fix(renderer): resolve delayed GPU page faults through buffer and texture caches

src/graphics/host_gpu/renderer/cache/bufferCache.cpp

@@ -394,6 +394,7 @@ void BufferCache::InvalidateMemory(uint64_t vaddr, uint64_t size) {
 }
 
 void BufferCache::ReadMemory(uint64_t vaddr, uint64_t size) {
+	(void)SynchronizeBacking(vaddr, size);
 	std::vector<DownloadCopy> copies;
 	{
 		FaultSafeCacheLock lock(this, m_mutex);
@@ -426,7 +427,7 @@ void BufferCache::ReadMemory(uint64_t vaddr, uint64_t size) {
 		    });
 	}
 	if (copies.empty()) {
-		EXIT("BufferCache: GPU-owned invalidation has no dirty byte ranges\n");
+		return;
 	}
 	auto downloads = RecordDownloads(copies);
 	m_scheduler.FinishCurrent();

src/graphics/host_gpu/renderer/cache/bufferCache.h

@@ -50,6 +50,7 @@ public:
 	[[nodiscard]] bool InvalidateMemory(PageFaultAccess access, uint64_t vaddr, uint64_t size,
 	                                    PageFaultPhase phase) noexcept;
 	void               InvalidateMemory(uint64_t vaddr, uint64_t size);
+	void               ReadMemory(uint64_t vaddr, uint64_t size);
 	void               UnmapMemory(uint64_t vaddr, uint64_t size);
 	[[nodiscard]] BufferBinding ObtainBuffer(CommandBuffer& command, uint64_t vaddr, uint64_t size,
 	                                         bool is_written = false, bool is_read = true,
@@ -111,7 +112,6 @@ private:
 	void QueueGarbageDownload(std::span<const DownloadCopy> copies, RetiredBuffer retire);
 	void RefreshInvalidatedRanges(CommandBuffer& command, CachedBuffer& cached, uint64_t vaddr,
 	                              uint64_t size, bool upload);
-	void ReadMemory(uint64_t vaddr, uint64_t size);
 	void DiscardGpuDirtyBytesLocked(uint64_t vaddr, uint64_t size, const char* operation);
 	void WriteHostMemory(uint64_t vaddr, std::span<const uint8_t> data);
 

src/graphics/host_gpu/renderer/cache/gpuResourceManager.cpp

@@ -36,7 +36,8 @@ bool GpuResourceManager::InvalidateMemory(PageFaultAccess access, uint64_t vaddr
 }
 
 bool GpuResourceManager::HandleFault(PageFaultAccess access, uint64_t fault_vaddr) noexcept {
-	if (!m_page_manager.IsMapped(fault_vaddr, 1)) {
+	constexpr uint64_t fault_size = 8;
+	if (!IsMapped(fault_vaddr, fault_size)) {
 		return false;
 	}
 	if (CommandScheduler::InDeferredOperation()) {
@@ -47,10 +48,15 @@ bool GpuResourceManager::HandleFault(PageFaultAccess access, uint64_t fault_vadd
 	bool       handled = false;
 	const auto resolve = [this, access, fault_vaddr, &handled](CommandProcessor& cp) {
 		cp.BeginReadbackTransaction();
-		(void)m_buffer_cache.SynchronizeBacking(fault_vaddr, 1);
 		{
 			ResourceMutex::FaultScope fault(m_resource_mutex);
-			handled = m_page_manager.HandleFault(access, fault_vaddr);
+			if (access == PageFaultAccess::Write) {
+				m_buffer_cache.InvalidateMemory(fault_vaddr, fault_size);
+				m_texture_cache.InvalidateMemory(fault_vaddr, fault_size);
+			} else {
+				m_buffer_cache.ReadMemory(fault_vaddr, fault_size);
+			}
+			handled = true;
 		}
 		cp.EndReadbackTransaction();
 	};