feat(bindings)!: add RVM/Program support across FFI and language bindings (#565)

- FFI: add RVM/Program APIs, execution state accessors, HostAwait handling, and buffer/result helpers in rvm.rs, common.rs, engine.rs.
- Compiler: emit HostAwait for __builtin_host_await in function_calls.rs.
- RVM tests: add HostAwait regression cases and extend harness for suspend/resume responses in host_await.yaml and mod.rs.
- C/C++: add RVM tests/examples and wrapper updates in rvm_tests.c, rvm_tests.cpp, regorus.hpp, plus CMake wiring.
- C#: add Program/Rvm bindings, SafeHandle/PInvoke, tests, and example usage in Regorus, RvmProgramTests.cs, Program.cs, and README updates.
- Go: add Program/Rvm bindings, tests, and examples in rvm.go, rvm_test.go, main.go.
- Java: add Program/Rvm bindings, JNI glue, and examples in lib.rs, regorus, Test.java.
- Python: add Program/Rvm bindings and examples in lib.rs, test.py.
- WASM: add Program/Rvm bindings and examples in lib.rs, test.js.
- Tooling: wire binding tests in xtask and ignore generated Java artifacts in .gitignore.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

bindings/csharp/README.md

@@ -64,3 +64,43 @@ Regorus.MemoryLimits.SetThreadFlushThresholdOverride(null);
 ```
 
 See bindings/csharp/Regorus.Tests/RegorusTests.cs for scenario coverage and bindings/csharp/TargetExampleApp/Program.cs for end-to-end usage.
+
+## RVM Usage Example
+
+The RVM API lets you compile a program from modules/entrypoints and execute it in a VM:
+
+```csharp
+using Regorus;
+
+const string Policy = """
+package demo
+default allow = false
+allow if {
+  input.user == "alice"
+  some role in data.roles[input.user]
+  role == "admin"
+}
+""";
+
+const string Data = """
+{ "roles": { "alice": ["admin"] } }
+""";
+
+const string Input = """
+{ "user": "alice" }
+""";
+
+var modules = new[] { new PolicyModule("demo.rego", Policy) };
+var entryPoints = new[] { "data.demo.allow" };
+
+using var program = Program.CompileFromModules(Data, modules, entryPoints);
+var listing = program.GenerateListing();
+
+using var vm = new Rvm();
+vm.LoadProgram(program);
+vm.SetDataJson(Data);
+vm.SetInputJson(Input);
+
+var result = vm.Execute();
+Console.WriteLine($"allow: {result}");
+```

bindings/csharp/Regorus.Tests/RvmProgramTests.cs

@@ -0,0 +1,119 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Regorus.Tests;
+
+[TestClass]
+public sealed class RvmProgramTests
+{
+    private const string Policy = """
+package demo
+default allow = false
+allow if {
+  input.user == "alice"
+  some role in data.roles[input.user]
+  role == "admin"
+  count(input.actions) > 0
+}
+""";
+
+    private const string Data = """
+{
+  "roles": {
+    "alice": ["admin", "reader"]
+  }
+}
+""";
+
+    private const string Input = """
+{
+  "user": "alice",
+  "actions": ["read"]
+}
+""";
+
+    private const string HostAwaitPolicy = """
+package demo
+import rego.v1
+
+default allow := false
+
+allow if {
+  input.account.active == true
+  details := __builtin_host_await(input.account.id, "account")
+  details.tier == "gold"
+}
+""";
+
+    private const string HostAwaitInput = """
+{
+  "account": {
+    "id": "acct-1",
+    "active": true
+  }
+}
+""";
+
+    [TestMethod]
+    public void Program_compile_and_execute_succeeds()
+    {
+        var modules = new[] { new PolicyModule("demo.rego", Policy) };
+        var entryPoints = new[] { "data.demo.allow" };
+
+        var program = Program.CompileFromModules(Data, modules, entryPoints);
+        var listing = program.GenerateListing();
+        Assert.IsFalse(string.IsNullOrWhiteSpace(listing), "listing should be generated");
+
+        var binary = program.SerializeBinary();
+        var rehydrated = Program.DeserializeBinary(binary, out var isPartial);
+        Assert.IsFalse(isPartial, "program should be fully deserialized");
+
+        using var vm = new Rvm();
+        vm.LoadProgram(rehydrated);
+        vm.SetDataJson(Data);
+        vm.SetInputJson(Input);
+
+        var result = vm.Execute();
+        Assert.AreEqual("true", result, "expected allow=true");
+    }
+
+    [TestMethod]
+    public void Program_compile_from_engine_succeeds()
+    {
+        using var engine = new Engine();
