Add microVM setup files

microvm/.gitignore

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+firecracker-config.json
+rootfs.ext4
+vmlinux.bin
+reticulum-go
+vsock.sock

microvm/README.md

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+# Reticulum-Go MicroVM
+
+Minimal Firecracker microVM setup for running Reticulum-Go.
+
+## Prerequisites
+
+- Firecracker binary installed
+- Go compiler
+- Root privileges (for network setup and KVM access)
+- Linux host system with KVM support
+- Access to `/dev/kvm`
+
+## Important: Nested Virtualization
+
+**If running inside a QEMU/KVM VM**, nested virtualization must be enabled:
+
+1. **Host QEMU configuration**: Start your QEMU VM with nested KVM:
+   ```bash
+   qemu-system-x86_64 -cpu host -enable-kvm -machine q35,accel=kvm ...
+   ```
+
+2. **Enable nested KVM on host** (if not already):
+   ```bash
+   # Check if nested is enabled
+   cat /sys/module/kvm_intel/parameters/nested  # Intel
+   cat /sys/module/kvm_amd/parameters/nested    # AMD
+   
+   # Enable nested (Intel)
+   echo "options kvm_intel nested=1" | sudo tee /etc/modprobe.d/kvm.conf
+   
+   # Enable nested (AMD)
+   echo "options kvm_amd nested=1" | sudo tee /etc/modprobe.d/kvm.conf
+   
+   # Reboot host
+   ```
+
+3. **Inside the VM**, check if `/dev/kvm` exists:
+   ```bash
+   ls -l /dev/kvm
+   ```
+
+**Alternative**: If nested virtualization isn't available, consider:
+- Running Firecracker directly on the host machine
+- Using QEMU directly instead of Firecracker
+- Using Docker/LXC containers instead
+
+## KVM Setup
+
+Ensure your user has access to `/dev/kvm`:
+
+```bash
+# Check if /dev/kvm exists
+ls -l /dev/kvm
+
+# Add your user to the kvm group (recommended)
+sudo usermod -aG kvm $USER
+
+# Or set ACL (alternative)
+sudo setfacl -m u:$USER:rw /dev/kvm
+
+# Log out and back in for group changes to take effect
+```
+
+## Setup
+
+Run the setup script:
+
+```bash
+./setup.sh
+```
+
+This will:
+- Check for Firecracker installation
+- Download vmlinux.bin kernel
+- Build Reticulum-Go binary
+- Create rootfs.ext4 disk image
+- Generate firecracker-config.json
+
+## Running
+
+1. Create tap interface:
+```bash
+sudo ip tuntap add tap0 mode tap
+sudo ip addr add 172.16.0.1/24 dev tap0
+sudo ip link set tap0 up
+```
+
+2. Enable IP forwarding:
+```bash
+sudo sysctl -w net.ipv4.ip_forward=1
+```
+
+3. Start Firecracker:
+```bash
+# Clean up any old socket files first
+rm -f /tmp/firecracker.sock microvm/vsock.sock
+
+firecracker --api-sock /tmp/firecracker.sock --config-file firecracker-config.json
+```
+
+4. Connect to console (in another terminal):
+```bash
+firecracker --api-sock /tmp/firecracker.sock
+```
+
+## Configuration
+
+- **CPU**: 1 vCPU
+- **Memory**: 128 MiB
+- **Network**: tap0 interface
+- **Disk**: rootfs.ext4 (100MB)
+
+Modify `firecracker-config.json` to adjust resources.
+
+## Files
+
+- `vmlinux.bin` - Linux kernel
+- `rootfs.ext4` - Root filesystem with binary
+- `firecracker-config.json` - Firecracker configuration
+- `reticulum-go` - Compiled binary
+

