High-performance I/O in Virtual Machines

SR-IOV et al is really cool, but it still leaves open the problems of hairpin routing, firewall enforcement, etc where the alacrity approach really helps. There is talk of hardware answers to that too, but its further down the pipe. This kind of hardware is going to be substantially more expensive in the short term as well, so having more efficient answers in software is a plus for the ecosystem overall.

Also interesting, not long after this article was published there was a patch made available to virtio (for pure kvm) that reduces the trips through userspace for that code too: https://lists.linux-foundation.org/pipermail/virtualizati...