From fbab9524726f378be6e194007f528f7347d48249 Mon Sep 17 00:00:00 2001
From: Stephen Miller <56742918+StevenMiller123@users.noreply.github.com>
Date: Thu, 15 May 2025 13:37:34 -0500
Subject: [PATCH] Attempt to handle MemoryMapFlags::NoOverwrite

Based on my interpretation of red_prig's descriptions. These changes are untested, as I'm not able to test right now.
---
 src/core/memory.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/core/memory.cpp b/src/core/memory.cpp
index 0778fe47d..f97023421 100644
--- a/src/core/memory.cpp
+++ b/src/core/memory.cpp
@@ -376,11 +376,17 @@ int MemoryManager::MapMemory(void** out_addr, VAddr virtual_addr, size_t size, M
         // To account for this, unmap any reserved areas within this mapping range first.
         auto unmap_addr = mapped_addr;
         auto unmap_size = size;
-        while (!vma.IsMapped() && unmap_addr < mapped_addr + size && remaining_size < size) {
+        // If flag NoOverwrite is provided, allow overwriting mapped VMAs.
+        // Otherwise, we can only overwrite unmapped or reserved VMAs.
+        auto should_overwrite = False(flags & MemoryMapFlags::NoOverwrite) || !vma.IsMapped();
+        while (should_overwrite && unmap_addr < mapped_addr + size && remaining_size < size) {
             auto unmapped = UnmapBytesFromEntry(unmap_addr, vma, unmap_size);
             unmap_addr += unmapped;
             unmap_size -= unmapped;
+            // Unmap addr should be the address of the next VMA
+            // if the previous VMA is fully unmapped.
             vma = FindVMA(unmap_addr)->second;
+            should_overwrite = False(flags & MemoryMapFlags::NoOverwrite) || !vma.IsMapped();
         }
 
         vma = FindVMA(mapped_addr)->second;