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Message-ID: <1380751112.645.64.camel@pasglop>
Subject: Re: [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on
 some powernv systems
From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: Alexander Graf <agraf@suse.de>
Date: Thu, 03 Oct 2013 07:58:32 +1000
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Cc: tytso@mit.edu, kvm@vger.kernel.org, Gleb Natapov <gleb@redhat.com>,
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On Wed, 2013-10-02 at 11:11 +0200, Alexander Graf wrote:

> Right, and the difference for the patch in question is really whether
> we handle in in kernel virtual mode or in QEMU, so the bulk of the
> overhead (kicking threads out of  guest context, switching MMU
> context, etc) happens either way.
> 
> So the additional overhead when handling it in QEMU here really boils
> down to the user space roundtrip (plus another random number read
> roundtrip).

Hrm, Michael had a real mode version ... not sure where it went then.

Cheers,
Ben.