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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 8115DC4321D for ; Thu, 16 Aug 2018 16:24:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E8BA2147A for ; Thu, 16 Aug 2018 16:24:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E8BA2147A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404095AbeHPTYQ (ORCPT ); Thu, 16 Aug 2018 15:24:16 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59404 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389145AbeHPTYP (ORCPT ); Thu, 16 Aug 2018 15:24:15 -0400 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7GGOhZf086384 for ; Thu, 16 Aug 2018 12:24:46 -0400 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0b-001b2d01.pphosted.com with ESMTP id 2kw9mh8egq-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 16 Aug 2018 12:24:44 -0400 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 16 Aug 2018 10:24:23 -0600 Received: from b03ledav003.gho.boulder.ibm.com (b03ledav003.gho.boulder.ibm.com [9.17.130.234]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7GGOKJ1983380 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 16 Aug 2018 09:24:20 -0700 Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6C6A06A054; Thu, 16 Aug 2018 10:24:20 -0600 (MDT) Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8F8FE6A04F; Thu, 16 Aug 2018 10:24:17 -0600 (MDT) Received: from oc8043147753.ibm.com (unknown [9.85.159.167]) by b03ledav003.gho.boulder.ibm.com (Postfix) with ESMTP; Thu, 16 Aug 2018 10:24:17 -0600 (MDT) Subject: Re: [PATCH v9 09/22] s390: vfio-ap: register matrix device with VFIO mdev framework To: Cornelia Huck , Tony Krowiak Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, borntraeger@de.ibm.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com, frankja@linux.ibm.com References: <1534196899-16987-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1534196899-16987-10-git-send-email-akrowiak@linux.vnet.ibm.com> <20180814131929.37d4b530.cohuck@redhat.com> From: Tony Krowiak Date: Thu, 16 Aug 2018 12:24:16 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20180814131929.37d4b530.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18081616-0036-0000-0000-00000A2402E0 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009555; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01074413; UDB=6.00553681; IPR=6.00854371; MB=3.00022758; MTD=3.00000008; XFM=3.00000015; UTC=2018-08-16 16:24:25 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18081616-0037-0000-0000-0000489AD455 Message-Id: <5b77a5e9-6d91-c7a3-5ada-d888735f0488@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-16_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=4 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808160169 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/14/2018 07:19 AM, Cornelia Huck wrote: > On Mon, 13 Aug 2018 17:48:06 -0400 > Tony Krowiak wrote: > >> From: Tony Krowiak >> >> Registers the matrix device created by the VFIO AP device >> driver with the VFIO mediated device framework. >> Registering the matrix device will create the sysfs >> structures needed to create mediated matrix devices >> each of which will be used to configure the AP matrix >> for a guest and connect it to the VFIO AP device driver. >> >> Registering the matrix device with the VFIO mediated device >> framework will create the following sysfs structures: >> >> /sys/devices/vfio_ap/matrix/ >> ...... [mdev_supported_types] >> ......... [vfio_ap-passthrough] >> ............ create >> >> To create a mediated device for the AP matrix device, write a UUID >> to the create file: >> >> uuidgen > create >> >> A symbolic link to the mediated device's directory will be created in the >> devices subdirectory named after the generated $uuid: >> >> /sys/devices/vfio_ap/matrix/ >> ...... [mdev_supported_types] >> ......... [vfio_ap-passthrough] >> ............ [devices] >> ............... [$uuid] >> >> A symbolic link to the mediated device will also be created >> in the vfio_ap matrix's directory: >> >> /sys/devices/vfio_ap/matrix/[$uuid] >> >> Signed-off-by: Tony Krowiak >> Reviewed-by: Halil Pasic >> Tested-by: Michael Mueller >> Tested-by: Farhan Ali >> Signed-off-by: Christian Borntraeger >> --- >> MAINTAINERS | 1 + >> drivers/s390/crypto/Makefile | 2 +- >> drivers/s390/crypto/vfio_ap_drv.c | 23 ++++++ >> drivers/s390/crypto/vfio_ap_ops.c | 124 +++++++++++++++++++++++++++++++++ >> drivers/s390/crypto/vfio_ap_private.h | 45 ++++++++++++ >> include/uapi/linux/vfio.h | 1 + >> 6 files changed, 195 insertions(+), 1 deletions(-) >> create mode 100644 drivers/s390/crypto/vfio_ap_ops.c >> > >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c >> new file mode 100644 >> index 0000000..8018c2d >> --- /dev/null >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -0,0 +1,124 @@ >> +// SPDX-License-Identifier: GPL-2.0+ >> +/* >> + * Adjunct processor matrix VFIO device driver callbacks. >> + * >> + * Copyright IBM Corp. 2018 >> + * >> + * Author(s): Tony Krowiak >> + * Halil Pasic >> + * Pierre Morel >> + */ >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#include "vfio_ap_private.h" >> + >> +#define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough" >> +#define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device" >> + >> +static void vfio_ap_matrix_init(struct ap_config_info *info, >> + struct ap_matrix *matrix) >> +{ >> + matrix->apm_max = info->apxa ? info->Na : 63; >> + matrix->aqm_max = info->apxa ? info->Nd : 15; >> + matrix->adm_max = info->apxa ? info->Nd : 15; >> +} >> + >> +static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev) >> +{ >> + struct ap_matrix_mdev *matrix_mdev; >> + >> + matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL); >> + if (!matrix_mdev) >> + return -ENOMEM; >> + >> + matrix_mdev->name = dev_name(mdev_dev(mdev)); >> + vfio_ap_matrix_init(&matrix_dev.info, &matrix_mdev->matrix); >> + mdev_set_drvdata(mdev, matrix_mdev); >> + >> + if (atomic_dec_if_positive(&matrix_dev.available_instances) < 0) { >> + kfree(matrix_mdev); >> + return -EPERM; >> + } > Maybe move this check to the top of the function? Please ignore my previous response to your comment. I can't move the call to atomic_dec_if_positive() to the top of the function because it decrements the available_instances and if the kzalloc() of matrix_mdev fails, then the value would have to then be incremented to remain valid. What I can do is this: 1. Check the value of available_instances using atomic_read() at the top of the function and if it is zero, return an error. 2. Replace the call to atomic_dec_if_positive() with a call to atomic_dec() to decrement the available_instances. I agree that it makes sense to return before attempting to allocate the matrix_mdev if available_instances is zero. > >> + >> + mutex_lock(&matrix_dev.lock); >> + list_add(&matrix_mdev->list, &matrix_dev.mdev_list); >> + mutex_unlock(&matrix_dev.lock); >> + >> + return 0; >> +}