CDVD: Add precaching option

common/ProgressCallback.cpp

@@ -101,9 +101,11 @@ void ProgressCallback::DisplayFormattedModalInformation(const char* format, ...)
 	ModalInformation(str.c_str());
 }
 
-class NullProgressCallbacks final : public ProgressCallback
+namespace
 {
-public:
+	class NullProgressCallbacks final : public ProgressCallback
+	{
+	public:
 		void PushState() override {}
 		void PopState() override {}
 
@@ -130,11 +132,17 @@ public:
 			return false;
 		}
 		void ModalInformation(const char* message) override { Console.WriteLn("%s", message); }
-};
+	};
+} // namespace
 
 static NullProgressCallbacks s_nullProgressCallbacks;
 ProgressCallback* ProgressCallback::NullProgressCallback = &s_nullProgressCallbacks;
 
+std::unique_ptr<ProgressCallback> ProgressCallback::CreateNullProgressCallback()
+{
+	return std::make_unique<NullProgressCallbacks>();
+}
+
 BaseProgressCallback::BaseProgressCallback()
 {
 }

common/ProgressCallback.h

@@ -3,6 +3,8 @@
 
 #pragma once
 #include "Pcsx2Defs.h"
+
+#include <memory>
 #include <string>
 
 /**
@@ -59,6 +61,8 @@ public:
 
 public:
 	static ProgressCallback* NullProgressCallback;
+
+	static std::unique_ptr<ProgressCallback> CreateNullProgressCallback();
 };
 
 class BaseProgressCallback : public ProgressCallback

pcsx2-gsrunner/Main.cpp

@@ -20,6 +20,7 @@
 #include "common/FileSystem.h"
 #include "common/MemorySettingsInterface.h"
 #include "common/Path.h"
+#include "common/ProgressCallback.h"
 #include "common/SettingsWrapper.h"
 #include "common/StringUtil.h"
 
@@ -165,6 +166,11 @@ void Host::SetDefaultUISettings(SettingsInterface& si)
 	// nothing
 }
 
+std::unique_ptr<ProgressCallback> Host::CreateHostProgressCallback()
+{
+	return ProgressCallback::CreateNullProgressCallback();
+}
+
 void Host::ReportErrorAsync(const std::string_view title, const std::string_view message)
 {
 	if (!title.empty() && !message.empty())

pcsx2-qt/QtHost.cpp

@@ -1704,6 +1704,247 @@ void Host::SetMouseMode(bool relative_mode, bool hide_cursor)
 	emit g_emu_thread->onMouseModeRequested(relative_mode, hide_cursor);
 }
 
