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 DCA99C43381 for ; Fri, 22 Feb 2019 05:11:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B83C2086C for ; Fri, 22 Feb 2019 05:11:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725888AbfBVFLw (ORCPT ); Fri, 22 Feb 2019 00:11:52 -0500 Received: from mga02.intel.com ([134.134.136.20]:17543 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725710AbfBVFLw (ORCPT ); Fri, 22 Feb 2019 00:11:52 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Feb 2019 21:11:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,398,1544515200"; d="scan'208";a="116884303" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga007.jf.intel.com with ESMTP; 21 Feb 2019 21:11:49 -0800 Cc: baolu.lu@linux.intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jis Ben Subject: Re: [PATCH] iommu/vt-d: Handle hotplug devices' default identity mapping setting To: James Dong , David Woodhouse , Joerg Roedel References: <20190222024455.20802-1-xmdong@google.com> From: Lu Baolu Message-ID: Date: Fri, 22 Feb 2019 13:06:47 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190222024455.20802-1-xmdong@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 2/22/19 10:44 AM, James Dong wrote: > With specific Linux command line option such as "iommu=pt", some types > of hotplug devices will be assigned to the static 1:1 iommu domain by > default during kernel init. > > If such a hotplug device is rescanned after being removed, for example, > with following sample commands: > echo 1 > /sys/bus/pci/devices/0000\:03\:00.1/remove > echo 1 > /sys/bus/pci/rescan > , an iommu group for this hotplug device will be added without attaching > it to the default static 1:1 domain. As a result, this device's I/O > operation won't work. What does "I/O operation won't work" exactly mean here? Do you see any IOMMU fault message? Or, something doesn't work as expected? > > Keep hotplug devices with default static 1:1 iommu mapping in their default > domain after such hotplug devices are rescanned. > > Signed-off-by: James Dong > Reported-by: Jis Ben > --- > drivers/iommu/intel-iommu.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 78188bf7e90d..4b02949e58ca 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -5230,6 +5230,7 @@ static int intel_iommu_add_device(struct device *dev) > struct intel_iommu *iommu; > struct iommu_group *group; > u8 bus, devfn; > + int ret = 0; > > iommu = device_to_iommu(dev, &bus, &devfn); > if (!iommu) > @@ -5242,8 +5243,19 @@ static int intel_iommu_add_device(struct device *dev) > if (IS_ERR(group)) > return PTR_ERR(group); > > + if (!iommu_group_default_domain(group) && > + !find_domain(dev) && iommu_should_identity_map(dev, 0)) { > + ret = domain_add_dev_info(si_domain, dev); > + if (!ret) > + pr_info("identity mapping for device %s\n", > + dev_name(dev)); > + else > + pr_info("identity mapping failed (%d) for device %s\n", > + ret, dev_name(dev)); > + } > + I am not sure about whether this is a good place to fix this problem before Intel IOMMU driver switches to default domain. Do you mind checking this? diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 6ecdcf8fc8c0..f62f30bc1339 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2632,6 +2632,9 @@ static struct dmar_domain *find_or_alloc_domain(struct device *dev, int gaw) goto out; } + if (!iommu_should_identity_map(dev, 0)) + return si_domain; + /* Allocate and initialize new domain for the device */ domain = alloc_domain(0); if (!domain) Best regards, Lu Baolu