From patchwork Mon Mar 27 09:40:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13188932 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 DDFD6C761A6 for ; Mon, 27 Mar 2023 09:41:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232953AbjC0JlO (ORCPT ); Mon, 27 Mar 2023 05:41:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233190AbjC0Jk6 (ORCPT ); Mon, 27 Mar 2023 05:40:58 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 833A44481; Mon, 27 Mar 2023 02:40:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679910057; x=1711446057; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=sKLKxqFXKGX9KDQkRuvOH4gy4KDtEaqzB9jFFWwkt6A=; b=nCi/h9yBcxDq/md6SrsLylW5q3V8d73fy36Uxl8oQWd4vKcLsdHQeFAL sZccP3N1973TNlHYsY8FPad2fhyq6DieQQzAEnup6LU+/v9TZeKhC4Fux OXe1PphRzRg31wxF3fbbHkguYbtQvvlRzQO4jVULr5H18ArIaUhmj8ePX mSr3cYhDpfAJYU17CFPpZeoHBa4KyYSLU0jnZYsTGSkkvbiFKyxQk3C7y rb2wEcFId/Oo2R+q/pSHvSa6fwEtO16yqBMpngGO1lCF25PhC1DniSOdP rpeITDu+JdX4z9l9okh/X6VIcu/1Yt9xuodu0vsTptDPDpe3Qp3yf+wOx A==; X-IronPort-AV: E=McAfee;i="6600,9927,10661"; a="426485322" X-IronPort-AV: E=Sophos;i="5.98,294,1673942400"; d="scan'208";a="426485322" 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 02:40:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10661"; a="660775744" X-IronPort-AV: E=Sophos;i="5.98,294,1673942400"; d="scan'208";a="660775744" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga006.jf.intel.com with ESMTP; 27 Mar 2023 02:40:56 -0700 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Cc: joro@8bytes.org, robin.murphy@arm.com, cohuck@redhat.com, eric.auger@redhat.com, nicolinc@nvidia.com, kvm@vger.kernel.org, mjrosato@linux.ibm.com, chao.p.peng@linux.intel.com, yi.l.liu@intel.com, yi.y.sun@linux.intel.com, peterx@redhat.com, jasowang@redhat.com, shameerali.kolothum.thodi@huawei.com, lulu@redhat.com, suravee.suthikulpanit@amd.com, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-s390@vger.kernel.org, xudong.hao@intel.com, yan.y.zhao@intel.com, terrence.xu@intel.com, yanting.jiang@intel.com Subject: [PATCH v8 09/24] vfio: Add cdev_device_open_cnt to vfio_group Date: Mon, 27 Mar 2023 02:40:32 -0700 Message-Id: <20230327094047.47215-10-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 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org for counting the devices that are opened via the cdev path. This count is increased and decreased by the cdev path. The group path checks it to achieve exclusion with the cdev path. With this, only one path (group path or cdev path) will claim DMA ownership. This avoids scenarios in which devices within the same group may be opened via different paths. Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Tested-by: Terrence Xu Tested-by: Nicolin Chen Tested-by: Matthew Rosato Signed-off-by: Yi Liu --- drivers/vfio/group.c | 33 +++++++++++++++++++++++++++++++++ drivers/vfio/vfio.h | 3 +++ 2 files changed, 36 insertions(+) diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c index 4f267ae7bebc..4de7a8fc3be1 100644 --- a/drivers/vfio/group.c +++ b/drivers/vfio/group.c @@ -383,6 +383,33 @@ static long vfio_group_fops_unl_ioctl(struct file *filep, } } +int vfio_device_block_group(struct vfio_device *device) +{ + struct vfio_group *group = device->group; + int ret = 0; + + mutex_lock(&group->group_lock); + if (group->opened_file) { + ret = -EBUSY; + goto out_unlock; + } + + group->cdev_device_open_cnt++; + +out_unlock: + mutex_unlock(&group->group_lock); + return ret; +} + +void vfio_device_unblock_group(struct vfio_device *device) +{ + struct vfio_group *group = device->group; + + mutex_lock(&group->group_lock); + group->cdev_device_open_cnt--; + mutex_unlock(&group->group_lock); +} + static int vfio_group_fops_open(struct inode *inode, struct file *filep) { struct vfio_group *group = @@ -405,6 +432,11 @@ static int vfio_group_fops_open(struct inode *inode, struct file *filep) goto out_unlock; } + if (group->cdev_device_open_cnt) { + ret = -EBUSY; + goto out_unlock; + } + /* * Do we need multiple instances of the group open? Seems not. */ @@ -479,6 +511,7 @@ static void vfio_group_release(struct device *dev) mutex_destroy(&group->device_lock); mutex_destroy(&group->group_lock); WARN_ON(group->iommu_group); + WARN_ON(group->cdev_device_open_cnt); ida_free(&vfio.group_ida, MINOR(group->dev.devt)); kfree(group); } diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index 854f2c97cb9a..b2f20b78a707 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -83,8 +83,11 @@ struct vfio_group { struct blocking_notifier_head notifier; struct iommufd_ctx *iommufd; spinlock_t kvm_ref_lock; + unsigned int cdev_device_open_cnt; }; +int vfio_device_block_group(struct vfio_device *device); +void vfio_device_unblock_group(struct vfio_device *device); int vfio_device_set_group(struct vfio_device *device, enum vfio_group_type type); void vfio_device_remove_group(struct vfio_device *device);