+        engine.AddPolicy("demo.rego", Policy);
+
+        var program = Program.CompileFromEngine(engine, new[] { "data.demo.allow" });
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+        vm.SetDataJson(Data);
+        vm.SetInputJson(Input);
+
+        var result = vm.Execute();
+        Assert.AreEqual("true", result, "expected allow=true");
+    }
+
+      [TestMethod]
+      public void Program_host_await_suspend_and_resume_succeeds()
+      {
+        var modules = new[] { new PolicyModule("host_await.rego", HostAwaitPolicy) };
+        var entryPoints = new[] { "data.demo.allow" };
+
+        using var program = Program.CompileFromModules("{}", modules, entryPoints);
+        using var vm = new Rvm();
+        vm.SetExecutionMode(1);
+        vm.LoadProgram(program);
+        vm.SetInputJson(HostAwaitInput);
+
+        var initial = vm.Execute();
+        var state = vm.GetExecutionState();
+        Assert.IsNotNull(state, "execution state should be available");
+        StringAssert.Contains(state!, "HostAwait", "expected HostAwait suspension");
+
+        var resumed = vm.Resume("{\"tier\":\"gold\"}");
+        Assert.AreEqual("true", resumed, "expected allow=true after resume");
+      }
+}

bindings/csharp/Regorus/CompiledPolicy.cs

@@ -180,7 +180,7 @@ namespace Regorus
             return handle;
         }
 
-        private T UseHandle<T>(Func<IntPtr, T> func)
+        internal T UseHandle<T>(Func<IntPtr, T> func)
         {
             var handle = GetHandleForUse();
             bool addedRef = false;
@@ -204,6 +204,11 @@ namespace Regorus
             }
         }
 
+        internal T UseHandleForInterop<T>(Func<IntPtr, T> func)
+        {
+            return UseHandle(func);
+        }
+
         private void UseHandle(Action<IntPtr> action)
         {
             UseHandle<object?>(handlePtr =>

bindings/csharp/Regorus/Engine.cs

@@ -441,7 +441,7 @@ namespace Regorus
             }
         }
 
-        private RegorusEngineHandle GetHandleForUse()
+        internal RegorusEngineHandle GetHandleForUse()
         {
             var handle = _handle;
             if (handle is null || handle.IsClosed || handle.IsInvalid)
@@ -451,7 +451,7 @@ namespace Regorus
             return handle;
         }
 
-        private void UseHandle(Action<IntPtr> action)
+        internal void UseHandle(Action<IntPtr> action)
         {
             UseHandle<object?>(handlePtr =>
             {
@@ -460,7 +460,7 @@ namespace Regorus
             });
         }
 
-        private T UseHandle<T>(Func<IntPtr, T> func)
+        internal T UseHandle<T>(Func<IntPtr, T> func)
         {
             var handle = GetHandleForUse();
             bool addedRef = false;
@@ -484,5 +484,10 @@ namespace Regorus
             }
         }
 
+        internal T UseHandleForInterop<T>(Func<IntPtr, T> func)
+        {
+            return UseHandle(func);
+        }
+
     }
 }

bindings/csharp/Regorus/NativeMethods.cs

@@ -26,6 +26,13 @@ namespace Regorus.Internal
         [DllImport(LibraryName, EntryPoint = "regorus_result_drop", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
         internal static extern void regorus_result_drop(RegorusResult result);
 
+        /// <summary>
+        /// Drop a RegorusBuffer.
+        /// data is not valid after drop.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_buffer_drop", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern void regorus_buffer_drop(RegorusBuffer* buffer);
+
         #endregion
 
         #region Memory Limit Methods
@@ -85,6 +92,12 @@ namespace Regorus.Internal
         [DllImport(LibraryName, EntryPoint = "regorus_engine_clone", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
         internal static extern RegorusEngine* regorus_engine_clone(RegorusEngine* engine);
 
+        /// <summary>
+        /// Compile an RVM program from the engine state with entry points.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_engine_compile_program_with_entrypoints", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_engine_compile_program_with_entrypoints(RegorusEngine* engine, byte** entryPoints, UIntPtr entryPointsLen);
+
         /// <summary>
         /// Drop a RegorusEngine.
         /// </summary>
@@ -92,6 +105,138 @@ namespace Regorus.Internal
         internal static extern void regorus_engine_drop(RegorusEngine* engine);
 
         /// <summary>
+
+        /// <summary>
+        /// Compile an RVM program from data/modules and entry points.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_program_compile_from_modules", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_program_compile_from_modules(byte* data_json, RegorusPolicyModule* modules, UIntPtr modules_len, byte** entry_points, UIntPtr entry_points_len);
+
+        /// <summary>
+        /// Construct a new empty program.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_program_new", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusProgram* regorus_program_new();
+
+        /// <summary>
+        /// Drop a program handle.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_program_drop", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern void regorus_program_drop(RegorusProgram* program);
+
+        /// <summary>
+        /// Serialize a program to binary format.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_program_serialize_binary", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_program_serialize_binary(RegorusProgram* program);
+
+        /// <summary>
+        /// Deserialize a program from binary format.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_program_deserialize_binary", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_program_deserialize_binary(byte* data, UIntPtr len, byte* is_partial);
+
+        /// <summary>
+        /// Generate a readable assembly listing for the program.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_program_generate_listing", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_program_generate_listing(RegorusProgram* program);
+
+        /// <summary>
+        /// Create a new RVM instance.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_new", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusRvm* regorus_rvm_new();
+
+        /// <summary>
+        /// Create a new RVM instance from a compiled policy.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_new_with_policy", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_new_with_policy(RegorusCompiledPolicy* compiled_policy);
+
+        /// <summary>
+        /// Drop an RVM instance.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_drop", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern void regorus_rvm_drop(RegorusRvm* vm);
+
+        /// <summary>
+        /// Load a program into the RVM.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_load_program", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_load_program(RegorusRvm* vm, RegorusProgram* program);
+
+        /// <summary>
+        /// Set the data document for the RVM.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_data", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_data(RegorusRvm* vm, byte* data_json);
+
+        /// <summary>
+        /// Set the input document for the RVM.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_input", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_input(RegorusRvm* vm, byte* input_json);
+
+        /// <summary>
+        /// Execute the program.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_execute", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_execute(RegorusRvm* vm);
+
+        /// <summary>
+        /// Execute an entry point by name.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_execute_entry_point_by_name", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_execute_entry_point_by_name(RegorusRvm* vm, byte* entry_point);
+
+        /// <summary>
+        /// Execute an entry point by index.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_execute_entry_point_by_index", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_execute_entry_point_by_index(RegorusRvm* vm, UIntPtr index);
+
+        /// <summary>
+        /// Resume execution.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_resume", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_resume(RegorusRvm* vm, byte* resume_value_json, [MarshalAs(UnmanagedType.I1)] bool has_value);
+
+        /// <summary>
+        /// Get the current execution state.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_get_execution_state", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_get_execution_state(RegorusRvm* vm);
+
+        /// <summary>
+        /// Set the maximum instruction limit.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_max_instructions", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_max_instructions(RegorusRvm* vm, UIntPtr max_instructions);
+
+        /// <summary>
+        /// Set strict builtin error handling.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_strict_builtin_errors", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_strict_builtin_errors(RegorusRvm* vm, [MarshalAs(UnmanagedType.I1)] bool strict);
+
+        /// <summary>
+        /// Set execution mode (0 run-to-completion, 1 suspendable).
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_execution_mode", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_execution_mode(RegorusRvm* vm, byte mode);
+
+        /// <summary>
+        /// Set step mode for suspendable execution.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_step_mode", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_step_mode(RegorusRvm* vm, [MarshalAs(UnmanagedType.I1)] bool enabled);
+
+        /// <summary>
+        /// Set execution timer configuration.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_execution_timer_config", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_execution_timer_config(RegorusRvm* vm, [MarshalAs(UnmanagedType.I1)] bool has_config, RegorusExecutionTimerConfig config);
         /// Add a policy.
         /// The policy is parsed into AST.
         /// See https://docs.rs/regorus/latest/regorus/struct.Engine.html#method.add_policy
@@ -617,6 +762,17 @@ namespace Regorus.Internal
         public uint check_interval;
     }
 
+    /// <summary>
+    /// Byte buffer returned from FFI.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    internal unsafe struct RegorusBuffer
+    {
+        public byte* data;
+        public UIntPtr len;
+        public UIntPtr capacity;
+    }
+
     /// <summary>
     /// Wrapper for regorus::Engine.
     /// </summary>
@@ -633,6 +789,22 @@ namespace Regorus.Internal
     {
     }
 
+    /// <summary>
+    /// Wrapper for regorus::rvm::Program.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    internal unsafe partial struct RegorusProgram
+    {
+    }
+
+    /// <summary>
+    /// Wrapper for regorus::rvm::RegoVM.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    internal unsafe partial struct RegorusRvm
+    {
+    }
+
     /// <summary>
     /// FFI wrapper for PolicyModule struct.
     /// </summary>

bindings/csharp/Regorus/Program.cs

@@ -0,0 +1,333 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+using Regorus.Internal;
+
+#nullable enable
+namespace Regorus
+{
+    /// <summary>
+    /// Represents a compiled RVM program.
+    /// </summary>
+    public unsafe sealed class Program : IDisposable
+    {
+        private RegorusProgramHandle? _handle;
+        private int _isDisposed;
+
+        private Program(RegorusProgramHandle handle)
+        {
+            _handle = handle ?? throw new ArgumentNullException(nameof(handle));
+        }
+
+        /// <summary>
+        /// Create an empty program.
+        /// </summary>
+        public static Program CreateEmpty()
+        {
+            return new Program(RegorusProgramHandle.Create());
+        }
+
+        /// <summary>
+        /// Compile an RVM program from modules and entry points.
