Kerneldev MCP - Kernel Development Configuration & Build Server

An MCP (Model Context Protocol) server for intelligent Linux kernel configuration management and building. This tool provides AI assistants with the ability to generate, manage, and optimize kernel configurations for different testing scenarios, plus build kernels with comprehensive error detection and reporting.

Features

Configuration Management

• Pre-built Configuration Templates: Ready-to-use configs for common testing scenarios

  • Networking testing (full TCP/IP stack, netfilter, eBPF/XDP)
  • BTRFS filesystem testing
  • General filesystem testing (ext4, XFS, BTRFS, F2FS, etc.)
  • Boot testing (minimal configs for fast iteration)
  • Virtualization testing (optimized for QEMU/KVM/virtme-ng)

• Debug Levels: Configurable debugging intensity

  • Minimal (production-like)
  • Basic (symbols + basic debugging)
  • Full debug (comprehensive debugging without sanitizers)
  • Sanitizers (KASAN, UBSAN, KCOV)
  • Lockdep (lock debugging and deadlock detection)
  • Performance (optimized for benchmarking)

• Configuration Fragments: Modular config components

  • KASAN (Kernel Address Sanitizer)
  • UBSAN (Undefined Behavior Sanitizer)
  • KCOV (code coverage for fuzzing)
  • Virtme-ng optimization
  • Performance tuning

• Smart Configuration Management

  • Merge multiple configs and fragments
  • Search Kconfig options
  • Validate configurations
  • Apply configs to kernel source tree

Kernel Building

• Build Validation: Build kernels and validate build success

  • Parallel builds with configurable job count
  • Timeout support to prevent hanging
  • Out-of-tree build support

• Error Detection & Reporting: Automatically parse and report build errors

  • GCC/Clang error parsing with file:line:column information
  • Warning detection and reporting
  • Linker error detection
  • Human-readable error summaries

• Build Management:

  • Build specific targets (all, vmlinux, modules, etc.)
  • Clean operations (clean, mrproper, distclean)
  • Check build requirements
  • Get kernel version information

Filesystem Testing (fstests)

• Automated fstests Integration: Complete support for filesystem regression testing

  • Install and manage fstests from git
  • Setup test/scratch devices (loop devices or existing)
  • Configure and run tests
  • Baseline comparison workflow for regression detection
  • Support for all major filesystems (ext4, btrfs, xfs, f2fs)

• Baseline Management: Track test results across kernel versions

  • Save baselines with metadata
  • Compare results to detect regressions
  • Identify new failures vs pre-existing issues
  • Essential for filesystem patch development

See docs/implementation/FSTESTS.md for detailed filesystem testing documentation.

Device Backing Options

Three device backing types are available for test devices:

1. null_blk (Fastest) - Memory-backed kernel devices

   • 10-100× faster than loop devices (7M+ IOPS vs 50K)
   • Zero-latency, no actual I/O
   • Requires Linux 5.0+ with null_blk module
   • Memory limits: 32GB/device, 70GB total (configurable)
   • Perfect for high-speed testing and benchmarking

2. tmpfs (Fast) - Loop devices backed by tmpfs

   • Memory-backed, faster than disk (200K+ IOPS)
   • Works on any system
   • No kernel module required
   • Good balance of speed and compatibility

3. disk (Universal) - Loop devices backed by sparse files

   • Slowest option (~50K IOPS)
   • No memory usage
   • Works everywhere
   • Default for maximum compatibility

Automatic Fallback: System automatically tries null_blk → tmpfs → disk until one succeeds.

See docs/implementation/null-blk-implementation.md for technical details.

