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 95927C43381 for ; Thu, 21 Mar 2019 10:34:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6BEC2218D3 for ; Thu, 21 Mar 2019 10:34:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728176AbfCUKeA (ORCPT ); Thu, 21 Mar 2019 06:34:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50492 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727867AbfCUKd7 (ORCPT ); Thu, 21 Mar 2019 06:33:59 -0400 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 0F0353082E02; Thu, 21 Mar 2019 10:33:59 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-12-199.pek2.redhat.com [10.72.12.199]) by smtp.corp.redhat.com (Postfix) with ESMTP id C38B019C57; Thu, 21 Mar 2019 10:33:50 +0000 (UTC) From: Lianbo Jiang To: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, akpm@linux-foundation.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, x86@kernel.org, hpa@zytor.com, dyoung@redhat.com, bhe@redhat.com, Thomas.Lendacky@amd.com Subject: [PATCH 3/3 v9] x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table Date: Thu, 21 Mar 2019 18:33:09 +0800 Message-Id: <20190321103309.27883-4-lijiang@redhat.com> In-Reply-To: <20190321103309.27883-1-lijiang@redhat.com> References: <20190321103309.27883-1-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 [10.5.110.46]); Thu, 21 Mar 2019 10:33:59 +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), kernel does not pass the e820 reserved ranges to the second kernel, which might cause two problems: The first one is the MMCONFIG issue. The basic problem is that this device is in PCI segment 1 and the kernel PCI probing can not find it without all the e820 I/O reservations being present in the e820 table. And the kdump kernel does not have those reservations because the kexec command does not pass the I/O reservation via the "memmap=xxx" command line option. (This problem does not show up for other vendors, as SGI is apparently the actually fails for everyone, but devices in segment 0 are then found by some legacy lookup method.) The workaround for this is to pass the I/O reserved regions to the kdump kernel. MMCONFIG(aka ECAM) space is described in the ACPI MCFG table. If you don't have ECAM: (a) PCI devices won't work at all on non-x86 systems that use only ECAM for config access, (b) you won't be albe to access devices on non-0 segments, (c) you won't be able to access extended config space( address 0x100-0xffff), which means none of the Extended Capabilities will be available(AER, ACS, ATS, etc). [Bjorn's comment] The second issue is that the SME kdump kernel doesn't work without the e820 reserved ranges. When SME is active in kdump kernel, actually, those reserved regions are still decrypted, but because those reserved ranges are not present at all in kdump kernel e820 table, those reserved regions are considered as encrypted, it goes wrong. 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 --- 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 17ffc869cab8..1db2754df9e9 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -381,6 +381,12 @@ 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