Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965598AbaGPSEM (ORCPT ); Wed, 16 Jul 2014 14:04:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53901 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965263AbaGPSEK (ORCPT ); Wed, 16 Jul 2014 14:04:10 -0400 From: Bandan Das 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 , Gleb Natapov , Paolo Bonzini Subject: Re: [PATCH v2 0/5] random,x86,kvm: Add and use MSR_KVM_GET_RNG_SEED References: Date: Wed, 16 Jul 2014 14:02:41 -0400 In-Reply-To: (Andy Lutomirski's message of "Wed, 16 Jul 2014 10:45:55 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andy Lutomirski writes: > 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. Whoa! the cover letter seems more like virtio-rng bashing rather than introduction to the patchset (and/or it's advantages over existing methods) :) That's ok though I guess, these won't be in the commit log. > I sent the corresponding kvm-unit-tests and qemu changes separately. > > There's room for bikeshedding on the same arch_get_slow_rng_u64. I > considered arch_get_rng_seed_u64, but that could be confused with > arch_get_random_seed_long, which is not interchangeable. > > Changes from v1: > - Split patches 2 and 3 > - Log all arch sources in init_std_data > - Fix the 32-bit kaslr build > > Andy Lutomirski (5): > 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 > random: Log how many bits we managed to seed with in init_std_data > 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/asm/processor.h | 21 ++++++++++++++++++--- > 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 | 20 ++++++++++++++++++-- > include/linux/random.h | 9 +++++++++ > 11 files changed, 139 insertions(+), 6 deletions(-) > create mode 100644 arch/x86/include/asm/archslowrng.h -- 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/