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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 AD9BAC43381 for ; Thu, 21 Feb 2019 07:38:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 662D42147A for ; Thu, 21 Feb 2019 07:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727025AbfBUHiH (ORCPT ); Thu, 21 Feb 2019 02:38:07 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59190 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725648AbfBUHiH (ORCPT ); Thu, 21 Feb 2019 02:38:07 -0500 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1L7PLB4060688 for ; Thu, 21 Feb 2019 02:38:05 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2qsn2dnmbv-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 21 Feb 2019 02:38:05 -0500 Received: from localhost by e06smtp01.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) Thu, 21 Feb 2019 07:38:01 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1L7c0cE28573866 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Feb 2019 07:38:00 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1A011A405B; Thu, 21 Feb 2019 07:38:00 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 99F44A4054; Thu, 21 Feb 2019 07:37:59 +0000 (GMT) Received: from oc7455500831.ibm.com (unknown [9.152.224.110]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 21 Feb 2019 07:37:59 +0000 (GMT) Subject: Re: [PATCH v2 1/1] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem To: Harald Freudenberger , Pierre Morel Cc: cohuck@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, akrowiak@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com References: <1550513328-12646-1-git-send-email-pmorel@linux.ibm.com> <1550513328-12646-2-git-send-email-pmorel@linux.ibm.com> From: Christian Borntraeger Openpgp: preference=signencrypt Autocrypt: addr=borntraeger@de.ibm.com; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 19022107-4275-0000-0000-000003121BC9 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19022107-4276-0000-0000-000038204E5D Message-Id: <3c3a90ca-f7ea-7800-453d-31e6d273e82f@de.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-21_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 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-1902210057 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20.02.2019 14:12, Harald Freudenberger wrote: > On 18.02.19 19:08, Pierre Morel wrote: >> Libudev relies on having a subsystem link for non-root devices. To >> avoid libudev (and potentially other userspace tools) choking on the >> matrix device let us introduce a vfio_ap bus and with that the vfio_ap >> bus subsytem, and make the matrix device reside within it. >> >> Doing this we need to suppress the forced link from the matrix device to >> the vfio_ap driver and we suppress the device_type we do not need >> anymore. >> >> Since the associated matrix driver is not the vfio_ap driver any more, >> we have to change the search for the devices on the vfio_ap driver in >> the function vfio_ap_verify_queue_reserved. >> >> Reported-by: Marc Hartmayer >> Reported-by: Christian Borntraeger >> Signed-off-by: Pierre Morel >> --- >> drivers/s390/crypto/vfio_ap_drv.c | 48 +++++++++++++++++++++++++++++------ >> drivers/s390/crypto/vfio_ap_ops.c | 4 +-- >> drivers/s390/crypto/vfio_ap_private.h | 1 + >> 3 files changed, 43 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c >> index 31c6c84..8e45559 100644 >> --- a/drivers/s390/crypto/vfio_ap_drv.c >> +++ b/drivers/s390/crypto/vfio_ap_drv.c >> @@ -24,10 +24,6 @@ MODULE_LICENSE("GPL v2"); >> >> static struct ap_driver vfio_ap_drv; >> >> -static struct device_type vfio_ap_dev_type = { >> - .name = VFIO_AP_DEV_TYPE_NAME, >> -}; >> - >> struct ap_matrix_dev *matrix_dev; >> >> /* Only type 10 adapters (CEX4 and later) are supported >> @@ -62,6 +58,27 @@ static void vfio_ap_matrix_dev_release(struct device *dev) >> kfree(matrix_dev); >> } >> >> +static int matrix_bus_match(struct device *dev, struct device_driver *drv) >> +{ >> + return 1; >> +} >> + >> +static struct bus_type