From patchwork Fri Jun 2 12:16:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13265237 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 1CCC4C77B7A for ; Fri, 2 Jun 2023 12:17:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235101AbjFBMRs (ORCPT ); Fri, 2 Jun 2023 08:17:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235253AbjFBMRS (ORCPT ); Fri, 2 Jun 2023 08:17:18 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2F9DE41; Fri, 2 Jun 2023 05:17:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1685708236; x=1717244236; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=LDpum0gyrhY92rh1Sf5oxFrVD6xqaXKz9c9zNny5DxE=; b=GaO8knOjs/xbX4socOCSrHwdl54R8446zM9D9H73xntjE3/ZLgcLfKLm kMdVYAlfocLAkJITUpnDNSFu8sAKlIgfp/RDSxvpU9wuIzdyZqnJtk15c xH5tkAxcHGP/utqpHspKeoHFnlsiHGeWwit0s9pc8HzAY6QI7W4J6YguL P1fGQ61AcG/kQCLf6dR8Uloc49AL2+rkdS3bRxoT/gwXjg/sX1AMmcq/Y jX/JXHmSMy/O1sNVNMpAGsIzKRjvRE6yYbqo6Rwayq3E4/NgGgk3qI/8K lqaAbJ+PaqZYrzdUQkUImy8Tdvv+9eWnc7TT6Jzj0dOGeAABOrJlPQECc g==; X-IronPort-AV: E=McAfee;i="6600,9927,10728"; a="384136672" X-IronPort-AV: E=Sophos;i="6.00,212,1681196400"; d="scan'208";a="384136672" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jun 2023 05:17:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10728"; a="1037947387" X-IronPort-AV: E=Sophos;i="6.00,212,1681196400"; d="scan'208";a="1037947387" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by fmsmga005.fm.intel.com with ESMTP; 02 Jun 2023 05:17:15 -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, zhenzhong.duan@intel.com, clegoate@redhat.com Subject: [PATCH v12 16/24] vfio: Move vfio_device_group_unregister() to be the first operation in unregister Date: Fri, 2 Jun 2023 05:16:45 -0700 Message-Id: <20230602121653.80017-17-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230602121653.80017-1-yi.l.liu@intel.com> References: <20230602121653.80017-1-yi.l.liu@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This avoids endless vfio_device refcount increasement by userspace, which would keep blocking the vfio_unregister_group_dev(). Tested-by: Yanting Jiang Tested-by: Shameer Kolothum Tested-by: Terrence Xu Signed-off-by: Yi Liu Reviewed-by: Jason Gunthorpe --- 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 df4f3e37268d..f00ba7603351 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -332,6 +332,12 @@ 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) { @@ -355,8 +361,6 @@ void vfio_unregister_group_dev(struct vfio_device *device) } } - vfio_device_group_unregister(device); - /* Balances device_add in register path */ device_del(&device->device);