> +struct sgx_encl_page { > + unsigned long addr; > + unsigned int flags; > + void *epc_page; > + struct sgx_va_page *va_page; > + unsigned int va_offset; > + struct list_head list; > +}; This can be without major streches hoops packed way more. There are 12 bits free for use in the addr field. I can use low three bits for flags and upper nine bits for va_offset. I think I can also quite easily union epc_page and va_page fields. With these changes the struct would shrink to: struct sgx_encl_page { unsigned long addr; union { void *epc_page; struct sgx_va_page *va_page; }; struct list_head list; }; I can rework this for v7. /Jarkko