feat(vm): add openshell-vm crate with libkrun microVM gateway (#611)

.github/workflows/release-vm-dev.yml

@@ -0,0 +1,518 @@
+name: Release VM Dev
+
+# Build openshell-vm binaries for all supported platforms and upload them to
+# the rolling "vm-dev" GitHub Release.  Each binary is self-extracting: it
+# embeds pre-built kernel runtime artifacts (from release-vm-kernel.yml) and a
+# base rootfs tarball.
+#
+# Prerequisites: the vm-dev release must already contain kernel runtime
+# tarballs.  Run the "Release VM Kernel" workflow first if they are missing.
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  packages: read
+
+# Serialize with release-vm-kernel.yml — both update the vm-dev release.
+concurrency:
+  group: vm-dev-release
+  cancel-in-progress: false
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  # ---------------------------------------------------------------------------
+  # Compute versions (reuse the same logic as release-dev.yml)
+  # ---------------------------------------------------------------------------
+  compute-versions:
+    name: Compute Versions
+    runs-on: build-amd64
+    timeout-minutes: 5
+    container:
+      image: ghcr.io/nvidia/openshell/ci:latest
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+    outputs:
+      cargo_version: ${{ steps.v.outputs.cargo }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      - name: Fetch tags
+        run: git fetch --tags --force
+
+      - name: Compute versions
+        id: v
+        run: |
+          set -euo pipefail
+          echo "cargo=$(uv run python tasks/scripts/release.py get-version --cargo)" >> "$GITHUB_OUTPUT"
+
+  # ---------------------------------------------------------------------------
+  # Download kernel runtime tarballs from the vm-dev release
+  # ---------------------------------------------------------------------------
+  download-kernel-runtime:
+    name: Download Kernel Runtime
+    runs-on: build-amd64
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Download all runtime tarballs
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+          mkdir -p runtime-artifacts
+
+          for platform in linux-aarch64 linux-x86_64 darwin-aarch64; do
+            echo "Downloading vm-runtime-${platform}.tar.zst..."
+            gh release download vm-dev \
+              --repo "${GITHUB_REPOSITORY}" \
+              --pattern "vm-runtime-${platform}.tar.zst" \
+              --dir runtime-artifacts \
+              --clobber
+          done
+
+          echo "Downloaded runtime artifacts:"
+          ls -lah runtime-artifacts/
+
+      - name: Verify downloads
+        run: |
+          set -euo pipefail
+          for platform in linux-aarch64 linux-x86_64 darwin-aarch64; do
+            file="runtime-artifacts/vm-runtime-${platform}.tar.zst"
+            if [ ! -f "$file" ]; then
+              echo "ERROR: Missing ${file}" >&2
+              echo "" >&2
+              echo "The vm-dev release does not have kernel runtime artifacts." >&2
+              echo "Run the 'Release VM Kernel' workflow first:" >&2
+              echo "  gh workflow run release-vm-kernel.yml" >&2
+              exit 1
+            fi
+            echo "OK: ${file} ($(du -sh "$file" | cut -f1))"
+          done
+
+      - name: Upload as workflow artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: kernel-runtime-tarballs
+          path: runtime-artifacts/vm-runtime-*.tar.zst
+          retention-days: 1
+
+  # ---------------------------------------------------------------------------
+  # Build base rootfs tarballs (architecture-specific)
+  # ---------------------------------------------------------------------------
+  build-rootfs:
+    name: Build Rootfs (${{ matrix.arch }})
+    needs: [compute-versions]
+    strategy:
+      matrix:
+        include:
+          - arch: arm64
+            runner: build-arm64
+            guest_arch: aarch64
+          - arch: amd64
+            runner: build-amd64
+            guest_arch: x86_64
+    runs-on: ${{ matrix.runner }}
+    timeout-minutes: 30
+    container:
+      image: ghcr.io/nvidia/openshell/ci:latest
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+      options: --privileged
+      volumes:
+        - /var/run/docker.sock:/var/run/docker.sock
+    env:
