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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 46CFDC77B71 for ; Mon, 27 Mar 2023 09:41:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0293310E374; Mon, 27 Mar 2023 09:41:05 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id E3AF610E374; Mon, 27 Mar 2023 09:40:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679910058; x=1711446058; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=8+5Y9ky6ahdVZEJskjMMF4oQKZ6S7sw1abBER9biMeQ=; b=aRCqQKJTuNWNBROLFHJ3rnJgf1M6isZJP+JNJnAukuWsB1MKEoJfXwLC IS2kH8Jyj1HvJ49rEJGT8Id2IsKdIHdwznm/Ot+Bh2FR1gqcxWtzni7kW 5W5ZpNJNT75RTvQQuPAhreS3gfmU1V2ttwA+NtwvrhAxnTHJR+CG2Saut XB61vnk1mWy9oYHWT1axX8oj6ceekTPtO+xpKoCpabzLS1eWCEqbrAzpf eQ5HfRLeBtu0xxcQPSwsLheF+T8aJ7L4GwhM/erpymARS668rUoHRqD0z Gf0tQceyUBebqlbjrUbE2I/8mL8Feyy4mcq9vgnSjFfCjzIEJP+/33VTh g==; X-IronPort-AV: E=McAfee;i="6600,9927,10661"; a="426485338" X-IronPort-AV: E=Sophos;i="5.98,294,1673942400"; d="scan'208";a="426485338" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2023 02:40:58 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10661"; a="660775765" X-IronPort-AV: E=Sophos;i="5.98,294,1673942400"; d="scan'208";a="660775765" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga006.jf.intel.com with ESMTP; 27 Mar 2023 02:40:57 -0700 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Date: Mon, 27 Mar 2023 02:40:33 -0700 Message-Id: <20230327094047.47215-11-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230327094047.47215-1-yi.l.liu@intel.com> References: <20230327094047.47215-1-yi.l.liu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Intel-gfx] [PATCH v8 10/24] vfio: Make vfio_device_open() single open for device cdev path X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mjrosato@linux.ibm.com, jasowang@redhat.com, xudong.hao@intel.com, peterx@redhat.com, terrence.xu@intel.com, chao.p.peng@linux.intel.com, linux-s390@vger.kernel.org, yi.l.liu@intel.com, kvm@vger.kernel.org, lulu@redhat.com, yanting.jiang@intel.com, joro@8bytes.org, nicolinc@nvidia.com, yan.y.zhao@intel.com, intel-gfx@lists.freedesktop.org, eric.auger@redhat.com, intel-gvt-dev@lists.freedesktop.org, yi.y.sun@linux.intel.com, cohuck@redhat.com, shameerali.kolothum.thodi@huawei.com, suravee.suthikulpanit@amd.com, robin.murphy@arm.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" VFIO group has historically allowed multi-open of the device FD. This was made secure because the "open" was executed via an ioctl to the group FD which is itself only single open. However, no known use of multiple device FDs today. It is kind of a strange thing to do because new device FDs can naturally be created via dup(). When we implement the new device uAPI (only used in cdev path) there is no natural way to allow the device itself from being multi-opened in a secure manner. Without the group FD we cannot prove the security context of the opener. Thus, when moving to the new uAPI we block the ability of opening a device multiple times. Given old group path still allows it we store a vfio_group pointer in struct vfio_device_file to differentiate. Reviewed-by: Kevin Tian Tested-by: Terrence Xu Signed-off-by: Yi Liu --- drivers/vfio/group.c | 2 ++ drivers/vfio/vfio.h | 2 ++ drivers/vfio/vfio_main.c | 7 +++++++ 3 files changed, 11 insertions(+) diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c index 4de7a8fc3be1..c0065e359db6 100644 --- a/drivers/vfio/group.c +++ b/drivers/vfio/group.c @@ -245,6 +245,8 @@ static struct file *vfio_device_open_file(struct vfio_device *device) goto err_out; } + df->group = device->group; + ret = vfio_device_group_open(df); if (ret) goto err_free; diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index b2f20b78a707..f1a448f9d067 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -18,6 +18,8 @@ struct vfio_container; struct vfio_device_file { struct vfio_device *device; + struct vfio_group *group; + bool access_granted; spinlock_t kvm_ref_lock; /* protect kvm field */ struct kvm *kvm; diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index b515bbda4c74..b3b7e2436aec 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -477,6 +477,13 @@ int vfio_device_open(struct vfio_device_file *df) lockdep_assert_held(&device->dev_set->lock); + /* + * Only the group path allows the device opened multiple times. + * The device cdev path doesn't have a secure way for it. + */ + if (device->open_count != 0 && !df->group) + return -EINVAL; + device->open_count++; if (device->open_count == 1) { ret = vfio_device_first_open(df); -- 2.34.1