diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..76a4725
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,364 @@
+name: Build
+
+on:
+  workflow_dispatch:
+
+concurrency:
+  group: build
+  cancel-in-progress: false
+
+permissions:
+  contents: read
+
+env:
+  VERSION: ${{ vars.MAJOR }}.${{ vars.MINOR }}.0.0
+
+  # Only these two repositories float. Each run resolves master once and then
+  # passes the exact SHA to BuildKit as a named Git context.
+  D3D11_REPO: https://github.com/qemus/virtio-d3d11.git
+  KMD_REPO: https://github.com/qemus/virtio-drivers-windows.git
+
+  # Everything below is pinned.
+  BUILDER_IMAGE: buildpack-deps:sid@sha256:dfc7595de3e15149f7eefe40b41477d6dc90fd46bf901890fd97f9a32d2b2fa0
+  DEBIAN_SNAPSHOT: "20260831T235959Z"
+  MINGW_GCC_PKG_VERSION: "16.2.0-1+29"
+  MINGW_HEADERS_PKG_VERSION: "14.0.0-1"
+
+  MESA_ARCHIVE_URL: https://gitlab.freedesktop.org/anonymix007/mesa/-/archive/venus-win32/mesa-venus-win32.tar.gz
+  MESA_TREE_SHA256: 9070b043639cf230dbcedbe2614d649101c12e0a9c4ab2836c201b8ab652eab0
+
+  MAKECAT_REF: ee7aa4dd1d10ad5f254020ca0637df5abcc95618
+  CLANG_CL_LINUX_REF: 84e723d170e7611c55fff30c44d24c5a04bd4cb7
+
+  EWDK_VERSION: "26100.6584"
+  EWDK_URL: https://software-static.download.prss.microsoft.com/dbazure/888969d5-f34g-4e03-ac9d-1f9786c66749/EWDK_ge_release_svc_prod1_26100_250904-1728.iso
+  EWDK_SHA256: 9f48251dd24ad31aac206d8256e95bda5f90a9783982c45a8aafeb9054562379
+  WINSDKVER: "10.0.26100.0"
+  VCTOOLSVER: "14.44.35207"
+
+  RUST_TOOLCHAIN: nightly-2026-08-31
+  CBINDGEN_VERSION: "0.29.4"
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-24.04
+    timeout-minutes: 240
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262
+
+      - name: Validate version
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          # Fail clearly if MAJOR/MINOR repository variables were not set.
+          test -n "${{ vars.MAJOR }}"
+          test -n "${{ vars.MINOR }}"
+
+          [[ "${{ vars.MAJOR }}" =~ ^[0-9]+$ ]]
+          [[ "${{ vars.MINOR }}" =~ ^[0-9]+$ ]]
+
+          # Windows DriverVer is w.x.y.z: four numeric components,
+          # each strictly less than 65535. Our release scheme is
+          # MAJOR.MINOR.0.0.
+          [[ "${VERSION}" =~ ^[0-9]+\.[0-9]+\.0\.0$ ]]
+
+          IFS='.' read -r v1 v2 v3 v4 <<< "${VERSION}"
+          for component in "${v1}" "${v2}" "${v3}" "${v4}"; do
+            [[ "${component}" =~ ^[0-9]+$ ]]
+            (( 10#${component} < 65535 ))
+          done
+
+          test "${v1}" = "${{ vars.MAJOR }}"
+          test "${v2}" = "${{ vars.MINOR }}"
+          test "${v3}" = "0"
+          test "${v4}" = "0"
+
+          echo "Building driver/release version ${VERSION}"
+
+      - name: Free runner disk space
+        shell: bash
+        run: |
+          set -euxo pipefail
+
+          df -h /
+
+          sudo rm -rf /usr/local/lib/android
+          sudo rm -rf /usr/share/dotnet
+          sudo rm -rf /opt/ghc
+          sudo rm -rf /usr/local/.ghcup
+          sudo rm -rf /opt/hostedtoolcache
+          sudo docker system prune --all --force || true
+          sudo apt-get clean
+
+          df -h /
+
+      - name: Resolve master commits
+        id: refs
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          d3d11_sha="$(
+            git ls-remote "${D3D11_REPO}" refs/heads/master | awk '{print $1}'
+          )"
+          kmd_sha="$(
+            git ls-remote "${KMD_REPO}" refs/heads/master | awk '{print $1}'
+          )"
+
+          [[ "${d3d11_sha}" =~ ^[0-9a-f]{40}$ ]]
+          [[ "${kmd_sha}" =~ ^[0-9a-f]{40}$ ]]
+
+          # Resolve the DXVK gitlink from the exact D3D11 commit without
+          # checking out the working tree.
+          tmp="$(mktemp -d)"
+          trap 'rm -rf "${tmp}"' EXIT
+
+          git -C "${tmp}" init --quiet
+          git -C "${tmp}" remote add origin "${D3D11_REPO}"
+          git -C "${tmp}" fetch --quiet --depth=1 origin "${d3d11_sha}"
+
+          fetched_sha="$(git -C "${tmp}" rev-parse FETCH_HEAD)"
+          test "${fetched_sha}" = "${d3d11_sha}"
+
+          dxvk_sha="$(
+            git -C "${tmp}" ls-tree "${d3d11_sha}" thirdparty/dxvk \
+              | awk '{print $3}'
+          )"
+          [[ "${dxvk_sha}" =~ ^[0-9a-f]{40}$ ]]
+
+          echo "D3D11 master: ${d3d11_sha}"
+          echo "DXVK gitlink: ${dxvk_sha}"
+          echo "KMD master:   ${kmd_sha}"
+
+          {
+            echo "d3d11_sha=${d3d11_sha}"
+            echo "dxvk_sha=${dxvk_sha}"
+            echo "kmd_sha=${kmd_sha}"
+          } >> "${GITHUB_OUTPUT}"
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f
+
+      - name: Prime reusable build cache
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8
+        with:
+          context: .