+namespace {
+class QtHostProgressCallback final : public BaseProgressCallback
+{
+public:
+	QtHostProgressCallback();
+	~QtHostProgressCallback() override;
+
+	__fi const std::string& GetName() const { return m_name; }
+
+	void PushState() override;
+	void PopState() override;
+
+	bool IsCancelled() const override;
+
+	void SetCancellable(bool cancellable) override;
+	void SetTitle(const char* title) override;
+	void SetStatusText(const char* text) override;
+	void SetProgressRange(u32 range) override;
+	void SetProgressValue(u32 value) override;
+
+	void DisplayError(const char* message) override;
+	void DisplayWarning(const char* message) override;
+	void DisplayInformation(const char* message) override;
+	void DisplayDebugMessage(const char* message) override;
+
+	void ModalError(const char* message) override;
+	bool ModalConfirmation(const char* message) override;
+	void ModalInformation(const char* message) override;
+
+	void SetCancelled();
+
+private:
+	struct SharedData
+	{
+		QProgressDialog* dialog = nullptr;
+		QString init_title;
+		QString init_status_text;
+		std::atomic_bool cancelled{false};
+		bool cancellable = true;
+		bool was_fullscreen = false;
+	};
+
+	void EnsureHasData();
+	static void EnsureDialogVisible(const std::shared_ptr<SharedData>& data);
+	void Redraw(bool force);
+
+	std::string m_name;
+	std::shared_ptr<SharedData> m_data;
+	int m_last_progress_percent = -1;
+};
+}
+
+QtHostProgressCallback::QtHostProgressCallback()
+	: BaseProgressCallback()
+{
+}
+
+QtHostProgressCallback::~QtHostProgressCallback()
+{
+	if (m_data)
+	{
+		QtHost::RunOnUIThread([data = m_data]() {
+			if (!data->dialog)
+				return;
+
+			data->dialog->close();
+			delete data->dialog;
+			if (data->was_fullscreen)
+				g_emu_thread->setFullscreen(true, false);
+		});
+	}
+}
+
+void QtHostProgressCallback::PushState()
+{
+	BaseProgressCallback::PushState();
+}
+
+void QtHostProgressCallback::PopState()
+{
+	BaseProgressCallback::PopState();
+	Redraw(true);
+}
+
+void QtHostProgressCallback::SetCancellable(bool cancellable)
+{
+	BaseProgressCallback::SetCancellable(cancellable);
+	EnsureHasData();
+	m_data->cancellable = cancellable;
+}
+
+void QtHostProgressCallback::SetTitle(const char* title)
+{
+	EnsureHasData();
+	QtHost::RunOnUIThread([data = m_data, title = QString::fromUtf8(title)]() {
+		if (data->dialog)
+			data->dialog->setWindowTitle(title);
+		else
+			data->init_title = title;
+	});
+}
+
+void QtHostProgressCallback::SetStatusText(const char* text)
+{
+	BaseProgressCallback::SetStatusText(text);
+	
+	EnsureHasData();
+	QtHost::RunOnUIThread([data = m_data, text = QString::fromUtf8(text)]() {
+		if (data->dialog)
+			data->dialog->setLabelText(text);
+		else
+			data->init_status_text = text;
+	});
+}
+
+void QtHostProgressCallback::SetProgressRange(u32 range)
+{
+	u32 last_range = m_progress_range;
+
+	BaseProgressCallback::SetProgressRange(range);
+
+	if (m_progress_range != last_range)
+		Redraw(false);
+}
+
+void QtHostProgressCallback::SetProgressValue(u32 value)
+{
+	u32 lastValue = m_progress_value;
+
+	BaseProgressCallback::SetProgressValue(value);
+
+	if (m_progress_value != lastValue)
+		Redraw(false);
+}
+
+void QtHostProgressCallback::Redraw(bool force)
+{
+	const int percent = static_cast<int>((static_cast<float>(m_progress_value) / static_cast<float>(m_progress_range)) * 100.0f);
+	if (percent == m_last_progress_percent && !force)
+		return;
+
+	// If this is the emu uthread, we need to process the un-fullscreen message.
+	if (g_emu_thread->isOnEmuThread())
+		Host::PumpMessagesOnCPUThread();
+
+	m_last_progress_percent = percent;
+	EnsureHasData();
+	QtHost::RunOnUIThread([data = m_data, percent]() {
+		EnsureDialogVisible(data);
+		data->dialog->setValue(percent);
+	});
+}
+
+void QtHostProgressCallback::DisplayError(const char* message)
+{
+	Console.Error(message);
+	Host::ReportErrorAsync("Error", message);
+}
+
+void QtHostProgressCallback::DisplayWarning(const char* message)
+{
+	Console.Warning(message);
+}
+
+void QtHostProgressCallback::DisplayInformation(const char* message)
+{
+	Console.WriteLn(message);
+}
+
+void QtHostProgressCallback::DisplayDebugMessage(const char* message)
+{
+	DevCon.WriteLn(message);
+}
+
+void QtHostProgressCallback::ModalError(const char* message)
+{
+	Console.Error(message);
+	Host::ReportErrorAsync("Error", message);
+}
+
+bool QtHostProgressCallback::ModalConfirmation(const char* message)
+{
+	return false;
+}
+
+void QtHostProgressCallback::ModalInformation(const char* message)
+{
+	Console.WriteLn(message);
+}
+
+void QtHostProgressCallback::SetCancelled()
+{
+	// not done here
+}
+
+bool QtHostProgressCallback::IsCancelled() const
+{
+	return m_data && m_data->cancelled.load(std::memory_order_acquire);
+}
+
+void QtHostProgressCallback::EnsureHasData()
+{
+	if (!m_data)
+		m_data = std::make_shared<SharedData>();
+}
+
+void QtHostProgressCallback::EnsureDialogVisible(const std::shared_ptr<SharedData>& data)
+{
+	pxAssert(data);
+	if (data->dialog)
+		return;
+
+	data->was_fullscreen = g_emu_thread->isFullscreen();
+	if (data->was_fullscreen)
+		g_emu_thread->setFullscreen(false, true);
+
+	data->dialog = new QProgressDialog(data->init_status_text,
+		data->cancellable ? qApp->translate("QtHost", "Cancel") : QString(),
+		0, 100, g_main_window);
+	if (data->cancellable)
+	{
+		data->dialog->connect(data->dialog, &QProgressDialog::canceled,
+			[data]() { data->cancelled.store(true, std::memory_order_release); });
+	}
+	data->dialog->setWindowIcon(QtHost::GetAppIcon());
+	data->dialog->setMinimumWidth(400);
+	data->dialog->show();
+	data->dialog->raise();
+	data->dialog->activateWindow();
+	if (!data->init_title.isEmpty())
+	{
+		data->dialog->setWindowTitle(data->init_title);
+		data->init_title = QString();
+	}
+}
+
+std::unique_ptr<ProgressCallback> Host::CreateHostProgressCallback()
+{
+	return std::make_unique<QtHostProgressCallback>();
+}
+
 //////////////////////////////////////////////////////////////////////////
 // Hotkeys
 //////////////////////////////////////////////////////////////////////////

