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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 4E0C1C43331 for ; Mon, 11 Nov 2019 05:03:15 +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 2B0B0214E0 for ; Mon, 11 Nov 2019 05:03:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2B0B0214E0 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 063B7C79; Mon, 11 Nov 2019 05:03:15 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 36B54B5F for ; Mon, 11 Nov 2019 05:03:14 +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 B89A14C3 for ; Mon, 11 Nov 2019 05:03:13 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Nov 2019 21:03:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,291,1569308400"; d="scan'208";a="228820825" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by fmsmga004.fm.intel.com with ESMTP; 10 Nov 2019 21:03:12 -0800 Subject: Re: [PATCH v2] iommu/vt-d: Turn off translations at shutdown To: Deepa Dinamani , linux-kernel@vger.kernel.org, joro@8bytes.org References: <20191110172744.12541-1-deepa.kernel@gmail.com> From: Lu Baolu Message-ID: <9f6b30fd-a827-c555-cc8f-f182e1be711f@linux.intel.com> Date: Mon, 11 Nov 2019 13:00:18 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191110172744.12541-1-deepa.kernel@gmail.com> Content-Language: en-US Cc: iommu@lists.linux-foundation.org, dwmw2@infradead.org 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Hi, On 11/11/19 1:27 AM, Deepa Dinamani wrote: > The intel-iommu driver assumes that the iommu state is > cleaned up at the start of the new kernel. > But, when we try to kexec boot something other than the > Linux kernel, the cleanup cannot be relied upon. > Hence, cleanup before we go down for reboot. > > Keeping the cleanup at initialization also, in case BIOS > leaves the IOMMU enabled. > > I considered turning off iommu only during kexec reboot, but a clean > shutdown seems always a good idea. But if someone wants to make it > conditional, such as VMM live update, we can do that. There doesn't > seem to be such a condition at this time. > > Tested that before, the info message > 'DMAR: Translation was enabled for but we are not in kdump mode' > would be reported for each iommu. The message will not appear when the > DMA-remapping is not enabled on entry to the kernel. > > Signed-off-by: Deepa Dinamani This patch looks good to me. Acked-by: Lu Baolu Best regards, baolu > --- > Changes since v1: > * move shutdown registration to iommu detection > > drivers/iommu/dmar.c | 5 ++++- > drivers/iommu/intel-iommu.c | 20 ++++++++++++++++++++ > include/linux/dmar.h | 2 ++ > 3 files changed, 26 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c > index eecd6a421667..3acfa6a25fa2 100644 > --- a/drivers/iommu/dmar.c > +++ b/drivers/iommu/dmar.c > @@ -895,8 +895,11 @@ int __init detect_intel_iommu(void) > } > > #ifdef CONFIG_X86 > - if (!ret) > + if (!ret) { > x86_init.iommu.iommu_init = intel_iommu_init; > + x86_platform.iommu_shutdown = intel_iommu_shutdown; > + } > + > #endif > > if (dmar_tbl) { > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index fe8097078669..7ac73410ba8e 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -4764,6 +4764,26 @@ static void intel_disable_iommus(void) > iommu_disable_translation(iommu); > } > > +void intel_iommu_shutdown(void) > +{ > + struct dmar_drhd_unit *drhd; > + struct intel_iommu *iommu = NULL; > + > + if (no_iommu || dmar_disabled) > + return; > + > + down_write(&dmar_global_lock); > + > + /* Disable PMRs explicitly here. */ > + for_each_iommu(iommu, drhd) > + iommu_disable_protect_mem_regions(iommu); > + > + /* Make sure the IOMMUs are switched off */ > + intel_disable_iommus(); > + > + up_write(&dmar_global_lock); > +} > + > static inline struct intel_iommu *dev_to_intel_iommu(struct device *dev) > { > struct iommu_device *iommu_dev = dev_to_iommu_device(dev); > diff --git a/include/linux/dmar.h b/include/linux/dmar.h > index a7cf3599d9a1..f64ca27dc210 100644 > --- a/include/linux/dmar.h > +++ b/include/linux/dmar.h > @@ -129,6 +129,7 @@ static inline int dmar_res_noop(struct acpi_dmar_header *hdr, void *arg) > #ifdef CONFIG_INTEL_IOMMU > extern int iommu_detected, no_iommu; > extern int intel_iommu_init(void); > +extern void intel_iommu_shutdown(void); > extern int dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg); > extern int dmar_parse_one_atsr(struct acpi_dmar_header *header, void *arg); > extern int dmar_check_one_atsr(struct acpi_dmar_header *hdr, void *arg); > @@ -137,6 +138,7 @@ extern int dmar_iommu_hotplug(struct dmar_drhd_unit *dmaru, bool insert); > extern int dmar_iommu_notify_scope_dev(struct dmar_pci_notify_info *info); > #else /* !CONFIG_INTEL_IOMMU: */ > static inline int intel_iommu_init(void) { return -ENODEV; } > +static inline void intel_iommu_shutdown(void) { } > > #define dmar_parse_one_rmrr dmar_res_noop > #define dmar_parse_one_atsr dmar_res_noop > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu