From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753517AbaHKNaf (ORCPT ); Mon, 11 Aug 2014 09:30:35 -0400 Received: from verein.lst.de ([213.95.11.211]:41470 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506AbaHKNae (ORCPT ); Mon, 11 Aug 2014 09:30:34 -0400 Date: Mon, 11 Aug 2014 15:30:30 +0200 From: Torsten Duwe To: Amit Shah Cc: "H. Peter Anvin" , jgarzik@bitpay.com, Virtualization List , Amos Kong , Rusty Russell , linux-kernel@vger.kernel.org, Ricardo Neri Subject: Re: [PATCH 1/2] rngd: add udev rule to source from hwrng if virtio-rng present Message-ID: <20140811133030.GA27247@lst.de> References: <53E3D3FF.70707@linux.intel.com> <20140808090715.GG14400@grmbl.mre> <53E54533.8030109@linux.intel.com> <20140811071527.GB4184@grmbl.mre> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140811071527.GB4184@grmbl.mre> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 11, 2014 at 12:45:27PM +0530, Amit Shah wrote: > > What's the suggested value for rng->quality, though, for virtio-rng > that I can use to ensure the kthread starts? > > Should I use the 700 (70%) as proposed in the original patchset? I'm > not exactly sure how that value will be used as well.. There is no such thing as a suggested value, every number is wrong to some degree. The quality is an estimation of how random your source really is; it's a property of your hardware. If the device is virtual you're in trouble ;-) Either you have a way to query the underlying real hardware, or you do your whitening and entropy estimation in the backend driver -- then you can claim 100%. Torsten