+          file: ./Dockerfile
+          target: cache-seed
+          push: false
+          pull: false
+          provenance: false
+
+          # Only D3D11 is needed by the prerequisite target. KMD is deliberately
+          # excluded so KMD master changes cannot invalidate this checkpoint.
+          build-contexts: |
+            d3d11=${{ env.D3D11_REPO }}#${{ steps.refs.outputs.d3d11_sha }}
+
+          build-args: |
+            BUILDER_IMAGE=${{ env.BUILDER_IMAGE }}
+            DEBIAN_SNAPSHOT=${{ env.DEBIAN_SNAPSHOT }}
+            MINGW_GCC_PKG_VERSION=${{ env.MINGW_GCC_PKG_VERSION }}
+            MINGW_HEADERS_PKG_VERSION=${{ env.MINGW_HEADERS_PKG_VERSION }}
+
+            D3D11_SHA=${{ steps.refs.outputs.d3d11_sha }}
+            DXVK_SHA=${{ steps.refs.outputs.dxvk_sha }}
+
+            MESA_ARCHIVE_URL=${{ env.MESA_ARCHIVE_URL }}
+            MESA_TREE_SHA256=${{ env.MESA_TREE_SHA256 }}
+
+            MAKECAT_REF=${{ env.MAKECAT_REF }}
+            CLANG_CL_LINUX_REF=${{ env.CLANG_CL_LINUX_REF }}
+
+            EWDK_VERSION=${{ env.EWDK_VERSION }}
+            EWDK_URL=${{ env.EWDK_URL }}
+            EWDK_SHA256=${{ env.EWDK_SHA256 }}
+            WINSDKVER=${{ env.WINSDKVER }}
+            VCTOOLSVER=${{ env.VCTOOLSVER }}
+
+            RUST_TOOLCHAIN=${{ env.RUST_TOOLCHAIN }}
+            CBINDGEN_VERSION=${{ env.CBINDGEN_VERSION }}
+
+          # Run the expensive prerequisite graph to completion without exporting
+          # a filesystem/image, then publish every stage to the shared GHA cache.
+          outputs: type=cacheonly
+          cache-from: type=gha,scope=qemus-virtio-gpu-x64
+          cache-to: type=gha,mode=max,scope=qemus-virtio-gpu-x64,ignore-error=false
+
+      - name: Build package
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8
+        with:
+          context: .
+          file: ./Dockerfile
+          target: artifact
+          push: false
+          pull: false
+          provenance: false
+
+          # The two current masters are resolved once above. Full 40-character
+          # commit fragments make each named context immutable for this run.
+          build-contexts: |
+            d3d11=${{ env.D3D11_REPO }}#${{ steps.refs.outputs.d3d11_sha }}
+            kmd=${{ env.KMD_REPO }}#${{ steps.refs.outputs.kmd_sha }}
+
+          build-args: |
+            BUILDER_IMAGE=${{ env.BUILDER_IMAGE }}
+            DEBIAN_SNAPSHOT=${{ env.DEBIAN_SNAPSHOT }}
+            MINGW_GCC_PKG_VERSION=${{ env.MINGW_GCC_PKG_VERSION }}
+            MINGW_HEADERS_PKG_VERSION=${{ env.MINGW_HEADERS_PKG_VERSION }}
+
+            VERSION_ARG=${{ env.VERSION }}
+
+            D3D11_SHA=${{ steps.refs.outputs.d3d11_sha }}
+            DXVK_SHA=${{ steps.refs.outputs.dxvk_sha }}
+            KMD_SHA=${{ steps.refs.outputs.kmd_sha }}
+
+            MESA_ARCHIVE_URL=${{ env.MESA_ARCHIVE_URL }}
+            MESA_TREE_SHA256=${{ env.MESA_TREE_SHA256 }}
+
+            MAKECAT_REF=${{ env.MAKECAT_REF }}
+            CLANG_CL_LINUX_REF=${{ env.CLANG_CL_LINUX_REF }}
+
+            EWDK_VERSION=${{ env.EWDK_VERSION }}
+            EWDK_URL=${{ env.EWDK_URL }}
+            EWDK_SHA256=${{ env.EWDK_SHA256 }}
+            WINSDKVER=${{ env.WINSDKVER }}
+            VCTOOLSVER=${{ env.VCTOOLSVER }}
+
+            RUST_TOOLCHAIN=${{ env.RUST_TOOLCHAIN }}
+            CBINDGEN_VERSION=${{ env.CBINDGEN_VERSION }}
+
+          outputs: type=local,dest=./out
+
+          # qemus master changes invalidate only stages consuming their named
+          # contexts. Pinned Mesa/EWDK/toolchain stages remain reusable.
+          cache-from: type=gha,scope=qemus-virtio-gpu-x64
+          cache-to: type=gha,mode=max,scope=qemus-virtio-gpu-x64,ignore-error=true
+
+      - name: Verify exported package and version
+        shell: bash
+        run: |
+          set -euxo pipefail
+
+          required=(
+            virtio_wddm_rs.inf
+            virtio_wddm_rs.cat
+            virtio_wddm_rs.sys
+            virtio_gpu_wddm_rs.pdb
+            dx11um_virtio.dll
+            dx11um_virtio.debug
+            vulkan_virtio.dll
+            vulkan_virtio.debug
+            virtio_icd.x86_64.json
+            virtio_test_signing.cer
+            BUILDINFO.txt
+          )
+
+          for file_name in "${required[@]}"; do
+            test -s "out/${file_name}"
+          done
+
+          # The release version must literally equal the installed Windows
+          # DriverVer version, not merely resemble it.
