From ce8b24dfa7fbc248a34d2e4d1ca486f789fb0f09 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Mon, 15 Jan 2024 13:40:13 -0600
Subject: [PATCH] Implement fast AES detection logic for Windows and macOS

---
 app/streaming/session.cpp     | 13 ++++++++++---
 app/streaming/streamutils.cpp | 29 +++++++++++++++++++++++++++++
 app/streaming/streamutils.h   |  3 +++
 3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/app/streaming/session.cpp b/app/streaming/session.cpp
index 93480dfa..61b193e4 100644
--- a/app/streaming/session.cpp
+++ b/app/streaming/session.cpp
@@ -604,9 +604,16 @@ bool Session::initialize()
     m_StreamConfig.bitrate = m_Preferences->bitrateKbps;
 
 #ifndef STEAM_LINK
-    // Enable audio encryption as long as we're not on Steam Link.
-    // That hardware can hardly handle Opus decoding at all.
-    m_StreamConfig.encryptionFlags = ENCFLG_AUDIO;
+    // Opt-in to all encryption features if we detect that the platform
+    // has AES cryptography acceleration instructions.
+    if (StreamUtils::hasFastAes()) {
+        m_StreamConfig.encryptionFlags = ENCFLG_ALL;
+    }
+    else {
+        // Enable audio encryption as long as we're not on Steam Link.
+        // That hardware can hardly handle Opus decoding at all.
+        m_StreamConfig.encryptionFlags = ENCFLG_AUDIO;
+    }
 #endif
 
     SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION,
diff --git a/app/streaming/streamutils.cpp b/app/streaming/streamutils.cpp
index 15a38980..c9f693ef 100644
--- a/app/streaming/streamutils.cpp
+++ b/app/streaming/streamutils.cpp
@@ -6,6 +6,10 @@
 #include <ApplicationServices/ApplicationServices.h>
 #endif
 
+#ifdef Q_OS_WINDOWS
+#include <Windows.h>
+#endif
+
 Uint32 StreamUtils::getPlatformWindowFlags()
 {
 #if defined(Q_OS_DARWIN)
@@ -95,6 +99,31 @@ int StreamUtils::getDisplayRefreshRate(SDL_Window* window)
     return mode.refresh_rate;
 }
 
+bool StreamUtils::hasFastAes()
+{
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+#if __has_builtin(__builtin_cpu_supports) && defined(Q_PROCESSOR_X86)
+    return __builtin_cpu_supports("aes");
+#elif defined(__BUILTIN_CPU_SUPPORTS__) && defined(Q_PROCESSOR_POWER)
+    return __builtin_cpu_supports("vcrypto");
+#elif defined(Q_OS_WINDOWS) && defined(Q_PROCESSOR_ARM)
+    return IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE);
+#elif defined(_MSC_VER) && defined(Q_PROCESSOR_X86)
+    int regs[4];
+    __cpuid(regs, 1);
+    return regs[2] & (1 << 25); // AES-NI
+#elif defined(Q_OS_DARWIN)
+    // Everything that runs Catalina and later has AES-NI or ARMv8 crypto instructions
+    return true;
+#else
+    // Assume AES is fast if we don't recognize the OS or processor
+    return true;
+#endif
+}
+
 bool StreamUtils::getNativeDesktopMode(int displayIndex, SDL_DisplayMode* mode)
 {
 #ifdef Q_OS_DARWIN
diff --git a/app/streaming/streamutils.h b/app/streaming/streamutils.h
index 3567b829..4d61a865 100644
--- a/app/streaming/streamutils.h
+++ b/app/streaming/streamutils.h
@@ -33,4 +33,7 @@ public:
 
     static
     int getDisplayRefreshRate(SDL_Window* window);
+
+    static
+    bool hasFastAes();
 };