ci: Enable caching

Now that most jobs are on the stable channel, enabling caching should be more
effective than it would have been on nightly.

.github/workflows/rust.yml

@@ -20,6 +20,8 @@ jobs:
     - name: Checkout sources
       uses: actions/checkout@v3
 
+    - uses: Swatinem/rust-cache@v2
+
     - name: Install qemu and OVMF
       run: |
         sudo apt-get update
@@ -36,6 +38,8 @@ jobs:
     - name: Checkout sources
       uses: actions/checkout@v3
 
+    - uses: Swatinem/rust-cache@v2
+
     - name: Install qemu and OVMF
       run: |
         sudo apt-get update
@@ -52,6 +56,8 @@ jobs:
     - name: Checkout sources
       uses: actions/checkout@v3
 
+    - uses: Swatinem/rust-cache@v2
+
     - name: Install qemu and OVMF
       run: |
         sudo apt-get update
@@ -68,6 +74,8 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v3
 
+      - uses: Swatinem/rust-cache@v2
+
       - name: Run cargo test (without unstable)
         run: cargo xtask test
 
@@ -78,6 +86,8 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v3
 
+      - uses: Swatinem/rust-cache@v2
+
       - name: Run cargo fmt
         run: |
           rustup component add rustfmt
@@ -112,6 +122,8 @@ jobs:
     - name: Set nightly toolchain
       run: cp .github/workflows/nightly_toolchain.toml rust-toolchain.toml
 
+    - uses: Swatinem/rust-cache@v2
+
     - name: Build
       run: cargo xtask test-latest-release
 
@@ -125,6 +137,8 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v3
 
+      - uses: Swatinem/rust-cache@v2
+
       - name: Run VM tests
         run: cargo xtask run --target x86_64 --ci
         timeout-minutes: 6
@@ -144,6 +158,8 @@ jobs:
     - name: Set toolchain
       run: cp .github/workflows/msrv_toolchain.toml rust-toolchain.toml
 
+    - uses: Swatinem/rust-cache@v2
+
     - name: Build
       run: cargo xtask build
 
@@ -159,6 +175,8 @@ jobs:
     - name: Set nightly toolchain so that `unstable` can be included
       run: cp .github/workflows/nightly_toolchain.toml rust-toolchain.toml
 
+    - uses: Swatinem/rust-cache@v2
+
     - name: Build
       run: cargo xtask build --feature-permutations
 
@@ -177,6 +195,8 @@ jobs:
     - name: Enable nightly toolchain
       run: cp .github/workflows/nightly_toolchain.toml rust-toolchain.toml
 
+    - uses: Swatinem/rust-cache@v2
+
     - name: Run VM tests with the `unstable` feature
       run: cargo xtask run --target x86_64 --headless --ci --unstable
       timeout-minutes: 4