From mboxrd@z Thu Jan 1 00:00:00 1970 From: KY Srinivasan Subject: RE: Standardizing an MSR or other hypercall to get an RNG seed? Date: Thu, 18 Sep 2014 17:20:44 +0000 Message-ID: References: <2aa00301e9af4826b5781e01709f81e7@BY2PR0301MB0711.namprd03.prod.outlook.com> <541AEF7D.2010007@zytor.com> <5b9c7dcde3824e49a25f3ee00844b868@BY2PR0301MB0711.namprd03.prod.outlook.com> <541B13B8.1020006@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Cc: Mathew John , Theodore Ts'o , "John Starks" , kvm list , "Gleb Natapov" , Niels Ferguson , "Andy Lutomirski" , David Hepkin , "H. Peter Anvin" , Jake Oshins , "Linux Virtualization" To: Paolo Bonzini , "Nakajima, Jun" Return-path: Received: from mail-bn1bon0142.outbound.protection.outlook.com ([157.56.111.142]:26784 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755755AbaIRRUr convert rfc822-to-8bit (ORCPT ); Thu, 18 Sep 2014 13:20:47 -0400 In-Reply-To: <541B13B8.1020006@redhat.com> Content-Language: en-US Sender: kvm-owner@vger.kernel.org List-ID: > -----Original Message----- > From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo > Bonzini > Sent: Thursday, September 18, 2014 10:18 AM > To: Nakajima, Jun; KY Srinivasan > Cc: Mathew John; Theodore Ts'o; John Starks; kvm list; Gleb Natapov; Niels > Ferguson; Andy Lutomirski; David Hepkin; H. Peter Anvin; Jake Oshins; Linux > Virtualization > Subject: Re: Standardizing an MSR or other hypercall to get an RNG seed? > > Il 18/09/2014 19:13, Nakajima, Jun ha scritto: > > In terms of the address for the MSR, I suggest that you choose one > > from the range between 40000000H - 400000FFH. The SDM (35.1 > > ARCHITECTURAL MSRS) says "All existing and future processors will not > > implement any features using any MSR in this range." Hyper-V already > > defines many synthetic MSRs in this range, and I think it would be > > reasonable for you to pick one for this to avoid a conflict? > > KVM is not using any MSR in that range. > > However, I think it would be better to have the MSR (and perhaps CPUID) > outside the hypervisor-reserved ranges, so that it becomes architecturally > defined. In some sense it is similar to the HYPERVISOR CPUID feature. Yes, given that we want this to be hypervisor agnostic. K. Y