FLAT_RING3_CS64 22 arch/x86/include/asm/xen/interface_64.h #define FLAT_KERNEL_CS64 FLAT_RING3_CS64 FLAT_RING3_CS64 32 arch/x86/include/asm/xen/interface_64.h #define FLAT_USER_CS64 FLAT_RING3_CS64