From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on
 some powernv systems
Date: Tue, 01 Oct 2013 11:58:11 +0200
Message-ID: <524A9CB3.6030103@redhat.com>
References: <1380177066-3835-1-git-send-email-michael@ellerman.id.au> <1380177066-3835-3-git-send-email-michael@ellerman.id.au> <5243F933.7000907@redhat.com> <20131001083426.GB27484@concordia>
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Cc: linux-kernel@vger.kernel.org,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>, gleb@redhat.com,
	agraf@suse.de, mpm@selenic.com, herbert@gondor.apana.org.au,
	linuxppc-dev@ozlabs.org, kvm@vger.kernel.org,
	kvm-ppc@vger.kernel.org, tytso@mit.edu
To: Michael Ellerman <michael@ellerman.id.au>
Return-path: <kvm-ppc-owner@vger.kernel.org>
In-Reply-To: <20131001083426.GB27484@concordia>
Sender: kvm-ppc-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

Il 01/10/2013 10:34, Michael Ellerman ha scritto:
>> If you really want to have the hypercall, implementing it in QEMU means
>> that you can support it on all systems, in fact even when running
>> without KVM.  
> 
> Sure, I can add a fallback to /dev/hwrng for full emulation.
> 
>> The QEMU command line would be something like "-object
>> rng-random,filename=/dev/random,id=rng0 -device spapr-rng,rng=rng0".
> 
> We can't use /dev/random like that. The PAPR specification, which is
> what we're implementing, implies that H_RANDOM provides data from a
> hardware source.

Then use /dev/hwrng.

I don't have POWER machines, but I still want to be able to test as much
as possible using emulation.

Paolo