pcsx2-qt/Settings/EmulationSettingsWidget.cpp

@@ -45,6 +45,7 @@ EmulationSettingsWidget::EmulationSettingsWidget(SettingsWindow* dialog, QWidget
 	SettingWidgetBinder::BindWidgetToBoolSetting(sif, m_ui.MTVU, "EmuCore/Speedhacks", "vuThread", false);
 	SettingWidgetBinder::BindWidgetToBoolSetting(sif, m_ui.instantVU1, "EmuCore/Speedhacks", "vu1Instant", true);
 	SettingWidgetBinder::BindWidgetToBoolSetting(sif, m_ui.fastCDVD, "EmuCore/Speedhacks", "fastCDVD", false);
+	SettingWidgetBinder::BindWidgetToBoolSetting(sif, m_ui.precacheCDVD, "EmuCore", "CdvdPrecache", false);
 
 	if (m_dialog->isPerGameSettings())
 	{
@@ -124,6 +125,9 @@ EmulationSettingsWidget::EmulationSettingsWidget(SettingsWindow* dialog, QWidget
 		   "Safe for most games, but a few games may exhibit graphical errors."));
 	dialog->registerWidgetHelp(m_ui.fastCDVD, tr("Enable Fast CDVD"), tr("Unchecked"),
 		tr("Fast disc access, less loading times. Check HDLoader compatibility lists for known games that have issues with this."));
+	dialog->registerWidgetHelp(m_ui.precacheCDVD, tr("Enable CDVD Precaching"), tr("Unchecked"),
+		tr("Loads the disc image into RAM before starting the virtual machine. Can reduce stutter on systems with hard drives that "
+		   "have long wake times, but significantly increases boot times."));
 	dialog->registerWidgetHelp(m_ui.cheats, tr("Enable Cheats"), tr("Unchecked"),
 		tr("Automatically loads and applies cheats on game start."));
 	dialog->registerWidgetHelp(m_ui.hostFilesystem, tr("Enable Host Filesystem"), tr("Unchecked"),

pcsx2-qt/Settings/EmulationSettingsWidget.ui

@@ -98,13 +98,20 @@
           </property>
          </widget>
         </item>
-        <item row="3" column="0">
+        <item row="2" column="1">
          <widget class="QCheckBox" name="fastCDVD">
           <property name="text">
            <string>Enable Fast CDVD</string>
           </property>
          </widget>
         </item>
+        <item row="2" column="0">
+         <widget class="QCheckBox" name="precacheCDVD">
+          <property name="text">
+           <string>Enable CDVD Precaching</string>
+          </property>
+         </widget>
+        </item>
        </layout>
       </item>
       <item row="1" column="0">

pcsx2/CDVD/CDVDcommon.cpp

@@ -12,8 +12,10 @@
 #include "common/Assertions.h"
 #include "common/Console.h"
 #include "common/EnumOps.h"
+#include "common/Error.h"
 #include "common/FileSystem.h"
 #include "common/Path.h"
+#include "common/ProgressCallback.h"
 #include "common/StringUtil.h"
 
 #include <ctype.h>
@@ -413,6 +415,13 @@ bool DoCDVDopen(Error* error)
 	return true;
 }
 
+bool DoCDVDprecache(ProgressCallback* progress, Error* error)
+{
+	CheckNullCDVD();
+	progress->SetTitle(TRANSLATE("CDVD", "Precaching CDVD"));
+	return CDVD->precache(progress, error);
+}
+
 void DoCDVDclose()
 {
 	CheckNullCDVD();
@@ -525,6 +534,11 @@ static bool NODISCopen(std::string filename, Error* error)
 	return true;
 }
 
+static bool NODISCprecache(ProgressCallback* progress, Error* error)
+{
+	return true;
+}
+
 static void NODISCclose()
 {
 }
@@ -592,6 +606,7 @@ const CDVD_API CDVDapi_NoDisc =
 	{
 		NODISCclose,
 		NODISCopen,
+		NODISCprecache,
 		NODISCreadTrack,
 		NODISCgetBuffer,
 		NODISCreadSubQ,

pcsx2/CDVD/CDVDcommon.h

@@ -8,6 +8,7 @@
 #include <string>
 
 class Error;
+class ProgressCallback;
 
 typedef struct _cdvdSubQ
 {
@@ -79,6 +80,7 @@ typedef struct _cdvdTN
 
 // CDVD
 typedef bool (*_CDVDopen)(std::string filename, Error* error);
+typedef bool (*_CDVDprecache)(ProgressCallback* progress, Error* error);
 
 // Initiates an asynchronous track read operation.
 // Returns -1 on error (invalid track)
@@ -118,6 +120,7 @@ struct CDVD_API
 	// Don't need init or shutdown.  iso/nodisc have no init/shutdown.
 
