diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3680136d89ff7..a0b03be27d98a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -61,6 +61,47 @@ jobs:
           - name: x86_64-gnu-tools
             os: ubuntu-20.04-16core-64gb
             env: {}
+          - name: x86_64-msvc
+            env:
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --enable-profiler"
+              SCRIPT: make ci-msvc
+            os: windows-2019-8core-32gb
+          - name: i686-msvc
+            env:
+              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-msvc"
+              SCRIPT: make ci-msvc
+            os: windows-2019-8core-32gb
+          - name: x86_64-msvc-ext
+            env:
+              SCRIPT: python x.py --stage 2 test src/tools/cargotest src/tools/cargo && src/ci/docker/host-x86_64/x86_64-gnu-tools/checktools.sh x.py /tmp/toolstate/toolstates.json windows
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --enable-lld --save-toolstates=/tmp/toolstate/toolstates.json"
+              DEPLOY_TOOLSTATES_JSON: toolstates-windows.json
+            os: windows-2019-8core-32gb
+          - name: i686-mingw
+            env:
+              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu"
+              SCRIPT: make ci-mingw
+              NO_DOWNLOAD_CI_LLVM: 1
+              CUSTOM_MINGW: 1
+            os: windows-2019-8core-32gb
+          - name: x86_64-mingw
+            env:
+              SCRIPT: make ci-mingw
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-profiler"
+              NO_DOWNLOAD_CI_LLVM: 1
+              CUSTOM_MINGW: 1
+            os: windows-2019-8core-32gb
+          - name: dist-aarch64-msvc
+            env:
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --host=aarch64-pc-windows-msvc --enable-full-tools --enable-profiler"
+              SCRIPT: python x.py dist bootstrap --include-default-paths
+              DIST_REQUIRE_ALL_TOOLS: 1
+            os: windows-2019-8core-32gb
+          - name: dist-x86_64-msvc-alt
+            env:
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --enable-extended --enable-profiler"
+              SCRIPT: python x.py dist bootstrap --include-default-paths
+            os: windows-2019-8core-32gb
     timeout-minutes: 600
     runs-on: "${{ matrix.os }}"
     steps:
diff --git a/src/ci/github-actions/ci.yml b/src/ci/github-actions/ci.yml
index 89b82d59d3176..66619fd694e27 100644
--- a/src/ci/github-actions/ci.yml
+++ b/src/ci/github-actions/ci.yml
@@ -327,6 +327,82 @@ jobs:
           - name: x86_64-gnu-tools
             <<: *job-linux-16c
 
+          - name: x86_64-msvc
+            env:
+              RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-profiler
+              SCRIPT: make ci-msvc
+            <<: *job-windows-8c
+
+          - name: i686-msvc
+            env:
+              RUST_CONFIGURE_ARGS: --build=i686-pc-windows-msvc
+              SCRIPT: make ci-msvc
+            <<: *job-windows-8c
+
+          - name: x86_64-msvc-ext
+            env:
+              SCRIPT: python x.py --stage 2 test src/tools/cargotest src/tools/cargo && src/ci/docker/host-x86_64/x86_64-gnu-tools/checktools.sh x.py /tmp/toolstate/toolstates.json windows
+              RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-lld --save-toolstates=/tmp/toolstate/toolstates.json
+              DEPLOY_TOOLSTATES_JSON: toolstates-windows.json
+            <<: *job-windows-8c
+
+          # 32/64-bit MinGW builds.
+          #
+          # We are using MinGW with POSIX threads since LLVM requires
+          # C++'s std::thread which is disabled in libstdc++ with win32 threads.
+          # FIXME: Libc++ doesn't have this limitation so we can avoid
+          # winpthreads if we switch to it.
+          #
+          # Instead of relying on the MinGW version installed on CI we download
+          # and install one ourselves so we won't be surprised by changes to CI's
+          # build image.
+          #
+          # Finally, note that the downloads below are all in the `rust-lang-ci` S3
+          # bucket, but they clearly didn't originate there! The downloads originally
+          # came from the mingw-w64 SourceForge download site. Unfortunately
+          # SourceForge is notoriously flaky, so we mirror it on our own infrastructure.
+
+          - name: i686-mingw
+            env:
+              RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
+              SCRIPT: make ci-mingw
+              # We are intentionally allowing an old toolchain on this builder (and that's
+              # incompatible with LLVM downloads today).
+              NO_DOWNLOAD_CI_LLVM: 1
+              CUSTOM_MINGW: 1
+            <<: *job-windows-8c
+
+          - name: x86_64-mingw
+            env:
+              SCRIPT: make ci-mingw
+              RUST_CONFIGURE_ARGS: >-
+                --build=x86_64-pc-windows-gnu
+                --enable-profiler
+              # We are intentionally allowing an old toolchain on this builder (and that's
+              # incompatible with LLVM downloads today).
+              NO_DOWNLOAD_CI_LLVM: 1
+              CUSTOM_MINGW: 1
+            <<: *job-windows-8c
+
+          - name: dist-aarch64-msvc
+            env:
+              RUST_CONFIGURE_ARGS: >-
+                --build=x86_64-pc-windows-msvc
+                --host=aarch64-pc-windows-msvc
+                --enable-full-tools
+                --enable-profiler
+              SCRIPT: python x.py dist bootstrap --include-default-paths
+              DIST_REQUIRE_ALL_TOOLS: 1
+            <<: *job-windows-8c
+
+          - name: dist-x86_64-msvc-alt
+            env:
+              RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-extended --enable-profiler
+              SCRIPT: python x.py dist bootstrap --include-default-paths
+            <<: *job-windows-8c
+
+
+
   auto:
     <<: *base-ci-job
     name: auto - ${{ matrix.name }}