From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Xen-devel] [RFC] Hypervisor RNG and enumeration
Date: Wed, 29 Oct 2014 15:01:13 +0100
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To: David Vrabel <david.vrabel@citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Andy Lutomirski <luto@amacapital.net>, Linux Virtualization <virtualization@lists.linux-foundation.org>
Cc: Mathew John <mathewj@microsoft.com>, Theodore Ts'o <tytso@mit.edu>, Jim Mattson <jmattson@vmware.com>, kvm list <kvm@vger.kernel.org>, Gleb Natapov <gleb@kernel.org>, Niels Ferguson <niels@microsoft.com>, Doug Covelli <dcovelli@vmware.com>, David Hepkin <davidhep@microsoft.com>, "H. Peter Anvin" <hpa@zytor.com>, Jake Oshins <jakeo@microsoft.com>, xen-devel@lists.xenproject.org, Alok Kataria <akataria@vmware.com>, John Starks <John.Starks@microsoft.com>
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On 10/29/2014 02:57 PM, David Vrabel wrote:
> Microsoft already has a specification to obtain a random number via an
> ACPI device.  The VM Generation ID.
> 
> http://www.microsoft.com/en-us/download/details.aspx?id=30707

That's a very different thing.  The VM Generation ID always returns the
same number if you run the VM from the same configuration file.

It tells the VM when it might need a reseed, but provides neither a best
effort random number like this spec does, nor an entropy source like
virtio-rng does.

Paolo