From: "H. Peter Anvin" <hpa@zytor.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>,
Anthony Liguori <aliguori@us.ibm.com>,
Andreas Faerber <afaerber@suse.de>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support
Date: Wed, 31 Oct 2012 07:15:15 -0700 [thread overview]
Message-ID: <50913273.5010502@zytor.com> (raw)
In-Reply-To: <5090D36C.9080807@redhat.com>
On 10/31/2012 12:29 AM, Paolo Bonzini wrote:
>
> Related to this, rdrand's "entropy content" in the worst case will be
> only 1/255th of the data it produces: Intel documents that one 256-bit
> seed will result in up to 1022 64-bit random numbers. Yet, it is good
> enough to drive rngd. Would it make sense for QEMU to implement the
> same kind of stretching of /dev/random data, to avoid depleting the
> host's entropy pool too fast?
>
Absolutely not; in fact, we have to do data reduction in rngd for
exactly this reason (and a Qemu backend would have to do the same).
There is a new RDSEED instruction in newer CPUs to correct this.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-10-31 14:15 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 14:43 [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support Anthony Liguori
2012-10-26 14:43 ` [Qemu-devel] [PATCH 1/6] vl: add -object option to create QOM objects from the command line Anthony Liguori
2012-10-26 14:43 ` [Qemu-devel] [PATCH 2/6] object: add object_property_add_bool (v2) Anthony Liguori
2012-10-26 14:43 ` [Qemu-devel] [PATCH 3/6] rng: add RndBackend abstract object class Anthony Liguori
2012-10-26 14:43 ` [Qemu-devel] [PATCH 4/6] rng-random: add an RNG backend that uses /dev/random Anthony Liguori
2012-10-26 14:43 ` [Qemu-devel] [PATCH 5/6] rng-egd: introduce EGD compliant RNG backend Anthony Liguori
2012-10-26 14:43 ` [Qemu-devel] [PATCH 6/6] virtio-rng: hardware random number generator device Anthony Liguori
2012-10-26 15:08 ` [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support Paolo Bonzini
2012-10-26 15:42 ` Anthony Liguori
2012-10-26 16:09 ` H. Peter Anvin
2012-10-26 18:24 ` Anthony Liguori
2012-10-26 18:26 ` H. Peter Anvin
2012-10-29 6:23 ` Amit Shah
2012-10-30 4:32 ` H. Peter Anvin
2012-10-26 18:58 ` Paolo Bonzini
2012-10-26 19:07 ` H. Peter Anvin
2012-10-26 19:51 ` Paolo Bonzini
2012-10-26 19:54 ` H. Peter Anvin
2012-10-26 20:29 ` H. Peter Anvin
2012-10-29 8:45 ` Paolo Bonzini
2012-10-30 4:34 ` H. Peter Anvin
2012-10-30 4:43 ` H. Peter Anvin
2012-10-30 9:05 ` Paolo Bonzini
2012-10-30 21:11 ` H. Peter Anvin
2012-10-31 7:29 ` Paolo Bonzini
2012-10-31 14:15 ` H. Peter Anvin [this message]
2012-10-31 14:27 ` Paolo Bonzini
2012-10-26 18:53 ` Paolo Bonzini
2012-10-29 7:01 ` Amit Shah
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