Making mshv3 the default mshv hypervisor in hyperlight_host (instead of mshv2)

.github/workflows/Benchmarks.yml

@@ -57,7 +57,7 @@ jobs:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Run Benchmarks
-        run: just bench-ci main release ${{ matrix.hypervisor == 'mshv3' && 'mshv3' || ''}}
+        run: just bench-ci main release ${{ matrix.hypervisor == 'mshv' && 'mshv2' || ''}}
 
       - uses: actions/upload-artifact@v4
         with:

.github/workflows/dep_rust.yml

@@ -128,7 +128,7 @@ jobs:
           CARGO_TERM_COLOR: always
         run: |
           # with default features
-          just test ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv3' && 'mshv3' || ''}}
+          just test ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv' && 'mshv2' || ''}}
 
           # with only one driver enabled (driver mshv/kvm feature is ignored on windows) + seccomp 
           just test ${{ matrix.config }} seccomp,${{ matrix.hypervisor == 'mshv' && 'mshv2' || matrix.hypervisor == 'mshv3' && 'mshv3' || 'kvm' }} 
@@ -154,20 +154,20 @@ jobs:
         env:
           CARGO_TERM_COLOR: always
           RUST_LOG: debug
-        run: just run-rust-examples-linux ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv3' && 'mshv3' || ''}}
+        run: just run-rust-examples-linux ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv' && 'mshv2' || ''}}
 
       - name: Run Rust Gdb tests - linux
         if: runner.os == 'Linux'
         env:
           CARGO_TERM_COLOR: always
           RUST_LOG: debug
-        run: just test-rust-gdb-debugging ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv3' && 'mshv3' || ''}}
+        run: just test-rust-gdb-debugging ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv' && 'mshv2' || ''}}
 
       - name: Run Rust Crashdump tests
         env:
           CARGO_TERM_COLOR: always
           RUST_LOG: debug
-        run: just test-rust-crashdump ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv3' && 'mshv3' || ''}}
+        run: just test-rust-crashdump ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv' && 'mshv2' || ''}}
 
       - name: Download benchmarks from "latest"
         run: just bench-download ${{ runner.os }} ${{ matrix.hypervisor }} ${{ matrix.cpu}} dev-latest # compare to prerelease
@@ -178,5 +178,5 @@ jobs:
 
       - name: Run benchmarks
         run: |
-          just bench-ci main ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv3' && 'mshv3' || ''}}
+          just bench-ci main ${{ matrix.config }} ${{ matrix.hypervisor == 'mshv' && 'mshv2' || ''}}
         if: ${{ matrix.config == 'release' }}

Justfile

@@ -73,7 +73,7 @@ clean-rust:
 # convenience recipe to run all tests with the given target and features (similar to CI)
 test-like-ci config=default-target hypervisor="kvm":
     @# with default features
-    just test {{config}} {{ if hypervisor == "mshv3" {"mshv3"} else {""} }}
+    just test {{config}} {{ if hypervisor == "mshv" {"mshv2"} else {""} }}
 
     @# with only one driver enabled + seccomp + build-metadata + init-paging
     just test {{config}} seccomp,build-metadata,init-paging,{{ if hypervisor == "mshv" {"mshv2"} else if hypervisor == "mshv3" {"mshv3"} else {"kvm"} }}
@@ -119,7 +119,7 @@ test-integration guest target=default-target features="":
 test-seccomp target=default-target features="":
     @# run seccomp test with feature "seccomp" on and off
     cargo test --profile={{ if target == "debug" { "dev" } else { target } }} -p hyperlight-host test_violate_seccomp_filters --lib {{ if features =="" {''} else { "--features " + features } }} -- --ignored
-    cargo test --profile={{ if target == "debug" { "dev" } else { target } }} -p hyperlight-host test_violate_seccomp_filters --no-default-features {{ if features =~"mshv3" {"--features init-paging,mshv3"} else {"--features mshv2,init-paging,kvm" } }} --lib -- --ignored
+    cargo test --profile={{ if target == "debug" { "dev" } else { target } }} -p hyperlight-host test_violate_seccomp_filters --no-default-features {{ if features =~"mshv2" {"--features init-paging,mshv2"} else {"--features mshv3,init-paging,kvm" } }} --lib -- --ignored
 