LVM Device Pools (Physical Storage)

• High-Performance Testing: Use LVM-managed physical storage instead of slow loop devices

  • 9-10× performance improvement for I/O-intensive tests (475K vs 50K IOPS)
  • Only ~5% overhead compared to raw device
  • LVM provides snapshots, resizing, and thin provisioning

• One-Time Setup: Configure once, use everywhere

  • Comprehensive safety validation (10-point checklist)
  • All operations use sudo (no special permissions needed)
  • VG name is persistent across reboots (auto-discovered by LVM)
  • Transactional operations with rollback on failure

• LVM Features:

  • Snapshots: Create backups before risky tests, rollback if kernel corrupts data
  • Dynamic Resizing: Grow or shrink volumes without recreating pool
  • Thin Provisioning: Overcommit storage when needed
  • Maximum Flexibility: Industry-standard volume management

• MCP Tools Available:

  • device_pool_setup: Create LVM pools with safety checks
  • device_pool_status: Health check and volume info
  • device_pool_teardown: Safe removal with cleanup
  • device_pool_list: List all pools
  • device_pool_resize: Resize logical volumes
  • device_pool_snapshot: Snapshot management

Quick Start:

# Identify available disk
lsblk

# Create LVM pool via MCP (uses sudo)
device_pool_setup --device=/dev/nvme1n1

# Enable auto-use
export KERNELDEV_DEVICE_POOL=default

# All tests now use LVM volumes automatically!
fstests_vm_boot_and_run --kernel=/path/to/kernel --fstests=/path/to/fstests

How it works:

• Creates VG with name kerneldev-default-vg (persistent across reboots)
• Each test auto-creates unique LVs (timestamp + random in name)
• Multiple Claudes can share same pool concurrently
• LVs auto-deleted after tests (unless you use keep_volumes=true)

Documentation:

• Device Pool Setup Guide - Complete setup instructions
• Architecture - Concurrency model and design details

Installation

# Clone the repository
cd kerneldev-mcp

# Install in development mode
pip install -e .

# Or install dependencies manually
pip install mcp pydantic

Usage

As MCP Server

Add to your MCP client configuration (e.g., Claude Desktop):

{
  "mcpServers": {
    "kerneldev": {
      "command": "python",
      "args": ["-m", "kerneldev_mcp.server"]
    }
  }
}

Available MCP Tools

Configuration Tools

1. list_config_presets

List all available configuration presets.

# Example call
{
  "tool": "list_config_presets",
  "params": {
    "category": "target"  # Optional: "target", "debug", or "fragment"
  }
}

2. get_config_template

Generate a complete kernel configuration from templates.

{
  "tool": "get_config_template",
  "params": {
    "target": "btrfs",           # Required: networking, btrfs, filesystem, boot, virtualization
    "debug_level": "sanitizers",  # Optional: minimal, basic, full_debug, sanitizers, lockdep, performance
    "architecture": "x86_64",     # Optional: x86_64, arm64, arm, riscv
    "additional_options": {       # Optional: extra CONFIG options
      "CONFIG_BTRFS_DEBUG": "y",
      "CONFIG_BTRFS_ASSERT": "y"
    },
    "fragments": ["kasan", "kcov"] # Optional: additional fragments to merge
  }
}

3. create_config_fragment

Create a custom configuration fragment.

{
  "tool": "create_config_fragment",
  "params": {
    "name": "my_debug",
    "options": {
      "CONFIG_DEBUG_CUSTOM": "y",
      "CONFIG_EXTRA_CHECKS": "y"
    },
    "description": "My custom debug options"
  }
}

4. merge_configs

Merge multiple configuration fragments.

{
  "tool": "merge_configs",
  "params": {
    "base": "target/networking",  # Base config (template name or file path)
    "fragments": ["kasan", "lockdep"],  # Fragments to merge
    "output": "/path/to/output.config"  # Optional: save to file
  }
}

5. apply_config

Apply configuration to kernel source tree.

{
  "tool": "apply_config",
  "params": {
    "kernel_path": "~/linux",
    "config_source": "target/btrfs",  # Template name or file path
    "merge_with_existing": false      # Optional: merge with existing .config
  }
}

6. validate_config

Validate a kernel configuration.

