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=-14.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 2938FC54E8D for ; Mon, 11 May 2020 19:17:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E635206E6 for ; Mon, 11 May 2020 19:17:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731388AbgEKTRj (ORCPT ); Mon, 11 May 2020 15:17:39 -0400 Received: from mga07.intel.com ([134.134.136.100]:51436 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731200AbgEKTRj (ORCPT ); Mon, 11 May 2020 15:17:39 -0400 IronPort-SDR: f+o19xsOfEVOJ3m64qNXx8Qi/s1MN1ofAYmInCFLE3jLvY5gfhXCaHFk10jJsvXCgdudwhTay1 UQX306pjdGyQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2020 12:17:38 -0700 IronPort-SDR: 7rI5Y2URj4Z3ZVTn5xNuUPdfFIBRovGG6XDdw2LDRlLTSmih0uTEq4GyrUiFsSnLjPbUTZVGdP mJBavOIgkTEg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,381,1583222400"; d="scan'208";a="261865903" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga003.jf.intel.com with ESMTP; 11 May 2020 12:17:34 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id CE171170; Mon, 11 May 2020 22:17:33 +0300 (EEST) From: "Kirill A. Shutemov" To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" Cc: Dan Williams , Tony Luck , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Dave Hansen , stable@vger.kernel.org Subject: [PATCH] x86/mm: Fix boot with some memory above MAXMEM Date: Mon, 11 May 2020 22:17:21 +0300 Message-Id: <20200511191721.1416-1-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Currently, we fail boot completely: NULL pointer dereference in subsection_map_init(). Skip creating a memblock for such memory instead and notify user that some memory is not addressable. Signed-off-by: Kirill A. Shutemov Reviewed-by: Dave Hansen Cc: stable@vger.kernel.org # v4.14 --- Tested with a hacked QEMU: https://gist.github.com/kiryl/d45eb54110944ff95e544972d8bdac1d --- arch/x86/kernel/e820.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index c5399e80c59c..d320d37d0f95 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -1280,8 +1280,8 @@ void __init e820__memory_setup(void) void __init e820__memblock_setup(void) { + u64 size, end, not_addressable = 0; int i; - u64 end; /* * The bootstrap memblock region count maximum is 128 entries @@ -1307,7 +1307,22 @@ void __init e820__memblock_setup(void) if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN) continue; - memblock_add(entry->addr, entry->size); + if (entry->addr >= MAXMEM) { + not_addressable += entry->size; + continue; + } + + end = min_t(u64, end, MAXMEM - 1); + size = end - entry->addr; + not_addressable += entry->size - size; + memblock_add(entry->addr, size); + } + + if (not_addressable) { + pr_err("%lldGB of physical memory is not addressable in the paging mode\n", + not_addressable >> 30); + if (!pgtable_l5_enabled()) + pr_err("Consider enabling 5-level paging\n"); } /* Throw away partial pages: */ -- 2.26.2