Re: [PATCH 0/4] random,x86,kvm: Add and use MSR_KVM_GET_RNG_SEED

[Daniel Borkmann]

On 07/16/2014 08:41 AM, Gleb Natapov wrote:
> On Tue, Jul 15, 2014 at 07:48:06PM -0700, Andy Lutomirski wrote:
> > virtio-rng is both too complicated and insufficient for initial rng
> > seeding.  It's far too complicated to use for KASLR or any other
> > early boot random number needs.  It also provides /dev/random-style
> > bits, which means that making guest boot wait for virtio-rng is
> > unacceptably slow, and doing it asynchronously means that
> > /dev/urandom might be predictable when userspace starts.
> >
> > This introduces a very simple synchronous mechanism to get
> > /dev/urandom-style bits.
>
> Why can't you use RDRAND instruction for that?

You mean using it directly? I think simply for the very same reasons
as in c2557a303a ...
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