From d335555277bcb02ba0d753335ef59ecbbac64b87 Mon Sep 17 00:00:00 2001
From: Ben Vanik <ben.vanik@gmail.com>
Date: Tue, 23 Jun 2015 17:37:09 -0700
Subject: [PATCH] Manually page align address range for write watch.

---
 src/xenia/cpu/mmio_handler.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/xenia/cpu/mmio_handler.cc b/src/xenia/cpu/mmio_handler.cc
index 4de22c4ec..95f5a2e54 100644
--- a/src/xenia/cpu/mmio_handler.cc
+++ b/src/xenia/cpu/mmio_handler.cc
@@ -104,7 +104,9 @@ uintptr_t MMIOHandler::AddPhysicalWriteWatch(uint32_t guest_address,
   // This means we need to round up, which will cause spurious access
   // violations and invalidations.
   // TODO(benvanik): only invalidate if actually within the region?
-  length = xe::round_up(length, xe::page_size());
+  length =
+      xe::round_up(length + (base_address % xe::page_size()), xe::page_size());
+  base_address = base_address - (base_address % xe::page_size());
 
   // Add to table. The slot reservation may evict a previous watch, which
   // could include our target, so we do it first.