From 8f7fa3933fd11e6a017cbc113f176ea866247ce2 Mon Sep 17 00:00:00 2001
From: ParantezTech <12572227+par274@users.noreply.github.com>
Date: Sun, 11 Oct 2026 01:40:16 +0300
Subject: [PATCH] [HLE] Write single-view guest memory without the region lock

---
 .../Memory/PhysicalVirtualMemory.cs            |  7 +++++++
 .../GuestMemory/GuestSpaceOwner.cs             |  2 ++
 .../GuestMemory/SharedBackingViews.cs          | 18 ++++++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/src/SharpEmu.Core/Memory/PhysicalVirtualMemory.cs b/src/SharpEmu.Core/Memory/PhysicalVirtualMemory.cs
index fe3b026..ea343fd 100644
--- a/src/SharpEmu.Core/Memory/PhysicalVirtualMemory.cs
+++ b/src/SharpEmu.Core/Memory/PhysicalVirtualMemory.cs
@@ -2070,6 +2070,13 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
         GuestImageWriteTracker.NotifyManagedWrite(virtualAddress, (ulong)source.Length);
         GuestGpuMemoryHook.MarkCpuWrite(virtualAddress, (ulong)source.Length);
 
+        if (!source.IsEmpty && _backedSpace is { } backed && !_disposed &&
+            backed.TryWriteSingleView(virtualAddress, source))
+        {
+            NotifyGuestWriteWatch(virtualAddress, source);
+            return true;
+        }
+
         var requiresExclusiveAccess = false;
         _gate.EnterReadLock();
         try
diff --git a/src/SharpEmu.HLE/GuestMemory/GuestSpaceOwner.cs b/src/SharpEmu.HLE/GuestMemory/GuestSpaceOwner.cs
index 2b44b28..1387921 100644
--- a/src/SharpEmu.HLE/GuestMemory/GuestSpaceOwner.cs
+++ b/src/SharpEmu.HLE/GuestMemory/GuestSpaceOwner.cs
@@ -67,6 +67,8 @@ public sealed class GuestSpaceOwner : IDisposable
     // Reads through a view that covers the whole range without any lock; false otherwise.
     public bool TryReadSingleView(ulong address, Span<byte> data) => _views.TryReadSingleView(address, data);
 
+    public bool TryWriteSingleView(ulong address, ReadOnlySpan<byte> data) => _views.TryWriteSingleView(address, data);
+
     public object AliasSnapshot => _views.AliasSnapshot;
 
     public bool TryEnterAliasAccess() => _views.TryEnterAliasAccess();
diff --git a/src/SharpEmu.HLE/GuestMemory/SharedBackingViews.cs b/src/SharpEmu.HLE/GuestMemory/SharedBackingViews.cs
index 43be043..1698426 100644
--- a/src/SharpEmu.HLE/GuestMemory/SharedBackingViews.cs
+++ b/src/SharpEmu.HLE/GuestMemory/SharedBackingViews.cs
@@ -118,6 +118,24 @@ public sealed unsafe class SharedBackingViews : IDisposable
         }
     }
 
+    public bool TryWriteSingleView(ulong address, ReadOnlySpan<byte> data)
+    {
+        if (!TryAccessSingleView(address, (ulong)data.Length, out var target))
+        {
+            return false;
+        }
+
+        try
+        {
+            data.CopyTo(new Span<byte>((void*)target, data.Length));
+            return true;
+        }
+        finally
+        {
+            Interlocked.Decrement(ref _activeAccesses);
+        }
+    }
+
     public bool TryReadBacking(ulong address, Span<byte> data)
     {
         if (TryAccessSingleView(address, (ulong)data.Length, out var source))