+      MISE_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      OPENSHELL_IMAGE_TAG: dev
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      - name: Log in to GHCR
+        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login ghcr.io -u "${{ github.actor }}" --password-stdin
+
+      - name: Install tools
+        run: mise install
+
+      - name: Build base rootfs tarball
+        run: |
+          set -euo pipefail
+          crates/openshell-vm/scripts/build-rootfs.sh \
+            --base \
+            --arch ${{ matrix.guest_arch }} \
+            target/rootfs-build
+
+          mkdir -p target/vm-runtime-compressed
+          tar -C target/rootfs-build -cf - . \
+            | zstd -19 -T0 -o target/vm-runtime-compressed/rootfs.tar.zst
+
+          echo "Rootfs tarball: $(du -sh target/vm-runtime-compressed/rootfs.tar.zst | cut -f1)"
+
+      - name: Upload rootfs artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: rootfs-${{ matrix.arch }}
+          path: target/vm-runtime-compressed/rootfs.tar.zst
+          retention-days: 1
+
+  # ---------------------------------------------------------------------------
+  # Build openshell-vm binary (Linux — native on each arch)
+  # ---------------------------------------------------------------------------
+  build-vm-linux:
+    name: Build VM (Linux ${{ matrix.arch }})
+    needs: [compute-versions, download-kernel-runtime, build-rootfs]
+    strategy:
+      matrix:
+        include:
+          - arch: arm64
+            runner: build-arm64
+            target: aarch64-unknown-linux-gnu
+            platform: linux-aarch64
+            guest_arch: aarch64
+          - arch: amd64
+            runner: build-amd64
+            target: x86_64-unknown-linux-gnu
+            platform: linux-x86_64
+            guest_arch: x86_64
+    runs-on: ${{ matrix.runner }}
+    timeout-minutes: 30
+    container:
+      image: ghcr.io/nvidia/openshell/ci:latest
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+      options: --privileged
+    env:
+      MISE_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      SCCACHE_MEMCACHED_ENDPOINT: ${{ vars.SCCACHE_MEMCACHED_ENDPOINT }}
+      OPENSHELL_IMAGE_TAG: dev
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      - name: Fetch tags
+        run: git fetch --tags --force
+
+      - name: Install tools
+        run: mise install
+
+      - name: Cache Rust target and registry
+        uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2
+        with:
+          shared-key: vm-linux-${{ matrix.arch }}
+          cache-directories: .cache/sccache
+          cache-targets: "true"
+
+      - name: Download kernel runtime tarball
+        uses: actions/download-artifact@v4
+        with:
+          name: kernel-runtime-tarballs
+          path: runtime-download/
+
+      - name: Download rootfs tarball
+        uses: actions/download-artifact@v4
+        with:
+          name: rootfs-${{ matrix.arch }}
+          path: rootfs-download/
+
+      - name: Stage compressed runtime for embedding
+        run: |
+          set -euo pipefail
+          COMPRESSED_DIR="${PWD}/target/vm-runtime-compressed"
+          mkdir -p "$COMPRESSED_DIR"
+
+          # Extract kernel runtime tarball and re-compress individual files
+          EXTRACT_DIR=$(mktemp -d)
+          zstd -d "runtime-download/vm-runtime-${{ matrix.platform }}.tar.zst" --stdout \
+            | tar -xf - -C "$EXTRACT_DIR"
+
+          echo "Extracted runtime files:"
+          ls -lah "$EXTRACT_DIR"
+
+          for file in "$EXTRACT_DIR"/*; do
+            [ -f "$file" ] || continue
+            name=$(basename "$file")
+            [ "$name" = "provenance.json" ] && continue
+            zstd -19 -f -q -T0 -o "${COMPRESSED_DIR}/${name}.zst" "$file"
+          done
+
+          # Copy rootfs tarball (already zstd-compressed)
+          cp rootfs-download/rootfs.tar.zst "${COMPRESSED_DIR}/rootfs.tar.zst"
+
+          echo "Staged compressed artifacts:"
+          ls -lah "$COMPRESSED_DIR"
+
+      - name: Scope workspace to VM crates
+        run: |
+          set -euo pipefail
+          sed -i 's|members = \["crates/\*"\]|members = ["crates/openshell-vm", "crates/openshell-core", "crates/openshell-bootstrap", "crates/openshell-policy"]|' Cargo.toml
