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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3C65C6FD18 for ; Tue, 28 Mar 2023 15:46:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234134AbjC1Pqu (ORCPT ); Tue, 28 Mar 2023 11:46:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232809AbjC1Pqb (ORCPT ); Tue, 28 Mar 2023 11:46:31 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29E76D311; Tue, 28 Mar 2023 08:46:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680018366; x=1711554366; h=date:from:to:cc:subject:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=aANfklT01Q50VoPynu4eI92dQQpk9aNu69RWvGsHYk8=; b=H4c7xOuG90nCeD10p/p27A5IteIcRDsaZIhTC2YQKwca+3jR1KRlUraC Z3JCKP+Vo0R9uZ2qqGakgjjkBFDglsXESewg78V5F7ZL7EbJsygkv9STx +dM3Li2I3eGR7/ZSsXjZ+Mof/fseTTa38DQlM1w9rrlU2RMcpjI6akW8q LK1Ggh4LM5unxEZCLqRGElPNuQpEvtXDj6zoworBWbnuiEOH5zQ7gYBzC KAhGrmxyAeLHdegLEG5gcHfHJ6TJAJAuMm01WOa/DpfbfW+jS36vK90Lv rYOzCh5XejH6o/2EeTkUBlH47AwO7T8P8Gpp2fS9JbLdMfnMmaynov7UC A==; X-IronPort-AV: E=McAfee;i="6600,9927,10663"; a="368365970" X-IronPort-AV: E=Sophos;i="5.98,297,1673942400"; d="scan'208";a="368365970" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Mar 2023 08:44:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10663"; a="753195774" X-IronPort-AV: E=Sophos;i="5.98,297,1673942400"; d="scan'208";a="753195774" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.24.100.114]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Mar 2023 08:44:52 -0700 Date: Tue, 28 Mar 2023 08:48:55 -0700 From: Jacob Pan To: Baolu Lu Cc: LKML , iommu@lists.linux.dev, Jason Gunthorpe , Joerg Roedel , dmaengine@vger.kernel.org, vkoul@kernel.org, Robin Murphy , Will Deacon , David Woodhouse , Raj Ashok , "Tian, Kevin" , Yi Liu , "Yu, Fenghua" , Dave Jiang , Tony Luck , "Zanussi, Tom" , jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v2 7/8] iommu: Export iommu_get_dma_domain Message-ID: <20230328084855.7b9cd981@jacob-builder> In-Reply-To: References: <20230327232138.1490712-1-jacob.jun.pan@linux.intel.com> <20230327232138.1490712-8-jacob.jun.pan@linux.intel.com> Organization: OTC X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Baolu, On Tue, 28 Mar 2023 14:04:15 +0800, Baolu Lu wrote: > On 3/28/23 7:21 AM, Jacob Pan wrote: > > Devices that use ENQCMDS to submit work needs to retrieve its DMA > > domain. It can then attach PASID to the DMA domain for shared mapping > > (with RID) established by DMA API. > > > > Signed-off-by: Jacob Pan > > --- > > drivers/iommu/iommu.c | 1 + > > include/linux/iommu.h | 5 +++++ > > 2 files changed, 6 insertions(+) > > > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > > index 10db680acaed..c51d343a75d2 100644 > > --- a/drivers/iommu/iommu.c > > +++ b/drivers/iommu/iommu.c > > @@ -2118,6 +2118,7 @@ struct iommu_domain *iommu_get_dma_domain(struct > > device *dev) { > > return dev->iommu_group->default_domain; > > } > > +EXPORT_SYMBOL_GPL(iommu_get_dma_domain); > > Directly exporting this function for external use seems unsafe. If the > caller is the kernel driver for this device, it's fine because default > domain remains unchanged during the life cycle of the driver. Otherwise, > using this function may cause UAF. Keep in mind that group's default > domain could be changed through sysfs. don't you have to unload the driver? > However, iommu_get_domain_for_dev() has already done so and has been > exported. Maybe I'm worried too much. :-) > > Best regards, > baolu Thanks, Jacob