+        /// </summary>
+        public static Program CompileFromModules(string dataJson, IEnumerable<PolicyModule> modules, IEnumerable<string> entryPoints)
+        {
+            var modulesArray = modules.ToArray();
+            var entryPointsArray = entryPoints.ToArray();
+            if (entryPointsArray.Length == 0)
+            {
+                throw new ArgumentException("At least one entry point is required.", nameof(entryPoints));
+            }
+
+            var nativeModules = new RegorusPolicyModule[modulesArray.Length];
+            var pinnedStrings = new List<Utf8Marshaller.PinnedUtf8>(modulesArray.Length * 2 + entryPointsArray.Length);
+            var entryPointers = new IntPtr[entryPointsArray.Length];
+
+            try
+            {
+                for (int i = 0; i < modulesArray.Length; i++)
+                {
+                    var idPinned = Utf8Marshaller.Pin(modulesArray[i].Id);
+                    var contentPinned = Utf8Marshaller.Pin(modulesArray[i].Content);
+                    pinnedStrings.Add(idPinned);
+                    pinnedStrings.Add(contentPinned);
+
+                    nativeModules[i] = new RegorusPolicyModule
+                    {
+                        id = idPinned.Pointer,
+                        content = contentPinned.Pointer
+                    };
+                }
+
+                for (int i = 0; i < entryPointsArray.Length; i++)
+                {
+                    var entryPinned = Utf8Marshaller.Pin(entryPointsArray[i]);
+                    pinnedStrings.Add(entryPinned);
+                    entryPointers[i] = (IntPtr)entryPinned.Pointer;
+                }
+
+                return Utf8Marshaller.WithUtf8(dataJson, dataPtr =>
+                {
+                    fixed (RegorusPolicyModule* modulesPtr = nativeModules)
+                    fixed (IntPtr* entryPtr = entryPointers)
+                    {
+                        var result = API.regorus_program_compile_from_modules(
+                            (byte*)dataPtr,
+                            modulesPtr,
+                            (UIntPtr)modulesArray.Length,
+                            (byte**)entryPtr,
+                            (UIntPtr)entryPointsArray.Length);
+
+                        return GetProgramResult(result);
+                    }
+                });
+            }
+            finally
+            {
+                foreach (var pinned in pinnedStrings)
+                {
+                    pinned.Dispose();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Compile an RVM program from an engine instance and entry points.
+        /// </summary>
+        public static Program CompileFromEngine(Engine engine, IEnumerable<string> entryPoints)
+        {
+            if (engine is null)
+            {
+                throw new ArgumentNullException(nameof(engine));
+            }
+
+            var entryPointsArray = entryPoints.ToArray();
+            if (entryPointsArray.Length == 0)
+            {
+                throw new ArgumentException("At least one entry point is required.", nameof(entryPoints));
+            }
+
+            var pinnedStrings = new List<Utf8Marshaller.PinnedUtf8>(entryPointsArray.Length);
+            var entryPointers = new IntPtr[entryPointsArray.Length];
+            try
+            {
+                for (int i = 0; i < entryPointsArray.Length; i++)
+                {
+                    var entryPinned = Utf8Marshaller.Pin(entryPointsArray[i]);
+                    pinnedStrings.Add(entryPinned);
+                    entryPointers[i] = (IntPtr)entryPinned.Pointer;
+                }
+
+                return engine.UseHandleForInterop(enginePtr =>
+                {
+                    fixed (IntPtr* entryPtr = entryPointers)
+                    {
+                        var result = API.regorus_engine_compile_program_with_entrypoints(
+                            (RegorusEngine*)enginePtr,
+                            (byte**)entryPtr,
+                            (UIntPtr)entryPointsArray.Length);
+
+                        return GetProgramResult(result);
+                    }
+                });
+            }
+            finally
+            {
+                foreach (var pinned in pinnedStrings)
+                {
+                    pinned.Dispose();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Deserialize an RVM program from binary format.
+        /// </summary>
+        public static Program DeserializeBinary(byte[] data, out bool isPartial)
+        {
+            if (data is null)
+            {
+                throw new ArgumentNullException(nameof(data));
+            }
+
+            byte partialFlag = 0;
+            fixed (byte* dataPtr = data)
+            {
+                var result = API.regorus_program_deserialize_binary(dataPtr, (UIntPtr)data.Length, &partialFlag);
+                var program = GetProgramResult(result);
+                isPartial = partialFlag != 0;
+                return program;
+            }
+        }
+
+        /// <summary>
+        /// Serialize the program to binary format.
+        /// </summary>
+        public byte[] SerializeBinary()
+        {
+            ThrowIfDisposed();
+            return UseHandle(programPtr =>
+            {
+                var result = API.regorus_program_serialize_binary((RegorusProgram*)programPtr);
+                return ExtractBuffer(result);
+            });
+        }
+
+        /// <summary>
+        /// Generate a readable assembly listing.
