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 0C824C46460 for ; Thu, 9 Aug 2018 08:34:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF5C521B31 for ; Thu, 9 Aug 2018 08:34:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF5C521B31 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 S1729994AbeHIK6g (ORCPT ); Thu, 9 Aug 2018 06:58:36 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:59238 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728170AbeHIK6g (ORCPT ); Thu, 9 Aug 2018 06:58:36 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w798TG0G009630 for ; Thu, 9 Aug 2018 04:34:48 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2krg1kmy4c-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 09 Aug 2018 04:34:48 -0400 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, 9 Aug 2018 09:34:29 +0100 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w798YSns34209968 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 9 Aug 2018 08:34:28 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0576942052; Thu, 9 Aug 2018 11:34:36 +0100 (BST) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 43E1042045; Thu, 9 Aug 2018 11:34:33 +0100 (BST) Received: from [10.0.2.15] (unknown [9.152.224.40]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 9 Aug 2018 11:34:33 +0100 (BST) Subject: Re: [PATCH v8 21/22] KVM: s390: CPU model support for AP virtualization To: David Hildenbrand , 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, Tony Krowiak References: <1533739472-7172-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1533739472-7172-22-git-send-email-akrowiak@linux.vnet.ibm.com> <58eed530-31b3-49fe-cbd7-4d101b94daa0@redhat.com> From: Harald Freudenberger Date: Thu, 9 Aug 2018 10:34:26 +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: <58eed530-31b3-49fe-cbd7-4d101b94daa0@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18080908-0016-0000-0000-000001F4495B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18080908-0017-0000-0000-0000324A5B8B Message-Id: <2fbfa34f-0a82-9fd2-3b52-60479d9eca1a@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-09_03:,, 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-1808090090 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09.08.2018 10:17, David Hildenbrand wrote: > On 08.08.2018 16:44, Tony Krowiak wrote: >> From: Tony Krowiak >> >> Introduces a new CPU model feature and two CPU model >> facilities to support AP virtualization for KVM guests. >> >> CPU model feature: >> >> The KVM_S390_VM_CPU_FEAT_AP feature indicates that >> AP instructions are available on the guest. This >> feature will be enabled by the kernel only if the AP >> instructions are installed on the linux host. This feature >> must be specifically turned on for the KVM guest from >> userspace to use the VFIO AP device driver for guest >> access to AP devices. >> >> CPU model facilities: >> >> 1. AP Query Configuration Information (QCI) facility is installed. >> >> This is indicated by setting facilities bit 12 for >> the guest. The kernel will not enable this facility >> for the guest if it is not set on the host. This facility >> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP >> feature is not installed. > Could it happen on real HW (not frankenstein CPU models), that > > !AP, but STFL 12 or 15 are indicated? What is your expectation here ? There are no AP instructions available but if there would be AP instructions available then there would be the QCI and or the T bit facility within the PQAP AP instruction valid ? >> If this facility is not set for the KVM guest, then only >> APQNs with an APQI less than 16 will be used by a Linux >> guest regardless of the matrix configuration for the virtual >> machine. This is a limitation of the Linux AP bus. >> >> 2. AP Facilities Test facility (APFT) is installed. >> >> This is indicated by setting facilities bit 15 for >> the guest. The kernel will not enable this facility for >> the guest if it is not set on the host. This facility >> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP >> feature is not installed. >> >> If this facility is not set for the KVM guest, then no >> AP devices will be available to the guest regardless of >> the guest's matrix configuration for the virtual >> machine. This is a limitation of the Linux AP bus. >> >> Signed-off-by: Tony Krowiak >> Reviewed-by: Christian Borntraeger >> Reviewed-by: Halil Pasic >> Tested-by: Michael Mueller >> Tested-by: Farhan Ali >> Signed-off-by: Christian Borntraeger >> --- >> arch/s390/kvm/kvm-s390.c | 7 +++++++ >> arch/s390/tools/gen_facilities.c | 2 ++ >> 2 files changed, 9 insertions(+), 0 deletions(-) >> >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index 9203f0b..7d4fe9b 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -367,6 +367,13 @@ static void kvm_s390_cpu_feat_init(void) >> >> if (MACHINE_HAS_ESOP) >> allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); >> + >> + /* >> + * Check if AP instructions installed on host >> + */ > Make this a one-line comment, please. > >> + if (ap_instructions_available() == 0) >> + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP); >> + >> /* >> * We need SIE support, ESOP (PROT_READ protection for gmap_shadow), >> * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing). >> diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c >> index 90a8c9e..a52290b 100644 >> --- a/arch/s390/tools/gen_facilities.c >> +++ b/arch/s390/tools/gen_facilities.c >> @@ -106,6 +106,8 @@ struct facility_def { >> >> .name = "FACILITIES_KVM_CPUMODEL", >> .bits = (int[]){ >> + 12, /* AP Query Configuration Information */ >> + 15, /* AP Facilities Test */ >> -1 /* END */ >> } >> }, >> >