From 463a096249bcf3f39414d6986f9e1456fd322f22 Mon Sep 17 00:00:00 2001
From: nmzik <Nmzik@mail.ru>
Date: Sun, 25 Oct 2026 03:50:55 +0100
Subject: [PATCH] graphics: unwatch image heap pages on writes next to a table

---
 src/graphics/host_gpu/renderer/pipeline/imageHeap.cpp |  8 +++++---
 tests/ShaderRecompilerComputeTests.cpp                | 11 +++++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/graphics/host_gpu/renderer/pipeline/imageHeap.cpp b/src/graphics/host_gpu/renderer/pipeline/imageHeap.cpp
index 7c1c50e8c..0258f4256 100644
--- a/src/graphics/host_gpu/renderer/pipeline/imageHeap.cpp
+++ b/src/graphics/host_gpu/renderer/pipeline/imageHeap.cpp
@@ -254,10 +254,12 @@ void ImageHeap::Unwatch(const Memory& memory) {
 void ImageHeap::InvalidateMemory(uint64_t address, uint64_t size) {
 	std::scoped_lock lock {m_mutex};
 	for (auto& memory: m_memories) {
-		const auto begin = std::max(address, memory->base);
-		const auto end   = std::min(address + size, memory->base + memory->size);
-		if (begin >= end) continue;
+		// Watches cover whole pages, so a write next to the table must unwatch its page too.
 		const auto origin = Common::AlignDown(memory->base, TRACKER_PAGE_SIZE);
+		const auto begin  = std::max(address, origin);
+		const auto end    = std::min(address + size,
+		                             origin + memory->dirty_pages.size() * TRACKER_PAGE_SIZE);
+		if (begin >= end) continue;
 		MarkDirty(*memory, (begin - origin) / TRACKER_PAGE_SIZE,
 		          (end - 1u - origin) / TRACKER_PAGE_SIZE + 1u);
 	}
diff --git a/tests/ShaderRecompilerComputeTests.cpp b/tests/ShaderRecompilerComputeTests.cpp
index 90aa7beb3..cdc8210b7 100644
--- a/tests/ShaderRecompilerComputeTests.cpp
+++ b/tests/ShaderRecompilerComputeTests.cpp
@@ -242,6 +242,10 @@ struct ImageHeapTestAccess {
   static ImageId ImageOf(const ImageHeap &heap, uint32_t entry) {
     return Element(heap, entry).binding.image_id;
   }
+  // Whether the newest table no longer watches its last page.
+  static bool TailPageDirty(const ImageHeap &heap) {
+    return heap.m_memories.back()->dirty_pages.back() != 0u;
+  }
 };
 
 struct TextureCacheTestAccess {
@@ -5518,6 +5522,13 @@ public:
               acquire(sampled, idle_table) && view.kinds.empty() &&
                   ImageHeapTestAccess::MemoryCount(heap) == 1u,
               "an all-null table was not kept resident");
+      // A write past a table's end, in its watched tail page, must unwatch the page.
+      constexpr uint64_t unaligned_table = base + 0x1a0800;
+      Require(name, "tail page fault",
+              acquire(sampled, unaligned_table) &&
+                  context.HandleFault(PageFaultAccess::Write, unaligned_table + table_size) &&
+                  ImageHeapTestAccess::TailPageDirty(heap),
+              "a write fault next to a table left its page watched");
       draw();
       context.UnmapMemory(base, idle_table - base);
       scheduler.Finish();