matrix_bus = { >> + .name = "vfio_ap", >> + .match = &matrix_bus_match, >> +}; >> + >> +static int matrix_probe(struct device *dev) >> +{ >> + return 0; >> +} >> + >> +static struct device_driver matrix_driver = { >> + .name = "vfio_ap", >> + .bus = &matrix_bus, >> + .probe = matrix_probe, >> +}; >> + >> static int vfio_ap_matrix_dev_create(void) >> { >> int ret; >> @@ -71,6 +88,10 @@ static int vfio_ap_matrix_dev_create(void) >> if (IS_ERR(root_device)) >> return PTR_ERR(root_device); >> >> + ret = bus_register(&matrix_bus); >> + if (ret) >> + goto bus_register_err; >> + >> matrix_dev = kzalloc(sizeof(*matrix_dev), GFP_KERNEL); >> if (!matrix_dev) { >> ret = -ENOMEM; >> @@ -87,30 +108,41 @@ static int vfio_ap_matrix_dev_create(void) >> mutex_init(&matrix_dev->lock); >> INIT_LIST_HEAD(&matrix_dev->mdev_list); >> >> - matrix_dev->device.type = &vfio_ap_dev_type; >> dev_set_name(&matrix_dev->device, "%s", VFIO_AP_DEV_NAME); >> matrix_dev->device.parent = root_device; >> + matrix_dev->device.bus = &matrix_bus; >> matrix_dev->device.release = vfio_ap_matrix_dev_release; >> - matrix_dev->device.driver = &vfio_ap_drv.driver; >> + matrix_dev->vfio_ap_drv = &vfio_ap_drv; >> >> ret = device_register(&matrix_dev->device); >> if (ret) >> goto matrix_reg_err; >> >> + ret = driver_register(&matrix_driver); >> + if (ret) >> + goto matrix_drv_err; >> + >> return 0; >> >> +matrix_drv_err: >> + device_unregister(&matrix_dev->device); >> matrix_reg_err: >> put_device(&matrix_dev->device); >> matrix_alloc_err: >> + bus_unregister(&matrix_bus); >> +bus_register_err: >> root_device_unregister(root_device); >> - >> return ret; >> } >> >> static void vfio_ap_matrix_dev_destroy(void) >> { >> + struct device *root_device = matrix_dev->device.parent; >> + >> + driver_unregister(&matrix_driver); >> device_unregister(&matrix_dev->device); >> - root_device_unregister(matrix_dev->device.parent); >> + bus_unregister(&matrix_bus); >> + root_device_unregister(root_device); >> } >> >> static int __init vfio_ap_init(void) >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c >> index 272ef42..900b9cf 100644 >> --- a/drivers/s390/crypto/vfio_ap_ops.c >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -198,8 +198,8 @@ static int vfio_ap_verify_queue_reserved(unsigned long *apid, >> qres.apqi = apqi; >> qres.reserved = false; >> >> - ret = driver_for_each_device(matrix_dev->device.driver, NULL, &qres, >> - vfio_ap_has_queue); >> + ret = driver_for_each_device(&matrix_dev->vfio_ap_drv->driver, NULL, >> + &qres, vfio_ap_has_queue); >> if (ret) >> return ret; >> >> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h >> index 5675492..76b7f98 100644 >> --- a/drivers/s390/crypto/vfio_ap_private.h >> +++ b/drivers/s390/crypto/vfio_ap_private.h >> @@ -40,6 +40,7 @@ struct ap_matrix_dev { >> struct ap_config_info info; >> struct list_head mdev_list; >> struct mutex lock; >> + struct ap_driver *vfio_ap_drv; >> }; >> >> extern struct ap_matrix_dev *matrix_dev; > > You are introducing a new bus just for a user space application which is unable > to deal with a device directly attached to the root of devices ? So you are fixing > kernel code because of disability of userspace code. Hm, you are switching > root cause and effect. However, not my job. the kernel rule is pretty simple. If userspace breaks due to a kernel change fix the kernel. > > Why do you need this dummy bus ? Did you evaluate using a "class" subsystem > instead ? This is very common and my assumption is that libudev is able to handle > this. I am using a "zcrypt" class for providing additional zcrypt device nodes and > this works fine together with udev. I would avoid the introduction and maintenance > of bus code at any cost. The class variant sounds promising. Pierre what do you think? > > Btw. having a look onto the naming ... the module is named "vfio_ap", the > driver is named "vfio_ap", the bus is named "vfio_ap", the root bus device is > named "vfio_ap" ... a bunch of vfio_aps naming different things. > > regards > Harald Freudenberger >