FLAT_RING3_DS64 19 arch/x86/include/asm/xen/interface_64.h #define FLAT_KERNEL_DS64 FLAT_RING3_DS64 FLAT_RING3_DS64 29 arch/x86/include/asm/xen/interface_64.h #define FLAT_USER_DS64 FLAT_RING3_DS64