+          driver_version="$(
+            sed -n 's/^DriverVer=[^,]*,[[:space:]]*//p' out/virtio_wddm_rs.inf
+          )"
+          test "${driver_version}" = "${VERSION}"
+
+          grep -Fq "Driver / release version:           ${VERSION}" out/BUILDINFO.txt
+          grep -Fq "${{ steps.refs.outputs.d3d11_sha }}" out/BUILDINFO.txt
+          grep -Fq "${{ steps.refs.outputs.dxvk_sha }}" out/BUILDINFO.txt
+          grep -Fq "${{ steps.refs.outputs.kmd_sha }}" out/BUILDINFO.txt
+          grep -Fq "${MESA_TREE_SHA256}" out/BUILDINFO.txt
+          grep -Fq "${BUILDER_IMAGE}" out/BUILDINFO.txt
+          grep -Fq "${DEBIAN_SNAPSHOT}" out/BUILDINFO.txt
+          grep -Fq "${MINGW_GCC_PKG_VERSION}" out/BUILDINFO.txt
+          grep -Fq "${MINGW_HEADERS_PKG_VERSION}" out/BUILDINFO.txt
+
+          echo
+          echo "Driver version: ${driver_version}"
+          cat out/BUILDINFO.txt
+          echo
+          find out -maxdepth 1 -type f -printf '%f\n' | sort
+
+      - name: Create release ZIP
+        shell: bash
+        run: |
+          set -euxo pipefail
+
+          archive="virtio-gpu-${VERSION}.zip"
+
+          python3 - "${archive}" <<'PY'
+          import sys
+          import zipfile
+          from pathlib import Path
+
+          archive = Path(sys.argv[1])
+          source = Path("out")
+
+          with zipfile.ZipFile(
+              archive,
+              "w",
+              compression=zipfile.ZIP_DEFLATED,
+              compresslevel=9,
+          ) as zf:
+              for path in sorted(source.iterdir()):
+                  if path.is_file():
+                      zf.write(path, path.name)
+          PY
+
+          test -s "${archive}"
+          sha256sum "${archive}"
+
+      - name: Upload Actions artifact
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02
+        with:
+          name: virtio-gpu-${{ env.VERSION }}
+          path: |
+            out/
+            virtio-gpu-${{ env.VERSION }}.zip
+          if-no-files-found: error
+          compression-level: 0
+          retention-days: 30
+
+      - name: Create a release
+        uses: action-pack/github-release@d887b892618f95e19985108bfbc0c26833efa505
+        with:
+          tag: "v${{ env.VERSION }}"
+          title: "v${{ env.VERSION }}"
+          token: ${{ secrets.REPO_ACCESS_TOKEN }}
+
+      - name: Add package to release
+        env:
+          GH_TOKEN: ${{ secrets.REPO_ACCESS_TOKEN }}
+        shell: bash
+        run: |
+          set -euxo pipefail
+          gh release upload \
+            "v${VERSION}" \
+            "virtio-gpu-${VERSION}.zip"
+
+      - name: Increment version variable
+        uses: action-pack/increment@1458c307cedd62641619be2480c6263cf39864ac
+        with:
+          name: 'MINOR'
+          token: ${{ secrets.REPO_ACCESS_TOKEN }}
+
+      - name: Send mail
+        uses: action-pack/send-mail@33d560748d5c56be2a180c578ba4cf92b22a4723
+        with:
+          to: ${{ secrets.MAILTO }}
+          from: Github Actions <${{ secrets.MAILTO }}>
+          connection_url: ${{ secrets.MAIL_CONNECTION }}
+          subject: Build of ${{ github.event.repository.name }} v${{ env.VERSION }} completed
+          body: |
+            The build job of ${{ github.event.repository.name }} v${{ env.VERSION }} was completed successfully!
+
+            Driver version: ${{ env.VERSION }}
+            D3D11: ${{ steps.refs.outputs.d3d11_sha }}
+            KMD: ${{ steps.refs.outputs.kmd_sha }}
+
+            See https://github.com/${{ github.repository }}/actions for more information.
diff --git a/.github/workflows/review.yml b/.github/workflows/review.yml
new file mode 100644
index 0000000..45f67a5
--- /dev/null
+++ b/.github/workflows/review.yml
@@ -0,0 +1,14 @@
+on:
+  pull_request:
+
+name: "Review"
+
+permissions:
+  contents: read
+  pull-requests: write
+  checks: write
+
+jobs:
+  review:
+    name: review
+    uses: action-pack/.github/.github/workflows/review.yml@master
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..05c9771
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,549 @@
+# syntax=docker/dockerfile:1.7@sha256:a57df69d0ea827fb7266491f2813635de6f17269be881f696fbfdf2d83dda33e
+
+ARG BUILDER_IMAGE=buildpack-deps:sid@sha256:dfc7595de3e15149f7eefe40b41477d6dc90fd46bf901890fd97f9a32d2b2fa0
+ARG DEBIAN_SNAPSHOT=20260831T235959Z
+ARG MINGW_GCC_PKG_VERSION=16.2.0-1+29
+ARG MINGW_HEADERS_PKG_VERSION=14.0.0-1
+
+FROM ${BUILDER_IMAGE} AS toolchain
+
+ARG DEBIAN_FRONTEND=noninteractive
+ARG DEBIAN_SNAPSHOT
+ARG MINGW_GCC_PKG_VERSION
+ARG MINGW_HEADERS_PKG_VERSION
+ARG RUST_TOOLCHAIN=nightly-2026-08-31
+ARG CBINDGEN_VERSION=0.29.4
+
+ENV RUSTUP_HOME=/opt/rustup
+ENV CARGO_HOME=/opt/cargo
+ENV PATH=/opt/cargo/bin:/opt/mingw-posix/bin:${PATH}
+
+# buildpack-deps already contains the generic native source-build stack
+# (gcc/g++/make, git, curl, file, common development libraries, etc.).
+# Only install the project-specific tools and the Windows cross compiler.
+# Use an immutable Debian archive snapshot so Sid cannot drift between runs.
