ID_AA64MMFR1_VMIDBITS_SHIFT
#define ID_AA64MMFR1_VMIDBITS_MASK (0xf << ID_AA64MMFR1_VMIDBITS_SHIFT)
#define ID_AA64MMFR1_VMIDBITS_8 (0x0 << ID_AA64MMFR1_VMIDBITS_SHIFT)
#define ID_AA64MMFR1_VMIDBITS_16 (0x2 << ID_AA64MMFR1_VMIDBITS_SHIFT)