From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752044AbaEAVBe (ORCPT ); Thu, 1 May 2014 17:01:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:40685 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751203AbaEAVBc (ORCPT ); Thu, 1 May 2014 17:01:32 -0400 Message-ID: <5362B618.50602@zytor.com> Date: Thu, 01 May 2014 14:01:12 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Andy Lutomirski , "Theodore Ts'o" , "linux-kernel@vger.kernel.org" , kvm list , Florian Weimer , Kees Cook Subject: Re: random: Providing a seed value to VM guests References: <20140501192618.GA25829@thunk.org> <900441a0-24e8-4976-ad35-3971805b9f34@email.android.com> <20140501203910.GB25829@thunk.org> In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/01/2014 01:56 PM, Andy Lutomirski wrote: > > Even if we could emulate RDSEED effectively**, I don't really > understand what the guest is expected to do with it. And I generally > dislike defining an interface with no known sensible users, because it > means that there's a good chance that the interface won't end up > working. > > ** Doing this sensibly in the host will be awkward. Is the host > supposed to use non-blocking reads of /dev/random? Getting anything > remotely fair may be difficult. The host can use nonblocking reads of /dev/random. Fairness would have to be implemented at the host level, but that is true for anything. -hpa