Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030357AbaGPQIV (ORCPT ); Wed, 16 Jul 2014 12:08:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13838 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030282AbaGPQIR (ORCPT ); Wed, 16 Jul 2014 12:08:17 -0400 Message-ID: <53C6A362.7090709@redhat.com> Date: Wed, 16 Jul 2014 18:08:02 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: "H. Peter Anvin" , Andy Lutomirski CC: Daniel Borkmann , Gleb Natapov , kvm list , "Theodore Ts'o" , "linux-kernel@vger.kernel.org" , Kees Cook , X86 ML , Srivatsa Vaddagiri , Raghavendra K T Subject: Re: [PATCH 0/4] random,x86,kvm: Add and use MSR_KVM_GET_RNG_SEED References: <20140716064110.GV18167@minantech.com> <53C62563.6050106@redhat.com> <53C62B68.50702@redhat.com> <53C6A236.7040904@zytor.com> In-Reply-To: <53C6A236.7040904@zytor.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 16/07/2014 18:03, H. Peter Anvin ha scritto: > I suggested emulating RDRAND *but not set the CPUID bit*. We already > developed a protocol in KVM/Qemu to enumerate emulated features (created > for MOVBE as I recall), specifically to service the semantic "feature X > will work but will be substantially slower than normal." But those will set the CPUID bit. There is currently no way for KVM guests to know if a CPUID bit is real or emulated. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/