IOC_IMASK
iova_space_size = ~(READ_REG(ioc->ioc_hpa + IOC_IMASK) & 0xFFFFFFFFUL) + 1;
WRITE_REG(ioc->imask, ioc->ioc_hpa + IOC_IMASK);
WRITE_REG(ioc->imask, ioc->ioc_hpa+IOC_IMASK);
DBG_INIT("IOC_IMASK : 0x%Lx\n", READ_REG64(hpa+IOC_IMASK));