 	_CDVDopen open;
+	_CDVDprecache precache;
 	_CDVDreadTrack readTrack;
 	_CDVDgetBuffer getBuffer;
 	_CDVDreadSubQ readSubQ;
@@ -152,6 +155,7 @@ extern CDVD_SourceType CDVDsys_GetSourceType();
 extern void CDVDsys_ClearFiles();
 
 extern bool DoCDVDopen(Error* error);
+extern bool DoCDVDprecache(ProgressCallback* progress, Error* error);
 extern void DoCDVDclose();
 extern s32 DoCDVDreadSector(u8* buffer, u32 lsn, int mode);
 extern s32 DoCDVDreadTrack(u32 lsn, int mode);

pcsx2/CDVD/CDVDdiscReader.cpp

@@ -1,8 +1,9 @@
-// SPDX-FileCopyrightText: 2002-2023 PCSX2 Dev Team
+// SPDX-FileCopyrightText: 2002-2024 PCSX2 Dev Team
 // SPDX-License-Identifier: LGPL-3.0+
 
 #include "CDVDdiscReader.h"
 #include "CDVD/CDVD.h"
+#include "Host.h"
 
 #include "common/Error.h"
 
@@ -192,6 +193,12 @@ static bool DISCopen(std::string filename, Error* error)
 	return true;
 }
 
+static bool DISCprecache(ProgressCallback* progress, Error* error)
+{
+	Error::SetStringView(error, TRANSLATE_SV("CDVD", "Precaching is not supported for discs."));
+	return false;
+}
+
 static void DISCclose()
 {
 	StopKeepAliveThread();
@@ -531,6 +538,7 @@ const CDVD_API CDVDapi_Disc =
 	{
 		DISCclose,
 		DISCopen,
+		DISCprecache,
 		DISCreadTrack,
 		DISCgetBuffer,
 		DISCreadSubQ,

pcsx2/CDVD/CDVDisoReader.cpp

@@ -55,6 +55,11 @@ static bool ISOopen(std::string filename, Error* error)
 	return true;
 }
 
+static bool ISOprecache(ProgressCallback* progress, Error* error)
+{
+	return iso.Precache(progress, error);
+}
+
 static s32 ISOreadSubQ(u32 lsn, cdvdSubQ* subq)
 {
 	// fake it
@@ -400,6 +405,7 @@ const CDVD_API CDVDapi_Iso =
 		ISOclose,
 
 		ISOopen,
+		ISOprecache,
 		ISOreadTrack,
 		ISOgetBuffer,
 		ISOreadSubQ,

pcsx2/CDVD/ChdFileReader.cpp

@@ -8,6 +8,8 @@
 #include "common/Error.h"
 #include "common/FileSystem.h"
 #include "common/Path.h"
+#include "common/ProgressCallback.h"
+#include "common/SmallString.h"
 #include "common/StringUtil.h"
 
 #include "libchdr/chd.h"
@@ -188,6 +190,32 @@ bool ChdFileReader::Open2(std::string filename, Error* error)
 	return true;
 }
 
+bool ChdFileReader::Precache2(ProgressCallback* progress, Error* error)
+{
+	if (!CheckAvailableMemoryForPrecaching(chd_get_compressed_size(ChdFile), error))
+		return false;
+
+	progress->SetProgressRange(100);
+
+	const auto callback = [](size_t pos, size_t total, void* param) -> bool {
+		ProgressCallback* progress = static_cast<ProgressCallback*>(param);
+		const u32 percent = static_cast<u32>((pos * 100) / total);
+		progress->SetProgressValue(std::min<u32>(percent, 100));
+		return !progress->IsCancelled();
+	};
+
+	const chd_error cerror = chd_precache_progress(ChdFile, callback, progress);
+	if (cerror != CHDERR_NONE)
+	{
+		if (cerror != CHDERR_CANCELLED)
+			Error::SetStringView(error, "Failed to read part of the file.");
+
+		return false;
+	}
+
+	return true;
+}
+
 ThreadedFileReader::Chunk ChdFileReader::ChunkForOffset(u64 offset)
 {
 	Chunk chunk = {0};

pcsx2/CDVD/ChdFileReader.h

@@ -17,6 +17,8 @@ public:
 
 	bool Open2(std::string filename, Error* error) override;
 	
+	bool Precache2(ProgressCallback* progress, Error* error) override;
+
 	Chunk ChunkForOffset(u64 offset) override;
 	int ReadChunk(void* dst, s64 blockID) override;
 

pcsx2/CDVD/CsoFileReader.cpp

@@ -84,6 +84,31 @@ bool CsoFileReader::Open2(std::string filename, Error* error)
 	return true;
 }
 
