From patchwork Tue Jul 11 02:59:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13308037 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 8D79EEB64DC for ; Tue, 11 Jul 2023 03:00:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230274AbjGKDAg (ORCPT ); Mon, 10 Jul 2023 23:00:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230392AbjGKDAc (ORCPT ); Mon, 10 Jul 2023 23:00:32 -0400 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15130E57; Mon, 10 Jul 2023 20:00:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689044402; x=1720580402; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=KEioUfhFqmicFFOSjjaN+vgUPr5HVAxqci7L2Sbe/5I=; b=WKWc2fv04615WdL24S6Jdclp4jV/ruxYUTtyWEAfpmRXw9HkCj8IS8/A VWOFiK9ur/0kGfRjfM9f/sSRds3XWGnu60bDezwByYGaWIZlfSFLSMN5L vFHUweyM+exsHg5xobNk63W4l6Bm6KSccXgZzYU99JQwBMR/9gFHog7O7 1B0UkzOGlV6z0AfzC6nnouDgn73wKuoqp+07SrVfZNcAOGL1ZT/g8Oki6 RbIsV/NPexL49C2HMKgStEnqKKrQ5kpLq6A5gAbuBnLTaMxva6OAdRsVb KB0n0hO2H4Ijeo4oG/aSrj6EokF17KBIKKtkPgNxrRKrEdcp+n+UA7/j0 w==; X-IronPort-AV: E=McAfee;i="6600,9927,10767"; a="361973137" X-IronPort-AV: E=Sophos;i="6.01,195,1684825200"; d="scan'208";a="361973137" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jul 2023 19:59:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10767"; a="724250896" X-IronPort-AV: E=Sophos;i="6.01,195,1684825200"; d="scan'208";a="724250896" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by fmsmga007.fm.intel.com with ESMTP; 10 Jul 2023 19:59:46 -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 v14 16/26] vfio: Move vfio_device_group_unregister() to be the first operation in unregister Date: Mon, 10 Jul 2023 19:59:18 -0700 Message-Id: <20230711025928.6438-17-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230711025928.6438-1-yi.l.liu@intel.com> References: <20230711025928.6438-1-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 increment by userspace, which would keep blocking the vfio_unregister_group_dev(). Reviewed-by: Jason Gunthorpe Tested-by: Nicolin Chen Tested-by: Matthew Rosato Tested-by: Yanting Jiang Tested-by: Shameer Kolothum Tested-by: Terrence Xu 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 c71c0d1a079f..6d45caa1f9a0 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);