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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 51F70C43441 for ; Thu, 15 Nov 2018 09:55:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 243BC21780 for ; Thu, 15 Nov 2018 09:55:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 243BC21780 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387958AbeKOUDB (ORCPT ); Thu, 15 Nov 2018 15:03:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52124 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728609AbeKOUDB (ORCPT ); Thu, 15 Nov 2018 15:03:01 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2407B168F; Thu, 15 Nov 2018 09:55:54 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-12-127.pek2.redhat.com [10.72.12.127]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5C4F219C65; Thu, 15 Nov 2018 09:55:48 +0000 (UTC) From: Lianbo Jiang To: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org, x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, akpm@linux-foundation.org, dyoung@redhat.com, bhe@redhat.com Subject: [PATCH 2/2 v7] x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table Date: Thu, 15 Nov 2018 17:55:29 +0800 Message-Id: <20181115095529.21220-3-lijiang@redhat.com> In-Reply-To: <20181115095529.21220-1-lijiang@redhat.com> References: <20181115095529.21220-1-lijiang@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 15 Nov 2018 09:55:54 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At present, when use the kexec_file_load syscall to load the kernel image and initramfs(for example: kexec -s -p xxx), the upstream kernel does not pass the e820 reserved ranges to the second kernel, which might cause two problems: The first one is the MMCONFIG issue, although which does not make the system crash or hang, this issue is still a potential risk, and also might lead to the hot-plug device could not be recognized in kdump kernel. Because the PCI MMCONFIG(extended mode) requires the reserved region otherwise it falls back to legacy mode. For example, the kdump kernel outputs the following log. Example: ...... [ 19.798354] PCI: MMCONFIG for domain 0000 [bus 00-ff] at [mem 0x80000000-0x8fffffff] (base 0x80000000) [ 19.800653] [Firmware Info]: PCI: MMCONFIG at [mem 0x80000000-0x8fffffff] not reserved in ACPI motherboard resources [ 19.800995] PCI: not using MMCONFIG ...... The correct kernel log is like this: ...... [ 0.082649] PCI: MMCONFIG for domain 0000 [bus 00-ff] at [mem 0x80000000-0x8fffffff] (base 0x80000000) [ 0.083610] PCI: MMCONFIG at [mem 0x80000000-0x8fffffff] reserved in E820 ...... The second issue is that the e820 reserved ranges do not setup in kdump kernel, which will cause some functions that related to the e820 reserved ranges to become invalid. For example: early_memremap()-> early_memremap_pgprot_adjust()-> memremap_should_map_decrypted()-> e820__get_entry_type() Please focus on these functions, early_memremap_pgprot_adjust() and memremap_should_map_decrypted(). In the first kernel, these ranges sit in e820 reserved ranges, so the memremap_should_map_decrypted() will return true, that is to say, the reserved memory is decrypted, then the early_memremap_pgprot_adjust() will call the pgprot_decrypted() to clear the memory encryption mask. In the second kernel, because the e820 reserved ranges are not passed to the second kernel, these ranges don't sit in the e820 reserved ranges, so the memremap_should_map_decrypted() will return false, that is to say, the reserved memory is encrypted, and then the early_memremap_pgprot_ adjust() will also call the pgprot_encrypted() to set the memory encryption mask. In fact, in the second kernel, the e820 reserved memory is still decrypted. Obviously, it has gone wrong. So, this issue must be fixed, otherwise kdump won't work in this case. The e820 reserved range is useful in kdump kernel, so it is necessary to pass the e820 reserved ranges to kdump kernel. Suggested-by: Dave Young Signed-off-by: Lianbo Jiang --- Changes since v5: 1. Improve the patch log Changes since v6: 1. Modify this patch, and walk through io resource based on the new descriptor 'IORES_DESC_RESERVED'. 2. Add comment in the code. arch/x86/kernel/crash.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index f631a3f15587..5354a84f1684 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -380,6 +380,12 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params) walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd, memmap_entry_callback); + /* Add e820 reserved ranges */ + cmd.type = E820_TYPE_RESERVED; + flags = IORESOURCE_MEM; + walk_iomem_res_desc(IORES_DESC_RESERVED, flags, 0, -1, &cmd, + memmap_entry_callback); + /* Add crashk_low_res region */ if (crashk_low_res.end) { ei.addr = crashk_low_res.start; -- 2.17.1