+        /// </summary>
+        public string? GenerateListing()
+        {
+            ThrowIfDisposed();
+            return UseHandle(programPtr =>
+            {
+                return CheckAndDropResult(API.regorus_program_generate_listing((RegorusProgram*)programPtr));
+            });
+        }
+
+        public void Dispose()
+        {
+            Dispose(disposing: true);
+            GC.SuppressFinalize(this);
+        }
+
+        private void Dispose(bool disposing)
+        {
+            if (System.Threading.Interlocked.CompareExchange(ref _isDisposed, 1, 0) == 0)
+            {
+                _handle?.Dispose();
+                _handle = null;
+            }
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (_isDisposed != 0 || _handle is null || _handle.IsClosed)
+            {
+                throw new ObjectDisposedException(nameof(Program));
+            }
+        }
+
+        internal RegorusProgramHandle GetHandleForUse()
+        {
+            var handle = _handle;
+            if (handle is null || handle.IsClosed || handle.IsInvalid)
+            {
+                throw new ObjectDisposedException(nameof(Program));
+            }
+            return handle;
+        }
+
+        internal T UseHandle<T>(Func<IntPtr, T> func)
+        {
+            var handle = GetHandleForUse();
+            bool addedRef = false;
+            try
+            {
+                handle.DangerousAddRef(ref addedRef);
+                var pointer = handle.DangerousGetHandle();
+                if (pointer == IntPtr.Zero)
+                {
+                    throw new ObjectDisposedException(nameof(Program));
+                }
+
+                return func(pointer);
+            }
+            finally
+            {
+                if (addedRef)
+                {
+                    handle.DangerousRelease();
+                }
+            }
+        }
+
+        private static Program GetProgramResult(RegorusResult result)
+        {
+            try
+            {
+                if (result.status != RegorusStatus.Ok)
+                {
+                    var message = Utf8Marshaller.FromUtf8(result.error_message);
+                    throw result.status.CreateException(message);
+                }
+
+                if (result.data_type != RegorusDataType.Pointer || result.pointer_value == null)
+                {
+                    throw new Exception("Expected program pointer but got different data type");
+                }
+
+                var handle = RegorusProgramHandle.FromPointer((IntPtr)result.pointer_value);
+                return new Program(handle);
+            }
+            finally
+            {
+                API.regorus_result_drop(result);
+            }
+        }
+
+        private static string? CheckAndDropResult(RegorusResult result)
+        {
+            try
+            {
+                if (result.status != RegorusStatus.Ok)
+                {
+                    var message = Utf8Marshaller.FromUtf8(result.error_message);
+                    throw result.status.CreateException(message);
+                }
+
+                return result.data_type switch
+                {
+                    RegorusDataType.String => Utf8Marshaller.FromUtf8(result.output),
+                    RegorusDataType.Boolean => result.bool_value.ToString().ToLowerInvariant(),
+                    RegorusDataType.Integer => result.int_value.ToString(),
+                    RegorusDataType.None => null,
+                    _ => Utf8Marshaller.FromUtf8(result.output)
+                };
+            }
+            finally
+            {
+                API.regorus_result_drop(result);
+            }
+        }
+
+        private static byte[] ExtractBuffer(RegorusResult result)
+        {
+            RegorusBuffer* buffer = null;
+            try
+            {
+                if (result.status != RegorusStatus.Ok)
+                {
+                    var message = Utf8Marshaller.FromUtf8(result.error_message);
+                    throw result.status.CreateException(message);
+                }
+
+                if (result.data_type != RegorusDataType.Pointer || result.pointer_value == null)
+                {
+                    throw new Exception("Expected buffer pointer but got different data type");
+                }
+
+                buffer = (RegorusBuffer*)result.pointer_value;
+                var length = checked((int)buffer->len);
+                var data = new byte[length];
+                if (length > 0)
+                {
+                    Marshal.Copy((IntPtr)buffer->data, data, 0, length);
+                }
+                return data;
+            }
+            finally
+            {
+                if (buffer != null)
+                {
+                    API.regorus_buffer_drop(buffer);
+                }
+                API.regorus_result_drop(result);
+            }
+        }
+    }
+}

bindings/csharp/Regorus/Rvm.cs

@@ -0,0 +1,292 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using Regorus.Internal;
+
+#nullable enable
+namespace Regorus
+{
+    /// <summary>
+    /// Wrapper for the Regorus RVM runtime.
+    /// </summary>
+    public unsafe sealed class Rvm : IDisposable
+    {
+        private RegorusRvmHandle? _handle;
+        private int _isDisposed;
+
+        public Rvm()
+        {
+            _handle = RegorusRvmHandle.Create();
+        }
+
+        private Rvm(RegorusRvmHandle handle)
+        {
+            _handle = handle ?? throw new ArgumentNullException(nameof(handle));
+        }
+
+        /// <summary>
+        /// Create an RVM instance backed by a compiled policy (for default rule evaluation).
+        /// </summary>
+        public static Rvm CreateWithPolicy(CompiledPolicy policy)
+        {
+            if (policy is null)
+            {
+                throw new ArgumentNullException(nameof(policy));
+            }
+
+            return policy.UseHandleForInterop(policyPtr =>
+            {
+                var result = API.regorus_rvm_new_with_policy((RegorusCompiledPolicy*)policyPtr);
+                return GetRvmResult(result);
+            });
+        }
+
+        /// <summary>
+        /// Load a program into the VM.