+bool CsoFileReader::Precache2(ProgressCallback* progress, Error* error)
+{
+	if (!m_src)
+		return false;
+
+	const s64 size = FileSystem::FSize64(m_src);
+	if (size < 0 || !CheckAvailableMemoryForPrecaching(static_cast<u64>(size), error))
+		return false;
+
+	m_file_cache_size = static_cast<size_t>(size);
+	m_file_cache = std::make_unique_for_overwrite<u8[]>(m_file_cache_size);
+	if (FileSystem::FSeek64(m_src, 0, SEEK_SET) != 0 ||
+		FileSystem::ReadFileWithProgress(
+			m_src, m_file_cache.get(), m_file_cache_size, progress, error) != m_file_cache_size)
+	{
+		m_file_cache.reset();
+		return false;
+	}
+
+	m_readBuffer.reset();
+	std::fclose(m_src);
+	m_src = nullptr;
+	return true;
+}
+
 bool CsoFileReader::ReadFileHeader(Error* error)
 {
 	CsoHeader hdr;
@@ -141,11 +166,7 @@ bool CsoFileReader::InitializeBuffers(Error* error)
 	// initialize zlib if not a ZSO
 	if (!m_uselz4)
 	{
-		m_z_stream = std::make_unique<z_stream>();
+		if (inflateInit2(&m_z_stream, -15) != Z_OK)
-		m_z_stream->zalloc = Z_NULL;
-		m_z_stream->zfree = Z_NULL;
-		m_z_stream->opaque = Z_NULL;
-		if (inflateInit2(m_z_stream.get(), -15) != Z_OK)
 		{
 			Error::SetString(error, "Unable to initialize zlib for CSO decompression.");
 			return false;
@@ -164,11 +185,10 @@ void CsoFileReader::Close2()
 		fclose(m_src);
 		m_src = nullptr;
 	}
-	if (m_z_stream)
+	if (m_file_cache)
-	{
+		m_file_cache.reset();
-		inflateEnd(m_z_stream.get());
+	if (!m_uselz4)
-		m_z_stream.reset();
+		inflateEnd(&m_z_stream);
-	}
 
 	m_readBuffer.reset();
 	m_index.reset();
@@ -213,6 +233,16 @@ int CsoFileReader::ReadChunk(void* dst, s64 chunkID)
 
 	if (!compressed)
 	{
+		if (m_file_cache)
+		{
+			if (frameRawPos >= m_file_cache_size)
+				return 0;
+
+			const size_t read_count = std::min<size_t>(m_file_cache_size - frameRawPos, frameRawSize);
+			std::memcpy(dst, &m_file_cache[frameRawPos], read_count);
+			return static_cast<int>(read_count);
+		}
+
 		// Just read directly, easy.
 		if (FileSystem::FSeek64(m_src, frameRawPos, SEEK_SET) != 0)
 		{
@@ -222,22 +252,37 @@ int CsoFileReader::ReadChunk(void* dst, s64 chunkID)
 		return fread(dst, 1, m_frameSize, m_src);
 	}
 	else
+	{
+		// This might be less bytes than frameRawSize in case of padding on the last frame.
+		// This is because the index positions must be aligned.
+		u32 readRawBytes;
+		u8* readBuffer;
+		if (m_file_cache)
+		{
+			if (frameRawPos >= m_file_cache_size)
+				return 0;
+
+			readRawBytes = static_cast<u32>(std::min<size_t>(m_file_cache_size - frameRawPos, frameRawSize));
+			readBuffer = &m_file_cache[frameRawPos];
+		}
+		else
 		{
 			if (FileSystem::FSeek64(m_src, frameRawPos, SEEK_SET) != 0)
 			{
 				Console.Error("Unable to seek to compressed CSO data.");
 				return 0;
 			}
-		// This might be less bytes than frameRawSize in case of padding on the last frame.
+			readBuffer = m_readBuffer.get();
-		// This is because the index positions must be aligned.
+			readRawBytes = fread(m_readBuffer.get(), 1, frameRawSize, m_src);
-		const u32 readRawBytes = fread(m_readBuffer.get(), 1, frameRawSize, m_src);
+		}
+
 		bool success = false;
 
 		if (m_uselz4)
 		{
 			const int src_size = static_cast<int>(readRawBytes);
 			const int dst_size = static_cast<int>(m_frameSize);
-			const char* src_buf = reinterpret_cast<const char*>(m_readBuffer.get());
+			const char* src_buf = reinterpret_cast<const char*>(readBuffer);
 			char* dst_buf = static_cast<char*>(dst);
 			
 			const int res = LZ4_decompress_safe_partial(src_buf, dst_buf, src_size, dst_size, dst_size);
@@ -245,20 +290,20 @@ int CsoFileReader::ReadChunk(void* dst, s64 chunkID)
 		}
 		else
 		{
-			m_z_stream->next_in = m_readBuffer.get();
+			m_z_stream.next_in = readBuffer;
-			m_z_stream->avail_in = readRawBytes;
+			m_z_stream.avail_in = readRawBytes;
-			m_z_stream->next_out = static_cast<Bytef*>(dst);
+			m_z_stream.next_out = static_cast<Bytef*>(dst);
-			m_z_stream->avail_out = m_frameSize;
+			m_z_stream.avail_out = m_frameSize;
 
