From 7b5bfb07433f1f8a172db13f92a41de13638888f Mon Sep 17 00:00:00 2001
From: MaranBr <maranbr@outlook.com>
Date: Tue, 26 Aug 2025 17:18:14 -0400
Subject: [PATCH] Add an option to control Host MMU Emulation

---
 src/common/settings.cpp                       | 3 +++
 src/common/settings.h                         | 9 +++++++++
 src/core/arm/dynarmic/arm_dynarmic_32.cpp     | 4 ++++
 src/core/arm/dynarmic/arm_dynarmic_64.cpp     | 4 ++++
 src/yuzu/configuration/shared_translation.cpp | 2 ++
 5 files changed, 22 insertions(+)

diff --git a/src/common/settings.cpp b/src/common/settings.cpp
index 63d46722ea..105e1510f5 100644
--- a/src/common/settings.cpp
+++ b/src/common/settings.cpp
@@ -158,6 +158,9 @@ bool IsFastmemEnabled() {
     if (values.cpu_debug_mode) {
         return static_cast<bool>(values.cpuopt_fastmem);
     }
+    if (Settings::values.cpu_accuracy.GetValue() == Settings::CpuAccuracy::Unsafe) {
+        return static_cast<bool>(values.cpuopt_unsafe_mmu);
+    }
     return true;
 }
 
diff --git a/src/common/settings.h b/src/common/settings.h
index b846f41318..c503707fd5 100644
--- a/src/common/settings.h
+++ b/src/common/settings.h
@@ -299,6 +299,15 @@ struct Values {
                                               Category::CpuDebug};
     Setting<bool> cpuopt_ignore_memory_aborts{linkage, true, "cpuopt_ignore_memory_aborts",
                                               Category::CpuDebug};
+
+    SwitchableSetting<bool> cpuopt_unsafe_mmu{linkage,
+#if defined(_WIN32) || defined(__linux__) || defined(__ANDROID__)
+                                        true,
+#else
+                                        false,
+#endif
+                                        "cpuopt_unsafe_mmu",
+                                        Category::CpuUnsafe};
     SwitchableSetting<bool> cpuopt_unsafe_unfuse_fma{linkage, true, "cpuopt_unsafe_unfuse_fma",
                                                      Category::CpuUnsafe};
     SwitchableSetting<bool> cpuopt_unsafe_reduce_fp_error{
diff --git a/src/core/arm/dynarmic/arm_dynarmic_32.cpp b/src/core/arm/dynarmic/arm_dynarmic_32.cpp
index db159388bf..fbc195d3f3 100644
--- a/src/core/arm/dynarmic/arm_dynarmic_32.cpp
+++ b/src/core/arm/dynarmic/arm_dynarmic_32.cpp
@@ -272,6 +272,10 @@ std::shared_ptr<Dynarmic::A32::Jit> ArmDynarmic32::MakeJit(Common::PageTable* pa
         // Unsafe optimizations
         if (Settings::values.cpu_accuracy.GetValue() == Settings::CpuAccuracy::Unsafe) {
             config.unsafe_optimizations = true;
+            if (!Settings::values.cpuopt_unsafe_mmu) {
+                config.fastmem_pointer = nullptr;
+                config.fastmem_exclusive_access = false;
+            }
             if (Settings::values.cpuopt_unsafe_unfuse_fma) {
                 config.optimizations |= Dynarmic::OptimizationFlag::Unsafe_UnfuseFMA;
             }
diff --git a/src/core/arm/dynarmic/arm_dynarmic_64.cpp b/src/core/arm/dynarmic/arm_dynarmic_64.cpp
index dcff0ddf3f..fa50b36d01 100644
--- a/src/core/arm/dynarmic/arm_dynarmic_64.cpp
+++ b/src/core/arm/dynarmic/arm_dynarmic_64.cpp
@@ -330,6 +330,10 @@ std::shared_ptr<Dynarmic::A64::Jit> ArmDynarmic64::MakeJit(Common::PageTable* pa
         // Unsafe optimizations
         if (Settings::values.cpu_accuracy.GetValue() == Settings::CpuAccuracy::Unsafe) {
             config.unsafe_optimizations = true;
+            if (!Settings::values.cpuopt_unsafe_mmu) {
+                config.fastmem_pointer = nullptr;
+                config.fastmem_exclusive_access = false;
+            }
             if (Settings::values.cpuopt_unsafe_unfuse_fma) {
                 config.optimizations |= Dynarmic::OptimizationFlag::Unsafe_UnfuseFMA;
             }
diff --git a/src/yuzu/configuration/shared_translation.cpp b/src/yuzu/configuration/shared_translation.cpp
index f6d590c0ee..61a1881b67 100644
--- a/src/yuzu/configuration/shared_translation.cpp
+++ b/src/yuzu/configuration/shared_translation.cpp
@@ -118,6 +118,8 @@ std::unique_ptr<TranslationMap> InitializeTranslations(QWidget* parent)
     // Cpu Debug
 
     // Cpu Unsafe
+    INSERT(Settings, cpuopt_unsafe_mmu, tr("Enable Host MMU Emulation"),
+           tr("This optimization speeds up memory accesses by the guest program.\nEnabling it causes guest memory reads/writes to be done directly into memory and make use of Host's MMU.\nDisabling this forces all memory accesses to use Software MMU Emulation."));
     INSERT(
         Settings,
         cpuopt_unsafe_unfuse_fma,