From 0c646f4bc2945b0593cd5c338d174bf2ef24ae91 Mon Sep 17 00:00:00 2001
From: Ben Vanik <ben.vanik@gmail.com>
Date: Sat, 9 May 2015 00:53:28 -0700
Subject: [PATCH] Prevent some stack overflows in MMIO handler.

---
 src/xenia/cpu/mmio_handler.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/xenia/cpu/mmio_handler.cc b/src/xenia/cpu/mmio_handler.cc
index c9f17eaca..b9e58fff6 100644
--- a/src/xenia/cpu/mmio_handler.cc
+++ b/src/xenia/cpu/mmio_handler.cc
@@ -185,6 +185,11 @@ bool MMIOHandler::CheckWriteWatch(void* thread_state, uint64_t fault_address) {
 
 bool MMIOHandler::HandleAccessFault(void* thread_state,
                                     uint64_t fault_address) {
+  if (fault_address < uint64_t(mapping_base_)) {
+    // Quick kill anything below our mapping base.
+    return false;
+  }
+
   // Access violations are pretty rare, so we can do a linear search here.
   const MMIORange* range = nullptr;
   for (const auto& test_range : mapped_ranges_) {