-			const int status = inflate(m_z_stream.get(), Z_FINISH);
+			const int status = inflate(&m_z_stream, Z_FINISH);
-			success = (status == Z_STREAM_END && m_z_stream->total_out == m_frameSize);
+			success = (status == Z_STREAM_END && m_z_stream.total_out == m_frameSize);
 		}
 
 		if (!success)
 			Console.Error(fmt::format("Unable to decompress CSO frame using {}", (m_uselz4)? "lz4":"zlib"));
 		
 		if (!m_uselz4)
-			inflateReset(m_z_stream.get());
+			inflateReset(&m_z_stream);
 
 		return success ? m_frameSize : 0;
 	}

pcsx2/CDVD/CsoFileReader.h

@@ -7,7 +7,6 @@
 #include <zlib.h>
 
 struct CsoHeader;
-typedef struct z_stream_s z_stream;
 
 class CsoFileReader final : public ThreadedFileReader
 {
@@ -19,6 +18,8 @@ public:
 
 	bool Open2(std::string filename, Error* error) override;
 
+	bool Precache2(ProgressCallback* progress, Error* error) override;
+
 	Chunk ChunkForOffset(u64 offset) override;
 	int ReadChunk(void* dst, s64 chunkID) override;
 
@@ -44,5 +45,7 @@ private:
 	u64 m_totalSize = 0;
 	// The actual source cso file handle.
 	std::FILE* m_src = nullptr;
-	std::unique_ptr<z_stream> m_z_stream;
+	std::unique_ptr<u8[]> m_file_cache;
+	size_t m_file_cache_size = 0;
+	z_stream m_z_stream = {};
 };

pcsx2/CDVD/FlatFileReader.cpp

@@ -38,6 +38,25 @@ bool FlatFileReader::Open2(std::string filename, Error* error)
 	return true;
 }
 
+bool FlatFileReader::Precache2(ProgressCallback* progress, Error* error)
+{
+	if (!m_file || !CheckAvailableMemoryForPrecaching(m_file_size, error))
+		return false;
+
+	m_file_cache = std::make_unique_for_overwrite<u8[]>(m_file_size);
+	if (FileSystem::FSeek64(m_file, 0, SEEK_SET) != 0 ||
+		FileSystem::ReadFileWithProgress(
+			m_file, m_file_cache.get(), m_file_size, progress, error) != m_file_size)
+	{
+		m_file_cache.reset();
+		return false;
+	}
+
+	std::fclose(m_file);
+	m_file = nullptr;
+	return true;
+}
+
 ThreadedFileReader::Chunk FlatFileReader::ChunkForOffset(u64 offset)
 {
 	ThreadedFileReader::Chunk chunk = {};
@@ -61,6 +80,16 @@ int FlatFileReader::ReadChunk(void* dst, s64 blockID)
 		return -1;
 
 	const u64 file_offset = static_cast<u64>(blockID) * CHUNK_SIZE;
+	if (m_file_cache)
+	{
+		if (file_offset >= m_file_size)
+			return -1;
+
+		const u64 read_size = std::min<u64>(m_file_size - file_offset, CHUNK_SIZE);
+		std::memcpy(dst, &m_file_cache[file_offset], read_size);
+		return static_cast<int>(read_size);
+	}
+
 	if (FileSystem::FSeek64(m_file, file_offset, SEEK_SET) != 0)
 		return -1;
 

pcsx2/CDVD/FlatFileReader.h

@@ -12,6 +12,7 @@ class FlatFileReader final : public ThreadedFileReader
 	DeclareNoncopyableObject(FlatFileReader);
 
 	std::FILE* m_file = nullptr;
+	std::unique_ptr<u8[]> m_file_cache;
 	u64 m_file_size = 0;
 
 public:
@@ -20,6 +21,8 @@ public:
 
 	bool Open2(std::string filename, Error* error) override;
 
+	bool Precache2(ProgressCallback* progress, Error* error) override;
+
 	Chunk ChunkForOffset(u64 offset) override;
 	int ReadChunk(void* dst, s64 blockID) override;
 

pcsx2/CDVD/InputIsoFile.cpp

@@ -221,6 +221,11 @@ bool InputIsoFile::Open(std::string srcfile, Error* error)
 	return true;
 }
 
