video_core/memory_manager: Add GPU address based flush method

Allow flushing rasterizer contents based on a GPU address.

src/video_core/memory_manager.cpp

@@ -314,6 +314,21 @@ void MemoryManager::WriteBlockUnsafe(GPUVAddr gpu_dest_addr, const void* src_buf
     }
 }
 
+void MemoryManager::FlushRegion(GPUVAddr gpu_addr, size_t size) const {
+    size_t remaining_size{size};
+    size_t page_index{gpu_addr >> page_bits};
+    size_t page_offset{gpu_addr & page_mask};
+    while (remaining_size > 0) {
+        const size_t num_bytes{std::min(page_size - page_offset, remaining_size)};
+        if (const auto page_addr{GpuToCpuAddress(page_index << page_bits)}; page_addr) {
+            rasterizer->FlushRegion(*page_addr + page_offset, num_bytes);
+        }
+        ++page_index;
+        page_offset = 0;
+        remaining_size -= num_bytes;
+    }
+}
+
 void MemoryManager::CopyBlock(GPUVAddr gpu_dest_addr, GPUVAddr gpu_src_addr, std::size_t size) {
     std::vector<u8> tmp_buffer(size);
     ReadBlock(gpu_src_addr, tmp_buffer.data(), size);

src/video_core/memory_manager.h

@@ -131,6 +131,8 @@ private:
     void TryLockPage(PageEntry page_entry, std::size_t size);
     void TryUnlockPage(PageEntry page_entry, std::size_t size);
 
+    void FlushRegion(GPUVAddr gpu_addr, size_t size) const;
+
     [[nodiscard]] static constexpr std::size_t PageEntryIndex(GPUVAddr gpu_addr) {
         return (gpu_addr >> page_bits) & page_table_mask;
     }