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=-0.8 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 4F659C6778A for ; Tue, 3 Jul 2018 12:20:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CABE24159 for ; Tue, 3 Jul 2018 12:20:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CABE24159 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 S1753186AbeGCMUX (ORCPT ); Tue, 3 Jul 2018 08:20:23 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:40374 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752401AbeGCMUU (ORCPT ); Tue, 3 Jul 2018 08:20:20 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w63CDjHK141302 for ; Tue, 3 Jul 2018 08:20:20 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2k08vvggfc-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 03 Jul 2018 08:20:20 -0400 Received: from localhost by e06smtp03.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) Tue, 3 Jul 2018 13:20:14 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w63CKDXm36045052 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 3 Jul 2018 12:20:13 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B4B3611C05E; Tue, 3 Jul 2018 15:20:38 +0100 (BST) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BB0F311C04A; Tue, 3 Jul 2018 15:20:37 +0100 (BST) Received: from oc3836556865.ibm.com (unknown [9.152.224.39]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 3 Jul 2018 15:20:37 +0100 (BST) Subject: Re: [PATCH v6 21/21] s390: doc: detailed specifications for AP virtualization To: Cornelia Huck Cc: Harald Freudenberger , Tony Krowiak , 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, Tony Krowiak References: <1530306683-7270-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1530306683-7270-22-git-send-email-akrowiak@linux.vnet.ibm.com> <49b11ac2-2230-ad74-1583-c6a57f8b31e3@linux.ibm.com> <6a330cae-2fe2-54df-edce-c3360117cf3c@linux.ibm.com> <13998e79-9bae-5c55-b83d-85e6db8d3b99@linux.ibm.com> <20180703135205.2ebb107f.cohuck@redhat.com> From: Halil Pasic Date: Tue, 3 Jul 2018 14:20:11 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180703135205.2ebb107f.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18070312-0012-0000-0000-000002864766 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18070312-0013-0000-0000-000020B7C39A Message-Id: <18532145-abeb-1251-926e-edbc6fa0bcb0@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-07-03_04:,, 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=8.0.1-1806210000 definitions=main-1807030142 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/03/2018 01:52 PM, Cornelia Huck wrote: > On Tue, 3 Jul 2018 11:22:10 +0200 > Halil Pasic wrote: > [..] >> >> Let me try to invoke the DASD analogy. If one for some reason wants to detach >> a DASD the procedure to follow seems to be (see >> https://www.ibm.com/support/knowledgecenter/en/linuxonibm/com.ibm.linux.z.lgdd/lgdd_t_dasd_online.html) >> the following: >> 1) Unmount. >> 2) Offline possibly using safe_offline. >> 3) Detach. >> >> Detaching a disk that is currently doing I/O asks for trouble, so the admin is encouraged >> to make sure there is no pending I/O. > > I don't think we can use dasd (block devices) as a good analogy for > every kind of device (for starters, consider network devices). > I did not use it for every kind of device. I used it for AP. I'm under the impression you find the analogy inappropriate. If, could you please explain why? >> In case of AP you can interpret my 'in use' as the queue is not empty. In my understanding >> unbind is supposed to be hard (I used the word radical). That's why I compared it to pulling >> a cable. So that's why I ask is there stuff the admin is supposed to do before doing the >> unbind. > > Are you asking for a kind of 'quiescing' operation? I would hope that > the crypto drivers already can deal with that via flushing the queue, > not allowing new requests, or whatever. This is not the block device > case. > The current implementation of vfio-ap which is a crypto driver too certainly can not deal 'with that'. Whether the rest of the drivers can, I don't know. Maybe Tony can tell. I'm aware of the fact that AP adapters are not block devices. But as stated above I don't understand what is the big difference regarding the unbind operation. > Anyway, this is an administrative issue. If you don't have a clear > concept which devices are for host usage and which for guest usage, you > already have problems. I'm trying to understand the whole solution. I agree, this is an administrative issue. But the document is trying to address such administrative issues. > > Speaking of administrative issues, is there libvirt support for vfio-ap > under development? It would be helpful to validate the approach. I full-heartedly agree. I guess Tony will have to answer this one too. Regards, Halil