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Josh Hilke 1583ef1175 vfio: selftests: igb: Add driver for Intel 82576 device
Add a VFIO selftest driver for the Intel Gigabit Ethernet controller
(IGB), specifically targeting the 82576 device. IGB is fully virtualized
in QEMU which makes it easy to run VFIO selftests without needing any
specific hardware.

Since IGB is an Ethernet device, it cannot support DMA transfers smaller
than the minimum Ethernet payload size (60 bytes) without hardware padding
corrupting adjacent memory. The driver asserts that the transfer size is
at least 60 bytes to prevent this.

All VFIO selftest drivers must implement DMA/memcpy operations, but IGB
doesn't have a native memcpy feature, so the loopback feature (described
in section 3.5.6.3 of IGB specification) is used to implement it. To
support testing on both QEMU and physical hardware, the driver uses PHY
internal loopback with some QEMU-specific fallbacks. The driver also
supports MSI-X routing and interrupt management, and disables PCIe
completion timeout retries to ensure clean recovery during invalid-DMA
tests.

Users can verify the driver works in QEMU by building the kernel,
building VFIO selftests, and then running the vfio_pci_driver_test using
this command:

vng \
--run arch/x86/boot/bzImage \
--user root \
--disable-microvm \
--memory 32G \
--cpus 8 \
--qemu-opts="-M q35,accel=kvm,kernel-irqchip=split" \
--qemu-opts="-device intel-iommu,intremap=on,caching-mode=on,device-iotlb=on" \
--qemu-opts="-netdev user,id=net0 -device igb,netdev=net0,addr=09.0" \
--append "console=ttyS0 earlyprintk=ttyS0 intel_iommu=on iommu=pt" \
--exec "modprobe vfio-pci && \
  ./tools/testing/selftests/vfio/scripts/setup.sh 0000:00:09.0 && \
  ./tools/testing/selftests/vfio/scripts/run.sh ./tools/testing/selftests/vfio/vfio_pci_driver_test"

Assisted-by: Claude:claude-opus-4-7
Assisted-by: Gemini:gemini-3.1-pro-preview
Co-developed-by: Alex Williamson <alex.williamson@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@nvidia.com>
Signed-off-by: Josh Hilke <jrhilke@google.com>
Acked-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20260805-igb_v3_b4-v10-2-9c86dc849c0d@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
History 2026-08-10 13:24:40 -06:00
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Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst