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 0188EC43381 for ; Wed, 27 Feb 2019 08:40:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B9C89218FE for ; Wed, 27 Feb 2019 08:40:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729786AbfB0IkX (ORCPT ); Wed, 27 Feb 2019 03:40:23 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44878 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726791AbfB0IkW (ORCPT ); Wed, 27 Feb 2019 03:40:22 -0500 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1R8dZRV100119 for ; Wed, 27 Feb 2019 03:40:21 -0500 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0b-001b2d01.pphosted.com with ESMTP id 2qwpaxau6u-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 27 Feb 2019 03:40:18 -0500 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 27 Feb 2019 08:40:17 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (9.149.109.195) by e06smtp05.uk.ibm.com (192.168.101.135) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 27 Feb 2019 08:40:15 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1R8eDN956623218 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 27 Feb 2019 08:40:13 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 93A5CA4057; Wed, 27 Feb 2019 08:40:13 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 08A1FA4040; Wed, 27 Feb 2019 08:40:13 +0000 (GMT) Received: from [9.152.224.140] (unknown [9.152.224.140]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 27 Feb 2019 08:40:12 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v4 2/7] s390: ap: new vfio_ap_queue structure To: Tony Krowiak , borntraeger@de.ibm.com Cc: 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, pasic@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> <1550849400-27152-3-git-send-email-pmorel@linux.ibm.com> <944bb7fe-2b2c-28d0-f63b-6fa84c324735@linux.ibm.com> From: Pierre Morel Date: Wed, 27 Feb 2019 09:40:12 +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: <944bb7fe-2b2c-28d0-f63b-6fa84c324735@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: 19022708-0020-0000-0000-0000031BCA87 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19022708-0021-0000-0000-0000216D3502 Message-Id: <581b859f-3959-aed2-90af-a31cb6b75d49@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-27_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-1902270059 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/02/2019 17:10, Tony Krowiak wrote: > On 2/22/19 10:29 AM, Pierre Morel wrote: >> The AP interruptions are assigned on a queue basis and >> the GISA structure is handled on a VM basis, so that >> we need to add a structure we can retrieve from both side >> holding the information we need to handle PQAP/AQIC interception >> and setup the GISA. >> >> Since we can not add more information to the ap_device >> we add a new structure vfio_ap_queue, to hold per queue >> information useful to handle interruptions and set it as >> driver's data of the standard ap_queue device. >> >> Usually, the device and the mediated device are linked together >> but in the vfio_ap driver design we have a bunch of "sub" devices >> (the ap_queue devices) belonging to the mediated device. >> >> Linking these structure to the mediated device it is assigned to, >> with the help of the vfio_ap_queue structure will help us to >> retrieve the AP devices associated with the mediated devices >> during the mediated device operations. >> >> ------------    ------------- >> | AP queue |--> | AP_vfio_q |<---- >> ------------    ------^------    |    --------------- >>                        |          <--->| matrix_mdev | >> ------------    ------v------    |    --------------- >> | AP queue |--> | AP_vfio_q |----- >> ------------    ------------- >> >> The vfio_ap_queue device will hold the following entries: >> - apqn: AP queue number (defined here) >> - isc : Interrupt subclass (defined later) >> - nib : notification information byte (defined later) >> - list: a list_head entry allowing to link this structure to a >>     matrix mediated device it is assigned to. >> >> The vfio_ap_queue structure is allocated when the vfio_ap_driver >> is probed and added as driver data to the ap_queue device. >> It is free on remove. >> >> The structure is linked to the matrix_dev host device at the >> probe of the device building some kind of free list for the >> matrix mediated devices. >> >> When the vfio_queue is associated to a matrix mediated device, >> the vfio_ap_queue device is linked to this matrix mediated device >> and unlinked when dissociated. >> >> This patch and the 3 next can be squashed together on the >> final release of this series. >> until then I separate them to ease the review. >> >> So please do not complain about unused functions or about >> squashing the patches together, this will be resolved during >> the last iteration. >> >> Signed-off-by: Pierre Morel >> --- >>   drivers/s390/crypto/vfio_ap_drv.c     | 27 ++++++++++++++++++++++++++- >>   drivers/s390/crypto/vfio_ap_private.h |  9 +++++++++ >>   2 files changed, 35 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c >> b/drivers/s390/crypto/vfio_ap_drv.c >> index e9824c3..eca0ffc 100644 >> --- a/drivers/s390/crypto/vfio_ap_drv.c >> +++ b/drivers/s390/crypto/vfio_ap_drv.c >> @@ -40,14 +40,38 @@ static struct ap_device_id ap_queue_ids[] = { >>   MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); >> +/** >> + * vfio_ap_queue_dev_probe: >> + * >> + * Allocate a vfio_ap_queue structure and associate it >> + * with the device as driver_data. >> + */ >>   static int vfio_ap_queue_dev_probe(struct ap_device *apdev) >>   { >> +    struct vfio_ap_queue *q; >> + >> +    q = kzalloc(sizeof(*q), GFP_KERNEL); >> +    if (!q) >> +        return -ENOMEM; >> +    dev_set_drvdata(&apdev->device, q); >> +    q->apqn = to_ap_queue(&apdev->device)->qid; >> +    INIT_LIST_HEAD(&q->list); >> +    list_add(&q->list, &matrix_dev->free_list); >>       return 0; >>   } >> +/** >> + * vfio_ap_queue_dev_remove: >> + * >> + * Free the associated vfio_ap_queue structure >> + */ >>   static void vfio_ap_queue_dev_remove(struct ap_device *apdev) >>   { >> -    /* Nothing to do yet */ >> +    struct vfio_ap_queue *q; >> + >> +    q = dev_get_drvdata(&apdev->device); >> +    list_del(&q->list); >> +    kfree(q); >>   } >>   static void vfio_ap_matrix_dev_release(struct device *dev) >> @@ -107,6 +131,7 @@ static int vfio_ap_matrix_dev_create(void) >>       matrix_dev->device.bus = &matrix_bus; >>       matrix_dev->device.release = vfio_ap_matrix_dev_release; >>       matrix_dev->vfio_ap_drv = &vfio_ap_drv; >> +    INIT_LIST_HEAD(&matrix_dev->free_list); >>       ret = device_register(&matrix_dev->device); >>       if (ret) >> diff --git a/drivers/s390/crypto/vfio_ap_private.h >> b/drivers/s390/crypto/vfio_ap_private.h >> index 76b7f98..2760178 100644 >> --- a/drivers/s390/crypto/vfio_ap_private.h >> +++ b/drivers/s390/crypto/vfio_ap_private.h >> @@ -39,6 +39,7 @@ struct ap_matrix_dev { >>       atomic_t available_instances; >>       struct ap_config_info info; >>       struct list_head mdev_list; >> +    struct list_head free_list; >>       struct mutex lock; >>       struct ap_driver  *vfio_ap_drv; >>   }; >> @@ -81,9 +82,17 @@ struct ap_matrix_mdev { >>       struct ap_matrix matrix; >>       struct notifier_block group_notifier; >>       struct kvm *kvm; >> +    struct list_head qlist; > > I do not see much value in maintaining two lists of at the > expense of complicating the code and introducing additional > processing (i.e., list rewinds etc.). IMHO, the only think it buys > us is being able to pass a smaller list to the vfio_ap_get_queue() > function to traverse. That function can traverse the list in > struct ap_matrix_dev to find a queue. I understand what you are > doing here in pulling vfio_ap_queue structs from the free_list > to add them to qlist for the mdev when adapter/domain assignment > takes place, but you are now maintaining links to the vfio_ap_queue > in multiple places; as drvdata as well as two lists. I think this > is over designing. This is not completely exact, the drvdata allows to retrieve the vfio_ap_queue structure from the AP device, which is global to all AP devices, and not related to a mediated device. The vfio_ap_queue structure is only linked to one of the different lists it can be linked to: the free_list or the mediated device list. The complication of the code you mention make us win almost 200 LOCs, some may see it as a simplification ;) . Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany