From patchwork Tue Feb 21 03:48:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13147374 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 61D8AC677F1 for ; Tue, 21 Feb 2023 03:48:47 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4DA5710E282; Tue, 21 Feb 2023 03:48:45 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 29B2410E19A; Tue, 21 Feb 2023 03:48:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676951314; x=1708487314; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=253CuN66Ju3s29mUzy/m62gz3DrLxjVPLRR1BM6zUrE=; b=gO+GEqHzdYr9He4SzCWOrc15B+2vECKl9q7ywf/qzhinmk0cI/WRl3QE CYeDc54tMtyVWGAOdoWy/h2/S+JOpwt7gjmi0anPDZg2UtFKQeTvBqZjo hsjcWL90Ezk6CbQone4kJJV9DiORXEtjprPp9XmqBxNt2+ACyaPsku9rM GZXGBvQxBFyr8zmFUnKr/BgxTdXLWhr0GRNcpVorzkNibPU5VyyAkRbE1 RkYwFdvPpdOLFVHo6vmGzFaIC3MdhabfAlGZ+Bkzr0YQgWPLz6g5LPHvE AF/+i/yeav/nx3VPl+Bscpbw+qeDv1Xi5oDZ46keJdktvU2jJ5uCBpkv9 Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10627"; a="397218507" X-IronPort-AV: E=Sophos;i="5.97,314,1669104000"; d="scan'208";a="397218507" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Feb 2023 19:48:25 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10627"; a="664822202" X-IronPort-AV: E=Sophos;i="5.97,314,1669104000"; d="scan'208";a="664822202" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga007.jf.intel.com with ESMTP; 20 Feb 2023 19:48:25 -0800 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Date: Mon, 20 Feb 2023 19:48:07 -0800 Message-Id: <20230221034812.138051-15-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230221034812.138051-1-yi.l.liu@intel.com> References: <20230221034812.138051-1-yi.l.liu@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v4 14/19] 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: linux-s390@vger.kernel.org, yi.l.liu@intel.com, yi.y.sun@linux.intel.com, kvm@vger.kernel.org, mjrosato@linux.ibm.com, joro@8bytes.org, cohuck@redhat.com, xudong.hao@intel.com, peterx@redhat.com, yan.y.zhao@intel.com, eric.auger@redhat.com, terrence.xu@intel.com, nicolinc@nvidia.com, shameerali.kolothum.thodi@huawei.com, suravee.suthikulpanit@amd.com, intel-gfx@lists.freedesktop.org, chao.p.peng@linux.intel.com, lulu@redhat.com, intel-gvt-dev@lists.freedesktop.org, jasowang@redhat.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 to multi-open the device. Old group path still allows it. vfio_device_open() needs to sustain both the legacy behavior i.e. multi-open in the group path and the new behavior i.e. single-open in the cdev path. This mixture leads to the introduction of a new is_cdev_device flag in struct vfio_device_file. Signed-off-by: Yi Liu Reviewed-by: Kevin Tian --- drivers/vfio/vfio.h | 2 ++ drivers/vfio/vfio_main.c | 10 +++++++++- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index bf84cf36eac7..68be0e8279c7 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; + bool is_cdev_device; + 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 484f89eef7e5..925127a38a3a 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -472,6 +472,13 @@ int vfio_device_open(struct vfio_device_file *df, lockdep_assert_held(&device->dev_set->lock); + /* + * Device cdev path cannot support multiple device open since + * it doesn't have a secure way for it. + */ + if (device->open_count != 0 && df->is_cdev_device) + return -EINVAL; + device->open_count++; if (device->open_count == 1) { ret = vfio_device_first_open(df, dev_id, pt_id); @@ -535,7 +542,8 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) struct vfio_device_file *df = filep->private_data; struct vfio_device *device = df->device; - vfio_device_group_close(df); + if (!df->is_cdev_device) + vfio_device_group_close(df); vfio_device_put_registration(device);