On Saturday 26 January 2013, Mark Kettenis wrote: > > As the entropy reserve of the host may not be unlimited, the > > OpenBSD guest should only ask for entropy when it actually needs > > it. > > If qemu really allows the guest to consume the complete entropy > reserve of the host then that's a bug in qemu and/or the host OS.
That's a red herring. Entropy is a sparse resource on most systems. If the guests don't make any effort to only use as much as they need, the host has no chance to dispense the existing entropy where it is actually needed. > > > Would it make sense to add an API that allows a driver to > > determine how full the entropy queue is? This could also be used > > by some hardware drivers to avoid polling for entropy if not > > necessary. E.g. amdpm does the polling in every timer tick, which > > is wasteful. > > Wasteful in what sense? I doubt that reading the hardware > registers once every 10ms noticibly affects performance of the > system. But many small improvements may give a noticable effect on performance in the end.