+
+      - name: Patch workspace version
+        if: needs.compute-versions.outputs.cargo_version != ''
+        run: |
+          set -euo pipefail
+          sed -i -E '/^\[workspace\.package\]/,/^\[/{s/^version[[:space:]]*=[[:space:]]*".*"/version = "'"${{ needs.compute-versions.outputs.cargo_version }}"'"/}' Cargo.toml
+
+      - name: Build openshell-vm
+        run: |
+          set -euo pipefail
+          OPENSHELL_VM_RUNTIME_COMPRESSED_DIR="${PWD}/target/vm-runtime-compressed" \
+            mise x -- cargo build --release -p openshell-vm
+
+      - name: sccache stats
+        if: always()
+        run: mise x -- sccache --show-stats
+
+      - name: Package binary
+        run: |
+          set -euo pipefail
+          mkdir -p artifacts
+          tar -czf "artifacts/openshell-vm-${{ matrix.target }}.tar.gz" \
+            -C target/release openshell-vm
+          ls -lh artifacts/
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: vm-linux-${{ matrix.arch }}
+          path: artifacts/*.tar.gz
+          retention-days: 5
+
+  # ---------------------------------------------------------------------------
+  # Build openshell-vm binary (macOS ARM64 via osxcross)
+  # ---------------------------------------------------------------------------
+  build-vm-macos:
+    name: Build VM (macOS)
+    needs: [compute-versions, download-kernel-runtime, build-rootfs]
+    runs-on: build-amd64
+    timeout-minutes: 60
+    container:
+      image: ghcr.io/nvidia/openshell/ci:latest
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+      options: --privileged
+      volumes:
+        - /var/run/docker.sock:/var/run/docker.sock
+    env:
+      MISE_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      SCCACHE_MEMCACHED_ENDPOINT: ${{ vars.SCCACHE_MEMCACHED_ENDPOINT }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      - name: Fetch tags
+        run: git fetch --tags --force
+
+      - name: Log in to GHCR
+        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login ghcr.io -u "${{ github.actor }}" --password-stdin
+
+      - name: Set up Docker Buildx
+        uses: ./.github/actions/setup-buildx
+
+      - name: Download kernel runtime tarball
+        uses: actions/download-artifact@v4
+        with:
+          name: kernel-runtime-tarballs
+          path: runtime-download/
+
+      - name: Download rootfs tarball (arm64)
+        uses: actions/download-artifact@v4
+        with:
+          name: rootfs-arm64
+          path: rootfs-download/
+
+      - name: Prepare compressed runtime directory
+        run: |
+          set -euo pipefail
+          COMPRESSED_DIR="${PWD}/target/vm-runtime-compressed-macos"
+          mkdir -p "$COMPRESSED_DIR"
+
+          # Extract the darwin runtime tarball and re-compress for embedding.
+          # The macOS embedded.rs expects: libkrun.dylib.zst, libkrunfw.5.dylib.zst, gvproxy.zst
+          EXTRACT_DIR=$(mktemp -d)
+          zstd -d "runtime-download/vm-runtime-darwin-aarch64.tar.zst" --stdout \
+            | tar -xf - -C "$EXTRACT_DIR"
+
+          echo "Extracted darwin runtime files:"
+          ls -lah "$EXTRACT_DIR"
+
+          for file in "$EXTRACT_DIR"/*; do
+            [ -f "$file" ] || continue
+            name=$(basename "$file")
+            [ "$name" = "provenance.json" ] && continue
+            zstd -19 -f -q -T0 -o "${COMPRESSED_DIR}/${name}.zst" "$file"
+          done
+
+          # The macOS VM guest is always Linux ARM64, so use the arm64 rootfs
+          cp rootfs-download/rootfs.tar.zst "${COMPRESSED_DIR}/rootfs.tar.zst"
+
+          echo "Staged macOS compressed artifacts:"
+          ls -lah "$COMPRESSED_DIR"
+
+      - name: Build macOS binary via Docker (osxcross)
+        run: |
+          set -euo pipefail
+          docker buildx build \
+            --file deploy/docker/Dockerfile.vm-macos \
+            --build-arg OPENSHELL_CARGO_VERSION="${{ needs.compute-versions.outputs.cargo_version }}" \
+            --build-arg OPENSHELL_IMAGE_TAG=dev \
+            --build-arg CARGO_TARGET_CACHE_SCOPE="${{ github.sha }}" \
+            --build-context vm-runtime-compressed="${PWD}/target/vm-runtime-compressed-macos" \
+            --target binary \
+            --output type=local,dest=out/ \
+            .
+
+      - name: Package binary
+        run: |
+          set -euo pipefail
+          mkdir -p artifacts
+          tar -czf artifacts/openshell-vm-aarch64-apple-darwin.tar.gz \
+            -C out openshell-vm
+          ls -lh artifacts/
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: vm-macos
+          path: artifacts/*.tar.gz
+          retention-days: 5
+
+  # ---------------------------------------------------------------------------
+  # Upload all VM binaries to the vm-dev rolling release
+  # ---------------------------------------------------------------------------
+  release-vm-dev:
+    name: Release VM Dev
+    needs: [build-vm-linux, build-vm-macos]
+    runs-on: build-amd64
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Download all VM binary artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: vm-*
+          path: release/
+          merge-multiple: true
+
+      - name: Filter to only binary tarballs
+        run: |
+          set -euo pipefail
+          mkdir -p release-final
+          # Only include the openshell-vm binary tarballs, not kernel runtime
+          cp release/openshell-vm-*.tar.gz release-final/
+          count=$(ls release-final/openshell-vm-*.tar.gz 2>/dev/null | wc -l)
+          if [ "$count" -eq 0 ]; then
+            echo "ERROR: No VM binary tarballs found in release/" >&2
+            exit 1
+          fi
+          echo "Release artifacts (${count} binaries):"
+          ls -lh release-final/
+
+      - name: Generate checksums
+        run: |
+          set -euo pipefail
+          cd release-final
+          sha256sum openshell-vm-*.tar.gz > vm-binary-checksums-sha256.txt
+          cat vm-binary-checksums-sha256.txt
+
+      - name: Ensure vm-dev tag exists
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git tag -fa vm-dev -m "VM Development Build" "${GITHUB_SHA}"
+          git push --force origin vm-dev
+
+      - name: Prune stale VM binary assets from vm-dev release
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const [owner, repo] = process.env.GITHUB_REPOSITORY.split('/');
+            let release;
+            try {
+              release = await github.rest.repos.getReleaseByTag({ owner, repo, tag: 'vm-dev' });
+            } catch (err) {
+              if (err.status === 404) {
+                core.info('No existing vm-dev release; will create fresh.');
+                return;
+              }
+              throw err;
+            }
+            // Delete old VM binary assets (keep kernel runtime assets)
+            for (const asset of release.data.assets) {
+              if (asset.name.startsWith('openshell-vm-') || asset.name === 'vm-binary-checksums-sha256.txt') {
+                core.info(`Deleting stale asset: ${asset.name}`);
+                await github.rest.repos.deleteReleaseAsset({ owner, repo, asset_id: asset.id });
+              }
+            }
+
+      - name: Upload to vm-dev GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          name: OpenShell VM Development Build
+          prerelease: true
+          tag_name: vm-dev
+          target_commitish: ${{ github.sha }}
+          body: |
+            Rolling development build of **openshell-vm** — the MicroVM runtime for OpenShell.
+
+            > **NOTE**: This is a development build, not a tagged release, and may be unstable.
+
+            ### Kernel Runtime Artifacts
+
+            Pre-built kernel runtime (libkrunfw + libkrun + gvproxy) for embedding into
+            the openshell-vm binary. These are rebuilt when the kernel config or pinned
+            dependency versions change.
+
+            | Platform | Artifact |
+            |----------|----------|
+            | Linux ARM64 | `vm-runtime-linux-aarch64.tar.zst` |
+            | Linux x86_64 | `vm-runtime-linux-x86_64.tar.zst` |
+            | macOS ARM64 | `vm-runtime-darwin-aarch64.tar.zst` |
+
+            ### VM Binaries
+
+            Self-extracting openshell-vm binaries with embedded kernel runtime and base
+            rootfs. These are rebuilt on every push to main.
