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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 0F9A0C3A5A4 for ; Mon, 26 Aug 2019 08:17:13 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D4C9E206BA for ; Mon, 26 Aug 2019 08:17:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4C9E206BA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 76624117C; Mon, 26 Aug 2019 08:17:12 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 638151176 for ; Mon, 26 Aug 2019 08:15:35 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id DB8FF89B for ; Mon, 26 Aug 2019 08:15:34 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Aug 2019 01:15:34 -0700 X-IronPort-AV: E=Sophos;i="5.64,431,1559545200"; d="scan'208";a="174133517" Received: from jkrzyszt-desk.ger.corp.intel.com ([172.22.244.17]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Aug 2019 01:15:31 -0700 From: Janusz Krzysztofik To: Lu Baolu Subject: Re: [RFC PATCH] iommu/vt-d: Fix IOMMU field not populated on device hot re-plug Date: Mon, 26 Aug 2019 10:15:21 +0200 Message-ID: <7536805.yzB8ZXLclH@jkrzyszt-desk.ger.corp.intel.com> Organization: Intel Technology Poland sp. z o.o. - ul. Slowackiego 173, 80-298 Gdansk - KRS 101882 - NIP 957-07-52-316 In-Reply-To: <00f1a3a7-7ff6-e9a0-d9de-a177af6fd64b@linux.intel.com> References: <20190822142922.31526-1-janusz.krzysztofik@linux.intel.com> <00f1a3a7-7ff6-e9a0-d9de-a177af6fd64b@linux.intel.com> MIME-Version: 1.0 Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, David Woodhouse , intel-gfx@lists.freedesktop.org, =?utf-8?B?TWljaGHFgg==?= Wajdeczko X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Hi Lu, On Friday, August 23, 2019 3:51:11 AM CEST Lu Baolu wrote: > Hi, > > On 8/22/19 10:29 PM, Janusz Krzysztofik wrote: > > When a perfectly working i915 device is hot unplugged (via sysfs) and > > hot re-plugged again, its dev->archdata.iommu field is not populated > > again with an IOMMU pointer. As a result, the device probe fails on > > DMA mapping error during scratch page setup. > > > > It looks like that happens because devices are not detached from their > > MMUIO bus before they are removed on device unplug. Then, when an > > already registered device/IOMMU association is identified by the > > reinstantiated device's bus and function IDs on IOMMU bus re-attach > > attempt, the device's archdata is not populated with IOMMU information > > and the bad happens. > > > > I'm not sure if this is a proper fix but it works for me so at least it > > confirms correctness of my analysis results, I believe. So far I > > haven't been able to identify a good place where the possibly missing > > IOMMU bus detach on device unplug operation could be added. > > Which kernel version are you testing with? Does it contain below commit? > > commit 458b7c8e0dde12d140e3472b80919cbb9ae793f4 > Author: Lu Baolu > Date: Thu Aug 1 11:14:58 2019 +0800 I was using an internal branch based on drm-tip which didn't contain this commit yet. Fortunately it has been already merged into drm-tip over last weekend and has effectively fixed the issue. Thanks, Janusz > iommu/vt-d: Detach domain when move device out of group > > When removing a device from an iommu group, the domain should > be detached from the device. Otherwise, the stale domain info > will still be cached by the driver and the driver will refuse > to attach any domain to the device again. > > Cc: Ashok Raj > Cc: Jacob Pan > Cc: Kevin Tian > Fixes: b7297783c2bb6 ("iommu/vt-d: Remove duplicated code for > device hotplug") > Reported-and-tested-by: Vlad Buslov > Suggested-by: Robin Murphy > Link: https://lkml.org/lkml/2019/7/26/1133 > Signed-off-by: Lu Baolu > Signed-off-by: Joerg Roedel > > Best regards, > Lu Baolu > > > > > Signed-off-by: Janusz Krzysztofik > > --- > > drivers/iommu/intel-iommu.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > > index 12d094d08c0a..7cdcd0595408 100644 > > --- a/drivers/iommu/intel-iommu.c > > +++ b/drivers/iommu/intel-iommu.c > > @@ -2477,6 +2477,9 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, > > if (info2) { > > found = info2->domain; > > info2->dev = dev; > > + > > + if (dev && !dev->archdata.iommu) > > + dev->archdata.iommu = info2; > > } > > } > > > > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu