From: "H. Peter Anvin" <hpa@linux.intel.com>
To: Torsten Duwe <duwe@lst.de>, Amit Shah <amit.shah@redhat.com>
Cc: jgarzik@bitpay.com,
Virtualization List <virtualization@lists.linux-foundation.org>,
Amos Kong <akong@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Subject: Re: [PATCH 1/2] rngd: add udev rule to source from hwrng if virtio-rng present
Date: Mon, 11 Aug 2014 09:50:20 -0700 [thread overview]
Message-ID: <53E8F44C.7030803@linux.intel.com> (raw)
In-Reply-To: <20140811133030.GA27247@lst.de>
On 08/11/2014 06:30 AM, Torsten Duwe wrote:
> On Mon, Aug 11, 2014 at 12:45:27PM +0530, Amit Shah wrote:
>>
>> What's the suggested value for rng->quality, though, for virtio-rng
>> that I can use to ensure the kthread starts?
>>
>> Should I use the 700 (70%) as proposed in the original patchset? I'm
>> not exactly sure how that value will be used as well..
>
> There is no such thing as a suggested value, every number is wrong
> to some degree. The quality is an estimation of how random your
> source really is; it's a property of your hardware. If the device is
> virtual you're in trouble ;-)
>
> Either you have a way to query the underlying real hardware, or
> you do your whitening and entropy estimation in the backend driver --
> then you can claim 100%.
>
virtio-rng I feel we could rank at 100%; it is supposed to feed
/dev/random-quality randomness from the VMM. If the VMM is hostile you
have already lost anyway.
-hpa
next prev parent reply other threads:[~2014-08-11 16:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-07 13:08 [PATCH 0/2] rng-tools: add udev rule for virtio-rng Amit Shah
2014-08-07 13:08 ` [PATCH 1/2] rngd: add udev rule to source from hwrng if virtio-rng present Amit Shah
2014-08-07 19:31 ` H. Peter Anvin
2014-08-08 9:07 ` Amit Shah
2014-08-08 21:46 ` H. Peter Anvin
2014-08-11 7:15 ` Amit Shah
2014-08-11 13:30 ` Torsten Duwe
2014-08-11 16:50 ` H. Peter Anvin [this message]
2014-08-07 13:09 ` [PATCH 2/2] Install udev rules in system-default directory Amit Shah
[not found] ` <3df55388b1b3acd142f391494f102c3ddb2270ed.1407416628.git.amit.shah__45224.3810439997$1407417016$gmane$org@redhat.com>
2014-08-19 17:20 ` Paolo Bonzini
2014-08-20 4:36 ` Amit Shah
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