+RUN set -eux; \
+    rm -f /etc/apt/sources.list.d/*.sources /etc/apt/sources.list; \
+    printf 'deb [check-valid-until=no] https://snapshot.debian.org/archive/debian/%s/ sid main\n' \
+      "${DEBIAN_SNAPSHOT}" > /etc/apt/sources.list; \
+    apt-get -o Acquire::Retries=5 update; \
+    apt-get install -y --no-install-recommends \
+      aria2 \
+      bison \
+      clang \
+      cmake \
+      flex \
+      gettext \
+      glslang-tools \
+      jq \
+      libclang-dev \
+      libexpat1-dev \
+      libwine-dev \
+      lld \
+      llvm \
+      gcc-mingw-w64-x86-64-posix="${MINGW_GCC_PKG_VERSION}" \
+      g++-mingw-w64-x86-64-posix="${MINGW_GCC_PKG_VERSION}" \
+      mingw-w64-x86-64-dev="${MINGW_HEADERS_PKG_VERSION}" \
+      ninja-build \
+      openssl \
+      osslsigncode \
+      p7zip-full \
+      pkg-config \
+      python3 \
+      python3-dev \
+      python3-venv; \
+    test "$(dpkg-query -W -f='${Version}' gcc-mingw-w64-x86-64-posix)" = "${MINGW_GCC_PKG_VERSION}"; \
+    test "$(dpkg-query -W -f='${Version}' g++-mingw-w64-x86-64-posix)" = "${MINGW_GCC_PKG_VERSION}"; \
+    test "$(dpkg-query -W -f='${Version}' mingw-w64-x86-64-dev)" = "${MINGW_HEADERS_PKG_VERSION}"; \
+    rm -rf /var/lib/apt/lists/*
+
+# Make the POSIX-threading MinGW compiler the unqualified x86_64-w64-mingw32
+# toolchain used by Mesa and virtio-d3d11.
+RUN set -eux; \
+    mkdir -p /opt/mingw-posix/bin; \
+    ln -s "$(command -v x86_64-w64-mingw32-gcc-posix)" /opt/mingw-posix/bin/x86_64-w64-mingw32-gcc; \
+    ln -s "$(command -v x86_64-w64-mingw32-g++-posix)" /opt/mingw-posix/bin/x86_64-w64-mingw32-g++; \
+    for tool in ar gcc-ar ld objcopy ranlib strip windres; do \
+      ln -s "$(command -v x86_64-w64-mingw32-${tool})" "/opt/mingw-posix/bin/x86_64-w64-mingw32-${tool}"; \
+    done; \
+    gcc_major="$(x86_64-w64-mingw32-gcc -dM -E -x c /dev/null | awk '$2 == "__GNUC__" { print $3 }')"; \
+    test "${gcc_major}" = "16"; \
+    printf '#include <windows.h>\nint main(void) { bool ok = true; return ok ? 0 : 1; }\n' > /tmp/c23-probe.c; \
+    x86_64-w64-mingw32-gcc -c /tmp/c23-probe.c -o /tmp/c23-probe.o; \
+    printf '#include <windows.h>\n_Maybenull_ int *p;\nint main(void) { return p != 0; }\n' > /tmp/sal-probe.c; \
+    x86_64-w64-mingw32-gcc -c /tmp/sal-probe.c -o /tmp/sal-probe.o; \
+    rm -f /tmp/c23-probe.c /tmp/c23-probe.o /tmp/sal-probe.c /tmp/sal-probe.o; \
+    x86_64-w64-mingw32-gcc --version | head -1
+
+# Pin the Rust compiler date and cbindgen version. rustup itself is only the
+# bootstrap mechanism; the installed compiler/toolchain is the dated nightly.
+RUN curl --proto '=https' --tlsv1.2 --fail --location \
+      https://sh.rustup.rs -o /tmp/rustup.sh \
+ && sh /tmp/rustup.sh -y --no-modify-path --profile minimal --default-toolchain none \
+ && rm /tmp/rustup.sh \
+ && rustup toolchain install "${RUST_TOOLCHAIN}" --profile minimal --component rust-src \
+ && rustup default "${RUST_TOOLCHAIN}" \
+ && rustup target add x86_64-pc-windows-msvc --toolchain "${RUST_TOOLCHAIN}" \
+ && cargo install cbindgen --version "${CBINDGEN_VERSION}" --locked \
+ && rustc --version \
+ && cargo --version \
+ && cbindgen --version
+
+
+FROM toolchain AS ewdk
+
+ARG EWDK_VERSION=26100.6584
+ARG EWDK_URL
+ARG EWDK_SHA256
+ARG VCTOOLSVER=14.44.35207
+ARG WINSDKVER=10.0.26100.0
+ARG CLANG_CL_LINUX_REF=84e723d170e7611c55fff30c44d24c5a04bd4cb7
+
+# The 18.6 GB ISO only exists during this RUN. It is deleted before the layer
+# is committed, so the cache stores the extracted toolchain subset, not the ISO.
