UFFD_PAGEFAULT_FLAG_WRITE
msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WRITE;
(void *)addr, !!(flags & UFFD_PAGEFAULT_FLAG_WRITE));
if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
(UFFD_PAGEFAULT_FLAG_WP | UFFD_PAGEFAULT_FLAG_MINOR | UFFD_PAGEFAULT_FLAG_WRITE))