microvm/setup.sh

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+#!/bin/sh
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+MICROVM_DIR="$SCRIPT_DIR"
+BINARY_NAME="reticulum-go"
+FIRECRACKER_VERSION="v1.8.0"
+FIRECRACKER_REPO="firecracker-microvm/firecracker"
+VMLINUX_URL="https://s3.amazonaws.com/spec.ccfc.min/img/hello/kernel/hello-vmlinux.bin"
+
+check_command() {
+    if ! command -v "$1" >/dev/null 2>&1; then
+        echo "Error: $1 is not installed" >&2
+        exit 1
+    fi
+}
+
+check_firecracker() {
+    if ! command -v firecracker >/dev/null 2>&1; then
+        echo "Error: firecracker binary is not installed" >&2
+        echo "Install from: https://github.com/firecracker-microvm/firecracker/releases" >&2
+        exit 1
+    fi
+    echo "Firecracker found: $(firecracker --version 2>&1 || echo 'version check failed')"
+}
+
+download_vmlinux() {
+    VMLINUX_PATH="$MICROVM_DIR/vmlinux.bin"
+    if [ -f "$VMLINUX_PATH" ]; then
+        echo "vmlinux.bin already exists, skipping download"
+        return
+    fi
+    
+    echo "Downloading vmlinux.bin from AWS S3..."
+    if ! command -v curl >/dev/null 2>&1; then
+        echo "Error: curl required to download vmlinux.bin" >&2
+        exit 1
+    fi
+    
+    curl -fsSL -o "$VMLINUX_PATH" "$VMLINUX_URL"
+    chmod +x "$VMLINUX_PATH"
+    echo "Downloaded: $VMLINUX_PATH"
+}
+
+build_binary() {
+    echo "Building binary..."
+    cd "$PROJECT_ROOT"
+    GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o "$MICROVM_DIR/$BINARY_NAME" ./cmd/reticulum-go
+    echo "Binary built: $MICROVM_DIR/$BINARY_NAME"
+}
+
+create_rootfs() {
+    ROOTFS_PATH="$MICROVM_DIR/rootfs.ext4"
+    if [ -f "$ROOTFS_PATH" ]; then
+        echo "rootfs.ext4 already exists, skipping creation"
+        return
+    fi
+    
+    echo "Creating rootfs..."
+    TMP_DIR=$(mktemp -d)
+    trap "rm -rf $TMP_DIR" EXIT
+    
+    mkdir -p "$TMP_DIR/bin" "$TMP_DIR/etc" "$TMP_DIR/dev" "$TMP_DIR/proc" "$TMP_DIR/sys" "$TMP_DIR/tmp"
+    
+    cp "$MICROVM_DIR/$BINARY_NAME" "$TMP_DIR/bin/"
+    chmod +x "$TMP_DIR/bin/$BINARY_NAME"
+    
+    cat > "$TMP_DIR/etc/inittab" <<EOF
+::sysinit:/bin/sh /etc/rc
+::respawn:/bin/sh
+ttyS0::respawn:/bin/sh
+EOF
+    
+    cat > "$TMP_DIR/etc/rc" <<EOF
+#!/bin/sh
+mount -t proc proc /proc
+mount -t sysfs sysfs /sys
+/bin/$BINARY_NAME
+EOF
+    chmod +x "$TMP_DIR/etc/rc"
+    
+    ROOTFS_SIZE_MB=100
+    dd if=/dev/zero of="$ROOTFS_PATH" bs=1M count="$ROOTFS_SIZE_MB" 2>/dev/null
+    mkfs.ext4 -F "$ROOTFS_PATH" >/dev/null 2>&1
+    
+    TMP_MOUNT=$(mktemp -d)
+    mount -o loop "$ROOTFS_PATH" "$TMP_MOUNT" 2>/dev/null || {
+        echo "Error: Failed to mount rootfs. You may need root privileges or use a different method." >&2
+        rm -rf "$TMP_DIR" "$TMP_MOUNT"
+        exit 1
+    }
+    trap "umount $TMP_MOUNT 2>/dev/null; rm -rf $TMP_DIR $TMP_MOUNT" EXIT
+    
+    cp -r "$TMP_DIR"/* "$TMP_MOUNT/"
+    umount "$TMP_MOUNT"
+    rm -rf "$TMP_DIR" "$TMP_MOUNT"
+    echo "Rootfs created: $ROOTFS_PATH"
+}
+
+create_config() {
+    CONFIG_PATH="$MICROVM_DIR/firecracker-config.json"
+    API_SOCK="${API_SOCK:-/tmp/firecracker.sock}"
+    VSOCK_SOCK="${VSOCK_SOCK:-$MICROVM_DIR/vsock.sock}"
+    
+    cat > "$CONFIG_PATH" <<EOF
+{
+  "boot-source": {
+    "kernel_image_path": "$MICROVM_DIR/vmlinux.bin",
+    "boot_args": "console=ttyS0 reboot=k panic=1 pci=off root=/dev/vda rw"
+  },
+  "drives": [
+    {
+      "drive_id": "rootfs",
+      "path_on_host": "$MICROVM_DIR/rootfs.ext4",
+      "is_root_device": true,
+      "is_read_only": false
+    }
+  ],
+  "machine-config": {
+    "vcpu_count": 1,
+    "mem_size_mib": 128,
+    "smt": false
+  },
+  "network-interfaces": [
+    {
+      "iface_id": "eth0",
+      "guest_mac": "AA:FC:00:00:00:01",
+      "host_dev_name": "tap0"
+    }
+  ],
+  "vsock": {
+    "guest_cid": 3,
+    "uds_path": "$VSOCK_SOCK"
+  }
+}
+EOF
+    echo "Config created: $CONFIG_PATH"
+    echo "API socket: $API_SOCK"
+    echo "VSock socket: $VSOCK_SOCK"
+}
+
+check_firecracker() {
+    if ! command -v firecracker >/dev/null 2>&1; then
+        echo "Error: firecracker binary is not installed" >&2
+        echo "Install from: https://github.com/firecracker-microvm/firecracker/releases" >&2
+        exit 1
+    fi
+    echo "Firecracker found: $(firecracker --version 2>&1 || echo 'version check failed')"
+}
+
+check_kvm() {
+    if [ ! -c /dev/kvm ]; then
+        echo "Warning: /dev/kvm not found. KVM may not be available." >&2
+        return
+    fi
+    
+    if [ ! -r /dev/kvm ] || [ ! -w /dev/kvm ]; then
+        echo "Warning: /dev/kvm exists but you may not have read/write access." >&2
+        echo "Add yourself to the kvm group: sudo usermod -aG kvm $USER" >&2
+        echo "Or set ACL: sudo setfacl -m u:$USER:rw /dev/kvm" >&2
+    else
+        echo "KVM access OK"
+    fi
+}
+
+cleanup_sockets() {
+    echo "Cleaning up old socket files..."
+    rm -f /tmp/firecracker.sock "$MICROVM_DIR/vsock.sock"
+    echo "Cleanup complete"
+}
+
+main() {
+    echo "Setting up microVM..."
+    
+    cleanup_sockets
+    
+    check_command go
+    check_firecracker
+    check_kvm
+    
+    download_vmlinux
+    build_binary
+    create_rootfs
+    create_config
+    
+    echo ""
+    echo "Setup complete!"
+    echo "Files created in: $MICROVM_DIR"
+    echo ""
+    echo "To run the microVM:"
+    echo "  1. Ensure KVM access: sudo usermod -aG kvm $USER (then logout/login)"
+    echo "  2. Create tap interface: sudo ip tuntap add tap0 mode tap"
+    echo "  3. Start firecracker: firecracker --api-sock /tmp/firecracker.sock --config-file $CONFIG_PATH"
+}
+
+main "$@"
+