On Thu, Sep 26, 2013 at 11:06:59AM +0200, Paolo Bonzini wrote: > Il 26/09/2013 08:31, Michael Ellerman ha scritto: > > Some powernv systems include a hwrng. Guests can access it via the > > H_RANDOM hcall. > > Is there any reason to do this in the kernel? It's less code, and it's faster :) > It does not have to be a particularly fast path; Sure, but do we have to make it slow on purpose? > on x86, we are simply forwarding /dev/hwrng or > /dev/random data to the guest. You can simply use virtio-rng. Not all guests support virtio-rng. > If you really want to have the hypercall, implementing it in QEMU means > that you can support it on all systems, in fact even when running > without KVM. Sure, I can add a fallback to /dev/hwrng for full emulation. > The QEMU command line would be something like "-object > rng-random,filename=/dev/random,id=rng0 -device spapr-rng,rng=rng0". We can't use /dev/random like that. The PAPR specification, which is what we're implementing, implies that H_RANDOM provides data from a hardware source. cheers -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