+        /// </summary>
+        public void LoadProgram(Program program)
+        {
+            ThrowIfDisposed();
+            if (program is null)
+            {
+                throw new ArgumentNullException(nameof(program));
+            }
+
+            program.UseHandle(programPtr =>
+            {
+                UseHandle(vmPtr =>
+                {
+                    CheckAndDropResult(API.regorus_rvm_load_program((RegorusRvm*)vmPtr, (RegorusProgram*)programPtr));
+                    return 0;
+                });
+                return 0;
+            });
+        }
+
+        /// <summary>
+        /// Set the data document for the VM.
+        /// </summary>
+        public void SetDataJson(string dataJson)
+        {
+            ThrowIfDisposed();
+            Utf8Marshaller.WithUtf8(dataJson, dataPtr =>
+            {
+                UseHandle(vmPtr =>
+                {
+                    CheckAndDropResult(API.regorus_rvm_set_data((RegorusRvm*)vmPtr, (byte*)dataPtr));
+                    return 0;
+                });
+            });
+        }
+
+        /// <summary>
+        /// Set the input document for the VM.
+        /// </summary>
+        public void SetInputJson(string inputJson)
+        {
+            ThrowIfDisposed();
+            Utf8Marshaller.WithUtf8(inputJson, inputPtr =>
+            {
+                UseHandle(vmPtr =>
+                {
+                    CheckAndDropResult(API.regorus_rvm_set_input((RegorusRvm*)vmPtr, (byte*)inputPtr));
+                    return 0;
+                });
+            });
+        }
+
+        /// <summary>
+        /// Set the execution mode (0 = run-to-completion, 1 = suspendable).
+        /// </summary>
+        public void SetExecutionMode(byte mode)
+        {
+            ThrowIfDisposed();
+            UseHandle(vmPtr =>
+            {
+                CheckAndDropResult(API.regorus_rvm_set_execution_mode((RegorusRvm*)vmPtr, mode));
+                return 0;
+            });
+        }
+
+        /// <summary>
+        /// Execute the program and return the JSON result.
+        /// </summary>
+        public string? Execute()
+        {
+            ThrowIfDisposed();
+            return UseHandle(vmPtr =>
+            {
+                return CheckAndDropResult(API.regorus_rvm_execute((RegorusRvm*)vmPtr));
+            });
+        }
+
+        /// <summary>
+        /// Execute a named entry point.
+        /// </summary>
+        public string? ExecuteEntryPoint(string entryPoint)
+        {
+            ThrowIfDisposed();
+            return Utf8Marshaller.WithUtf8(entryPoint, entryPtr =>
+            {
+                return UseHandle(vmPtr =>
+                {
+                    return CheckAndDropResult(API.regorus_rvm_execute_entry_point_by_name((RegorusRvm*)vmPtr, (byte*)entryPtr));
+                });
+            });
+        }
+
+        /// <summary>
+        /// Execute an entry point by index.
+        /// </summary>
+        public string? ExecuteEntryPoint(ulong index)
+        {
+            ThrowIfDisposed();
+            return UseHandle(vmPtr =>
+            {
+                return CheckAndDropResult(API.regorus_rvm_execute_entry_point_by_index((RegorusRvm*)vmPtr, (UIntPtr)index));
+            });
+        }
+
+        /// <summary>
+        /// Resume execution with an optional value.
+        /// </summary>
+        public string? Resume(string? resumeValueJson)
+        {
+            ThrowIfDisposed();
+            if (resumeValueJson is null)
+            {
+                return UseHandle(vmPtr =>
+                {
+                    return CheckAndDropResult(API.regorus_rvm_resume((RegorusRvm*)vmPtr, null, has_value: false));
+                });
+            }
+
+            return Utf8Marshaller.WithUtf8(resumeValueJson, valuePtr =>
+            {
+                return UseHandle(vmPtr =>
+                {
+                    return CheckAndDropResult(API.regorus_rvm_resume((RegorusRvm*)vmPtr, (byte*)valuePtr, has_value: true));
+                });
+            });
+        }
+
+        /// <summary>
+        /// Get the current execution state.
