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 D57C2C4321D for ; Thu, 23 Aug 2018 14:59:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 780AE2098B for ; Thu, 23 Aug 2018 14:59:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 780AE2098B 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 S1732705AbeHWS33 (ORCPT ); Thu, 23 Aug 2018 14:29:29 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:42654 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732158AbeHWS33 (ORCPT ); Thu, 23 Aug 2018 14:29:29 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7NEtTeR078560 for ; Thu, 23 Aug 2018 10:59:25 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0b-001b2d01.pphosted.com with ESMTP id 2m1y3xg5km-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 23 Aug 2018 10:59:25 -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) Thu, 23 Aug 2018 15:59:19 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7NExItu34930900 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 23 Aug 2018 14:59:18 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 681124C052; Thu, 23 Aug 2018 17:59:19 +0100 (BST) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B71884C04E; Thu, 23 Aug 2018 17:59:18 +0100 (BST) Received: from [9.152.224.92] (unknown [9.152.224.92]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 23 Aug 2018 17:59:18 +0100 (BST) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v9 21/22] KVM: s390: CPU model support for AP virtualization To: David Hildenbrand , Halil Pasic , Tony Krowiak , Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, borntraeger@de.ibm.com, cohuck@redhat.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, frankja@linux.ibm.com References: <1534196899-16987-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1534196899-16987-22-git-send-email-akrowiak@linux.vnet.ibm.com> <2c2c4859-ed3e-a492-dd59-78529c7768b2@redhat.com> <95e6ee74-69aa-9805-3233-b9ec81fce516@redhat.com> <7e7a35f5-d1eb-7719-c5e8-57d6f19db675@linux.ibm.com> <8d6ae58f-967b-5e4e-0e54-8fb4962cb843@linux.ibm.com> <049c5e8a-4f21-a079-0eb6-abe78d812de7@linux.ibm.com> <1721a153-13f0-e695-6c01-cf6b65e1bbfa@linux.ibm.com> From: Pierre Morel Date: Thu, 23 Aug 2018 16:59:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18082314-0012-0000-0000-0000029DBE95 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18082314-0013-0000-0000-000020D106EF Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-23_07:,, 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=8.0.1-1807170000 definitions=main-1808230157 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/08/2018 15:38, David Hildenbrand wrote: > On 23.08.2018 15:22, Halil Pasic wrote: >> >> >> On 08/23/2018 02:47 PM, Pierre Morel wrote: >>> On 23/08/2018 13:12, David Hildenbrand wrote: >> [..] >>>>>>> >>>>>>> I'm confused, which 128 bit? >>>>>> >>>>>> >>>>>> Me too :) , I was assuming this block to be 128bit, but the qci block >>>>>> has 128 bytes.... >>>>>> >>>>>> And looking at arch/s390/include/asm/ap.h, there is a lot of information >>>>>> contained that is definitely not of interest for CPU models... >>>>>> >>>>>> I wonder if there is somewhere defined which bits are reserved for >>>>>> future features/facilities, compared to ap masks and such. >>>>>> >>>>>> This is really hard to understand/plan without access to documentation. >>>>>> >>>>>> You (Halil, Tony, Pier, ...) should have a look if what I described >>>>>> related to PQAP(QCI) containing features that should get part of the CPU >>>>>> model makes sense or not. For now I was thinking that there is some part >>>>>> inside of QCI that is strictly reserved for facilities/features that we >>>>>> can use. >> >> No there is no such part. The architecture documentation is quite confusing >> with some aspects (e.g. persistence) of how exactly some of these features >> work and are indicated. I'm having a hard time finding my opinion. I may >> end up asking some questions later, but for now i have to think first. >> >> Just one hint. There is a programming note stating that if bit 2 of the >> QCI block is one there is at least one AP card in the machine that actually >> has APXA installed. >> >> I read the architecture so that the APXA has a 'cpu part' (if we are >> doing APXA the cpu can't spec exception on certain bits not being zor9) >> and a 'card(s) part'. >> >> Since the stuff seems quite difficult to sort out properly, I ask myself >> are there real problems we must solve? >> >> This ultimately seems to be about the migration, right? You say 'This helps >> to catch nasty migration bugs (e.g. APXA suddenly disappearing).' at the very >> beginning of the discussion. Yes, we don't have to have an vfio_ap device, >> he guest can and will start looking for AP resources if >> only the cpu model features installed. So the guest could observe >> a disappearing APXA, but I don't think that would lead to problems (with >> Linux at least). >> >> And there ain't much AP a guest can sanely do without if no AP resources >> are there. >> >> I would really prefer not rushing a solution if we don't have to. >> >>> >>> >>>> >>>> What is apsc, qact, rc8a in the qci blocks? are the facility bits? >>> >>> Yes, facility bits concerning the AP instructions >>> >> >> According to the current AR document rc8a ain't a facility but bits >> 0-2 and 4-7 kind of are. >> > > Easy ( :) ) answer. Everything that is the CPU part should get into the > CPU model. Everything that is AP specific not. If APXA is not a CPU > facility, fine with me to leave it out. > > Ack to not rushing, but also ack to not leaving out important things. > Ack that this stuff is hard to ficure out. APXA is not a CPU part, it is a machine part (SIE) and a AP part (QCI,TAPQ), it has no influence on CPU instructions but on the AP instructions. Consequently, if I understood the definition correctly, it should not go in the CPU model. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany