PMCR_EL0
u64 pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0);
if ((__vcpu_sys_reg(vcpu, PMCR_EL0) ^ val) & ARMV8_PMU_PMCR_E)
__vcpu_assign_sys_reg(vcpu, PMCR_EL0, (val & ~(ARMV8_PMU_PMCR_C | ARMV8_PMU_PMCR_P)));
{ PMU_SYS_REG(PMCR_EL0), .access = access_pmcr, .reset = reset_pmcr,
.reg = PMCR_EL0, .get_user = get_pmcr, .set_user = set_pmcr },