+        /// </summary>
+        public string? GetExecutionState()
+        {
+            ThrowIfDisposed();
+            return UseHandle(vmPtr =>
+            {
+                return CheckAndDropResult(API.regorus_rvm_get_execution_state((RegorusRvm*)vmPtr));
+            });
+        }
+
+        public void Dispose()
+        {
+            Dispose(disposing: true);
+            GC.SuppressFinalize(this);
+        }
+
+        private void Dispose(bool disposing)
+        {
+            if (System.Threading.Interlocked.CompareExchange(ref _isDisposed, 1, 0) == 0)
+            {
+                _handle?.Dispose();
+                _handle = null;
+            }
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (_isDisposed != 0 || _handle is null || _handle.IsClosed)
+            {
+                throw new ObjectDisposedException(nameof(Rvm));
+            }
+        }
+
+        internal RegorusRvmHandle GetHandleForUse()
+        {
+            var handle = _handle;
+            if (handle is null || handle.IsClosed || handle.IsInvalid)
+            {
+                throw new ObjectDisposedException(nameof(Rvm));
+            }
+            return handle;
+        }
+
+        internal T UseHandle<T>(Func<IntPtr, T> func)
+        {
+            var handle = GetHandleForUse();
+            bool addedRef = false;
+            try
+            {
+                handle.DangerousAddRef(ref addedRef);
+                var pointer = handle.DangerousGetHandle();
+                if (pointer == IntPtr.Zero)
+                {
+                    throw new ObjectDisposedException(nameof(Rvm));
+                }
+
+                return func(pointer);
+            }
+            finally
+            {
+                if (addedRef)
+                {
+                    handle.DangerousRelease();
+                }
+            }
+        }
+
+        private static Rvm GetRvmResult(RegorusResult result)
+        {
+            try
+            {
+                if (result.status != RegorusStatus.Ok)
+                {
+                    var message = Utf8Marshaller.FromUtf8(result.error_message);
+                    throw result.status.CreateException(message);
+                }
+
+                if (result.data_type != RegorusDataType.Pointer || result.pointer_value == null)
+                {
+                    throw new Exception("Expected RVM pointer but got different data type");
+                }
+
+                var handle = RegorusRvmHandle.FromPointer((IntPtr)result.pointer_value);
+                return new Rvm(handle);
+            }
+            finally
+            {
+                API.regorus_result_drop(result);
+            }
+        }
+
+        private static string? CheckAndDropResult(RegorusResult result)
+        {
+            try
+            {
+                if (result.status != RegorusStatus.Ok)
+                {
+                    var message = Utf8Marshaller.FromUtf8(result.error_message);
+                    throw result.status.CreateException(message);
+                }
+
+                return result.data_type switch
+                {
+                    RegorusDataType.String => Utf8Marshaller.FromUtf8(result.output),
+                    RegorusDataType.Boolean => result.bool_value.ToString().ToLowerInvariant(),
+                    RegorusDataType.Integer => result.int_value.ToString(),
+                    RegorusDataType.None => null,
+                    _ => Utf8Marshaller.FromUtf8(result.output)
+                };
+            }
+            finally
+            {
+                API.regorus_result_drop(result);
+            }
+        }
+    }
+}

bindings/csharp/Regorus/SafeHandles.cs

@@ -87,4 +87,100 @@ namespace Regorus
             return true;
         }
     }
+
+    internal sealed class RegorusProgramHandle : SafeHandleZeroOrMinusOneIsInvalid
+    {
+        private RegorusProgramHandle() : base(ownsHandle: true)
+        {
+        }
+
+        internal static RegorusProgramHandle Create()
+        {
+            unsafe
+            {
+                var raw = Internal.API.regorus_program_new();
+                if (raw is null)
+                {
+                    throw new InvalidOperationException("Failed to create Regorus program.");
+                }
+
+                var handle = new RegorusProgramHandle();
+                handle.SetHandle((IntPtr)raw);
+                return handle;
+            }
+        }
+
+        internal static RegorusProgramHandle FromPointer(IntPtr pointer)
+        {
+            if (pointer == IntPtr.Zero)
+            {
+                throw new ArgumentException("Pointer cannot be zero.", nameof(pointer));
+            }
+
+            var handle = new RegorusProgramHandle();
+            handle.SetHandle(pointer);
+            return handle;
+        }
+
+        protected override bool ReleaseHandle()
+        {
+            if (!IsInvalid && !IsClosed)
+            {
+                unsafe
+                {
+                    Internal.API.regorus_program_drop((Internal.RegorusProgram*)handle);
+                }
+                SetHandle(IntPtr.Zero);
+            }
+            return true;
+        }
+    }
+
+    internal sealed class RegorusRvmHandle : SafeHandleZeroOrMinusOneIsInvalid
+    {
+        private RegorusRvmHandle() : base(ownsHandle: true)
+        {
+        }
+
+        internal static RegorusRvmHandle Create()
+        {
+            unsafe
+            {
+                var raw = Internal.API.regorus_rvm_new();
+                if (raw is null)
