[cpu] made guest image cpu sync opt-in

src/SharpEmu.GUI/MainWindow.axaml.cs

@@ -242,7 +242,9 @@ public partial class MainWindow : Window
         EnvLogNpToggle.IsCheckedChanged += (_, _) =>
             SetEnvironmentToggle("SHARPEMU_LOG_NP", EnvLogNpToggle.IsChecked == true);
         EnvGuestImageCpuSyncToggle.IsCheckedChanged += (_, _) =>
-            SetGuestImageCpuSync(EnvGuestImageCpuSyncToggle.IsChecked == true);
+            SetEnvironmentToggle(
+                "SHARPEMU_GUEST_IMAGE_CPU_SYNC",
+                EnvGuestImageCpuSyncToggle.IsChecked == true);
         LanguageBox.SelectionChanged += (_, _) => OnLanguageChanged();
 
         GameList.AddHandler(ContextRequestedEvent, OnGameContextRequested, RoutingStrategies.Tunnel);
@@ -853,10 +855,8 @@ public partial class MainWindow : Window
         EnvLogDirectMemoryToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_LOG_DIRECT_MEMORY");
         EnvLogIoToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_LOG_IO");
         EnvLogNpToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_LOG_NP");
-        EnvGuestImageCpuSyncToggle.IsChecked = IsEnvironmentEnabled(
+        EnvGuestImageCpuSyncToggle.IsChecked =
-            _settings.EnvironmentToggles,
+            _settings.EnvironmentToggles.Contains("SHARPEMU_GUEST_IMAGE_CPU_SYNC");
-            "SHARPEMU_GUEST_IMAGE_CPU_SYNC",
-            defaultValue: true);
         WindowModeBox.SelectedIndex = ChoiceIndex(_settings.WindowMode, "Windowed", "Borderless", "Exclusive");
         LoadHostDisplayOptions();
         ScalingModeBox.SelectedIndex = ChoiceIndex(_settings.ScalingMode, "Fit", "Cover", "Stretch", "Integer");
@@ -1083,40 +1083,6 @@ public partial class MainWindow : Window
         }
     }
 
-    private void SetGuestImageCpuSync(bool enabled)
-    {
-        const string name = "SHARPEMU_GUEST_IMAGE_CPU_SYNC";
-        _settings.EnvironmentToggles.RemoveAll(entry =>
-            string.Equals(entry, name, StringComparison.OrdinalIgnoreCase) ||
-            string.Equals(entry, name + "=0", StringComparison.OrdinalIgnoreCase));
-        if (!enabled)
-        {
-            _settings.EnvironmentToggles.Add(name + "=0");
-        }
-    }
-
-    private static bool IsEnvironmentEnabled(
-        IEnumerable<string> entries,
-        string name,
-        bool defaultValue)
-    {
-        foreach (var entry in entries)
-        {
-            if (string.Equals(entry, name + "=0", StringComparison.OrdinalIgnoreCase))
-            {
-                return false;
-            }
-
-            if (string.Equals(entry, name, StringComparison.OrdinalIgnoreCase) ||
-                string.Equals(entry, name + "=1", StringComparison.OrdinalIgnoreCase))
-            {
-                return true;
-            }
-        }
-
-        return defaultValue;
-    }
-
     private string SelectedLogLevel()
     {
         return LogLevelBox.SelectedIndex switch

src/SharpEmu.GUI/PerGameSettingsDialog.cs

@@ -241,7 +241,7 @@ public sealed class PerGameSettingsDialog : Window
         _hdrMode.SelectedItem = ChoiceOrDefault(HdrModes, global.HdrMode, "Auto");
         foreach (var (name, box) in _envBoxes)
         {
-            box.IsChecked = IsEnvironmentEnabled(global.EnvironmentToggles, name, defaultValue: name == "SHARPEMU_GUEST_IMAGE_CPU_SYNC");
+            box.IsChecked = IsEnvironmentEnabled(global.EnvironmentToggles, name, defaultValue: false);
         }
 
         if (existing is null)
@@ -295,7 +295,7 @@ public sealed class PerGameSettingsDialog : Window
             _envRow.IsOverridden = true;
             foreach (var (name, box) in _envBoxes)
             {
-                box.IsChecked = IsEnvironmentEnabled(env, name, defaultValue: name == "SHARPEMU_GUEST_IMAGE_CPU_SYNC");
+                box.IsChecked = IsEnvironmentEnabled(env, name, defaultValue: false);
             }
         }
     }
@@ -396,17 +396,10 @@ public sealed class PerGameSettingsDialog : Window
 
     private List<string> BuildEnvironmentEntries()
     {
-        const string guestImageCpuSync = "SHARPEMU_GUEST_IMAGE_CPU_SYNC";
+        return _envBoxes
-        var entries = _envBoxes
+            .Where(entry => entry.Box.IsChecked == true)
-            .Where(entry => entry.Name != guestImageCpuSync && entry.Box.IsChecked == true)
             .Select(entry => entry.Name)
             .ToList();
-        if (_envBoxes.First(entry => entry.Name == guestImageCpuSync).Box.IsChecked != true)
-        {
-            entries.Add(guestImageCpuSync + "=0");
-        }
-
-        return entries;
     }
 
     private static bool IsEnvironmentEnabled(

src/SharpEmu.HLE/GuestImageWriteTracker.cs

@@ -87,13 +87,10 @@ public static unsafe class GuestImageWriteTracker
 
     private static RangeSnapshot _rangeSnapshot = RangeSnapshot.Empty;
 
-    // CPU-written guest image synchronization is the compatible default. A few
-    // titles (currently GTA V) require the lower-overhead watch-only path and
-    // opt out explicitly with SHARPEMU_GUEST_IMAGE_CPU_SYNC=0.
     private static readonly bool _enabled =
-        !string.Equals(
+        string.Equals(
             Environment.GetEnvironmentVariable("SHARPEMU_GUEST_IMAGE_CPU_SYNC"),
-            "0",
+            "1",
             StringComparison.Ordinal);
     private static readonly (bool Wildcard, ulong[] Addresses) _lifetimeTraceFilter =
         ParseAddressList(Environment.GetEnvironmentVariable("SHARPEMU_TRACE_GUEST_IMAGE_ADDRS"));