GEN4_IM23XLMT_OFFSET
iowrite64(bar_addr, mmio + GEN4_IM23XLMT_OFFSET);
bar_addr = ioread64(mmio + GEN4_IM23XLMT_OFFSET);
u.v64 = ioread64(mmio + GEN4_IM23XLMT_OFFSET);
.bar2_limit = GEN4_IM23XLMT_OFFSET,