Same release/acquire fence pattern as the other PCI drivers.
The ixgbe (10 GbE) has the same hand-off semantics as e1000/rtl8168
(OWN/OWN-bit), so the same ordering is required: release fence
before TDT (TX doorbell) and RDT (RX doorbell), and an acquire
fence before reading the descriptor status.
The Linux ixgbe driver applies the same fences in the same
places; see afadba9..c17924b in the upstream tree. The original
Redox port from ixy.rs didn't carry them, which is a real bug
on aarch64 (or on any future cache-coherent extension).
Red Bear OS
f904dbbb4c