From patchwork Fri Jun 25 21:26:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 12345925 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93963C49EA7 for ; Fri, 25 Jun 2021 21:26:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B6AD61949 for ; Fri, 25 Jun 2021 21:26:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229959AbhFYV3E (ORCPT ); Fri, 25 Jun 2021 17:29:04 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:53391 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229940AbhFYV3E (ORCPT ); Fri, 25 Jun 2021 17:29:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624656402; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=U5JMFqwvnJzjcO6eOQllRPvApgbp6PzTgwXB8WE2yLw=; b=fYAE475nHOEmBseyxIJ2AeXEPAi2kIORBJYc/E1TKbaq4gw+U137lpoACVpzlyKIQ1sKzl vt00M6alpR3yh+CP37BYRCLYhJs9b8yrQWv0ejizfxLX4DXpR0ERT9jjWKCz8Gl5podh7K 3yEbu6Hj3HPbG571gECjNaPYc2glBAc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-206-QZHdCQNiNXuqdRC_v7fxhQ-1; Fri, 25 Jun 2021 17:26:38 -0400 X-MC-Unique: QZHdCQNiNXuqdRC_v7fxhQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B735618A0765; Fri, 25 Jun 2021 21:26:37 +0000 (UTC) Received: from [172.30.41.16] (ovpn-112-106.phx2.redhat.com [10.3.112.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id EA68869290; Fri, 25 Jun 2021 21:26:11 +0000 (UTC) Subject: [PATCH] vfio/mtty: Enforce available_instances From: Alex Williamson To: alex.williamson@redhat.com Cc: kwankhede@nvidia.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, cohuck@redhat.com, jgg@nvidia.com Date: Fri, 25 Jun 2021 15:26:11 -0600 Message-ID: <162465624894.3338367.12935940647049917981.stgit@omen> User-Agent: StGit/1.0-8-g6af9-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The sample mtty mdev driver doesn't actually enforce the number of device instances it claims are available. Implement this properly. Signed-off-by: Alex Williamson Reviewed-by: Jason Gunthorpe Reviewed-by: Cornelia Huck --- Applies to vfio next branch + Jason's atomic conversion samples/vfio-mdev/mtty.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index ffbaf07a17ea..8b26fecc4afe 100644 --- a/samples/vfio-mdev/mtty.c +++ b/samples/vfio-mdev/mtty.c @@ -144,7 +144,7 @@ struct mdev_state { int nr_ports; }; -static atomic_t mdev_used_ports; +static atomic_t mdev_avail_ports = ATOMIC_INIT(MAX_MTTYS); static const struct file_operations vd_fops = { .owner = THIS_MODULE, @@ -707,11 +707,20 @@ static int mtty_probe(struct mdev_device *mdev) { struct mdev_state *mdev_state; int nr_ports = mdev_get_type_group_id(mdev) + 1; + int avail_ports = atomic_read(&mdev_avail_ports); int ret; + do { + if (avail_ports < nr_ports) + return -ENOSPC; + } while (!atomic_try_cmpxchg(&mdev_avail_ports, + &avail_ports, avail_ports - nr_ports)); + mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL); - if (mdev_state == NULL) + if (mdev_state == NULL) { + atomic_add(nr_ports, &mdev_avail_ports); return -ENOMEM; + } vfio_init_group_dev(&mdev_state->vdev, &mdev->dev, &mtty_dev_ops); @@ -724,6 +733,7 @@ static int mtty_probe(struct mdev_device *mdev) if (mdev_state->vconfig == NULL) { kfree(mdev_state); + atomic_add(nr_ports, &mdev_avail_ports); return -ENOMEM; } @@ -735,9 +745,9 @@ static int mtty_probe(struct mdev_device *mdev) ret = vfio_register_group_dev(&mdev_state->vdev); if (ret) { kfree(mdev_state); + atomic_add(nr_ports, &mdev_avail_ports); return ret; } - atomic_add(mdev_state->nr_ports, &mdev_used_ports); dev_set_drvdata(&mdev->dev, mdev_state); return 0; @@ -746,12 +756,13 @@ static int mtty_probe(struct mdev_device *mdev) static void mtty_remove(struct mdev_device *mdev) { struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev); + int nr_ports = mdev_state->nr_ports; - atomic_sub(mdev_state->nr_ports, &mdev_used_ports); vfio_unregister_group_dev(&mdev_state->vdev); kfree(mdev_state->vconfig); kfree(mdev_state); + atomic_add(nr_ports, &mdev_avail_ports); } static int mtty_reset(struct mdev_state *mdev_state) @@ -1271,8 +1282,7 @@ static ssize_t available_instances_show(struct mdev_type *mtype, { unsigned int ports = mtype_get_type_group_id(mtype) + 1; - return sprintf(buf, "%d\n", - (MAX_MTTYS - atomic_read(&mdev_used_ports)) / ports); + return sprintf(buf, "%d\n", atomic_read(&mdev_avail_ports) / ports); } static MDEV_TYPE_ATTR_RO(available_instances);