Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support

[H. Peter Anvin]

On 10/28/2012 11:23 PM, Amit Shah wrote:
> One solution could be to feed host's /dev/urandom to readers of
> guests' /dev/urandom.  We could then pass the rare true entropy bits
> from host's /dev/hwrng or /dev/random to the guest via
> virtio-rng-pci's /dev/hwrng interface in the guest.
>
> If this is a valid idea (host /dev/urandom goes directly to guest's
> /dev/urandom), we would need some guest-side surgery, but it shouldn't
> be huge work, and would remove several bottlenecks.
>
> Is this a very crazy idea?

It's not crazy, it's just pointless.  You're doing a completely 
unnecessary hypercall to run the PRNG in host space.

        -hpa


--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.