Support memory aliasing (#2954)

* Back to the origins: Make memory manager take guest PA rather than host address once again

* Direct mapping with alias support on Windows

* Fixes and remove more of the emulated shared memory

* Linux support

* Make shared and transfer memory not depend on SharedMemoryStorage

* More efficient view mapping on Windows (no more restricted to 4KB pages at a time)

* Handle potential access violations caused by partial unmap

* Implement host mapping using shared memory on Linux

* Add new GetPhysicalAddressChecked method, used to ensure the virtual address is mapped before address translation

Also align GetRef behaviour with software memory manager

* We don't need a mirrorable memory block for software memory manager mode

* Disable memory aliasing tests while we don't have shared memory support on Mac

* Shared memory & SIGBUS handler for macOS

* Fix typo + nits + re-enable memory tests

* Set MAP_JIT_DARWIN on x86 Mac too

* Add back the address space mirror

* Only set MAP_JIT_DARWIN if we are mapping as executable

* Disable aliasing tests again (still fails on Mac)

* Fix UnmapView4KB (by not casting size to int)

* Use ref counting on memory blocks to delay closing the shared memory handle until all blocks using it are disposed

* Address PR feedback

* Make RO hold a reference to the guest process memory manager to avoid early disposal

Co-authored-by: nastys <nastys@users.noreply.github.com>

ARMeilleure/Signal/NativeSignalHandler.cs

@@ -103,7 +103,7 @@ namespace ARMeilleure.Signal
                     // Unix siginfo struct locations.
                     // NOTE: These are incredibly likely to be different between kernel version and architectures.
 
-                    config.StructAddressOffset = 16; // si_addr
+                    config.StructAddressOffset = OperatingSystem.IsMacOS() ? 24 : 16; // si_addr
                     config.StructWriteOffset = 8; // si_code
 
                     _signalHandlerPtr = Marshal.GetFunctionPointerForDelegate(GenerateUnixSignalHandler(_handlerConfig));

ARMeilleure/Signal/UnixSignalHandlerRegistration.cs

@@ -21,6 +21,7 @@ namespace ARMeilleure.Signal
     static class UnixSignalHandlerRegistration
     {
         private const int SIGSEGV = 11;
+        private const int SIGBUS = 10;
         private const int SA_SIGINFO = 0x00000004;
 
         [DllImport("libc", SetLastError = true)]
@@ -43,7 +44,17 @@ namespace ARMeilleure.Signal
 
             if (result != 0)
             {
-                throw new InvalidOperationException($"Could not register sigaction. Error: {result}");
+                throw new InvalidOperationException($"Could not register SIGSEGV sigaction. Error: {result}");
+            }
+
+            if (OperatingSystem.IsMacOS())
+            {
+                result = sigaction(SIGBUS, ref sig, out SigAction oldb);
+
+                if (result != 0)
+                {
+                    throw new InvalidOperationException($"Could not register SIGBUS sigaction. Error: {result}");
+                }
             }
 
             return old;
@@ -51,7 +62,7 @@ namespace ARMeilleure.Signal
 
         public static bool RestoreExceptionHandler(SigAction oldAction)
         {
-            return sigaction(SIGSEGV, ref oldAction, out SigAction _) == 0;
+            return sigaction(SIGSEGV, ref oldAction, out SigAction _) == 0 && (!OperatingSystem.IsMacOS() || sigaction(SIGBUS, ref oldAction, out SigAction _) == 0);
         }
     }
 }

ARMeilleure/Translation/IntervalTree.cs

@@ -8,7 +8,7 @@ namespace ARMeilleure.Translation
     /// </summary>
     /// <typeparam name="K">Key</typeparam>
     /// <typeparam name="V">Value</typeparam>
-    public class IntervalTree<K, V> where K : IComparable<K>
+    class IntervalTree<K, V> where K : IComparable<K>
     {
         private const int ArrayGrowthSize = 32;
 
@@ -53,7 +53,7 @@ namespace ARMeilleure.Translation
         /// <returns>Number of intervals found</returns>
         public int Get(K start, K end, ref K[] overlaps, int overlapCount = 0)
         {
-            GetValues(_root, start, end, ref overlaps, ref overlapCount);
+            GetKeys(_root, start, end, ref overlaps, ref overlapCount);
 
             return overlapCount;
         }
@@ -180,20 +180,20 @@ namespace ARMeilleure.Translation
         }
 
         /// <summary>
-        /// Retrieve all values that overlap the given start and end keys.
+        /// Retrieve all keys that overlap the given start and end keys.
         /// </summary>
         /// <param name="start">Start of the range</param>
         /// <param name="end">End of the range</param>
         /// <param name="overlaps">Overlaps array to place results in</param>
         /// <param name="overlapCount">Overlaps count to update</param>
-        private void GetValues(IntervalTreeNode<K, V> node, K start, K end, ref K[] overlaps, ref int overlapCount)
+        private void GetKeys(IntervalTreeNode<K, V> node, K start, K end, ref K[] overlaps, ref int overlapCount)
         {
             if (node == null || start.CompareTo(node.Max) >= 0)
             {
                 return;
             }
 
-            GetValues(node.Left, start, end, ref overlaps, ref overlapCount);
+            GetKeys(node.Left, start, end, ref overlaps, ref overlapCount);
 
             bool endsOnRight = end.CompareTo(node.Start) > 0;
             if (endsOnRight)
@@ -208,7 +208,7 @@ namespace ARMeilleure.Translation
                     overlaps[overlapCount++] = node.Start;
                 }
 
-                GetValues(node.Right, start, end, ref overlaps, ref overlapCount);
+                GetKeys(node.Right, start, end, ref overlaps, ref overlapCount);
             }
         }
 
@@ -717,40 +717,40 @@ namespace ARMeilleure.Translation
     /// </summary>
     /// <typeparam name="K">Key type of the node</typeparam>
     /// <typeparam name="V">Value type of the node</typeparam>
-    internal class IntervalTreeNode<K, V>
+    class IntervalTreeNode<K, V>
     {
-        internal bool Color = true;
-        internal IntervalTreeNode<K, V> Left = null;
-        internal IntervalTreeNode<K, V> Right = null;
-        internal IntervalTreeNode<K, V> Parent = null;
+        public bool Color = true;
+        public IntervalTreeNode<K, V> Left = null;
+        public IntervalTreeNode<K, V> Right = null;
+        public IntervalTreeNode<K, V> Parent = null;
 
         /// <summary>
         /// The start of the range.
         /// </summary>
-        internal K Start;
+        public K Start;
 
         /// <summary>
         /// The end of the range.
         /// </summary>
-        internal K End;
+        public K End;
 
         /// <summary>
         /// The maximum end value of this node and all its children.
         /// </summary>
-        internal K Max;
+        public K Max;
 
         /// <summary>
         /// Value stored on this node.
         /// </summary>
-        internal V Value;
+        public V Value;
 
         public IntervalTreeNode(K start, K end, V value, IntervalTreeNode<K, V> parent)
         {
-            this.Start = start;
-            this.End = end;
-            this.Max = end;
-            this.Value = value;
-            this.Parent = parent;
+            Start = start;
+            End = end;
+            Max = end;
+            Value = value;
+            Parent = parent;
         }
     }
 }