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=-0.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 C6ED2C433E0 for ; Thu, 9 Jul 2020 00:33:19 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 887AF20739 for ; Thu, 9 Jul 2020 00:33:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=intel.onmicrosoft.com header.i=@intel.onmicrosoft.com header.b="upwa+K4O" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 887AF20739 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 247212206D; Thu, 9 Jul 2020 00:33:19 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JLL5blL-bkax; Thu, 9 Jul 2020 00:33:17 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id DDB582094C; Thu, 9 Jul 2020 00:33:17 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id BF08BC077B; Thu, 9 Jul 2020 00:33:17 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id C1B6BC077B for ; Thu, 9 Jul 2020 00:33:16 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id CB1608506A for ; Thu, 9 Jul 2020 00:32:34 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oOPzsysOSJgu for ; Thu, 9 Jul 2020 00:32:34 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 1007785008 for ; Thu, 9 Jul 2020 00:32:33 +0000 (UTC) IronPort-SDR: EEYBuXaHUkaTuPQDpI5FHHHblVpLoL4PCtNvRFlmZrU8uz50Kly7v4FrQcLGNELRCSX2mAwJkd nHo2kTdtmMJw== X-IronPort-AV: E=McAfee;i="6000,8403,9676"; a="209448544" X-IronPort-AV: E=Sophos;i="5.75,329,1589266800"; d="scan'208";a="209448544" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2020 17:32:32 -0700 IronPort-SDR: BaUwxieJGuqUwT8PtO+JuM2JjifaRRJ8x5siHuOqVfCjZCcM8si5DUiw/qJ/I/w8gI431nTMOv VyltOKLssHyw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,329,1589266800"; d="scan'208";a="297889269" Received: from fmsmsx107.amr.corp.intel.com ([10.18.124.205]) by orsmga002.jf.intel.com with ESMTP; 08 Jul 2020 17:32:32 -0700 Received: from fmsmsx123.amr.corp.intel.com (10.18.125.38) by fmsmsx107.amr.corp.intel.com (10.18.124.205) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 8 Jul 2020 17:32:29 -0700 Received: from FMSEDG002.ED.cps.intel.com (10.1.192.134) by fmsmsx123.amr.corp.intel.com (10.18.125.38) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 8 Jul 2020 17:32:29 -0700 Received: from NAM12-MW2-obe.outbound.protection.outlook.com (104.47.66.48) by edgegateway.intel.com (192.55.55.69) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 8 Jul 2020 17:32:28 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ICsWRKYZzrJahS5Ua5VeBob4Lb1mLHFTcPA161n9XsS/rQDTVe88KkGMqeN/HALEJbWY1ktlTVIX+sZnyxO+uR6Iu81v3eFrX1HxFMZWMAHIz5o7tkPPWbQhPALjvprpIt6IYmnb8IeAVTSwmBxc12WGUztfWB21/vnWWQxVSXAtOfOJMuMB6e/TDKm7uea0oY/rNheWvVs3QkzeH2aH7ECQDoaM1wDK7imKgM9r0/tEniwRnROA/HKTANEN6n7+KKUB5binbnpaBcyYvCc4l/IiIiWxydCzQnw5oQCZUh68McziB+W1F0jHwY3dbIWp4GIjLZsqTUqxyE5HaFf/lQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=+6AwG8tJAesQ/Esu1JRKsY3eI0ikWGIJ2b+XgOeEZ2M=; b=RG+PVyO3BUAZJAuLo+pqWhoPWShGCh2exWkf8qWzYzTni740ZN+gSAy+PmmiXdU1KfHuMl1CDXuU4YbKY7ViZXMc2DzkhOtvFwv9rQnNqv9Ql4ZVGLSvHYPj0QQ5Ehy7oNg2+jWzBwToYHi2R3ZeiCkfMHye+hB7tlJHc/dmzpYCC86Pgdwh1uc+whXfOp/iw4tIkcQ85dhWu//fYCZRzeFL8XejI8J6T5D1XddbKTtxrHkf5A1gs7lLM7LgeRCFVrkjPd2TT6B3KYbs3eRV/bnWMApfAifeQYW4V2ubrUsZG9Yt9FTIazsmKBHO4Dcu++32Ip1nTQnfPHqMstExXg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel.onmicrosoft.com; s=selector2-intel-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=+6AwG8tJAesQ/Esu1JRKsY3eI0ikWGIJ2b+XgOeEZ2M=; b=upwa+K4Oz2rt071lAAefxk1h4+dZQfY7lcncpx6hon20Bnf5uFFxyMegd7+1L/auLTjPImcf1E2IX9DFLeglUAqgWpnwwOorEAF0CsF5fkwdjSR+hWx4akjYwIo7E16jAxn5yMqupIkdWDlx/SqzrWGHJXXFSAEv+yomGKUZ9Eg= Received: from DM5PR11MB1435.namprd11.prod.outlook.com (2603:10b6:4:7::18) by DM6PR11MB4201.namprd11.prod.outlook.com (2603:10b6:5:200::33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3174.20; Thu, 9 Jul 2020 00:32:27 +0000 Received: from DM5PR11MB1435.namprd11.prod.outlook.com ([fe80::9002:97a2:d8c0:8364]) by DM5PR11MB1435.namprd11.prod.outlook.com ([fe80::9002:97a2:d8c0:8364%10]) with mapi id 15.20.3174.021; Thu, 9 Jul 2020 00:32:27 +0000 From: "Liu, Yi L" To: Alex Williamson , "jacob.jun.pan@linux.intel.com" Subject: RE: [PATCH v3 06/14] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Thread-Topic: [PATCH v3 06/14] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Thread-Index: AQHWSgRRzB2G/Oy5QEmxCHQWFS0FB6j02KQAgACUCyCAB/5SUIAAxDYAgABLnwA= Date: Thu, 9 Jul 2020 00:32:27 +0000 Message-ID: References: <1592988927-48009-1-git-send-email-yi.l.liu@intel.com> <1592988927-48009-7-git-send-email-yi.l.liu@intel.com> <20200702151832.048b44d1@x1.home> <20200708135444.4eac48a4@x1.home> In-Reply-To: <20200708135444.4eac48a4@x1.home> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-reaction: no-action dlp-version: 11.2.0.6 dlp-product: dlpe-windows authentication-results: redhat.com; dkim=none (message not signed) header.d=none;redhat.com; dmarc=none action=none header.from=intel.com; x-originating-ip: [117.169.230.114] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: db8bf2f3-3cef-4357-9a45-08d8239f8e8c x-ms-traffictypediagnostic: DM6PR11MB4201: x-ld-processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:10000; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: A1ET7/XyJyfwUOxfH+0I6JhTpYCIRkrX4SDBRFeCbZU97EuBQLid0kQOYM06sVvTLHfV7JzmEbPmrBJiEEsEPgtcurRhxa/C6KJPrbPgbWLaInMJshTHK48YcO2ALsz0tnBSHTWaMd4nILtw7jFkVCjooU5YMh6S8tZ0GN6IeeHjNNTdsmJbqP05LyOZA12qBG4Rg+iXPCoc1jISo31LiHfFyH03PPkhcLtVNTtZIunMu3uzdw1P7LYqb3Mc2BVeOXd+Q45bn/fHymWrA03DRTfttYaVlY4PuFMwD/+7QIkzf1o/jUZraja2OnAbWlDm7sTU/2F08dsYPluyBeYLow== x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:DM5PR11MB1435.namprd11.prod.outlook.com; PTR:; CAT:NONE; SFTY:; SFS:(4636009)(366004)(396003)(39860400002)(376002)(136003)(346002)(26005)(33656002)(8676002)(316002)(71200400001)(8936002)(478600001)(66556008)(66476007)(66946007)(64756008)(76116006)(66446008)(5660300002)(52536014)(186003)(4326008)(110136005)(7416002)(54906003)(55016002)(9686003)(83380400001)(7696005)(86362001)(2906002)(6506007); DIR:OUT; SFP:1102; x-ms-exchange-antispam-messagedata: 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 MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DM5PR11MB1435.