From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CB77C433DF for ; Wed, 10 Jun 2020 08:42:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE50E20812 for ; Wed, 10 Jun 2020 08:42:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591778554; bh=wjjPmI+WG54Mz1EL7HwR233NE+u8BMlzD5wxbDmEoOM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=fqzWckAsPmQNq1kzpaL+3bkFjzRDqYN/dV/UeYc/4InEdZXJqHR9y9DgrQkCCryZK uP8Co1U4Wj27vl4q5/Em3agZWE11G5n+rooZOoiPm8A2Y6DSOzh1yNZ9Yw70zavnc2 32skvjhx7j1t0mLl0nNXRXHAEAMvGwNabwJh6Mm8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726874AbgFJImd (ORCPT ); Wed, 10 Jun 2020 04:42:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:53442 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726424AbgFJIma (ORCPT ); Wed, 10 Jun 2020 04:42:30 -0400 Received: from kernel.org (unknown [87.70.26.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CD9A320734; Wed, 10 Jun 2020 08:42:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591778550; bh=wjjPmI+WG54Mz1EL7HwR233NE+u8BMlzD5wxbDmEoOM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oIJl3PxAd6TD5nHzwj0UKLRZMXYmocYU4/TUG9EvAfB4xNNfdmxYRGV0shFVvn3Pk URWZzVLrf1BNkBqOD4VV3l4aP2i+WGka8F5JjZ7ztm7TgcoAaC8sYeVJSgWcFvTatG HPGyY4wcqKg3LD+WQrlEMnuJcnMtmBEjLG5R9qw0= Date: Wed, 10 Jun 2020 11:42:23 +0300 From: Mike Rapoport To: "Kirill A. Shutemov" Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Dan Williams , Tony Luck , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen , stable@vger.kernel.org Subject: Re: [PATCHv2 2/2] x86/boot/KASLR: Fix boot with some memory above MAXMEM Message-ID: <20200610084223.GE1151302@kernel.org> References: <20200608125424.70198-1-kirill.shutemov@linux.intel.com> <20200608125424.70198-3-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200608125424.70198-3-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 08, 2020 at 03:54:24PM +0300, Kirill A. Shutemov wrote: > A 5-level paging capable machine can have memory above 46-bit in the > physical address space. This memory is only addressable in the 5-level > paging mode: we don't have enough virtual address space to create direct > mapping for such memory in the 4-level paging mode > > Teach KASLR to avoid memory regions above MAXMEM or truncate the region > if the end is above MAXMEM. > > Signed-off-by: Kirill A. Shutemov > Reviewed-by: Dave Hansen > Cc: stable@vger.kernel.org # v4.14 Reviewed-by: Mike Rapoport > --- > arch/x86/boot/compressed/kaslr.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > index d7408af55738..99db18eeb40e 100644 > --- a/arch/x86/boot/compressed/kaslr.c > +++ b/arch/x86/boot/compressed/kaslr.c > @@ -695,7 +695,18 @@ static bool process_mem_region(struct mem_vector *region, > unsigned long long minimum, > unsigned long long image_size) > { > + unsigned long long end; > int i; > + > + /* Cannot access memory region above MAXMEM: skip it. */ > + if (region->start >= MAXMEM) > + return 0; > + > + /* Truncate the region if the end is above MAXMEM */ > + end = region->start + region->size; > + end = min_t(unsigned long long, end, MAXMEM - 1); > + region->size = end - region->start; > + > /* > * If no immovable memory found, or MEMORY_HOTREMOVE disabled, > * use @region directly. > -- > 2.26.2 > > -- Sincerely yours, Mike.