Upstream Kernel Testing With virtme-ng

bpfcompat has two kernel validation lanes:

Lane	Backend	Purpose
Distro matrix	QEMU/KVM cloud images	Validate against customer-like distro kernels, userspace, BTF state, and packaging differences.
Upstream kernel matrix	virtme-ng	Validate against bootable upstream-mainline kernels without waiting for distro images.

The upstream lane is an alpha backend. It is useful for early regression detection, but the QEMU/KVM distro lane remains the default customer compatibility proof.

Requirements

• Linux host with /dev/kvm
• vng from virtme-ng
• qemu-system-x86_64
• curl
• jq
• normal build dependencies from make doctor

Check the host:

make doctor-virtme

Generate Runnable Upstream Targets

make upstream-kernel-runnable

This reads https://www.kernel.org/releases.json for current release context, checks https://kernel.ubuntu.com/mainline/ for virtme-ng prebuilt kernels, preflight-boots candidate kernels with /bin/true, and writes:

• generated profiles: vm/profiles/kernelorg-*.yaml
• generated matrix: matrices/upstream-kernel-runnable.yaml

The generated files are intentionally ignored by git because they change as upstream releases and local virtme-ng bootability change. If the newest exact kernel.org patch or RC is not bootable through the installed vng, the generator selects the newest runnable upstream-mainline major/minor kernel and logs the skipped candidate.

Run The Upstream Kernel Sweep

make acceptance-upstream-kernel

Equivalent CLI form:

./bin/bpfcompat test \
  --runner virtme-ng \
  --artifact examples/functional-execve/functional_execve.bpf.o \
  --manifest examples/functional-execve/manifest-upstream-kernel.yaml \
  --matrix matrices/upstream-kernel-runnable.yaml \
  --out reports/functional-execve-upstream-kernel.json \
  --markdown reports/functional-execve-upstream-kernel.md \
  --timeout 20m \
  --concurrency 1

Current Scope

Implemented:

• explicit --runner virtme-ng
• boot-aware generated upstream-mainline profiles
• normal JSON/Markdown compatibility reports
• local artifact history/provenance reuse
• GitHub workflow: .github/workflows/upstream-kernel-compatibility.yml

Not implemented yet:

• building arbitrary kernel source trees through vng --build
• linux-next source-tree execution
• ARM64 upstream-kernel validation
• Firecracker backend

For ARM64, use .github/workflows/arm64-build-smoke.yml for native ARM64 compile proof and .github/workflows/multiarch-compatibility.yml on a real ARM64 self-hosted KVM runner for VM-backed validation.