 # tests compilation with no default features on different platforms
 test-compilation-no-default-features target=default-target:
@@ -239,7 +239,7 @@ tar-static-lib: (build-rust-capi "release") (build-rust-capi "debug")
 # Downloads the benchmarks result from the given release tag.
 # If tag is not given, defaults to latest release
 # Options for os: "Windows", or "Linux"
-# Options for Linux hypervisor: "kvm", "mshv"
+# Options for Linux hypervisor: "kvm", "mshv", "mshv3"
 # Options for Windows hypervisor: "hyperv"
 # Options for cpu: "amd", "intel"
 bench-download os hypervisor cpu tag="":

src/hyperlight_host/Cargo.toml

@@ -118,7 +118,7 @@ cfg_aliases = "0.2.1"
 built = { version = "0.8.0", optional = true, features = ["chrono", "git2"] }
 
 [features]
-default = ["kvm", "mshv2", "seccomp", "build-metadata", "init-paging"]
+default = ["kvm", "mshv3", "seccomp", "build-metadata", "init-paging"]
 seccomp = ["dep:seccompiler"]
 function_call_metrics = []
 executable_heap = []
@@ -127,6 +127,7 @@ print_debug = []
 # Dumps the VM state to a file on unexpected errors or crashes. The path of the file will be printed on stdout and logged.
 crashdump = ["dep:chrono"]
 kvm = ["dep:kvm-bindings", "dep:kvm-ioctls"]
+# This feature is deprecated in favor of mshv3
 mshv2 = ["dep:mshv-bindings2", "dep:mshv-ioctls2"]
 mshv3 = ["dep:mshv-bindings3", "dep:mshv-ioctls3"]
 # This enables easy debug in the guest

src/hyperlight_host/build.rs

@@ -96,11 +96,11 @@ fn main() -> Result<()> {
         crashdump: { all(feature = "crashdump") },
         // print_debug feature is aliased with debug_assertions to make it only available in debug-builds.
         print_debug: { all(feature = "print_debug", debug_assertions) },
-        // the following features are mutually exclusive but rather than enforcing that here we are enabling mshv3 to override mshv2 when both are enabled
-        // because mshv2 is in the default feature set we want to allow users to enable mshv3 without having to set --no-default-features and the re-enable
+        // the following features are mutually exclusive but rather than enforcing that here we are enabling mshv2 to override mshv3 when both are enabled
+        // because mshv3 is in the default feature set we want to allow users to enable mshv2 without having to set --no-default-features and the re-enable
         // the other features they want.
-        mshv2: { all(feature = "mshv2", not(feature="mshv3"), target_os = "linux") },
-        mshv3: { all(feature = "mshv3", target_os = "linux") },
+        mshv2: { all(feature = "mshv2", target_os = "linux") },
+        mshv3: { all(feature = "mshv3", not(feature="mshv2"), target_os = "linux") },
     }
 
     #[cfg(feature = "build-metadata")]

src/hyperlight_host/examples/guest-debugging/main.rs

@@ -146,9 +146,9 @@ mod tests {
         write_cmds_file(&cmd_file_path, &out_file_path)
             .expect("Failed to write gdb commands to file");
 
-        #[cfg(mshv3)]
-        let features = "gdb,mshv3";
-        #[cfg(not(mshv3))]
+        #[cfg(mshv2)] // mshv3 is a default feature is mutually exclusive with the mshv2 feature
+        let features = "gdb,mshv2";
+        #[cfg(not(mshv2))]
         let features = "gdb";
 
         let mut guest_child = Command::new("cargo")