From 33f5d9cb9c687f4952a7090f0cab45f076308274 Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Thu, 16 Mar 2023 19:33:59 +1000
Subject: [PATCH] System: Remove BIOS from save state

Makes the states smaller, as well as not creating potential piracy
issues when sending across the wire.
---
 src/core/bus.cpp              |  8 +++++++-
 src/core/save_state_version.h |  2 +-
 src/core/system.cpp           | 17 +++++++++++++++++
 src/util/state_wrapper.cpp    | 11 +++++++++++
 src/util/state_wrapper.h      |  3 ++-
 5 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/core/bus.cpp b/src/core/bus.cpp
index ec5e85d2b..13c591ef1 100644
--- a/src/core/bus.cpp
+++ b/src/core/bus.cpp
@@ -211,7 +211,13 @@ bool DoState(StateWrapper& sw)
   sw.Do(&m_cdrom_access_time);
   sw.Do(&m_spu_access_time);
   sw.DoBytes(g_ram, g_ram_size);
-  sw.DoBytes(g_bios, BIOS_SIZE);
+
+  if (sw.GetVersion() < 58)
+  {
+    Log_WarningPrint("Overwriting loaded BIOS with old save state.");
+    sw.DoBytes(g_bios, BIOS_SIZE);
+  }
+
   sw.DoArray(m_MEMCTRL.regs, countof(m_MEMCTRL.regs));
   sw.Do(&m_ram_size_reg);
   sw.Do(&m_tty_line_buffer);
diff --git a/src/core/save_state_version.h b/src/core/save_state_version.h
index 248ecb303..29bbdc7b0 100644
--- a/src/core/save_state_version.h
+++ b/src/core/save_state_version.h
@@ -5,7 +5,7 @@
 #include "types.h"
 
 static constexpr u32 SAVE_STATE_MAGIC = 0x43435544;
-static constexpr u32 SAVE_STATE_VERSION = 57;
+static constexpr u32 SAVE_STATE_VERSION = 58;
 static constexpr u32 SAVE_STATE_MINIMUM_VERSION = 42;
 
 static_assert(SAVE_STATE_VERSION >= SAVE_STATE_MINIMUM_VERSION);
diff --git a/src/core/system.cpp b/src/core/system.cpp
index c05ae33e6..2e01579d6 100644
--- a/src/core/system.cpp
+++ b/src/core/system.cpp
@@ -1661,6 +1661,23 @@ bool System::DoState(StateWrapper& sw, GPUTexture** host_texture, bool update_di
   sw.Do(&s_frame_number);
   sw.Do(&s_internal_frame_number);
 
+  // Don't bother checking this at all for memory states, since they won't have a different BIOS...
+  if (!is_memory_state)
+  {
+    BIOS::Hash bios_hash = s_bios_hash;
+    sw.DoBytesEx(bios_hash.bytes, sizeof(bios_hash.bytes), 58, s_bios_hash.bytes);
+    if (bios_hash != s_bios_hash)
+    {
+      Log_WarningPrintf("BIOS hash mismatch: System: %s | State: %s", s_bios_hash.ToString().c_str(),
+                        bios_hash.ToString().c_str());
+      Host::AddKeyedOSDMessage(
+        "StateBIOSMismatch",
+        Host::TranslateStdString("OSDMessage", "This save state was created with a different BIOS version or patch "
+                                               "options. This may cause stability issues."),
+        10.0f);
+    }
+  }
+
   if (!sw.DoMarker("CPU") || !CPU::DoState(sw))
     return false;
 
diff --git a/src/util/state_wrapper.cpp b/src/util/state_wrapper.cpp
index 6e9d353f7..9e4ec032c 100644
--- a/src/util/state_wrapper.cpp
+++ b/src/util/state_wrapper.cpp
@@ -29,6 +29,17 @@ void StateWrapper::DoBytes(void* data, size_t length)
   }
 }
 
+void StateWrapper::DoBytesEx(void* data, size_t length, u32 version_introduced, const void* default_value)
+{
+  if (m_mode == Mode::Read && m_version < version_introduced)
+  {
+    std::memcpy(data, default_value, length);
+    return;
+  }
+
+  DoBytes(data, length);
+}
+
 void StateWrapper::Do(bool* value_ptr)
 {
   if (m_mode == Mode::Read)
diff --git a/src/util/state_wrapper.h b/src/util/state_wrapper.h
index a4b71905f..d9ec78058 100644
--- a/src/util/state_wrapper.h
+++ b/src/util/state_wrapper.h
@@ -104,6 +104,7 @@ public:
   }
 
   void DoBytes(void* data, size_t length);
+  void DoBytesEx(void* data, size_t length, u32 version_introduced, const void* default_value);
 
   void Do(bool* value_ptr);
   void Do(std::string* value_ptr);
@@ -182,7 +183,7 @@ public:
   template<typename T>
   void DoEx(T* data, u32 version_introduced, T default_value)
   {
-    if (m_version < version_introduced)
+    if (m_mode == Mode::Read && m_version < version_introduced)
     {
       *data = std::move(default_value);
       return;