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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 09E3DC43141 for ; Thu, 21 Jun 2018 05:42:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C0D4E2075E for ; Thu, 21 Jun 2018 05:42:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C0D4E2075E 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 S932899AbeFUFmd (ORCPT ); Thu, 21 Jun 2018 01:42:33 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56612 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932583AbeFUFmc (ORCPT ); Thu, 21 Jun 2018 01:42:32 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id EEE78401C96A; Thu, 21 Jun 2018 05:42:31 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-127.pek2.redhat.com [10.72.12.127]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3C4C4178B9; Thu, 21 Jun 2018 05:42:27 +0000 (UTC) Subject: Re: [PATCH 3/4 V3] Remap the device table of IOMMU in encrypted manner for kdump To: Tom Lendacky , linux-kernel@vger.kernel.org Cc: iommu@lists.linux-foundation.org, kexec@lists.infradead.org, dyoung@redhat.com References: <20180616082714.32035-1-lijiang@redhat.com> <20180616082714.32035-4-lijiang@redhat.com> <60c6f00e-0eb3-d39c-6a1e-8a1dc1e095af@amd.com> From: lijiang Message-ID: Date: Thu, 21 Jun 2018 13:42:24 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <60c6f00e-0eb3-d39c-6a1e-8a1dc1e095af@amd.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 21 Jun 2018 05:42:32 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 21 Jun 2018 05:42:32 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'lijiang@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2018年06月21日 00:42, Tom Lendacky 写道: > On 6/16/2018 3:27 AM, Lianbo Jiang wrote: >> In kdump mode, it will copy the device table of IOMMU from the old >> device table, which is encrypted when SME is enabled in the first >> kernel. So we must remap it in encrypted manner in order to be >> automatically decrypted when we read. >> >> Signed-off-by: Lianbo Jiang >> --- >> Some changes: >> 1. add some comments >> 2. clean compile warning. >> >> drivers/iommu/amd_iommu_init.c | 15 ++++++++++++++- >> 1 file changed, 14 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c >> index 904c575..a20af4c 100644 >> --- a/drivers/iommu/amd_iommu_init.c >> +++ b/drivers/iommu/amd_iommu_init.c >> @@ -889,11 +889,24 @@ static bool copy_device_table(void) >> } >> >> old_devtb_phys = entry & PAGE_MASK; >> + >> + /* >> + * When sme enable in the first kernel, old_devtb_phys includes the >> + * memory encryption mask(sme_me_mask), we must remove the memory >> + * encryption mask to obtain the true physical address in kdump mode. >> + */ >> + if (mem_encrypt_active() && is_kdump_kernel()) >> + old_devtb_phys = __sme_clr(old_devtb_phys); >> + > > You can probably just use "if (is_kdump_kernel())" here, since memory > encryption is either on in both the first and second kernel or off in > both the first and second kernel. At which point __sme_clr() will do > the proper thing. > > Actually, this needs to be done no matter what. When doing either the > ioremap_encrypted() or the memremap(), the physical address should not > include the encryption bit/mask. > > Thanks, > Tom > Thanks for your comments. If we don't remove the memory encryption mask, it will return false because the 'old_devtb_phys >= 0x100000000ULL' may become true. Lianbo >> if (old_devtb_phys >= 0x100000000ULL) { >> pr_err("The address of old device table is above 4G, not trustworthy!\n"); >> return false; >> } >> - old_devtb = memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB); >> + old_devtb = (mem_encrypt_active() && is_kdump_kernel()) >> + ? (__force void *)ioremap_encrypted(old_devtb_phys, >> + dev_table_size) >> + : memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB);> + >> if (!old_devtb) >> return false; >> >>