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 BB70EC77B77 for ; Sat, 1 Apr 2023 15:19:03 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C78F010E105; Sat, 1 Apr 2023 15:19:02 +0000 (UTC) Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8ECE210E105; Sat, 1 Apr 2023 15:18:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680362327; x=1711898327; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=UGMAQSzJDGu2jFNVvQm9xR08gZhYc2KjsQ3tE+TSPbo=; b=Pl+pPJabRkYLQPS3A1BCS4/iHzIe/wh8GMZcaX20U0nGAtmw7miiaAlV 3CG+Q0AMd8HwURVsDuJIrhAYD+N3fy/H1XGWi+EArA+WqcCiyuPhZzyly zXjcyHhR1jtMtjgZTyfK2Ent8uv1q2McQvAuoxeN/3fy7tbe+8i8O2kxm 4gTNqPe3cZ5ima0XII3TPPNPYsZ5Glh3WLRYeTMhEwAsS2RcOEviwHUSS LJ7L+enlZu4pc0gwwKHJon4XrY/69b53jT5uQ5SNXWmmADqr7fvrl5DaD cLQ41TSlMZLZ8ZJrvuTACKaVPXM+TBgnzYq6K1o1/nN3Tgu1UObHuNz6n g==; X-IronPort-AV: E=McAfee;i="6600,9927,10667"; a="404411370" X-IronPort-AV: E=Sophos;i="5.98,310,1673942400"; d="scan'208";a="404411370" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2023 08:18:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10667"; a="678937225" X-IronPort-AV: E=Sophos;i="5.98,310,1673942400"; d="scan'208";a="678937225" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga007.jf.intel.com with ESMTP; 01 Apr 2023 08:18:46 -0700 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Date: Sat, 1 Apr 2023 08:18:28 -0700 Message-Id: <20230401151833.124749-21-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230401151833.124749-1-yi.l.liu@intel.com> References: <20230401151833.124749-1-yi.l.liu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Intel-gfx] [PATCH v9 20/25] vfio: Move vfio_device_group_unregister() to be the first operation in unregister 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" This can avoid endless vfio_device refcount increasement by userspace, which would keep blocking the vfio_unregister_group_dev(). Signed-off-by: Yi Liu --- drivers/vfio/vfio_main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 0337d1ace716..6c31212740fa 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -320,6 +320,12 @@ void vfio_unregister_group_dev(struct vfio_device *device) bool interrupted = false; long rc; + /* + * Prevent new device opened by userspace via the + * VFIO_GROUP_GET_DEVICE_FD in the group path. + */ + vfio_device_group_unregister(device); + vfio_device_put_registration(device); rc = try_wait_for_completion(&device->comp); while (rc <= 0) { @@ -343,8 +349,6 @@ void vfio_unregister_group_dev(struct vfio_device *device) } } - vfio_device_group_unregister(device); - /* Balances device_add in register path */ device_del(&device->device); -- 2.34.1