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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 ED4BFC4363D for ; Wed, 23 Sep 2020 02:32:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A20AA20725 for ; Wed, 23 Sep 2020 02:32:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="b8KdMM/Z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727216AbgIWCcy (ORCPT ); Tue, 22 Sep 2020 22:32:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:55268 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726548AbgIWCcy (ORCPT ); Tue, 22 Sep 2020 22:32:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600828372; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=2MO7lymMp9srQF8kov4JxrV28TWE85qvWXzbFlo1Ctk=; b=b8KdMM/ZsAlXaV1hoIS+Q1Rgk60NAoxaer2Ip8ZwhyPlGnhbI1b3XXYBwBve5h+e/o6jQ9 lLe1K3HbNmbv35u64xJGWk/tc2LWbFneU4Rwahwh5eAk6H4gfdjU90gD7uOesE+g0R96/K 5azZBPAC1b4epOcXB2174sXXYY2Xgr8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-557-VUP15onONwOwCZEB1an0-A-1; Tue, 22 Sep 2020 22:32:48 -0400 X-MC-Unique: VUP15onONwOwCZEB1an0-A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2BA6D1074641; Wed, 23 Sep 2020 02:32:47 +0000 (UTC) Received: from localhost (ovpn-12-42.pek2.redhat.com [10.72.12.42]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8796F5D9CC; Wed, 23 Sep 2020 02:32:46 +0000 (UTC) Date: Wed, 23 Sep 2020 10:32:44 +0800 From: Baoquan He To: joro@8bytes.org, ahuang12@lenovo.com Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, jsnitsel@redhat.com Subject: Re: [PATCH] Revert "iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions" Message-ID: <20200923023244.GK25604@MiWiFi-R3L-srv> References: <20200923022655.750-1-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200923022655.750-1-bhe@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Forgot CC-ing Jerry, add him. On 09/23/20 at 10:26am, Baoquan He wrote: > A regression failure of kdump kernel boot was reported on a HPE system. > Bisect points at commit 387caf0b759ac43 ("iommu/amd: Treat per-device > exclusion ranges as r/w unity-mapped regions") as criminal. Reverting it > fix the failure. > > With the commit, kdump kernel will always print below error message, then > naturally AMD iommu can't function normally during kdump kernel bootup. > > ~~~~~~~~~ > AMD-Vi: [Firmware Bug]: IVRS invalid checksum > > Why commit 387caf0b759ac43 causing it haven't been made clear. Hi Joerg, Adrian We only have one machine which can reproduce the issue, it's a gen10-01 of HPE. If any log or info are needed, please let me know, I can attach here. Thanks Baoquan > > From the commit log, a discussion thread link is pasted. In that discussion > thread, Adrian told the fix is for a system with already broken BIOS, and > Joerg suggested two options. Finally option 2) is taken. Maybe option 1) > should be the right approach? > > 1) Bail out and disable the IOMMU as the BIOS screwed up > 2) Treat per-device exclusion ranges just as r/w unity-mapped > regions. > > https://lists.linuxfoundation.org/pipermail/iommu/2019-November/040117.html > Signed-off-by: Baoquan He > --- > drivers/iommu/amd/init.c | 21 +++++++++++++-------- > 1 file changed, 13 insertions(+), 8 deletions(-) > > diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c > index 9aa1eae26634..bbe7ceae5949 100644 > --- a/drivers/iommu/amd/init.c > +++ b/drivers/iommu/amd/init.c > @@ -1109,17 +1109,22 @@ static int __init add_early_maps(void) > */ > static void __init set_device_exclusion_range(u16 devid, struct ivmd_header *m) > { > + struct amd_iommu *iommu = amd_iommu_rlookup_table[devid]; > + > if (!(m->flags & IVMD_FLAG_EXCL_RANGE)) > return; > > - /* > - * Treat per-device exclusion ranges as r/w unity-mapped regions > - * since some buggy BIOSes might lead to the overwritten exclusion > - * range (exclusion_start and exclusion_length members). This > - * happens when there are multiple exclusion ranges (IVMD entries) > - * defined in ACPI table. > - */ > - m->flags = (IVMD_FLAG_IW | IVMD_FLAG_IR | IVMD_FLAG_UNITY_MAP); > + if (iommu) { > + /* > + * We only can configure exclusion ranges per IOMMU, not > + * per device. But we can enable the exclusion range per > + * device. This is done here > + */ > + set_dev_entry_bit(devid, DEV_ENTRY_EX); > + iommu->exclusion_start = m->range_start; > + iommu->exclusion_length = m->range_length; > + } > + > } > > /* > -- > 2.17.2 > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu >