Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934803AbaGPGlU (ORCPT ); Wed, 16 Jul 2014 02:41:20 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:61670 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933132AbaGPGlS (ORCPT ); Wed, 16 Jul 2014 02:41:18 -0400 Date: Wed, 16 Jul 2014 09:41:11 +0300 From: Gleb Natapov To: Andy Lutomirski Cc: kvm@vger.kernel.org, "H. Peter Anvin" , "Theodore Ts'o" , linux-kernel@vger.kernel.org, Kees Cook , x86@kernel.org, Daniel Borkmann , Srivatsa Vaddagiri , Raghavendra K T Subject: Re: [PATCH 0/4] random,x86,kvm: Add and use MSR_KVM_GET_RNG_SEED Message-ID: <20140716064110.GV18167@minantech.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 15, 2014 at 07:48:06PM -0700, Andy Lutomirski wrote: > virtio-rng is both too complicated and insufficient for initial rng > seeding. It's far too complicated to use for KASLR or any other > early boot random number needs. It also provides /dev/random-style > bits, which means that making guest boot wait for virtio-rng is > unacceptably slow, and doing it asynchronously means that > /dev/urandom might be predictable when userspace starts. > > This introduces a very simple synchronous mechanism to get > /dev/urandom-style bits. Why can't you use RDRAND instruction for that? > > This is a KVM change: am I supposed to write a unit test somewhere? > > Andy Lutomirski (4): > x86,kvm: Add MSR_KVM_GET_RNG_SEED and a matching feature bit > random,x86: Add arch_get_slow_rng_u64 > random: Seed pools from arch_get_slow_rng_u64 at startup > x86,kaslr: Use MSR_KVM_GET_RNG_SEED for KASLR if available > > Documentation/virtual/kvm/cpuid.txt | 3 +++ > arch/x86/Kconfig | 4 ++++ > arch/x86/boot/compressed/aslr.c | 27 +++++++++++++++++++++++++++ > arch/x86/include/asm/archslowrng.h | 30 ++++++++++++++++++++++++++++++ > arch/x86/include/uapi/asm/kvm_para.h | 2 ++ > arch/x86/kernel/kvm.c | 22 ++++++++++++++++++++++ > arch/x86/kvm/cpuid.c | 3 ++- > arch/x86/kvm/x86.c | 4 ++++ > drivers/char/random.c | 14 +++++++++++++- > include/linux/random.h | 9 +++++++++ > 10 files changed, 116 insertions(+), 2 deletions(-) > create mode 100644 arch/x86/include/asm/archslowrng.h > > -- > 1.9.3 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb. -- 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/