lkml.org 
[lkml]   [2013]   [Sep]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Resend PATCH 2/2] s390: provide hardware randomness from zcrypt card to /dev/random
On 09/12/2013 02:41 AM, Torsten Duwe wrote:
>
> Running completely virtualised, system Z severely lacks good true random sources.
> Gathering entropy in a virtual environment is difficult. To compensate, there is
> specialised crypto hardware which includes a source for hardware randomness;
> the zcrypt driver is able to access this random source. This patch adds a kernel
> thread that feeds the random bits via the interface created with the previous patch.
>
> Signed-off-by: Torsten Duwe <duwe@lst.de>

From what I can gather from the patch this is too heavyweight (need
locks and so on) to use as arch_get_random*(). There has been a lot of
discussion about the pros and cons of allowing the kernel to bypass
rngd, but I would think that any such plumbing -- once it gets past the
fully synchronous low latency properties of arch_get_random*() -- really
should be implemented as an option in the existing hwrng device
infrastructure.

In other words, start by implementing a hwrng device. That will work
right now with rngd running. Then we can consider if we want to allow
bypass of rngd for certain hwrng devices -- which may include zcrypt,
virtio_rng and so on.

-hpa




\
 
 \ /
  Last update: 2013-09-13 00:21    [W:0.095 / U:0.540 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site