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From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 2/2] VirtIO RNG
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To: Ian Molton <ian.molton@collabora.co.uk>
Cc: Paul Brook <paul@codesourcery.com>, qemu-devel@nongnu.org

On 04/20/10 23:31, Ian Molton wrote:

> Using virtio-rng means that the data is going into the guest
> kernels hwrng subsystem.

Which is *the* major advantage of the virtio-rng driver.  In case the 
guest kernel is recent enougth to have support for it, it will 
JustWork[tm].  No need for guest configuration, no need for some 
userspace tool.  I'd like to see this driver being merged.

With any kind of serial port (be it a emulated 16550 or virtio-serial) 
you'll need some daemon running inside the guest grabbing entropy data 
from the port and feeding it back into the kernel.  Nobody prevents you 
from doing that if you want (or have to due to lack of virtio-rng 
support in the guest).  Just link the port with the egd chardev and 
configure the guest accordingly.

cheers,
   Gerd