From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757466AbdLTV6a (ORCPT ); Wed, 20 Dec 2017 16:58:30 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:53219 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757416AbdLTV6L (ORCPT ); Wed, 20 Dec 2017 16:58:11 -0500 Message-Id: <20171220215444.718688274@linutronix.de> User-Agent: quilt/0.63-1 Date: Wed, 20 Dec 2017 22:35:53 +0100 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Linus Torvalds , Andy Lutomirsky , Peter Zijlstra , Dave Hansen , Borislav Petkov , Greg KH , keescook@google.com, hughd@google.com, Brian Gerst , Josh Poimboeuf , Denys Vlasenko , Rik van Riel , Boris Ostrovsky , Juergen Gross , David Laight , Eduardo Valentin , aliguori@amazon.com, Will Deacon , Vlastimil Babka , daniel.gruss@iaik.tugraz.at, Dave Hansen , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-mm@kvack.org Subject: [patch V181 50/54] x86/mm/pti: Add Kconfig References: <20171220213503.672610178@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0056-x86-mm-pti-Add-Kconfig.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen Finally allow CONFIG_PAGE_TABLE_ISOLATION to be enabled. PARAVIRT generally requires that the kernel not manage its own page tables. It also means that the hypervisor and kernel must agree wholeheartedly about what format the page tables are in and what they contain. PAGE_TABLE_ISOLATION, unfortunately, changes the rules and they can not be used together. I've seen conflicting feedback from maintainers lately about whether they want the Kconfig magic to go first or last in a patch series. It's going last here because the partially-applied series leads to kernels that can not boot in a bunch of cases. I did a run through the entire series with CONFIG_PAGE_TABLE_ISOLATION=y to look for build errors, though. [ tglx: Removed SMP and !PARAVIRT dependencies as they not longer exist ] Signed-off-by: Dave Hansen Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org --- security/Kconfig | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/security/Kconfig +++ b/security/Kconfig @@ -54,6 +54,16 @@ config SECURITY_NETWORK implement socket and networking access controls. If you are unsure how to answer this question, answer N. +config PAGE_TABLE_ISOLATION + bool "Remove the kernel mapping in user mode" + depends on X86_64 && !UML + help + This feature reduces the number of hardware side channels by + ensuring that the majority of kernel addresses are not mapped + into userspace. + + See Documentation/x86/pagetable-isolation.txt for more details. + config SECURITY_INFINIBAND bool "Infiniband Security Hooks" depends on SECURITY && INFINIBAND