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 97BC0C43381 for ; Fri, 15 Mar 2019 13:26:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61FAE21019 for ; Fri, 15 Mar 2019 13:26:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729097AbfCON0o (ORCPT ); Fri, 15 Mar 2019 09:26:44 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:36722 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727547AbfCON0n (ORCPT ); Fri, 15 Mar 2019 09:26:43 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x2FDNbHW024152 for ; Fri, 15 Mar 2019 09:26:42 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2r8brtvakt-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 15 Mar 2019 09:26:41 -0400 Received: from localhost by e06smtp07.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) Fri, 15 Mar 2019 13:26:37 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x2FDQZXt60489982 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 15 Mar 2019 13:26:35 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A042BAE04D; Fri, 15 Mar 2019 13:26:35 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E8FE3AE045; Fri, 15 Mar 2019 13:26:34 +0000 (GMT) Received: from [9.145.170.151] (unknown [9.145.170.151]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 15 Mar 2019 13:26:34 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v5 1/7] s390: ap: kvm: add PQAP interception for AQIC To: Cornelia Huck Cc: borntraeger@de.ibm.com, alex.williamson@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@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, freude@linux.ibm.com, mimu@linux.ibm.com References: <1552493104-30510-1-git-send-email-pmorel@linux.ibm.com> <1552493104-30510-2-git-send-email-pmorel@linux.ibm.com> <20190315112032.13b259c2.cohuck@redhat.com> From: Pierre Morel Date: Fri, 15 Mar 2019 14:26:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190315112032.13b259c2.cohuck@redhat.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: 19031513-0028-0000-0000-000003546FB0 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19031513-0029-0000-0000-000024130051 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-03-15_09:,, 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-1903150096 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/03/2019 11:20, Cornelia Huck wrote: > On Wed, 13 Mar 2019 17:04:58 +0100 > Pierre Morel wrote: > >> +/* >> + * handle_pqap: Handling pqap interception >> + * @vcpu: the vcpu having issue the pqap instruction >> + * >> + * We now support PQAP/AQIC instructions and we need to correctly >> + * answer the guest even if no dedicated driver's hook is available. >> + * >> + * The intercepting code calls a dedicated callback for this instruction >> + * if a driver did register one in the CRYPTO satellite of the >> + * SIE block. >> + * >> + * For PQAP/AQIC instructions only, verify privilege and specifications. >> + * >> + * If no callback available, the queues are not available, return this to >> + * the caller. >> + * Else return the value returned by the callback. >> + */ >> +static int handle_pqap(struct kvm_vcpu *vcpu) >> +{ >> + uint8_t fc; >> + struct ap_queue_status status = {}; >> + int ret; >> + /* Verify that the AP instruction are available */ >> + if (!ap_instructions_available()) >> + return -EOPNOTSUPP; >> + /* Verify that the guest is allowed to use AP instructions */ >> + if (!(vcpu->arch.sie_block->eca & ECA_APIE)) >> + return -EOPNOTSUPP; >> + /* Verify that the function code is AQIC */ >> + fc = vcpu->run->s.regs.gprs[0] >> 24; >> + /* We do not want to change the behavior we had before this patch*/ >> + if (fc != 0x03) >> + return -EOPNOTSUPP; >> + >> + /* PQAP instructions are allowed for guest kernel only */ >> + if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) >> + return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); >> + /* AQIC instruction is allowed only if facility 65 is available */ >> + if (!test_kvm_facility(vcpu->kvm, 65)) >> + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); >> + /* Verify that the hook callback is registered and call it */ >> + if (vcpu->kvm->arch.crypto.pqap_hook) { >> + if (!try_module_get(vcpu->kvm->arch.crypto.pqap_hook->owner)) >> + return -EOPNOTSUPP; >> + ret = vcpu->kvm->arch.crypto.pqap_hook->hook(vcpu); >> + module_put(vcpu->kvm->arch.crypto.pqap_hook->owner); >> + return ret; >> + } >> + /* >> + * It is the duty of the vfio_driver to register a hook >> + * If it does not and we get an exception on AQIC we must >> + * guess that there is no vfio_ap_driver at all and no one >> + * to handle the guests's CRYCB and the CRYCB is empty. >> + */ >> + status.response_code = 0x01; > > I'm still confused here, sorry. From previous discussions I recall that > this indicates "no crypto device" (please correct me if I'm wrong.) > > Before this patch, we had: > - guest issues PQAP/AQIC -> drop to userspace > > With a correct implementation, we get: > - guest issues PQAP/AQIC -> callback does what needs to be done > > With an incorrect implementation (no callback), we get: > - guest issues PQAP/AQIC -> guest gets response code 0x01 > > Why not drop to userspace in that case? This is what I had in the previous patches. Hum, I do not remember which discussion lead me to modify this. Anyway, now that you put the finger on this problem, I think the problem is worse. The behavior with old / new Linux, vfio driver and qemu is: LINUX VFIO_AP QEMU PGM OLD x x OPERATION NEW - OLD SPECIFICATION NEW - NEW/aqic=off SPECIFICATION NEW x NEW/aqic=on - x = whatever - = absent/none So yes there is a change in behavior for the userland for the case QEMU do not set the AQIC facility 65, OLD QEMU or NEW QEMU wanting to behave like an older one. I fear we have the same problem with the privileged operation... For the last case, when the kvm_facility(65) is set, the explication is the following: This is related to the handling of PQAP AQIC which is now authorized by this patch series. If we authorize PQAP AQIC, by setting the bit for facility 65, the guest can use this instruction. If the instruction follows the specifications we must answer something realistic and since there is nothing in the CRYCB (no driver) we answer that there is no queue. Conclusion: we must handle this in userland, it will have the benefit to keep old behavior when there is no callback. OLD QEMU will not see change as they will not set aqic facility NEW QEMU will handle this correctly. In this case we also do not need to handle all other tests here but can move it to the callback as Tony wanted. Would you agree with something simple like: static int handle_pqap(struct kvm_vcpu *vcpu) { int ret = -EOPNOTSUPP; /* Verify that the hook callback is registered and call it */ if (pqap_hook) if (try_module_get(pqap_hook->owner)) { ret = pqap_hook->hook(vcpu); module_put(pqap_hook->owner); } return ret; } All other tests in QEMU and in the callback. Thanks for the comments. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany