From: Jeff Garzik <jgarzik@pobox.com>
To: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
Fenghua Yu <fenghua.yu@intel.com>, Matt Mackall <mpm@selenic.com>,
Herbert Xu <herbert@gondor.hengli.com.au>,
"Theodore Ts'o" <tytso@mit.edu>,
linux-kernel@vger.kernel.org
Subject: Re: [RFD] Direct support for the x86 RDRAND instruction
Date: Fri, 29 Jul 2011 17:05:38 -0400 [thread overview]
Message-ID: <4E3320A2.1040808@pobox.com> (raw)
In-Reply-To: <1311971867-25124-1-git-send-email-hpa@linux.intel.com>
On 07/29/2011 04:37 PM, H. Peter Anvin wrote:
> From: "H. Peter Anvin"<hpa@linux.intel.com>
>
> This is a proposed patchset to enable the new x86 RDRAND instruction,
> labelled "Bull Mountain Technology" by Intel. It is a different beast
> than any other hardware random number generator that I have personally
> encountered: it is not just a random number source, but contains a
> high bandwidth random number generator, an AES cryptographic whitener,
> and integrity monitoring all in hardware.
>
> For technical documentation see:
>
> http://software.intel.com/en-us/articles/download-the-latest-bull-mountain-software-implementation-guide/
>
> This proposed patchset enables RDRAND bypass for current users of the
> nonblocking random pool (that is, for /dev/urandom and its equvalent
> in-kernel users) but not for the blocking pool (/dev/random). This is
> because RDRAND, although reseeded way more frequently than what is
> practical to do in software, is technically a nonblocking source that
> can behave as a PRNG. It can be used as a source for randomness for
> /dev/random, but that is not addressed by this patchset.
This does not cover the one question I [predictably] have: why not do
this in rngd, rather than the kernel?
Since many (all?) TPM chips include a random number generator, Dell has
made sure that most distros have a useful copy of the rng-tools
userspace pkg I've been maintaining.
It would seem straightforward to add this to rngd, and enable RDRAND on
older distros and kernels, as well as current distros / kernels. This
also gets useful entropy to /dev/random as part of normal operation,
rather than only merely speeding up /dev/urandom.
Though for the record, I do agree that this is a nice, small and clean
kernel implementation.
Jeff
next prev parent reply other threads:[~2011-07-29 21:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-29 20:37 [RFD] Direct support for the x86 RDRAND instruction H. Peter Anvin
2011-07-29 20:37 ` [PATCH 1/2] random: Add support for architectural random hooks H. Peter Anvin
2011-07-29 21:16 ` Matt Mackall
2011-07-30 6:20 ` Linus Torvalds
2011-07-30 16:34 ` Arjan van de Ven
2011-07-30 17:45 ` Matt Mackall
2011-07-30 18:20 ` Linus Torvalds
2011-07-30 19:13 ` Matt Mackall
2011-07-30 19:29 ` Linus Torvalds
2011-07-30 22:25 ` Ted Ts'o
2011-07-31 1:13 ` Linus Torvalds
2011-07-31 1:32 ` H. Peter Anvin
2011-07-31 1:43 ` Linus Torvalds
2011-07-31 21:26 ` [PATCH v3 0/3] Add support for architectural random number generator H. Peter Anvin
2011-07-31 21:26 ` [PATCH v3 1/3] random: Add support for architectural random hooks H. Peter Anvin
2011-07-31 21:26 ` [PATCH v3 2/3] x86, random: Architectural inlines to get random integers with RDRAND H. Peter Anvin
2011-07-31 21:26 ` [PATCH v3 3/3] x86, random: Verify RDRAND functionality and allow it to be disabled H. Peter Anvin
2011-08-05 12:00 ` [PATCH v3 0/3] Add support for architectural random number generator Herbert Xu
2011-08-05 16:28 ` H. Peter Anvin
2011-08-06 0:09 ` Herbert Xu
2011-07-29 20:37 ` [PATCH 2/2] x86, random: " H. Peter Anvin
2011-07-29 21:05 ` Jeff Garzik [this message]
2011-07-29 21:17 ` [RFD] Direct support for the x86 RDRAND instruction H. Peter Anvin
2011-07-30 6:03 ` Linus Torvalds
2011-07-30 22:26 ` [PATCH v2 0/2] Add support for architectural random number generator H. Peter Anvin
2011-07-30 22:26 ` [PATCH v2 1/2] random: Add support for architectural random hooks H. Peter Anvin
2011-07-30 22:26 ` [PATCH v2 2/2] x86, random: Add support for architectural random number generator H. Peter Anvin
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