{
  "tool": "validate_config",
  "params": {
    "config_path": "~/linux/.config",
    "kernel_path": "~/linux"  # Optional: for Kconfig validation
  }
}

7. search_config_options

Search for kernel configuration options.

{
  "tool": "search_config_options",
  "params": {
    "query": "KASAN",
    "kernel_path": "~/linux"
  }
}

8. generate_build_config

Generate optimized build configuration and commands.

Build Tools

9. build_kernel

Build the Linux kernel and validate the build.

{
  "tool": "build_kernel",
  "params": {
    "kernel_path": "~/linux",
    "jobs": 16,                   # Optional: parallel jobs
    "verbose": False,             # Optional: detailed output
    "keep_going": False,          # Optional: continue despite errors
    "target": "all",              # Optional: make target
    "build_dir": "/tmp/build",    # Optional: out-of-tree build
    "timeout": 3600,              # Optional: timeout in seconds
    "clean_first": False          # Optional: clean before building
  }
}

Returns build status with errors/warnings parsed and formatted.

10. check_build_requirements

Check if kernel source is ready to build.

{
  "tool": "check_build_requirements",
  "params": {
    "kernel_path": "~/linux"
  }
}

Returns validation of kernel source, configuration, and build tools.

11. clean_kernel_build

Clean kernel build artifacts.

{
  "tool": "clean_kernel_build",
  "params": {
    "kernel_path": "~/linux",
    "clean_type": "clean"  # clean, mrproper, or distclean
  }
}

{
  "tool": "generate_build_config",
  "params": {
    "target": "btrfs",
    "optimization": "speed",  # speed, debug, or size
    "ccache": true,
    "out_of_tree": true,
    "kernel_path": "~/linux"
  }
}

MCP Resources

Access configuration templates directly:

• config://presets - JSON list of all available presets
• config://templates/target/{name} - Target configurations (networking, btrfs, etc.)
• config://templates/debug/{name} - Debug level configurations
• config://templates/fragment/{name} - Configuration fragments

Configuration Templates

Targets

1. networking - Comprehensive network stack testing

   • Full TCP/IP, IPv6, netfilter, eBPF/XDP
   • Virtual networking (veth, bridges, VLANs)
   • Traffic control and QoS

2. btrfs - BTRFS filesystem development

   • BTRFS with all features and debugging
   • Device mapper, RAID, snapshots
   • Compression and checksumming

3. filesystem - General filesystem testing

   • All major filesystems (ext4, XFS, BTRFS, F2FS)
   • Network filesystems (NFS, CIFS)
   • FUSE, overlay, quota support

4. boot - Minimal boot testing

   • Fast boot for iteration
   • Console and early debugging
   • Virtio drivers for QEMU

5. virtualization - Virtualization testing

   • KVM support
   • VirtIO drivers (optimized for virtme-ng)
   • VirtioFS and 9P filesystem

Debug Levels

1. minimal - Production-like build with minimal overhead
2. basic - Debug symbols + basic debugging (CONFIG_DEBUG_INFO, FRAME_POINTER)
3. full_debug - Comprehensive debugging without sanitizers
4. sanitizers - Memory sanitizers (KASAN, UBSAN, KCOV, KFENCE)
5. lockdep - Lock debugging and deadlock detection
6. performance - Optimized for performance testing and benchmarking

Fragments

• kasan - Kernel Address Sanitizer (memory error detection)
• ubsan - Undefined Behavior Sanitizer
• kcov - Code coverage for fuzzing (syzkaller)
• virtme - Optimizations for virtme-ng testing
• performance - Performance monitoring and profiling

Example Workflows

1. Configure kernel for BTRFS testing with KASAN

# Generate config
get_config_template(
    target="btrfs",
    debug_level="sanitizers",
    fragments=["kasan"]
)

# Apply to kernel
apply_config(
    kernel_path="~/linux",
    config_source="target/btrfs"
)

# Build
# Output will include build commands

2. Quick virtme-ng testing setup

get_config_template(
    target="virtualization",
    debug_level="minimal",
    fragments=["virtme"]
)

