_RING_CTL_BUF_SIZE
s.ring_size = _RING_CTL_BUF_SIZE(workload->rb_ctl);
workload->rb_start, _RING_CTL_BUF_SIZE(workload->rb_ctl));
guest_rb_size = _RING_CTL_BUF_SIZE(workload->rb_ctl);
_RING_CTL_BUF_SIZE(ctl))) {