+
+            | Platform | Artifact |
+            |----------|----------|
+            | Linux ARM64 | `openshell-vm-aarch64-unknown-linux-gnu.tar.gz` |
+            | Linux x86_64 | `openshell-vm-x86_64-unknown-linux-gnu.tar.gz` |
+            | macOS ARM64 | `openshell-vm-aarch64-apple-darwin.tar.gz` |
+
+            **macOS users:** The binary must be codesigned with the Hypervisor entitlement:
+            ```bash
+            codesign --entitlements crates/openshell-vm/entitlements.plist --force -s - ./openshell-vm
+            ```
+
+          files: |
+            release-final/openshell-vm-aarch64-unknown-linux-gnu.tar.gz
+            release-final/openshell-vm-x86_64-unknown-linux-gnu.tar.gz
+            release-final/openshell-vm-aarch64-apple-darwin.tar.gz
+            release-final/vm-binary-checksums-sha256.txt

.github/workflows/release-vm-kernel.yml

@@ -0,0 +1,247 @@
+name: Release VM Kernel
+
+# Build custom libkrunfw (kernel firmware) + libkrun (VMM) + gvproxy for all
+# supported openshell-vm platforms.  Artifacts are uploaded to the rolling
+# "vm-dev" GitHub Release and consumed by release-vm-dev.yml when building the
+# openshell-vm binary.
+#
+# This workflow runs on-demand (or when kernel config / pins change).  It is
+# intentionally decoupled from the per-commit VM binary build because the
+# kernel rarely changes and takes 15-45 minutes to compile.
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+# Serialize with release-vm-dev.yml — both update the vm-dev release.
+concurrency:
+  group: vm-dev-release
+  cancel-in-progress: false
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  # ---------------------------------------------------------------------------
+  # Linux ARM64 — native kernel + libkrun build
+  # ---------------------------------------------------------------------------
+  build-runtime-linux-arm64:
+    name: Build Runtime (Linux ARM64)
+    runs-on: build-arm64
+    timeout-minutes: 60
+    container:
+      image: ghcr.io/nvidia/openshell/ci:latest
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+      options: --privileged
+    env:
+      MISE_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      - name: Build libkrunfw + libkrun from source
+        run: tasks/scripts/vm/build-libkrun.sh
+
+      - name: Package runtime tarball
+        run: |
+          tasks/scripts/vm/package-vm-runtime.sh \
+            --platform linux-aarch64 \
+            --build-dir target/libkrun-build \
+            --output artifacts/vm-runtime-linux-aarch64.tar.zst
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: vm-runtime-linux-arm64
+          path: artifacts/vm-runtime-linux-aarch64.tar.zst
+          retention-days: 5
+
+  # ---------------------------------------------------------------------------
+  # Linux AMD64 — native kernel + libkrun build
+  # ---------------------------------------------------------------------------
+  build-runtime-linux-amd64:
+    name: Build Runtime (Linux AMD64)
+    runs-on: build-amd64
+    timeout-minutes: 60
+    container:
+      image: ghcr.io/nvidia/openshell/ci:latest
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+      options: --privileged
+    env:
+      MISE_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      - name: Build libkrunfw + libkrun from source
+        run: tasks/scripts/vm/build-libkrun.sh
+
+      - name: Package runtime tarball
+        run: |
+          tasks/scripts/vm/package-vm-runtime.sh \
+            --platform linux-x86_64 \
+            --build-dir target/libkrun-build \
+            --output artifacts/vm-runtime-linux-x86_64.tar.zst
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: vm-runtime-linux-amd64
+          path: artifacts/vm-runtime-linux-x86_64.tar.zst
+          retention-days: 5
+
+  # ---------------------------------------------------------------------------
+  # macOS ARM64 — kernel built via krunvm, libkrun built natively
+  # ---------------------------------------------------------------------------
+  build-runtime-macos-arm64:
+    name: Build Runtime (macOS ARM64)
+    runs-on: macos-latest-xlarge
+    timeout-minutes: 90
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          set -euo pipefail
+          brew install rust lld dtc xz
+          # libkrunfw from Homebrew (used as a fallback/reference by build scripts)
+          brew install libkrunfw
+          # krunvm is needed to build the Linux kernel inside a Fedora VM
+          brew tap slp/krun
+          brew install krunvm
+
+      - name: Build custom libkrunfw (kernel)
+        run: crates/openshell-vm/runtime/build-custom-libkrunfw.sh
+
+      - name: Build portable libkrun
+        run: tasks/scripts/vm/build-libkrun-macos.sh
+
+      - name: Package runtime tarball
+        env:
+          CUSTOM_PROVENANCE_DIR: target/custom-runtime
+        run: |
+          tasks/scripts/vm/package-vm-runtime.sh \
+            --platform darwin-aarch64 \
+            --build-dir target/libkrun-build \
+            --output artifacts/vm-runtime-darwin-aarch64.tar.zst
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: vm-runtime-macos-arm64
+          path: artifacts/vm-runtime-darwin-aarch64.tar.zst
+          retention-days: 5
+
+  # ---------------------------------------------------------------------------
+  # Upload all runtime tarballs to the vm-dev rolling release
+  # ---------------------------------------------------------------------------
+  release-kernel:
+    name: Release Kernel Runtime
+    needs: [build-runtime-linux-arm64, build-runtime-linux-amd64, build-runtime-macos-arm64]
+    runs-on: build-amd64
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Download all runtime artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: vm-runtime-*
+          path: release/
+          merge-multiple: true
+
+      - name: Generate checksums
+        run: |
+          set -euo pipefail
+          cd release
+          sha256sum vm-runtime-*.tar.zst > vm-runtime-checksums-sha256.txt
+          cat vm-runtime-checksums-sha256.txt
+
+      - name: Ensure vm-dev tag exists
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git tag -fa vm-dev -m "VM Development Build" "${GITHUB_SHA}"
+          git push --force origin vm-dev
+
+      - name: Prune stale runtime assets from vm-dev release
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const [owner, repo] = process.env.GITHUB_REPOSITORY.split('/');
+            let release;
+            try {
+              release = await github.rest.repos.getReleaseByTag({ owner, repo, tag: 'vm-dev' });
+            } catch (err) {
+              if (err.status === 404) {
+                core.info('No existing vm-dev release; will create fresh.');
+                return;
+              }
+              throw err;
+            }
+            // Delete old runtime tarballs and checksums (keep vm binary assets)
+            for (const asset of release.data.assets) {
+              if (asset.name.startsWith('vm-runtime-')) {
+                core.info(`Deleting stale asset: ${asset.name}`);
+                await github.rest.repos.deleteReleaseAsset({ owner, repo, asset_id: asset.id });
+              }
+            }
+
+      - name: Create / update vm-dev GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          name: OpenShell VM Development Build
+          prerelease: true
+          tag_name: vm-dev
+          target_commitish: ${{ github.sha }}
+          body: |
+            Rolling development build of **openshell-vm** — the MicroVM runtime for OpenShell.
+
+            > **NOTE**: This is a development build, not a tagged release, and may be unstable.
+            > The VM implementation itself is also experimental and may change or break without
+            > notice.
+
+            ### Kernel Runtime Artifacts
+
+            Pre-built kernel runtime (libkrunfw + libkrun + gvproxy) for embedding into
+            the openshell-vm binary. These are rebuilt when the kernel config or pinned
+            dependency versions change.
+
+            | Platform | Artifact |
+            |----------|----------|
+            | Linux ARM64 | `vm-runtime-linux-aarch64.tar.zst` |
+            | Linux x86_64 | `vm-runtime-linux-x86_64.tar.zst` |
+            | macOS ARM64 | `vm-runtime-darwin-aarch64.tar.zst` |
+
+            ### VM Binaries
+
+            Self-extracting openshell-vm binaries with embedded kernel runtime and base
+            rootfs. These are rebuilt on every push to main.
+
+            | Platform | Artifact |
+            |----------|----------|
+            | Linux ARM64 | `openshell-vm-aarch64-unknown-linux-gnu.tar.gz` |
+            | Linux x86_64 | `openshell-vm-x86_64-unknown-linux-gnu.tar.gz` |
+            | macOS ARM64 | `openshell-vm-aarch64-apple-darwin.tar.gz` |
+
+            **macOS users:** The binary must be codesigned with the Hypervisor entitlement:
+            ```bash
+            codesign --entitlements crates/openshell-vm/entitlements.plist --force -s - ./openshell-vm
+            ```
+
+          files: |
+            release/vm-runtime-linux-aarch64.tar.zst
+            release/vm-runtime-linux-x86_64.tar.zst
+            release/vm-runtime-darwin-aarch64.tar.zst
+            release/vm-runtime-checksums-sha256.txt