From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753320AbeBLP0d (ORCPT ); Mon, 12 Feb 2018 10:26:33 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:43104 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752604AbeBLP0b (ORCPT ); Mon, 12 Feb 2018 10:26:31 -0500 Date: Mon, 12 Feb 2018 16:26:30 +0100 From: Pavel Machek To: Tom Lendacky Cc: x86@kernel.org, Dave Hansen , linux-kernel@vger.kernel.org, Ingo Molnar , Andy Lutomirski , "H. Peter Anvin" , Thomas Gleixner , Borislav Petkov Subject: Re: [PATCH] x86/cpu, x86/pti: Do not enable PTI on AMD processors Message-ID: <20180212152630.GD13962@amd> References: <20171227054354.20369.94587.stgit@tlendack-t1.amdoffice.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="cHMo6Wbp1wrKhbfi" Content-Disposition: inline In-Reply-To: <20171227054354.20369.94587.stgit@tlendack-t1.amdoffice.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --cHMo6Wbp1wrKhbfi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue 2017-12-26 23:43:54, Tom Lendacky wrote: > AMD processors are not subject to the types of attacks that the kernel > page table isolation feature protects against. The AMD microarchitecture > does not allow memory references, including speculative references, that > access higher privileged data when running in a lesser privileged mode > when that access would result in a page fault. >=20 > Disable page table isolation by default on AMD processors by not setting > the X86_BUG_CPU_INSECURE feature, which controls whether X86_FEATURE_PTI > is set. PTI was originally meant to protect KASLR from memory leaks, before Spectre was public. I guess that's still valid use on AMD cpus? Pavel =09 --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --cHMo6Wbp1wrKhbfi Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlqBsiYACgkQMOfwapXb+vI0CgCfVrZd5vC5OX/hitH4ItrbOUMC ZusAn0aXDXi+ymU4jXez0o+WoLC+1sJ4 =mMm8 -----END PGP SIGNATURE----- --cHMo6Wbp1wrKhbfi--