape, the doorbell / DMA primitives that bridge host ↔ DPU, the per-sub-library capability-query family (doca_devemu_*_cap_*), the per-sub-library pkg-config module name, the Device Emulation error taxonomy mapped onto the cross-library DOCA_ERROR_* set, the observability surface, the library-vs-packaged-service path-selection rule, and the safety policy that gates env preconditions (DPU-side privileges, BlueField firmware-level emulation type enablement, BlueField generation actually supporting the emulation class).

  • the tasks companion — step-by-step workflows for the six in-scope Device Emulation verbs: configure, build, modify, run, test, debug. Plus a Deferred task verbs block that points out-of-scope questions at the right next skill.

The skill assumes a host + BlueField pair where DOCA is already installed at the standard location on both sides, the BlueField firmware has the emulation type the user wants to build enabled, the user has the privileges their public install profile expects (in particular, sudo on the DPU side to perform PCIe-level emulation), and the host kernel ships the standard driver for the emulated device class the user is building. It does not cover installing DOCA, flipping firmware-level configuration, or installing host-side kernel drivers — those paths go through doca-setup/SKILL.md.

Loading order

  1. Read this skill first to confirm the user's question is in scope (custom emulated PCIe device built on the doca-devemu library, not the packaged SNAP / Virtio-net services, not the host-side kernel driver, not standard NIC behavior).

  2. For the umbrella architecture, the sub-library selection rule (PCI Generic vs virtio-net vs virtio-fs), the per- sub-library Core context shape, the doorbell / DMA primitives, the per-sub-library capability-query rule, the per-sub-library pkg-config modules, the library-vs- packaged-service path-selection rule, the error taxonomy, the observability surface, and the safety policy, see the capabilities companion.

  3. For step-by-step workflows — configure, build, modify, run, test, debug — see the tasks companion.

Both companion files cross-link to each other, doca-version/SKILL.md for the canonical DOCA version-handling rules (with the Device Emulation overlay that the chosen sub-library's pkg-config module plus the firmware-level emulation slot plus the doca_devemu_*_cap_* query are all part of "is this emulation supported here"), and doca-public-knowledge-map/SKILL.md whenever the right answer is "look it up in the public DOCA Device Emulation umbrella guide, the per-sub-library guide linked from it, the DOCA SNAP / Virtio-net Service guide, or in the on-disk install layout" rather than "Device Emulation- specific guidance".

  • doca-public-knowledge-map/SKILL.md — the routing table for every public DOCA documentation source and the on-disk layout of an installed DOCA package. The Device Emulation umbrella URL is https://docs.nvidia.com/doca/sdk/DOCA-Device-Emulation/index.html; per-sub-library guides are linked from the umbrella, and the packaged DOCA SNAP / Virtio-net services are listed under the DOCA Services umbrella as separate artifacts.

  • doca-setup/SKILL.md — env preparation, install verification, DPU-side privilege checks, BlueField firmware configuration (including the per-sub-library emulation type enable), and the I have no install yet path with the public NGC DOCA container. This skill assumes its preconditions are satisfied AND that the firmware-level emulation type for the user's chosen sub-library is enabled.

  • doca-version/SKILL.md — canonical DOCA version-handling rules. This skill's Version compatibility overlay cross-links the four-way match rule and adds the Device Emulation-specific per-sub-library pkg-config + doca_devemu_*_cap_* overlay.

  • doca-structured-tools-contract/SKILL.md — the bundle's structured-tools precedence rule (detect / prefer / fall back / report). The Command appendix in the tasks companion honors this contract.

  • doca-programming-guide/SKILL.md — general DOCA programming patterns shared by every library: the canonical pkg-config + meson build pattern, the universal modify-a-shipped-sample first-app workflow, the universal Core-context lifecycle, the cross-library DOCA_ERROR_* taxonomy, and the program-side debug order. This skill layers Device Emulation specifics on top.

  • doca-comch/SKILL.md — the right library when the user wants a control-plane channel between a host process and a DPU process over PCIe but does NOT want the host to see the DPU as an emulated PCIe device with a standard host kernel driver. Device Emulation hides the DPU behind a real-looking PCIe device class; Comch is an explicit host ↔ DPU IPC.

  • doca-flow/SKILL.md and doca-eth/SKILL.md — the right libraries when the user wants to shape traffic on the BlueField's built-in NIC personality, not expose a custom emulated PCIe device. Device Emulation is for new emulated PCIe devices the host did not previously see; Flow / Eth are for the BlueField's existing NIC surface.

  • doca-debug/SKILL.md — the cross-cutting debug ladder (install / version / build / link / runtime / program / driver). Device Emulation-specific debug (firmware-level emulation type not enabled, sub-library mis-selected, host kernel driver not binding to the emulated device, virtio feature-negotiation failures) overlays on top of that ladder.

Files

LICENSE

Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.


                                 Apache License
                           Version 2.0, January 2004
                        http://www.apache.org/licenses/

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all
      other entities that control, are controlled by, or are under common
      control with that entity. For the purposes of this definition,
      "control" means (i) the power, direct or indirect, to cause the
      direction or management of such entity, whether by contract or
      otherwise, or (ii) ownership of fifty percent (50%) or more of the
      outstanding shares, or (iii) beneficial ownership of such entity.

      "You" (or "Your") shall mean an individual or Legal Entity
      exercising permissions granted by this License.

      "Source" form shall mean the preferred form for making modifications,
      including but not limited to software source code, documentation
      source, and configuration files.

      "Object" form shall mean any form resulting from mechanical
      transformation or translation of a Source form, including but
      not limited to compiled object code, generated documentation,
      and conversions to other media types.

      "Work" shall mean the work of authorship, whether in Source or
      Object form, made available under the License, as indicated by a
      copyright notice that is included in or attached to the work
      (an example is provided in the Appendix below).

      "Derivative Works" shall mean any work, whether in Source or Object
      form, that is based on (or derived from) the Work and for which the
      editorial revisions, annotations, elaborations, or other modifications
      represent, as a whole, an original work of authorship. For the purposes
      of this License, Derivative Works shall not include works that remain
      separable from, or merely link (or bind by name) to the interfaces of,
      the Work and Derivative Works thereof.

      "Contribution" shall mean any work of authorship, including
      the original version of the Work and any modifications or additions
      to that Work or Derivative Works thereof, that is intentionally
      submitted to Licensor for inclusion in the Work by the copyright owner
      or by an individual or Legal Entity authorized to submit on behalf of
      the copyright owner. For the purposes of this definition, "submitted"
      means any form of electronic, verbal, or written communication sent
      to the Licensor or its representatives, including but not limited to
      communication on electronic mailing lists, source code control systems,
      and issue tracking systems that are managed by, or on behalf of, the
      Licensor for the purpose of discussing and improving the Work, but
      excluding communication that is conspicuously marked or otherwise
      designated in writing by the copyright owner as "Not a Contribution."

      "Contributor" shall mean Licensor and any individual or Legal Entity
      on behalf of whom a Contribution has been received by Licensor and
      subsequently incorporated within the Work.

   2. Grant of Copyright License. Subject to the terms and conditions of
      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      copyright license to reproduce, prepare Derivative Works of,
      publicly display, publicly perform, sublicense, and distribute the
      Work and such Derivative Works in Source or Object form.

   3. Grant of Patent License. Subject to the terms and conditions of
      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)
      with the Work to which such Contribution(s) was submitted. If You
      institute patent litigation against any entity (including a
      cross-claim or counterclaim in a lawsuit) alleging that the Work
      or a Contribution incorporated within the Work constitutes direct
      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You
      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and
          attribution notices from the Source form of the Work,
          excluding those notices that do not pertain to any part of
          the Derivative Works; and

      (d) If the Work includes a "NOTICE" text file as part of its
          distribution, then any Derivative Works that You distribute must
          include a readable copy of the attribution notices contained
          within such NOTICE file, excluding those notices that do not
          pertain to any part of the Derivative Works, in at least one
          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,
          within a display generated by the Derivative Works, if and
          wherever such third-party notices normally appear. The contents
          of the NOTICE file are for informational purposes only and
          do not modify the License. You may add Your own attribution
          notices within Derivative Works that You distribute, alongside
          or as an addendum to the NOTICE text from the Work, provided
          that such additional attribution notices cannot be construed
          as modifying the License.

      You may add Your own copyright statement to Your modifications and
      may provide additional or different license terms and conditions
      for use, reproduction, or distribution of Your modifications, or
      for any such Derivative Works as a whole, provided Your use,
      reproduction, and distribution of the Work otherwise complies with
      the conditions stated in this License.

   5. Submission of Contributions. Unless You explicitly state otherwise,
      any Contribution intentionally submitted for inclusion in the Work
      by You to the Licensor shall be under the terms and conditions of
      this License, without any additional terms or conditions.
      Notwithstanding the above, nothing herein shall supersede or modify
      the terms of any separate license agreement you may have executed
      with Licensor regarding such Contributions.

   6. Trademarks. This License does not grant permission to use the trade
      names, trademarks, service marks, or product names of the Licensor,
      except as required for reasonable and customary use in describing the
      origin of the Work and reproducing the content of the NOTICE file.

   7. Disclaimer of Warranty. Unless required by applicable law or
      agreed to in writing, Licensor provides the Work (and each
      Contributor provides its Contributions) on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
      implied, including, without limitation, any warranties or conditions
      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
      PARTICULAR PURPOSE. You are solely responsible for determining the
      appropriateness of using or redistributing the Work and assume any
      risks associated with Your exercise of permissions under this License.

   8. Limitation of Liability. In no event and under no legal theory,
      whether in tort (including negligence), contract, or otherwise,
      unless required by applicable law (such as deliberate and grossly
      negligent acts) or agreed to in writing, shall any Contributor be
      liable to You for damages, including any direct, indirect, special,
      incidental, or consequential damages of any character arising as a
      result of this License or out of the use or inability to use the
      Work (including but not limited to damages for loss of goodwill,
      work stoppage, computer failure or malfunction, or any and all
      other commercial damages or losses), even if such Contributor
      has been advised of the possibility of such damages.

   9. Accepting Warranty or Additional Liability. While redistributing
      the Work or Derivative Works thereof, You may choose to offer,
      and charge a fee for, acceptance of support, warranty, indemnity,
      or other liability obligations and/or rights consistent with this
      License. However, in accepting such obligations, You may act only
      on Your own behalf and on Your sole responsibility, not on behalf
      of any other Contributor, and only if You agree to indemnify,
      defend, and hold each Contributor harmless for any liability
      incurred by, or claims asserted against, such Contributor by reason
      of your accepting any such warranty or additional liability.

   END OF TERMS AND CONDITIONS

   APPENDIX: How to apply the Apache License to your work.

      To apply the Apache License to your work, attach the following
      boilerplate notice, with the fields enclosed by brackets "[]"
      replaced with your own identifying information. (Don't include
      the brackets!)  The text should be enclosed in the appropriate
      comment syntax for the file format. We also recommend that a
      file or class name and description of purpose be included on the
      same "printed page" as the copyright notice for easier
      identification within third-party archives.

   Copyright [yyyy] [name of copyright owner]

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

The author says: Requires DOCA SDK installed at /opt/mellanox/doca on BOTH the host AND the BlueField DPU (Ubuntu 22.04/24.04 or RHEL/SLES), with firmware emulation (PCI Generic / virtio-net / virtio-fs) enabled and the host kernel shipping the matching driver (virtio_net / virtio_fs / generic PCIe). Reads pkg-config for the chosen sub-library and inspects /opt/mellanox/doca/{lib,include,samples/doca_devemu}. The validation steps require a live DOCA install.

Security

What our scanner noticed· Medium risk

  • Large base64-encoded blobs

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Created by
NVIDIA
Publisher
NVIDIA (Official)
Source
NVIDIA/skills · skills/doca-devemu · commit fce3cca
Licence
Apache License 2.0 (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE-APACHE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

AutoGineer is not affiliated with or endorsed by NVIDIA or NVIDIA.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download doca-devemu.zip