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: db8bf2f3-3cef-4357-9a45-08d8239f8e8c X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Jul 2020 00:32:27.0516 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: +4geHyDl5JmQHtp61P7TQWso4n9e7E5Z++IMrQB+6cBmjCl1UvFeLQdJw6BiKjZ/uwgWebgQNB+WryQH+N8KPg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR11MB4201 X-OriginatorOrg: intel.com Cc: "jean-philippe@linaro.org" , "Tian, Kevin" , "Raj, Ashok" , "kvm@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "Sun, Yi Y" , "Wu, Hao" , "Tian, Jun J" X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 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 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" Hi Alex, > Alex Williamson > Sent: Thursday, July 9, 2020 3:55 AM > > On Wed, 8 Jul 2020 08:16:16 +0000 > "Liu, Yi L" wrote: > > > Hi Alex, > > > > > From: Liu, Yi L < yi.l.liu@intel.com> > > > Sent: Friday, July 3, 2020 2:28 PM > > > > > > Hi Alex, > > > > > > > From: Alex Williamson > > > > Sent: Friday, July 3, 2020 5:19 AM > > > > > > > > On Wed, 24 Jun 2020 01:55:19 -0700 > > > > Liu Yi L wrote: > > > > > > > > > This patch allows user space to request PASID allocation/free, e.g. > > > > > when serving the request from the guest. > > > > > > > > > > PASIDs that are not freed by userspace are automatically freed when > > > > > the IOASID set is destroyed when process exits. > > [...] > > > > > +static int vfio_iommu_type1_pasid_request(struct vfio_iommu *iommu, > > > > > + unsigned long arg) > > > > > +{ > > > > > + struct vfio_iommu_type1_pasid_request req; > > > > > + unsigned long minsz; > > > > > + > > > > > + minsz = offsetofend(struct vfio_iommu_type1_pasid_request, > range); > > > > > + > > > > > + if (copy_from_user(&req, (void __user *)arg, minsz)) > > > > > + return -EFAULT; > > > > > + > > > > > + if (req.argsz < minsz || (req.flags & > ~VFIO_PASID_REQUEST_MASK)) > > > > > + return -EINVAL; > > > > > + > > > > > + if (req.range.min > req.range.max) > > > > > > > > Is it exploitable that a user can spin the kernel for a long time in > > > > the case of a free by calling this with [0, MAX_UINT] regardless of their > actual > > > allocations? > > > > > > IOASID can ensure that user can only free the PASIDs allocated to the user. > but > > > it's true, kernel needs to loop all the PASIDs within the range provided > > > by user. > it > > > may take a long time. is there anything we can do? one thing may limit the > range > > > provided by user? > > > > thought about it more, we have per-VM pasid quota (say 1000), so even if > > user passed down [0, MAX_UNIT], kernel will only loop the 1000 pasids at > > most. do you think we still need to do something on it? > > How do you figure that? vfio_iommu_type1_pasid_request() accepts the > user's min/max so long as (max > min) and passes that to > vfio_iommu_type1_pasid_free(), then to vfio_pasid_free_range() which > loops as: > > ioasid_t pasid = min; > for (; pasid <= max; pasid++) > ioasid_free(pasid); > > A user might only be able to allocate 1000 pasids, but apparently they > can ask to free all they want. > > It's also not obvious to me that calling ioasid_free() is only allowing > the user to free their own passid. Does it? It would be a pretty > gaping hole if a user could free arbitrary pasids. A r-b tree of > passids might help both for security and to bound spinning in a loop. oh, yes. BTW. instead of r-b tree in VFIO, maybe we can add an ioasid_set parameter for ioasid_free(), thus to prevent the user from freeing PASIDs that doesn't belong to it. I remember Jacob mentioned it before. @Jacob, is it still in your plan? Regards, Yi Liu > Thanks, > > Alex _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu