virt_to_page
page_to_phys(virt_to_page(fbi->screen_buffer));
SetPageReserved(virt_to_page((void *)addr));
ClearPageReserved(virt_to_page((void *)addr));
kunmap(virt_to_page(addr));
__free_page(virt_to_page(addr));
struct page *page = virt_to_page(engine->status_page.page_addr);
d_page->p = virt_to_page(vaddr);