3. Network testing with lockdep

get_config_template(
    target="networking",
    debug_level="lockdep"
)

4. High-performance testing with null_blk devices

# Boot kernel with ultra-fast null_blk devices
boot_kernel_test(
    kernel_path="~/linux",
    devices=[
        {"size": "10G", "name": "test", "backing": "null_blk", "env_var": "TEST_DEV"},
        {"size": "10G", "name": "scratch", "backing": "null_blk", "env_var": "SCRATCH_DEV"}
    ]
)
# 7M+ IOPS performance, uses RAM (watch memory!)

# Or let it automatically fall back if null_blk unavailable
boot_kernel_test(
    kernel_path="~/linux",
    devices=[
        {"size": "10G", "backing": "null_blk"}  # Falls back to tmpfs or disk
    ]
)

Memory Limits (configurable via environment):

export KERNELDEV_NULL_BLK_MAX_SIZE=32    # Max GB per device (default: 32)
export KERNELDEV_NULL_BLK_TOTAL=70       # Max GB total (default: 70)

5. Custom configuration

# Start with base
merge_configs(
    base="target/filesystem",
    fragments=["kasan", "ubsan", "kcov"]
)

# Add custom options
get_config_template(
    target="filesystem",
    debug_level="sanitizers",
    additional_options={
        "CONFIG_CUSTOM_FEATURE": "y"
    }
)

Integration with Kernel Development Workflow

This MCP server is designed to work with the linux-dev-context project, which provides comprehensive kernel development context files for AI assistants.

Typical workflow:

1. Use this MCP to generate kernel config for your testing target
2. Apply config to kernel source
3. Build kernel (optionally with virtme-ng)
4. Test using appropriate test suite (fstests, network tests, etc.)

Testing

# Run tests
pytest tests/

# Run specific test file
pytest tests/test_config_manager.py

# Run with verbose output
pytest -v

Project Structure

kerneldev-mcp/
├── src/
│   ├── kerneldev_mcp/
│   │   ├── __init__.py
│   │   ├── server.py           # Main MCP server
│   │   ├── config_manager.py   # Config generation and merging
│   │   ├── templates.py        # Template management
│   └── config_templates/
│       ├── targets/            # Target configurations
│       ├── debug/              # Debug level configurations
│       └── fragments/          # Modular fragments
├── tests/
│   ├── test_templates.py
│   ├── test_config_manager.py
│   └── test_server.py
├── pyproject.toml
└── README.md

Contributing

Contributions welcome! Please:

1. Add new configuration templates for additional testing scenarios
2. Improve existing templates based on kernel development best practices
3. Add tests for new functionality
4. Update documentation

Development Setup

After cloning the repository, set up git hooks to ensure code quality:

./setup-hooks.sh

This configures:

• pre-commit hook: Checks code formatting, linting, and runs unit tests
  • Code formatting with ruff format --check (instant)
  • Code quality with ruff check (instant)
  • Ensures all 384 unit tests pass before code is committed
  • Helps catch formatting, quality issues, and regressions early
  • Can be bypassed with git commit --no-verify (not recommended)

If checks fail:

# Fix formatting
ruff format .

# Fix linting issues
ruff check . --fix

The hooks are stored in the hooks/ directory and are version-controlled, ensuring all contributors use the same quality checks.

License

GPL-2.0 (to match Linux kernel licensing)

References

• Linux Kernel Documentation
• Kernel Configuration (Kconfig)
• Model Context Protocol (MCP)
• virtme-ng - Fast kernel testing tool

Support

For issues and questions:

• GitHub Issues: [your-repo/kerneldev-mcp/issues]
• Related: linux-dev-context