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 6FC34C43381 for ; Wed, 13 Mar 2019 10:20:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 477F92087C for ; Wed, 13 Mar 2019 10:20:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726219AbfCMKUD (ORCPT ); Wed, 13 Mar 2019 06:20:03 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:56732 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725870AbfCMKUD (ORCPT ); Wed, 13 Mar 2019 06:20:03 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x2DAJDcd031162 for ; Wed, 13 Mar 2019 06:20:02 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2r6y6vafgm-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 13 Mar 2019 06:20:01 -0400 Received: from localhost by e06smtp02.uk.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) Wed, 13 Mar 2019 10:19:56 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x2DAJsOo52101278 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Mar 2019 10:19:54 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BBCE952059; Wed, 13 Mar 2019 10:19:53 +0000 (GMT) Received: from [9.152.224.140] (unknown [9.152.224.140]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 145EB52051; Wed, 13 Mar 2019 10:19:53 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v4 3/7] s390: ap: associate a ap_vfio_queue and a matrix mdev To: Tony Krowiak , Halil Pasic Cc: borntraeger@de.ibm.com, alex.williamson@redhat.com, cohuck@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com References: <1550849400-27152-1-git-send-email-pmorel@linux.ibm.com> <1550849400-27152-4-git-send-email-pmorel@linux.ibm.com> <20190304030935.525f4223@oc2783563651> <17fc3369-2496-2113-5a1a-1630df84f067@linux.ibm.com> From: Pierre Morel Date: Wed, 13 Mar 2019 11:19:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <17fc3369-2496-2113-5a1a-1630df84f067@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19031310-0008-0000-0000-000002CC0F04 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19031310-0009-0000-0000-0000223832BF Message-Id: <52eaf739-3fad-9be8-a2f7-9657000ace3e@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-03-13_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 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=8.0.1-1810050000 definitions=main-1903130075 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/03/2019 22:39, Tony Krowiak wrote: > On 3/3/19 9:09 PM, Halil Pasic wrote: >> On Fri, 22 Feb 2019 16:29:56 +0100 >> Pierre Morel wrote: >> >>> We need to associate the ap_vfio_queue, which will hold the >>> per queue information for interrupt with a matrix mediated device >>> which hold the configuration and the way to the CRYCB. >> [..] >>> +static int vfio_ap_get_all_domains(struct ap_matrix_mdev >>> *matrix_mdev, int apid) >>> +{ >>> +    int apqi, apqn; >>> +    int ret = 0; >>> +    struct vfio_ap_queue *q; >>> +    struct list_head q_list; >>> + >>> +    INIT_LIST_HEAD(&q_list); >>> + >>> +    for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) { >>> +        apqn = AP_MKQID(apid, apqi); >>> +        q = vfio_ap_get_queue(apqn, &matrix_dev->free_list); >>> +        if (!q) { >>> +            ret = -EADDRNOTAVAIL; >>> +            goto rewind; >>> +        } >>> +        if (q->matrix_mdev) { >>> +            ret = -EADDRINUSE; >> >> You tried to get the q from matrix_dev->free_list thus modulo races >> q->matrix_mdev should be 0. This change breaks the error codes in a >> sense that it becomes impossible to provoke EADDRINUSE (the proper >> error code for taken by another matrix_mdev). > > It is necessary to determine if the queue is in use by another mdev, so > it will still be necessary to traverse all of the matrix_mdev structs to > see if q is in matrix_mdev->qlist. It seems that maintaining the qlist > does not buy us much. > Tony, Halil already pointed out this issue and I already answered. Please, no need to duplicate the remarks. Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany