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 F3948C43381 for ; Thu, 28 Feb 2019 13:11:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF54A2171F for ; Thu, 28 Feb 2019 13:11:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731740AbfB1NKn (ORCPT ); Thu, 28 Feb 2019 08:10:43 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53252 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727717AbfB1NKm (ORCPT ); Thu, 28 Feb 2019 08:10:42 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1SD1Tuo127060 for ; Thu, 28 Feb 2019 08:10:41 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qxfhktdh3-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 28 Feb 2019 08:10:40 -0500 Received: from localhost by e06smtp04.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, 28 Feb 2019 13:10:34 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1SDAXgk17891404 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 28 Feb 2019 13:10:33 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3F185A4057; Thu, 28 Feb 2019 13:10:33 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A2356A4055; Thu, 28 Feb 2019 13:10:32 +0000 (GMT) Received: from [9.152.224.140] (unknown [9.152.224.140]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 28 Feb 2019 13:10:32 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v4 1/7] s390: ap: kvm: add PQAP interception for AQIC To: Christian Borntraeger , Tony Krowiak 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> <1550849400-27152-2-git-send-email-pmorel@linux.ibm.com> <9f1d9241-39b9-adbc-d0e9-cb702e609cbc@linux.ibm.com> <4dc59125-7f96-cba8-651b-382ed8f8bff8@linux.ibm.com> <8526f468-9a4d-68d2-3868-0dad5ce16f46@linux.ibm.com> <6058a017-6404-af3c-62ef-2452214ac97c@de.ibm.com> <2391adc2-6611-034c-61c5-feb46e2a751b@de.ibm.com> From: Pierre Morel Date: Thu, 28 Feb 2019 14:10:32 +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: <2391adc2-6611-034c-61c5-feb46e2a751b@de.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: 19022813-0016-0000-0000-0000025C07A5 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19022813-0017-0000-0000-000032B67534 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-28_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=866 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902280091 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/02/2019 12:03, Christian Borntraeger wrote: > > > On 28.02.2019 10:42, Christian Borntraeger wrote: > [...] >>> Okay, let's go back to the genesis of this discussion; namely, my >>> suggestion about moving the fc == 0x03 check into the hook code. If >>> the vfio_ap module is not loaded, there will be no hook code. In that >>> case, the check for the hook will fail and ultimately response code >>> 0x01 will be set in the status word (which may not be the right thing >>> to do?). You have not stated a single good reason for keeping this >>> check, but I'm done with this silly argument. It certainly doesn't >>> hurt anything. >> >> The instruction handler must handle the basic checks for the >> instruction itself as outlined above. >> >> Do we want to allow QEMU to fully emulate everything (the ECA_APIE case being off)? >> The we should pass along everything to QEMU, but this is already done with the >> ECA_APIE check, correct? >> >> Do we agree that when we are beyond the ECA_APIE check, that we do not emulate >> in QEMU and we have enabled the AP instructions interpretion? >> If yes then this has some implication: >> >> 1. ECA is on and we should only get PQAP interception for specific FC (namely 3). >> 2. What we certainly should check is the facility bit of the guest (65) and reject fc==3 >> right away with a specification exception. I do not want the hook to mess with >> the kvm cpu model. @Pierre would be good to actually check test_kvm_facility(vcpu->kvm, 65)) >> 3. What shall we do when fc == 0x3? We can certainly do the check here OR in the >> hook. As long as we have only fc==3 this does not matter. >> >> Correct? > > Thinking more about that, I think we should inject a specification exception for all > unknown FCc != 0x3. That would also qualify for keeping it in the instruction handler. > May be return a privileged operation exception if issued from guest's program state, but generally I agree with the idea of handling all PQAP functions here. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany