graphics: stream clean guest buffers without backing-store lookups

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

@@ -454,7 +454,8 @@ std::pair<Buffer*, uint64_t> BufferCache::ObtainBuffer(uint64_t vaddr, uint64_t
 		const auto alignment = std::max<uint64_t>(
 		    m_graphics.physical_device_properties.limits.minUniformBufferOffsetAlignment, 1);
 		auto [mapped, offset] = m_stream_buffer.Map(size, alignment, false);
-		if (mapped != nullptr && Libs::LibKernel::Memory::TryReadBacking(vaddr, mapped, size)) {
+		if (mapped != nullptr) {
+			std::memcpy(mapped, reinterpret_cast<const void*>(vaddr), size);
 			m_stream_buffer.Commit();
 			return {&m_stream_buffer, offset};
 		}