+bool InputIsoFile::Precache(ProgressCallback* progress, Error* error)
+{
+	return m_reader->Precache(progress, error);
+}
+
 void InputIsoFile::Close()
 {
 	if (m_reader)

pcsx2/CDVD/IsoFileFormats.h

@@ -10,6 +10,7 @@
 #include <vector>
 
 class Error;
+class ProgressCallback;
 
 enum isoType
 {
@@ -65,6 +66,7 @@ public:
 	}
 
 	bool Open(std::string srcfile, Error* error);
+	bool Precache(ProgressCallback* progress, Error* error);
 	void Close();
 	bool Detect(bool readType = true);
 

pcsx2/CDVD/ThreadedFileReader.cpp

@@ -2,8 +2,15 @@
 // SPDX-License-Identifier: LGPL-3.0+
 
 #include "ThreadedFileReader.h"
+#include "Host.h"
 
+#include "common/Error.h"
+#include "common/HostSys.h"
+#include "common/Path.h"
+#include "common/ProgressCallback.h"
+#include "common/SmallString.h"
 #include "common/Threading.h"
+
 #include <cstring>
 
 // Make sure buffer size is bigger than the cutoff where PCSX2 emulates a seek
@@ -244,6 +251,36 @@ bool ThreadedFileReader::TryCachedRead(void*& buffer, u64& offset, u32& size, co
 	return allDone;
 }
 
+bool ThreadedFileReader::Precache(ProgressCallback* progress, Error* error)
+{
+	CancelAndWaitUntilStopped();
+	progress->SetStatusText(SmallString::from_format("Precaching {}...", Path::GetFileName(m_filename)).c_str());
+	return Precache2(progress, error);
+}
+
+bool ThreadedFileReader::Precache2(ProgressCallback* progress, Error* error)
+{
+	Error::SetStringView(error, "Precaching is not supported for this file format.");
+	return false;
+}
+
+bool ThreadedFileReader::CheckAvailableMemoryForPrecaching(u64 required_size, Error* error)
+{
+	// Don't allow precaching to use more than 50% of system memory.
+	// Hopefully nobody's running 2-4GB potatoes anymore....
+	const u64 memory_size = GetPhysicalMemory();
+	const u64 max_precache_size = memory_size / 2;
+	if (required_size > max_precache_size)
+	{
+		Error::SetStringFmt(error,
+			TRANSLATE_FS("CDVD", "Required memory ({}GB) is the above the maximum allowed ({}GB)."),
+			required_size / _1gb, max_precache_size / _1gb);
+		return false;
+	}
+
+	return true;
+}
+
 bool ThreadedFileReader::Open(std::string filename, Error* error)
 {
 	CancelAndWaitUntilStopped();

pcsx2/CDVD/ThreadedFileReader.h

@@ -11,6 +11,7 @@
 #include <condition_variable>
 
 class Error;
+class ProgressCallback;
 
 /// A file reader for use with compressed formats
 /// Calls decompression code on a separate thread to make a synchronous decompression API async
@@ -42,8 +43,12 @@ protected:
 	virtual int ReadChunk(void* dst, s64 chunkID) = 0;
 	/// AsyncFileReader open but ThreadedFileReader needs prep work first
 	virtual bool Open2(std::string filename, Error* error) = 0;
+	/// AsyncFileReader precache but ThreadedFileReader needs prep work first
+	virtual bool Precache2(ProgressCallback* progress, Error* error);
 	/// AsyncFileReader close but ThreadedFileReader needs prep work first
 	virtual void Close2() = 0;
+	/// Checks system memory, to ensure that precaching would not exceed a reasonable amount.
+	bool CheckAvailableMemoryForPrecaching(u64 required_size, Error* error);
 
 	ThreadedFileReader();
 
@@ -109,7 +114,9 @@ public:
 
 	virtual u32 GetBlockCount() const = 0;
 
+
 	bool Open(std::string filename, Error* error);
+	bool Precache(ProgressCallback* progress, Error* error);
 	int ReadSync(void* pBuffer, u32 sector, u32 count);
 	void BeginRead(void* pBuffer, u32 sector, u32 count);
 	int FinishRead();

pcsx2/Config.h

@@ -1111,6 +1111,7 @@ struct Pcsx2Config
 	bool
 		CdvdVerboseReads : 1, // enables cdvd read activity verbosely dumped to the console
 		CdvdDumpBlocks : 1, // enables cdvd block dumping
+		CdvdPrecache : 1, // enables cdvd precaching of compressed images
 		EnablePatches : 1, // enables patch detection and application
 		EnableCheats : 1, // enables cheat detection and application
 		EnablePINE : 1, // enables inter-process communication

pcsx2/Host.h

@@ -16,6 +16,7 @@
 #include <string_view>
 #include <vector>
 
+class ProgressCallback;
 class SettingsInterface;
 
 namespace Host
@@ -131,6 +132,9 @@ namespace Host
 	/// Sets host-specific default settings.
 	void SetDefaultUISettings(SettingsInterface& si);
 
+	/// Creates a progress callback that displays in the host.
+	std::unique_ptr<ProgressCallback> CreateHostProgressCallback();
+
 	namespace Internal
 	{
 		/// Retrieves the base settings layer. Must call with lock held.

pcsx2/ImGui/FullscreenUI.cpp

@@ -3330,6 +3330,9 @@ void FullscreenUI::DrawEmulationSettingsPage()
 			"EmuCore/Speedhacks", "fastCDVD", false);
 	}
 
+	DrawToggleSetting(bsi, FSUI_CSTR("Enable CDVD Precaching"), FSUI_CSTR("Loads the disc image into RAM before starting the virtual machine."),
+		"EmuCore", "CdvdPrecache", false);
+
 	MenuHeading(FSUI_CSTR("Frame Pacing/Latency Control"));
 
 	bool optimal_frame_pacing = (bsi->GetIntValue("EmuCore/GS", "VsyncQueueSize", DEFAULT_FRAME_LATENCY) == 0);
@@ -6949,6 +6952,8 @@ TRANSLATE_NOOP("FullscreenUI", "Enable Host Filesystem");
 TRANSLATE_NOOP("FullscreenUI", "Enables access to files from the host: namespace in the virtual machine.");
 TRANSLATE_NOOP("FullscreenUI", "Enable Fast CDVD");
 TRANSLATE_NOOP("FullscreenUI", "Fast disc access, less loading times. Not recommended.");
+TRANSLATE_NOOP("FullscreenUI", "Enable CDVD Precaching");
+TRANSLATE_NOOP("FullscreenUI", "Loads the disc image into RAM before starting the virtual machine.");
 TRANSLATE_NOOP("FullscreenUI", "Frame Pacing/Latency Control");
 TRANSLATE_NOOP("FullscreenUI", "Maximum Frame Latency");
 TRANSLATE_NOOP("FullscreenUI", "Sets the number of frames which can be queued.");

pcsx2/Pcsx2Config.cpp

@@ -1706,6 +1706,7 @@ void Pcsx2Config::LoadSaveCore(SettingsWrapper& wrap)
 
 	SettingsWrapBitBool(CdvdVerboseReads);
 	SettingsWrapBitBool(CdvdDumpBlocks);
+	SettingsWrapBitBool(CdvdPrecache);
 	SettingsWrapBitBool(EnablePatches);
 	SettingsWrapBitBool(EnableCheats);
 	SettingsWrapBitBool(EnablePINE);

pcsx2/VMManager.cpp

@@ -113,6 +113,7 @@ namespace VMManager
 	static void ReportGameChangeToHost();
 	static bool HasBootedELF();
 	static bool HasValidOrInitializingVM();
+	static void PrecacheCDVDFile();
 
 	static std::string GetCurrentSaveStateFileName(s32 slot);
 	static bool DoLoadState(const char* filename);
@@ -1223,6 +1224,27 @@ bool VMManager::AutoDetectSource(const std::string& filename)
 	}
 }
 
+void VMManager::PrecacheCDVDFile()
+{
+	Error error;
+	std::unique_ptr<ProgressCallback> progress = Host::CreateHostProgressCallback();
+	if (!DoCDVDprecache(progress.get(), &error))
+	{
+		if (progress->IsCancelled())
+		{
+			Host::AddIconOSDMessage("PrecacheCDVDFile", ICON_FA_COMPACT_DISC,
+				TRANSLATE_STR("VMManager", "CDVD precaching was cancelled."),
+				Host::OSD_WARNING_DURATION);
+		}
+		else
+		{
+			Host::AddIconOSDMessage("PrecacheCDVDFile", ICON_FA_EXCLAMATION_TRIANGLE,
+				fmt::format(TRANSLATE_FS("VMManager", "CDVD precaching failed: {}"), error.GetDescription()),
+				Host::OSD_ERROR_DURATION);
+		}
+	}
+}
+
 bool VMManager::Initialize(VMBootParameters boot_params)
 {
 	const Common::Timer init_timer;
@@ -1522,6 +1544,9 @@ bool VMManager::Initialize(VMBootParameters boot_params)
 	close_cdvd_files.Cancel();
 	close_state.Cancel();
 
+	if (EmuConfig.CdvdPrecache)
+		PrecacheCDVDFile();
+
 	hwReset();
 
 	Console.WriteLn("VM subsystems initialized in %.2f ms", init_timer.GetTimeMilliseconds());

tests/ctest/core/StubHost.cpp

@@ -11,6 +11,7 @@
 #include "pcsx2/ImGui/ImGuiManager.h"
 #include "pcsx2/Input/InputManager.h"
 #include "pcsx2/VMManager.h"
+#include "common/ProgressCallback.h"
 
 void Host::CommitBaseSettingChanges()
 {
@@ -33,6 +34,11 @@ void Host::SetDefaultUISettings(SettingsInterface& si)
 {
 }
 
+std::unique_ptr<ProgressCallback> Host::CreateHostProgressCallback()
+{
+	return ProgressCallback::CreateNullProgressCallback();
+}
+
 void Host::ReportErrorAsync(const std::string_view title, const std::string_view message)
 {
 }