From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752442AbeB1Lk6 (ORCPT ); Wed, 28 Feb 2018 06:40:58 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53150 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752396AbeB1Lk4 (ORCPT ); Wed, 28 Feb 2018 06:40:56 -0500 Subject: Re: [PATCH v2 04/15] 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, 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, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com References: <1519741693-17440-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1519741693-17440-5-git-send-email-akrowiak@linux.vnet.ibm.com> <38deecae-53b4-c5cb-3dba-24bdfab3d9d0@redhat.com> From: Christian Borntraeger Date: Wed, 28 Feb 2018 12:40:48 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <38deecae-53b4-c5cb-3dba-24bdfab3d9d0@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18022811-0040-0000-0000-000004184B3F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18022811-0041-0000-0000-0000261B4D90 Message-Id: <3a3ff176-4e6b-963c-7831-cdcd10b556eb@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-28_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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802280141 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/28/2018 10:48 AM, David Hildenbrand wrote: > On 27.02.2018 15:28, Tony Krowiak wrote: >> 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 the >> AP facilities are installed on the KVM guest. This >> feature will be enabled by the kernel only if the AP >> facilities are installed on the linux host. This feature >> must be specifically turned on for the KVM guest from >> userspace to allow guest access to AP devices installed >> on the linux host. >> >> 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. >> >> 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. >> >> Reviewed-by: Christian Borntraeger >> Reviewed-by: Halil Pasic >> Signed-off-by: Tony Krowiak >> --- >> arch/s390/include/uapi/asm/kvm.h | 1 + >> arch/s390/kvm/kvm-s390.c | 4 ++++ >> arch/s390/tools/gen_facilities.c | 2 ++ >> 3 files changed, 7 insertions(+), 0 deletions(-) >> >> diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h >> index 4cdaa55..a580dec 100644 >> --- a/arch/s390/include/uapi/asm/kvm.h >> +++ b/arch/s390/include/uapi/asm/kvm.h >> @@ -130,6 +130,7 @@ struct kvm_s390_vm_cpu_machine { >> #define KVM_S390_VM_CPU_FEAT_PFMFI 11 >> #define KVM_S390_VM_CPU_FEAT_SIGPIF 12 >> #define KVM_S390_VM_CPU_FEAT_KSS 13 >> +#define KVM_S390_VM_CPU_FEAT_AP 14 >> struct kvm_s390_vm_cpu_feat { >> __u64 feat[16]; >> }; >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index de1e299..c68ca86 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -347,6 +347,10 @@ static void kvm_s390_cpu_feat_init(void) >> >> if (MACHINE_HAS_ESOP) >> allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); >> + >> + if (ap_instructions_installed()) /* AP instructions installed on host */ >> + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP); > > Don't we have a SIE specific AP feature? So is it true, that once we > have AP instructions, we are allowed to use them for SIE? Isn't there a > "AP interpretation facility" or anything like that? (that unlocks ECA_APIE) This seems to be coupled to the AP facility and there is no facility or scp bit. AP is too old to have that (predates STFLE)