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Date: Tue, 22 Jul 2014 14:08:02 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Andy Lutomirski <luto@amacapital.net>
CC: "Theodore Ts'o" <tytso@mit.edu>, kvm list <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Kees Cook <keescook@chromium.org>, X86 ML <x86@kernel.org>,
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        Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
        Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
        Gleb Natapov <gleb@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
        Bandan Das <bsd@redhat.com>, Andrew Honig <ahonig@google.com>
Subject: Re: [PATCH v4 2/5] random: Add and use arch_get_rng_seed
References: <cover.1405620944.git.luto@amacapital.net> <9c2a0549519b4eb5eee2d5d480f8e83a574273df.1405620944.git.luto@amacapital.net> <20140722135915.GB25291@thunk.org> <CALCETrVY9KNLsbxhtLRatdb34ZP3XvMyys358dpB3oCKezdBwA@mail.gmail.com> <53CED031.9090907@zytor.com> <CALCETrV3FHinFXSWJsQjnsXM2H5OyuAbR3_1A401raLes6fNAg@mail.gmail.com>
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On 07/22/2014 02:04 PM, Andy Lutomirski wrote:
> 
> Just to check: do you mean the RDRAND is very likely to work (i.e.
> arch_get_random_long will return true) or that RDRAND will actually
> reseed several times during initialization?
> 

I mean that RDRAND will actually reseed several times during
initialization.  The documented architectural limit is actually
extremely conservative.

Either way, it isn't really different from seeding from a VM hosts
/dev/urandom...

	-hpa