XEN_IPL2SIR
int sir = XEN_IPL2SIR(ih->ih_level);
iplmask &= ~(1ULL << XEN_IPL2SIR(ih->ih_level));
evts->ev_imask |= (1 << XEN_IPL2SIR(ih->ih_level));
int sir = XEN_IPL2SIR(ih->ih_level);
int sir = XEN_IPL2SIR(level);