+RUN set -eux; \
+    test -n "${EWDK_URL}"; \
+    test -n "${EWDK_SHA256}"; \
+    iso=/tmp/ewdk.iso; \
+    aria2c \
+      --continue=true \
+      --max-connection-per-server=8 \
+      --min-split-size=10M \
+      --split=8 \
+      --file-allocation=none \
+      --dir=/tmp \
+      --out=ewdk.iso \
+      "${EWDK_URL}"; \
+    echo "${EWDK_SHA256}  ${iso}" | sha256sum --check -; \
+    mkdir -p /opt/ewdk; \
+    7z x -y -r "${iso}" -o/opt/ewdk \
+      "Program Files/Microsoft Visual Studio/2022/BuildTools/VC/Tools/MSVC/${VCTOOLSVER}/include/*" \
+      "Program Files/Microsoft Visual Studio/2022/BuildTools/VC/Tools/MSVC/${VCTOOLSVER}/lib/x64/*" \
+      "Program Files/Windows Kits/10/Include/${WINSDKVER}/*" \
+      "Program Files/Windows Kits/10/Include/wdf/kmdf/1.27/*" \
+      "Program Files/Windows Kits/10/Lib/${WINSDKVER}/km/x64/*" \
+      "Program Files/Windows Kits/10/Lib/wdf/kmdf/x64/1.27/*"; \
+    rm -f "${iso}"; \
+    test -d "/opt/ewdk/Program Files/Microsoft Visual Studio/2022/BuildTools/VC/Tools/MSVC/${VCTOOLSVER}/include"; \
+    test -f "/opt/ewdk/Program Files/Windows Kits/10/Include/${WINSDKVER}/km/ntddk.h"; \
+    test -f "/opt/ewdk/Program Files/Windows Kits/10/Include/wdf/kmdf/1.27/wdf.h"; \
+    test -d "/opt/ewdk/Program Files/Windows Kits/10/Lib/${WINSDKVER}/km/x64"; \
+    test -d "/opt/ewdk/Program Files/Windows Kits/10/Lib/wdf/kmdf/x64/1.27"
+
+# Pin clang-cl-linux by immutable commit and retain only the VFS generator.
+RUN curl --fail --location --retry 5 \
+      "https://raw.githubusercontent.com/tmp64/clang-cl-linux/${CLANG_CL_LINUX_REF}/generate_vfs.py" \
+      -o /opt/ewdk/generate_vfs.py \
+ && python3 /opt/ewdk/generate_vfs.py \
+      --msvc "/opt/ewdk/Program Files/Microsoft Visual Studio/2022/BuildTools/VC/Tools/MSVC" \
+      --sdk "/opt/ewdk/Program Files/Windows Kits/10" \
+      --out /opt/ewdk/vfs-overlay.json \
+ && test -s /opt/ewdk/vfs-overlay.json
+
+
+FROM toolchain AS makecat-build
+
+ARG MAKECAT_REF=ee7aa4dd1d10ad5f254020ca0637df5abcc95618
+
+RUN set -eux; \
+    git init /src/makecat; \
+    git -C /src/makecat remote add origin https://github.com/anonymix007/makecat.git; \
+    git -C /src/makecat fetch --depth=1 origin "${MAKECAT_REF}"; \
+    git -C /src/makecat checkout --detach FETCH_HEAD; \
+    test "$(git -C /src/makecat rev-parse HEAD)" = "${MAKECAT_REF}"
+
+WORKDIR /src/makecat
+RUN --mount=type=cache,target=/opt/cargo/registry \
+    --mount=type=cache,target=/opt/cargo/git \
+    cargo build --release --locked \
+ && install -Dm755 target/release/makecat /out/makecat
+
+
+FROM toolchain AS mesa-build
+
+ARG MESA_ARCHIVE_URL=https://gitlab.freedesktop.org/anonymix007/mesa/-/archive/venus-win32/mesa-venus-win32.tar.gz
+ARG MESA_TREE_SHA256=9070b043639cf230dbcedbe2614d649101c12e0a9c4ab2836c201b8ab652eab0
+ARG WINSDKVER=10.0.26100.0
+
+COPY --from=ewdk /opt/ewdk /opt/ewdk
+
+# Mesa is content-pinned. The URL may name the branch, but the normalized
+# extracted tree must match MESA_TREE_SHA256 exactly or the production build
+# stops. Changing the pin intentionally invalidates this layer.
+RUN set -eux; \
+    mkdir -p /src/mesa; \
+    curl --fail --location --retry 5 "${MESA_ARCHIVE_URL}" -o /tmp/mesa.tar.gz; \
+    tar -xzf /tmp/mesa.tar.gz -C /src/mesa --strip-components=1; \
+    rm /tmp/mesa.tar.gz; \
+    actual="$(cd /src/mesa && tar \
+      --sort=name \
+      --mtime='UTC 1970-01-01' \
+      --owner=0 \
+      --group=0 \
+      --numeric-owner \
+      -cf - . | sha256sum | awk '{print $1}')"; \
+    echo "Mesa normalized tree: ${actual}"; \
+    test "${actual}" = "${MESA_TREE_SHA256}"
+
+# Populate precisely the WDK headers listed by the pinned Mesa source tree.