+                {
+                    throw new InvalidOperationException("Failed to create Regorus RVM.");
+                }
+
+                var handle = new RegorusRvmHandle();
+                handle.SetHandle((IntPtr)raw);
+                return handle;
+            }
+        }
+
+        internal static RegorusRvmHandle FromPointer(IntPtr pointer)
+        {
+            if (pointer == IntPtr.Zero)
+            {
+                throw new ArgumentException("Pointer cannot be zero.", nameof(pointer));
+            }
+
+            var handle = new RegorusRvmHandle();
+            handle.SetHandle(pointer);
+            return handle;
+        }
+
+        protected override bool ReleaseHandle()
+        {
+            if (!IsInvalid && !IsClosed)
+            {
+                unsafe
+                {
+                    Internal.API.regorus_rvm_drop((Internal.RegorusRvm*)handle);
+                }
+                SetHandle(IntPtr.Zero);
+            }
+            return true;
+        }
+    }
 }

bindings/csharp/TargetExampleApp/Program.cs

@@ -65,6 +65,55 @@ triplet_count := count([1 |
     private const string EXECUTION_TIMER_QUERY = "data.limits.timer.triplet_count";
     private const int EXECUTION_TIMER_VALUE_COUNT = 40;
 
+        private const string RVM_POLICY = """
+package demo
+import rego.v1
+
+default allow := false
+
+allow if {
+        input.user == "alice"
+        some role in data.roles[input.user]
+        role == "admin"
+}
+""";
+
+        private const string RVM_DATA = """
+{
+    "roles": {
+        "alice": ["admin", "reader"]
+    }
+}
+""";
+
+        private const string RVM_INPUT = """
+{
+    "user": "alice"
+}
+""";
+
+        private const string HOST_AWAIT_POLICY = """
+package demo
+import rego.v1
+
+default allow := false
+
+allow if {
+    input.account.active == true
+    details := __builtin_host_await(input.account.id, "account")
+    details.tier == "gold"
+}
+""";
+
+        private const string HOST_AWAIT_INPUT = """
+    {
+        "account": {
+            "id": "acct-1",
+            "active": true
+        }
+    }
+    """;
+
     // Test data constants
     private const string COMPLIANT_STORAGE_ACCOUNT = @"{
   ""type"": ""Microsoft.Storage/storageAccounts"",
@@ -174,6 +223,15 @@ triplet_count := count([1 |
 
         Console.WriteLine("\n5. Execution timer configuration:");
         DemonstrateExecutionTimer();
+
+        Console.WriteLine("\n6. RVM program execution:");
+        DemonstrateRvmUsage();
+
+        Console.WriteLine("\n7. RVM program compilation from engine:");
+        DemonstrateRvmCompileFromEngine();
+
+        Console.WriteLine("\n8. RVM host await (suspend/resume):");
+        DemonstrateRvmHostAwait();
     }
 
     static void DemonstrateConcurrentEvaluation(Regorus.CompiledPolicy compiledPolicy)
@@ -359,4 +417,77 @@ triplet_count := count([1 |
             Regorus.Engine.ClearFallbackExecutionTimerConfig();
         }
     }
+
+    static void DemonstrateRvmUsage()
+    {
+        var modules = new List<Regorus.PolicyModule>
+        {
+            new Regorus.PolicyModule("demo.rego", RVM_POLICY)
+        };
+        var entryPoints = new[] { "data.demo.allow" };
+
+        using var program = Regorus.Program.CompileFromModules(RVM_DATA, modules, entryPoints);
+        var binary = program.SerializeBinary();
+        using var rehydrated = Regorus.Program.DeserializeBinary(binary, out var isPartial);
+        if (isPartial)
+        {
+            throw new InvalidOperationException("RVM program deserialization returned a partial program.");
+        }
+
+        Console.WriteLine($"Serialized program size: {binary.Length} bytes");
+
+        var listing = rehydrated.GenerateListing();
+
+        Console.WriteLine("RVM listing:");
+        Console.WriteLine(listing);
+
+        using var vm = new Regorus.Rvm();
+        vm.LoadProgram(rehydrated);
+        vm.SetDataJson(RVM_DATA);
+        vm.SetInputJson(RVM_INPUT);
+
+        var result = vm.Execute();
+        Console.WriteLine($"RVM result: {result}");
+    }
+
+    static void DemonstrateRvmCompileFromEngine()
+    {
+        using var engine = new Regorus.Engine();
+        engine.AddPolicy("demo.rego", RVM_POLICY);
+        engine.AddDataJson(RVM_DATA);
+
+        var entryPoints = new[] { "data.demo.allow" };
+        using var program = Regorus.Program.CompileFromEngine(engine, entryPoints);
+
+        using var vm = new Regorus.Rvm();
+        vm.LoadProgram(program);
+        vm.SetDataJson(RVM_DATA);
+        vm.SetInputJson(RVM_INPUT);
+
+        var result = vm.ExecuteEntryPoint("data.demo.allow");
+        Console.WriteLine($"RVM result from engine-compiled program: {result}");
+    }
+
+    static void DemonstrateRvmHostAwait()
+    {
+        var modules = new List<Regorus.PolicyModule>
+        {
+            new Regorus.PolicyModule("host_await.rego", HOST_AWAIT_POLICY)
+        };
+        var entryPoints = new[] { "data.demo.allow" };
+
+        using var program = Regorus.Program.CompileFromModules("{}", modules, entryPoints);
+        using var vm = new Regorus.Rvm();
+        vm.SetExecutionMode(1);
+        vm.LoadProgram(program);
+        vm.SetInputJson(HOST_AWAIT_INPUT);
+
+        var initial = vm.Execute();
+        var state = vm.GetExecutionState();
+        Console.WriteLine($"HostAwait initial result: {initial}");
+        Console.WriteLine($"Execution state: {state}");
+
+        var resumed = vm.Resume("{\"tier\":\"gold\"}");
+        Console.WriteLine($"HostAwait resumed result: {resumed}");
+    }
 }