Re: [RFC PATCH] hwrng: sysfs entry rng_seed_kernel, was: "Re: [PATCH v2 1/2] hwrng: fetch randomness only after device init"

From: Amit Shah
Date: Fri Jul 11 2014 - 09:27:16 EST

On (Wed) 09 Jul 2014 [12:07:25], Jason Cooper wrote:
> Amit, Kees,


> I'm cooling to the idea of the init function for virtio-rng, and it
> might be best just to admit that there's no way to seed the entropy pool
> from the virtio-rng at probe time. After all, once userspace is up, the
> system should take advantage of /dev/hwrng for the generation of
> long-term keys. Either via rngd feeding /dev/random, or directly.
> As for the follow-on patch you asked about, I think that's fine. More
> entropy can't hurt.
> The below patch might be worth considering so that the user of a system
> with only virtio-rng can kick the entropy pool as they see fit. It's
> probably not too kosher as is, but if the idea is liked, I could clean
> it up and submit.
> The advantage is that users don't need to have rngd installed and
> running on the system in order to jump-start the entropy pool.

... so a udev rule that looks for the new sysfs file, and asks the
kernel to do its thing?

And maybe even a patch to rngd that looks for this file and does a
similar thing?

There's also the option to use a delayed workqueue item, that will
succeed if probe has finished. This method doesn't have userspace


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