Fix Windows build with --no-default-features

.github/workflows/dep_rust.yml

@@ -138,8 +138,8 @@ jobs:
           cargo check -p hyperlight-host --features print_debug
           cargo check -p hyperlight-host --features gdb
 
-          # without any driver (shouldn't compile)
-          just test-compilation-fail ${{ matrix.config }}
+          # without any features
+          just test-compilation-no-default-features ${{ matrix.config }}
 
         # One of the examples is flaky on Windows GH runners, so this allows us to disable it for now
       - name: Run Rust examples - windows

Justfile

@@ -84,7 +84,7 @@ test-like-ci config=default-target hypervisor="kvm":
     cargo check -p hyperlight-host --features gdb
 
     @# without any driver (should fail to compile)
-    just test-compilation-fail {{config}}
+    just test-compilation-no-default-features {{config}}
 
     @# test the crashdump feature
     just test-rust-crashdump {{config}}
@@ -121,10 +121,16 @@ test-seccomp target=default-target features="":
     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
 
-# runs tests that ensure compilation fails when it should
-test-compilation-fail target=default-target:
-    @# the following should fail on linux because one of kvm, mshv, or mshv3 feature must be specified, which is why the exit code is inverted with an !.
-    {{ if os() == "linux" { "! cargo check -p hyperlight-host --no-default-features 2> /dev/null"} else { "" } }}
+# tests compilation with no default features on different platforms
+test-compilation-no-default-features target=default-target:
+    @# Linux should fail without a hypervisor feature (kvm, mshv, or mshv3)
+    {{ if os() == "linux" { "! cargo check -p hyperlight-host --no-default-features 2> /dev/null" } else { "" } }}
+    @# Windows should succeed even without default features
+    {{ if os() == "windows" { "cargo check -p hyperlight-host --no-default-features" } else { "" } }}
+    @# Linux should succeed with a hypervisor driver but without init-paging
+    {{ if os() == "linux" { "cargo check -p hyperlight-host --no-default-features --features kvm" } else { "" } }}
+    {{ if os() == "linux" { "cargo check -p hyperlight-host --no-default-features --features mshv2" } else { "" } }}
+    {{ if os() == "linux" { "cargo check -p hyperlight-host --no-default-features --features mshv3" } else { "" } }}    
 
 # runs tests that exercise gdb debugging
 test-rust-gdb-debugging target=default-target features="":

src/hyperlight_host/src/hypervisor/hyperv_linux.rs

@@ -479,6 +479,28 @@ impl HypervLinuxDriver {
             cs: SegmentRegister {
                 base: 0,
                 selector: 0,
+                limit: 0xFFFF,
+                type_: 11,
+                present: 1,
+                s: 1,
+                ..Default::default()
+            },
+            ds: SegmentRegister {
+                base: 0,
+                selector: 0,
+                limit: 0xFFFF,
+                type_: 3,
+                present: 1,
+                s: 1,
+                ..Default::default()
+            },
+            tr: SegmentRegister {
+                base: 0,
+                selector: 0,
+                limit: 0xFFFF,
+                type_: 11,
+                present: 1,
+                s: 0,
                 ..Default::default()
             },
             ..Default::default()

src/hyperlight_host/src/hypervisor/hyperv_windows.rs

@@ -25,8 +25,11 @@ use tracing::{Span, instrument};
 use windows::Win32::System::Hypervisor::{
     WHV_MEMORY_ACCESS_TYPE, WHV_PARTITION_HANDLE, WHV_REGISTER_VALUE, WHV_RUN_VP_EXIT_CONTEXT,
     WHV_RUN_VP_EXIT_REASON, WHV_X64_SEGMENT_REGISTER, WHV_X64_SEGMENT_REGISTER_0,
-    WHvCancelRunVirtualProcessor, WHvX64RegisterCr0, WHvX64RegisterCr3, WHvX64RegisterCr4,
-    WHvX64RegisterCs, WHvX64RegisterEfer,
+    WHvCancelRunVirtualProcessor, WHvX64RegisterCs,
+};
+#[cfg(feature = "init-paging")]
+use windows::Win32::System::Hypervisor::{
+    WHvX64RegisterCr0, WHvX64RegisterCr3, WHvX64RegisterCr4, WHvX64RegisterEfer,
 };
 #[cfg(crashdump)]
 use {super::crashdump, std::path::Path};
@@ -399,16 +402,22 @@ impl HypervWindowsDriver {
         ])?;
 
         #[cfg(not(feature = "init-paging"))]
-        proc.set_registers(&[(
-            WHvX64RegisterCs,
-            WHV_REGISTER_VALUE {
-                Segment: WHV_X64_SEGMENT_REGISTER {
-                    Base: 0,
-                    Selector: 0,
-                    ..Default::default()
+        {
+            proc.set_registers(&[(
+                WHvX64RegisterCs,
+                WHV_REGISTER_VALUE {
+                    Segment: WHV_X64_SEGMENT_REGISTER {
+                        Base: 0,
+                        Selector: 0,
+                        Limit: 0xFFFF,
+                        Anonymous: WHV_X64_SEGMENT_REGISTER_0 {
+                            Attributes: 0b1011 | (1 << 4) | (1 << 7), // Type (11: Execute/Read, accessed) | S (code segment) | P (present)
+                        },
+                        ..Default::default()
+                    },
                 },
-            },
-        )])?;
+            )])?;
+        }
 
         Ok(())
     }

src/hyperlight_host/src/sandbox/uninitialized_evolve.rs

@@ -33,7 +33,7 @@ use crate::mem::mgr::SandboxMemoryManager;
 use crate::mem::ptr::{GuestPtr, RawPtr};
 use crate::mem::ptr_offset::Offset;
 use crate::mem::shared_mem::GuestSharedMemory;
-#[cfg(feature = "init-paging")]
+#[cfg(any(feature = "init-paging", target_os = "windows"))]
 use crate::mem::shared_mem::SharedMemory;
 #[cfg(gdb)]
 use crate::sandbox::config::DebugInfo;