Add Windows-only support for a shared memory mapping on Kernel & User…

… Memory

src/core/psxemulator.h

@@ -167,6 +167,7 @@ class Emulator {
     typedef Setting<bool, TYPESTRING("Mcd2Inserted"), true> SettingMcd2Inserted;
     typedef Setting<bool, TYPESTRING("Dynarec"), true> SettingDynarec;
     typedef Setting<bool, TYPESTRING("8Megs"), false> Setting8MB;
+    typedef Setting<bool, TYPESTRING("SharedMemoryMap"), false> SettingSharedMemoryMap;
     typedef Setting<int, TYPESTRING("GUITheme"), 0> SettingGUITheme;
     typedef Setting<int, TYPESTRING("Dither"), 1> SettingDither;
     typedef Setting<bool, TYPESTRING("UseCachedDithering"), false> SettingCachedDithering;
@@ -188,8 +189,8 @@ class Emulator {
 
     Settings<SettingMcd1, SettingMcd2, SettingBios, SettingPpfDir, SettingPsxExe,
              SettingXa, SettingSpuIrq, SettingBnWMdec, SettingScaler, SettingAutoVideo, SettingVideo, SettingFastBoot,
-             SettingDebugSettings, SettingRCntFix, SettingIsoPath, SettingLocale, SettingMcd1Inserted,
-             SettingMcd2Inserted, SettingDynarec, Setting8MB, SettingGUITheme, SettingDither, SettingCachedDithering,
+             SettingDebugSettings, SettingRCntFix, SettingIsoPath, SettingLocale, SettingMcd1Inserted, SettingMcd2Inserted,
+             SettingDynarec, Setting8MB, SettingSharedMemoryMap,SettingGUITheme, SettingDither, SettingCachedDithering,
              SettingGLErrorReporting, SettingGLErrorReportingSeverity, SettingFullCaching, SettingHardwareRenderer,
              SettingShownAutoUpdateConfig, SettingAutoUpdate, SettingMSAA, SettingLinearFiltering, SettingKioskMode,
              SettingMcd1Pocketstation, SettingMcd2Pocketstation, SettingBiosBrowsePath, SettingEXP1Filepath,

src/core/psxmem.cc

@@ -89,7 +89,46 @@ int PCSX::Memory::init() {
     m_readLUT = (uint8_t **)calloc(0x10000, sizeof(void *));
     m_writeLUT = (uint8_t **)calloc(0x10000, sizeof(void *));
 
+#ifdef _WIN32
+    size_t wramSize = 0x00800000;
+    bool doFallbackAlloc = true;
+
+    // Try to create a shared memory mapping, if enabled
+    const bool memoryMappingEnabled = PCSX::g_emulator->settings.get<PCSX::Emulator::SettingSharedMemoryMap>();
+    if (memoryMappingEnabled) {
+        // Create the name of our memory mapping handle which we can search for externally
+        auto handleName = fmt::format("pcsx-redux-{}", GetCurrentProcessId());
+        // Create the memory mapping handle
+        m_wramFileHandle = CreateFileMappingA(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0,
+            static_cast<uint32_t>(wramSize), handleName.c_str());
+        if (m_wramFileHandle != INVALID_HANDLE_VALUE) {
+            // Create a view of the memory mapping
+            void *base_pointer = MapViewOfFileEx(m_wramFileHandle, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0,
+                static_cast<uint32_t>(wramSize), nullptr);
+            // Validate success and assign the view to m_wram
+            if (base_pointer != nullptr) {
+                doFallbackAlloc = false;
+                m_wram = (uint8_t *)base_pointer;
+            } else {
+                CloseHandle(m_wramFileHandle);
+                m_wramFileHandle = nullptr;
+                g_system->message("MapViewOfFileEx failed, falling back to memory alloc, last error: %d\n",
+                    (int)GetLastError());
+            }
+        } else {
+            m_wramFileHandle = nullptr;
+            g_system->message("CreateFileMappingA failed, falling back to memory alloc, last error: %d\n",
+                (int)GetLastError());
+        }
+    }
+
+    if (doFallbackAlloc) {
+        m_wram = (uint8_t *)calloc(wramSize, 1);
+    }
+#else
     m_wram = (uint8_t *)calloc(0x00800000, 1);
+#endif
+
     m_exp1 = (uint8_t *)calloc(0x00800000, 1);
     m_hard = (uint8_t *)calloc(0x00010000, 1);
     m_bios = (uint8_t *)calloc(0x00080000, 1);
@@ -239,7 +278,21 @@ The distributed OpenBIOS.bin file can be an appropriate BIOS replacement.
 }
 
 void PCSX::Memory::shutdown() {
+#ifdef _WIN32
+    if (m_wramFileHandle != nullptr) {
+        bool result = static_cast<bool>(UnmapViewOfFile(m_wram));
+        if (!result) {
+            g_system->printf("Failed to unmap view of Kernel & User Memory.\n");
+        }
+        m_wram = nullptr;
+        CloseHandle(m_wramFileHandle);
+        m_wramFileHandle = nullptr;
+    } else {
+        free(m_wram);
+    }
+#else
     free(m_wram);
+#endif
     free(m_exp1);
     free(m_hard);
     free(m_bios);

src/core/psxmem.h

@@ -183,6 +183,11 @@ class Memory {
     friend class MemoryAsFile;
     IO<MemoryAsFile> m_memoryAsFile;
 
+#ifdef _WIN32
+    // Used to wrap wram in a shared memory map
+    void *m_wramFileHandle = nullptr;
+#endif
+
     int m_writeok = 1;
     uint32_t m_biosCRC = 0;
 

src/gui/gui.cc

@@ -1900,6 +1900,12 @@ this setting may not have any effect for you.)"));
         ImGuiHelpers::ShowHelpMarker(_(R"(Emulates an installed 8MB system,
 instead of the normal 2MB. Useful for working
 with development binaries and games.)"));
+        changed |= ImGui::Checkbox(_("Shared Memory Map"), &settings.get<Emulator::SettingSharedMemoryMap>().value);
+        ImGuiHelpers::ShowHelpMarker(_(R"(Wraps kernel & user memory in a named memory mapping,
+allowing it to be modified from external processes.
+Available on Windows platforms only, and requires a restart of the emulator to take effect.
+The mapping name is 'pcsx-redux-[process ID]', e.g. 'pcsx-redux-36722'.
+See Win32 app documentation for 'Creating Named Shared Memory' for more information.)"));
         changed |=
             ImGui::Checkbox(_("OpenGL GPU *ALPHA STATE*"), &settings.get<Emulator::SettingHardwareRenderer>().value);
         ImGuiHelpers::ShowHelpMarker(_(R"(Enables the OpenGL GPU renderer.

src/main/main.cc

@@ -266,6 +266,13 @@ int pcsxMain(int argc, char **argv) {
             emuSettings.get<PCSX::Emulator::Setting8MB>() = false;
         }
 
+        if (args.get<bool>("sharedmemorymap")) {
+            emuSettings.get<PCSX::Emulator::SettingSharedMemoryMap>() = true;
+        }
+        if (args.get<bool>("no-sharedmemorymap")) {
+            emuSettings.get<PCSX::Emulator::SettingSharedMemoryMap>() = false;
+        }
+
         if (args.get<bool>("fastboot")) {
             emuSettings.get<PCSX::Emulator::SettingFastBoot>() = true;
         }