FLAT_RING3_DS32    20 arch/x86/include/asm/xen/interface_64.h #define FLAT_KERNEL_DS32 FLAT_RING3_DS32
FLAT_RING3_DS32    30 arch/x86/include/asm/xen/interface_64.h #define FLAT_USER_DS32 FLAT_RING3_DS32