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 26484C46464 for ; Thu, 9 Aug 2018 20:27:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5BE6208E3 for ; Thu, 9 Aug 2018 20:27:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5BE6208E3 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 S1727225AbeHIWyP (ORCPT ); Thu, 9 Aug 2018 18:54:15 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:52796 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726953AbeHIWyP (ORCPT ); Thu, 9 Aug 2018 18:54:15 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w79KP31w102204 for ; Thu, 9 Aug 2018 16:27:46 -0400 Received: from e11.ny.us.ibm.com (e11.ny.us.ibm.com [129.33.205.201]) by mx0a-001b2d01.pphosted.com with ESMTP id 2krt2p5yuv-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 09 Aug 2018 16:27:46 -0400 Received: from localhost by e11.ny.us.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 16:27:41 -0400 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w79KRdEN9699940 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 9 Aug 2018 20:27:39 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C98C0AC059; Thu, 9 Aug 2018 16:28:07 -0400 (EDT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DF17FAC05E; Thu, 9 Aug 2018 16:28:06 -0400 (EDT) Received: from oc8043147753.ibm.com (unknown [9.60.75.213]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 9 Aug 2018 16:28:06 -0400 (EDT) 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 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: Tony Krowiak Date: Thu, 9 Aug 2018 16:27:38 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <58eed530-31b3-49fe-cbd7-4d101b94daa0@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18080920-2213-0000-0000-000002D85321 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009515; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01071406; UDB=6.00551719; IPR=6.00851103; MB=3.00022619; MTD=3.00000008; XFM=3.00000015; UTC=2018-08-09 20:27:44 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18080920-2214-0000-0000-00005B252B72 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-09_08:,, 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-1808090203 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/09/2018 04:17 AM, 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? I suspect that if AP instructions are not installed, then neither STFLE.12 nor STFLE.15 would be set in the real hardware. This comment, however, is talking about an administrator setting the facility for a guest, not real hardware. Having said that and after thinking about it a little more, I am going to remove that last sentence because the CPU model configuration (e.g., as specified on the qemu command line) will fail if the QCI or APFT facility is enabled when the CPU model feature KVM_S390_VM_CPU_FEAT_AP is not. > >> 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. Will do > >> + 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 */ >> } >> }, >> >