+RUN set -eux; \
+    sdk="/opt/ewdk/Program Files/Windows Kits/10/Include/${WINSDKVER}"; \
+    mkdir -p /src/mesa/include/winddk; \
+    while IFS= read -r header; do \
+      test -n "${header}" || continue; \
+      source_header="$(find "${sdk}" -type f -iname "${header}" -print -quit)"; \
+      if [ -z "${source_header}" ]; then \
+        echo "Missing EWDK header for Mesa: ${header}" >&2; \
+        exit 1; \
+      fi; \
+      cp "${source_header}" "/src/mesa/include/winddk/${header}"; \
+    done < /src/mesa/include/winddk/.gitignore
+
+RUN cat > /tmp/mingw-x86_64.ini <<'EOF'
+[binaries]
+c = 'x86_64-w64-mingw32-gcc'
+cpp = 'x86_64-w64-mingw32-g++'
+ar = 'x86_64-w64-mingw32-ar'
+strip = 'x86_64-w64-mingw32-strip'
+windres = 'x86_64-w64-mingw32-windres'
+
+[host_machine]
+system = 'windows'
+cpu_family = 'x86_64'
+cpu = 'x86_64'
+endian = 'little'
+
+[properties]
+needs_exe_wrapper = true
+EOF
+
+RUN python3 -m venv /opt/mesa-venv \
+ && /opt/mesa-venv/bin/pip install --no-cache-dir \
+      "meson==1.7.2" \
+      "jinja2==3.1.6" \
+      "mako==1.3.10" \
+      "packaging==25.0" \
+      "ply==3.11" \
+      "pyyaml==6.0.2"
+
+ENV PATH=/opt/mesa-venv/bin:/opt/cargo/bin:/opt/mingw-posix/bin:${PATH}
+
+RUN meson setup \
+      /src/mesa/build-win64 \
+      /src/mesa \
+      --cross-file /tmp/mingw-x86_64.ini \
+      --buildtype=release \
+      --prefix=/ \
+      -Dplatforms=windows \
+      -Dvulkan-drivers=virtio \
+      -Dgallium-drivers= \
+      -Dopengl=false \
+      -Degl=disabled \
+      -Dglx=disabled \
+      -Dgbm=disabled \
+      -Dllvm=disabled \
+      -Dxmlconfig=disabled \
+      -Dbuild-tests=false \
+      -Dvulkan-manifest-per-architecture=true \
+ && meson compile -C /src/mesa/build-win64 -j "$(nproc)" \
+ && DESTDIR=/tmp/mesa-stage meson install -C /src/mesa/build-win64 \
+ && mesa_dll="$(find /tmp/mesa-stage -type f -name vulkan_virtio.dll -print -quit)" \
+ && mesa_json="$(find /tmp/mesa-stage -type f -name virtio_icd.x86_64.json -print -quit)" \
+ && test -n "${mesa_dll}" \
+ && test -n "${mesa_json}" \
+ && mkdir -p /out \
+ && cp "${mesa_dll}" /out/vulkan_virtio.dll \
+ && cp "${mesa_json}" /out/virtio_icd.x86_64.json \
+ && cp /src/mesa/src/virtio/virtio-gpu/wddm_hw.h /out/mesa_wddm_hw.h \
+ && grep -q 'vulkan_virtio.dll' /out/virtio_icd.x86_64.json \
+ && file /out/vulkan_virtio.dll | grep -q 'PE32+'
+
+
+FROM toolchain AS d3d11-build
+
+ARG D3D11_SHA
+ARG DXVK_SHA
+ARG WINSDKVER=10.0.26100.0
+
+COPY --from=ewdk /opt/ewdk /opt/ewdk
+COPY --from=d3d11 / /src/d3d11/
+
+# The named Git context is recursively cloned by BuildKit, including the DXVK
+# submodule. D3D11_SHA/DXVK_SHA are recorded and checked by the workflow.
+RUN set -eux; \
+    test -n "${D3D11_SHA}"; \
+    test -n "${DXVK_SHA}"; \
+    test -f /src/d3d11/thirdparty/dxvk/version.h.in; \
+    test -f /src/d3d11/include/virtio_wddm_uapi.h
+
+# Fill in the ignored WDK headers from the pinned EWDK.
+RUN set -eux; \
+    sdk="/opt/ewdk/Program Files/Windows Kits/10/Include/${WINSDKVER}"; \
+    mkdir -p /src/d3d11/include/winddk; \
+    while IFS= read -r header; do \
+      test -n "${header}" || continue; \
+      source_header="$(find "${sdk}" -type f -iname "${header}" -print -quit)"; \
+      if [ -z "${source_header}" ]; then \
+        echo "Missing EWDK header for D3D11: ${header}" >&2; \
+        exit 1; \
+      fi; \
+      cp "${source_header}" "/src/d3d11/include/winddk/${header}"; \
+    done < /src/d3d11/include/winddk/.gitignore
+
+WORKDIR /src/d3d11
+RUN set -eux; \
+    vulkan_import="$(find /usr/lib -type f -path '*/wine/x86_64-windows/libvulkan-1.a' -print -quit)"; \
+    test -s "${vulkan_import}"; \
+    test -d /usr/x86_64-w64-mingw32/lib; \
+    install -m0644 "${vulkan_import}" /usr/x86_64-w64-mingw32/lib/libvulkan-1.dll.a; \
+    printf '%s\n' \
+      '__declspec(dllimport) void *vkGetInstanceProcAddr(void *, const char *);' \
+      'int main(void) { return vkGetInstanceProcAddr(0, 0) != 0; }' \
+      > /tmp/vulkan-link-probe.c; \
+    x86_64-w64-mingw32-gcc \
+      /tmp/vulkan-link-probe.c \
+      -o /tmp/vulkan-link-probe.exe \
+      -lvulkan-1; \
+    file /tmp/vulkan-link-probe.exe | grep -q 'PE32+'; \
+    x86_64-w64-mingw32-objdump -p /tmp/vulkan-link-probe.exe \
+      | grep -Eiq 'DLL Name: .*vulkan-1\.dll'; \
+    rm -f /tmp/vulkan-link-probe.c /tmp/vulkan-link-probe.exe; \
+    make -j"$(nproc)" DXVK_GIT_VERSION="${DXVK_SHA}"; \
+    test -f build/dist/dx11um_virtio.dll; \
+    test -f build/dist/dx11um_virtio.debug; \
+    mkdir -p /out; \
+    cp build/dist/dx11um_virtio.dll /out/; \
+    cp build/dist/dx11um_virtio.debug /out/; \
+    cp include/virtio_wddm_uapi.h /out/d3d11_virtio_wddm_uapi.h; \
+    file /out/dx11um_virtio.dll | grep -q 'PE32+'; \
+    if x86_64-w64-mingw32-objdump -p /out/dx11um_virtio.dll \
+       | grep -Eiq 'DLL Name: (libgcc_s|libstdc\+\+|libwinpthread)'; then \
+      echo "Unexpected MinGW runtime dependency in dx11um_virtio.dll" >&2; \
+      exit 1; \
+    fi
+
+
+# Successful cache checkpoint for all expensive prerequisites.
+# The CI workflow builds this target first with the cache-only exporter so
+# these layers are published even if the later KMD/package stage fails.
+FROM scratch AS cache-seed
+COPY --from=ewdk /opt/ewdk/vfs-overlay.json /ewdk-vfs-overlay.json
+COPY --from=makecat-build /out/makecat /makecat
+COPY --from=mesa-build /out/vulkan_virtio.dll /vulkan_virtio.dll
+COPY --from=d3d11-build /out/dx11um_virtio.dll /dx11um_virtio.dll
+
+FROM toolchain AS package
+
+ARG BUILDER_IMAGE
+ARG DEBIAN_SNAPSHOT
+ARG MINGW_GCC_PKG_VERSION
+ARG MINGW_HEADERS_PKG_VERSION
+ARG VERSION_ARG
+ARG KMD_SHA
+ARG D3D11_SHA
+ARG DXVK_SHA
+ARG MESA_TREE_SHA256
+ARG MAKECAT_REF
+ARG CLANG_CL_LINUX_REF
+ARG EWDK_VERSION
+ARG VCTOOLSVER
+ARG WINSDKVER
+ARG RUST_TOOLCHAIN
+ARG CBINDGEN_VERSION
+
+ENV VCTOOLSVER=${VCTOOLSVER}
+ENV WINSDKVER=${WINSDKVER}
+ENV RUSTUP_TOOLCHAIN=${RUST_TOOLCHAIN}
+ENV RUSTUP_AUTO_INSTALL=0
+ENV AR_x86_64_pc_windows_msvc=llvm-lib
+
+COPY --from=ewdk /opt/ewdk /opt/ewdk
+COPY --from=makecat-build /out/makecat /usr/local/bin/makecat
+COPY --from=kmd / /src/kmd/
+COPY --from=mesa-build /out/ /opt/mesa-artifacts/
+COPY --from=d3d11-build /out/ /opt/d3d11-artifacts/
+
+WORKDIR /src/kmd
+
+# Configure the EWDK exactly the way the Rust WDK helper expects it.
+RUN cat > /src/kmd/ewdk.env <<EOF
+#!/bin/bash
+export EWDK_ROOT="/opt/ewdk"
+export VCTOOLSVER="${VCTOOLSVER}"
+export VCTOOLSDIR="/opt/ewdk/Program Files/Microsoft Visual Studio/2022/BuildTools/VC/Tools/MSVC/${VCTOOLSVER}"
+export WINSDKVER="${WINSDKVER}"
+export WINSDKDIR="/opt/ewdk/Program Files/Windows Kits/10"
+export VFSOVERLAY="/opt/ewdk/vfs-overlay.json"
+EOF
+
+# The GitHub workflow owns the package version. Windows requires DriverVer to
+# use four numeric components, so VERSION_ARG is already the exact value used
+# for the GitHub Release (for example 20.16.0.0). Patch only the throw-away
+# BuildKit copy of the floating KMD source; upstream master remains untouched.
+RUN set -eux; \
+    test -n "${VERSION_ARG}"; \
+    echo "${VERSION_ARG}" | grep -Eq '^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$'; \
+    test "$(grep -c '^DriverVer=' /src/kmd/virtio_wddm_rs.inx)" -eq 1; \
+    sed -i \
+      "s|^DriverVer=.*$|DriverVer=%%BUILDDATE%%, ${VERSION_ARG}|" \
+      /src/kmd/virtio_wddm_rs.inx; \
+    grep -Fx "DriverVer=%%BUILDDATE%%, ${VERSION_ARG}" \
+      /src/kmd/virtio_wddm_rs.inx
+
+# ABI gate:
+#   1. Generate the canonical C ABI from the floating KMD master.
+#   2. Require it to match the pinned Mesa snapshot.
+#   3. Require it to match the floating D3D11 snapshot.
+# This stage changes when either qemus context changes, but Mesa itself remains
+# independently cached.
+RUN set -eux; \
+    mkdir -p /tmp/uapi; \
+    cbindgen \
+      --config /src/kmd/gpu-wddm/cbindgen.toml \
+      /src/kmd/gpu-wddm/src/uapi.rs \
+      > /tmp/uapi/virtio_wddm_uapi.h; \
+    cmp -s /tmp/uapi/virtio_wddm_uapi.h /opt/mesa-artifacts/mesa_wddm_hw.h || { \
+      echo "Mesa WDDM ABI snapshot differs from current KMD master." >&2; \
+      diff -u /opt/mesa-artifacts/mesa_wddm_hw.h /tmp/uapi/virtio_wddm_uapi.h || true; \
+      exit 1; \
+    }; \
+    cmp -s /tmp/uapi/virtio_wddm_uapi.h /opt/d3d11-artifacts/d3d11_virtio_wddm_uapi.h || { \
+      echo "D3D11 WDDM ABI snapshot differs from current KMD master." >&2; \
+      diff -u /opt/d3d11-artifacts/d3d11_virtio_wddm_uapi.h /tmp/uapi/virtio_wddm_uapi.h || true; \
+      exit 1; \
+    }; \
+    echo "WDDM ABI snapshots match."
+
+# Stage UMDs exactly where the current KMD dist.sh expects them.
+RUN mkdir -p /src/kmd/target/mesa \
+ && cp /opt/mesa-artifacts/vulkan_virtio.dll /src/kmd/target/mesa/ \
+ && cp /opt/mesa-artifacts/virtio_icd.x86_64.json /src/kmd/target/mesa/ \
+ && cp /opt/d3d11-artifacts/dx11um_virtio.dll /src/kmd/target/mesa/ \
+ && cp /opt/d3d11-artifacts/dx11um_virtio.debug /src/kmd/target/mesa/
+
+# Generate a long-lived TEST certificate. Production signing can replace this
+# stage later without changing any compiler/source inputs.
+RUN set -eux; \
+    mkdir -p /opt/test-cert; \
+    cat > /opt/test-cert/openssl.cnf <<'EOF'
+[req]
+distinguished_name = dn
+x509_extensions = extensions
+prompt = no
+
+[dn]
+CN = qemus VirtIO GPU CI test signing
+
+[extensions]
+basicConstraints = critical, CA:TRUE
+keyUsage = critical, digitalSignature, keyCertSign
+extendedKeyUsage = codeSigning
+subjectKeyIdentifier = hash
+authorityKeyIdentifier = keyid:always
+EOF
+RUN openssl req \
+      -x509 \
+      -newkey rsa:3072 \
+      -nodes \
+      -sha256 \
+      -days 3650 \
+      -config /opt/test-cert/openssl.cnf \
+      -keyout /opt/test-cert/key.pem \
+      -out /opt/test-cert/cert.pem \
+ && openssl x509 \
+      -in /opt/test-cert/cert.pem \
+      -outform der \
+      -out /opt/test-cert/virtio_test_signing.cer \
+ && cat > /src/kmd/cert.env <<'EOF'
+#!/bin/bash
+export CERT="/opt/test-cert/cert.pem"
+export KEY="/opt/test-cert/key.pem"
+EOF
+
+# Build/package the floating KMD master using the pinned environment and the
+# two UMD artifacts. RUSTUP_TOOLCHAIN overrides the repository's floating
+# rust-toolchain.toml (`channel = "nightly"`), while RUSTUP_AUTO_INSTALL=0
+# prevents rustup from silently downloading a different nightly.
+RUN set -eux; \
+    rustup show active-toolchain | grep -F "${RUST_TOOLCHAIN}"; \
+    rustup target list --installed | grep -Fx 'x86_64-pc-windows-msvc'; \
+    test "$(command -v "${AR_x86_64_pc_windows_msvc}")" = "/usr/bin/llvm-lib"; \
+    llvm-lib /? >/tmp/llvm-lib-help.txt 2>&1 || true; \
+    grep -qi 'LLVM Lib' /tmp/llvm-lib-help.txt; \
+    rm -f /tmp/llvm-lib-help.txt; \
+    sysroot="$(rustc --print sysroot)"; \
+    test -f "${sysroot}/lib/rustlib/src/rust/library/Cargo.lock"; \
+    rustc --version; \
+    cargo --version
+
+RUN --mount=type=cache,target=/opt/cargo/registry \
+    --mount=type=cache,target=/opt/cargo/git \
+    ./dist.sh
+
+RUN set -eux; \
+    dist=/src/kmd/target/dist; \
+    cp /opt/test-cert/virtio_test_signing.cer "${dist}/"; \
+    cat > "${dist}/BUILDINFO.txt" <<EOF
+qemus VirtIO GPU WDDM build
+==========================
+
+Driver / release version:           ${VERSION_ARG}
+
+Floating sources resolved once per workflow:
+qemus/virtio-d3d11 master:         ${D3D11_SHA}
+  DXVK submodule:                  ${DXVK_SHA}
+qemus/virtio-drivers-windows:      ${KMD_SHA}
+
+Pinned sources/toolchain:
+Mesa venus-win32 normalized tree:  ${MESA_TREE_SHA256}
+anonymix007/makecat:               ${MAKECAT_REF}
+tmp64/clang-cl-linux:              ${CLANG_CL_LINUX_REF}
+EWDK:                              ${EWDK_VERSION}
+Windows SDK:                       ${WINSDKVER}
+MSVC tools:                        ${VCTOOLSVER}
+Rust:                              ${RUST_TOOLCHAIN}
+cbindgen:                          ${CBINDGEN_VERSION}
+Builder image:                     ${BUILDER_IMAGE}
+Debian package snapshot:            ${DEBIAN_SNAPSHOT}
+MinGW GCC packages:                 ${MINGW_GCC_PKG_VERSION}
+MinGW-w64 headers:                  ${MINGW_HEADERS_PKG_VERSION}
+EOF
+
+# Final package validation.
+RUN set -eux; \
+    dist=/src/kmd/target/dist; \
+    for file_name in \
+      virtio_wddm_rs.inf \
+      virtio_wddm_rs.cat \
+      virtio_wddm_rs.sys \
+      virtio_gpu_wddm_rs.pdb \
+      dx11um_virtio.dll \
+      dx11um_virtio.debug \
+      vulkan_virtio.dll \
+      vulkan_virtio.debug \
+      virtio_icd.x86_64.json \
+      virtio_test_signing.cer \
+      BUILDINFO.txt; do \
+        test -s "${dist}/${file_name}"; \
+    done; \
+    grep -q 'dx11um_virtio.dll' "${dist}/virtio_wddm_rs.inf"; \
+    grep -q 'vulkan_virtio.dll' "${dist}/virtio_wddm_rs.inf"; \
+    grep -q 'virtio_icd.x86_64.json' "${dist}/virtio_wddm_rs.inf"; \
+    grep -Fq ", ${VERSION_ARG}" "${dist}/virtio_wddm_rs.inf"; \
+    test "$(grep -c '^DriverVer=' "${dist}/virtio_wddm_rs.inf")" -eq 1; \
+    grep -q 'vulkan_virtio.dll' "${dist}/virtio_icd.x86_64.json"; \
+    file "${dist}/virtio_wddm_rs.sys" | grep -q 'PE32+'; \
+    file "${dist}/dx11um_virtio.dll" | grep -q 'PE32+'; \
+    file "${dist}/vulkan_virtio.dll" | grep -q 'PE32+'; \
+    for dll in "${dist}/dx11um_virtio.dll" "${dist}/vulkan_virtio.dll"; do \
+      if x86_64-w64-mingw32-objdump -p "${dll}" \
+         | grep -Eiq 'DLL Name: (libgcc_s|libstdc\+\+|libwinpthread)'; then \
+        echo "Unexpected MinGW runtime dependency in ${dll}" >&2; \
+        exit 1; \
+      fi; \
+    done; \
+    find "${dist}" -maxdepth 1 -type f -printf '%f\n' | sort
+
+
+FROM scratch AS artifact
+COPY --from=package /src/kmd/target/dist/ /