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 27BA1C43381 for ; Thu, 21 Feb 2019 08:07:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF5712086C for ; Thu, 21 Feb 2019 08:07:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726680AbfBUIHq (ORCPT ); Thu, 21 Feb 2019 03:07:46 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:54846 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726038AbfBUIHp (ORCPT ); Thu, 21 Feb 2019 03:07:45 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1L7wlOU041146 for ; Thu, 21 Feb 2019 03:07:44 -0500 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qsr1sgj26-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 21 Feb 2019 03:07:44 -0500 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) Thu, 21 Feb 2019 08:07:38 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1L87ak219726446 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Feb 2019 08:07:36 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8292B5206B; Thu, 21 Feb 2019 08:07:35 +0000 (GMT) Received: from [10.0.2.15] (unknown [9.152.224.114]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 149C752067; Thu, 21 Feb 2019 08:07:35 +0000 (GMT) Subject: Re: [PATCH v2 1/1] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem To: Christian Borntraeger , 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> <3c3a90ca-f7ea-7800-453d-31e6d273e82f@de.ibm.com> From: Harald Freudenberger Date: Thu, 21 Feb 2019 09:07:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <3c3a90ca-f7ea-7800-453d-31e6d273e82f@de.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 19022108-0008-0000-0000-000002C3152A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19022108-0009-0000-0000-0000222F4EBC Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-21_06:,, 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-1902210061 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21.02.19 08:37, Christian Borntraeger wrote: > > 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? I checked that. My additional zcrypt devices (you can easily create one with just echo "blubber" >/sys/class/zcrypt/create) and then have a look to the new device entry in sysfs at /sys/devices/virtual/zcrypt/blubber). Maybe you need to alloc device numbers for this - I am not sure if it is sufficient to device_register() without a device number. However, have a look into zcrpyt_api.c zcdn_init() and zcdn_create(). With a new class, you can also remove the root device needed as an anchor for the old and for the bus code. >> 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 >>