From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752454AbeB1Jsa (ORCPT ); Wed, 28 Feb 2018 04:48:30 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:41802 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752066AbeB1Js2 (ORCPT ); Wed, 28 Feb 2018 04:48:28 -0500 Subject: Re: [PATCH v2 04/15] KVM: s390: CPU model support for AP virtualization To: 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, 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> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <38deecae-53b4-c5cb-3dba-24bdfab3d9d0@redhat.com> Date: Wed, 28 Feb 2018 10:48:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <1519741693-17440-5-git-send-email-akrowiak@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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) > + > /* > * 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 */ > } > }, > So only if this feature is enabled, we later on allow to kvm_ap_enable_ie_mode, right? So basically, without this feature: 1. We will never set the execution control ECA_APIE. 2. The masks will always be 0. Which also results in VSIE never having masks set. -- Thanks, David / dhildenb