From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756099AbeDQQOj (ORCPT ); Tue, 17 Apr 2018 12:14:39 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:46758 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755979AbeDQQON (ORCPT ); Tue, 17 Apr 2018 12:14:13 -0400 Subject: Re: [PATCH v4 05/15] KVM: s390: enable/disable AP interpretive execution 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, 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 References: <1523827345-11600-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1523827345-11600-6-git-send-email-akrowiak@linux.vnet.ibm.com> <15b60572-40d6-0f03-11f9-c50cb7eb00e8@linux.vnet.ibm.com> From: Pierre Morel Date: Tue, 17 Apr 2018 18:13:57 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18041716-0040-0000-0000-0000044E9717 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041716-0041-0000-0000-000020F2E055 Message-Id: <6cba35df-b0de-8000-bb39-c4cec8622c57@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-17_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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804170142 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/04/2018 17:02, Tony Krowiak wrote: > On 04/16/2018 06:51 AM, Pierre Morel wrote: >> On 15/04/2018 23:22, Tony Krowiak wrote: >>> The VFIO AP device model exploits interpretive execution of AP >>> instructions (APIE) to provide guests passthrough access to AP >>> devices. This patch introduces a new interface to enable and >>> disable APIE. >>> >>> Signed-off-by: Tony Krowiak >>> --- >>>   arch/s390/include/asm/kvm-ap.h   |   16 ++++++++++++++++ >>>   arch/s390/include/asm/kvm_host.h |    1 + >>>   arch/s390/kvm/kvm-ap.c           |   20 ++++++++++++++++++++ >>>   arch/s390/kvm/kvm-s390.c         |    9 +++++++++ >>>   4 files changed, 46 insertions(+), 0 deletions(-) >>> >>> diff --git a/arch/s390/include/asm/kvm-ap.h >>> b/arch/s390/include/asm/kvm-ap.h >>> index 736e93e..a6c092e 100644 >>> --- a/arch/s390/include/asm/kvm-ap.h >>> +++ b/arch/s390/include/asm/kvm-ap.h >>> @@ -35,4 +35,20 @@ >>>    */ >>>   void kvm_ap_build_crycbd(struct kvm *kvm); >>> >>> +/** >>> + * kvm_ap_interpret_instructions >>> + * >>> + * Indicate whether AP instructions shall be interpreted. If they >>> are not >>> + * interpreted, all AP instructions will be intercepted and routed >>> back to >>> + * userspace. >>> + * >>> + * @kvm: the virtual machine attributes >>> + * @enable: indicates whether AP instructions are to be interpreted >>> (true) or >>> + *        or not (false). >>> + * >>> + * Returns 0 if completed successfully; otherwise, returns -EOPNOTSUPP >>> + * indicating that AP instructions are not installed on the guest. >>> + */ >>> +int kvm_ap_interpret_instructions(struct kvm *kvm, bool enable); >>> + >>>   #endif /* _ASM_KVM_AP */ >>> diff --git a/arch/s390/include/asm/kvm_host.h >>> b/arch/s390/include/asm/kvm_host.h >>> index 3162783..5470685 100644 >>> --- a/arch/s390/include/asm/kvm_host.h >>> +++ b/arch/s390/include/asm/kvm_host.h >>> @@ -715,6 +715,7 @@ struct kvm_s390_crypto { >>>       __u32 crycbd; >>>       __u8 aes_kw; >>>       __u8 dea_kw; >>> +    __u8 apie; >>>   }; >>> >>>   #define APCB0_MASK_SIZE 1 >>> diff --git a/arch/s390/kvm/kvm-ap.c b/arch/s390/kvm/kvm-ap.c >>> index 991bae4..55d11b5 100644 >>> --- a/arch/s390/kvm/kvm-ap.c >>> +++ b/arch/s390/kvm/kvm-ap.c >>> @@ -58,3 +58,23 @@ void kvm_ap_build_crycbd(struct kvm *kvm) >>>       } >>>   } >>>   EXPORT_SYMBOL(kvm_ap_build_crycbd); >>> + >>> +int kvm_ap_interpret_instructions(struct kvm *kvm, bool enable) >>> +{ >>> +    int ret = 0; >>> + >>> +    mutex_lock(&kvm->lock); >>> + >>> +    if (!test_kvm_cpu_feat(kvm, KVM_S390_VM_CPU_FEAT_AP)) { >> >> Do we really need to test CPU_FEAT_AP? > > Yes we do. really? why? > >> >> >> I understand that KVM_S390_VM_CPU_FEAT_AP means AP instructions are >> interpreted. >> shouldn't we add this information in the name? >> like KVM_S390_VM_CPU_FEAT_APIE > > KVM_S390_VM_CPU_FEAT_AP does NOT mean AP instructions are interpreted, > it means > AP instructions are installed. Right same error I made all along this review. But AFAIK it means AP instructions are provided to the guest. Then should this function be called if the guest has no AP instructions ? > >> >>> +        ret = -EOPNOTSUPP; >>> +        goto done; >>> +    } >>> + >>> +    kvm->arch.crypto.apie = enable; >>> +    kvm_s390_vcpu_crypto_reset_all(kvm); >>> + >>> +done: >>> +    mutex_unlock(&kvm->lock); >>> +    return ret; >>> +} >>> +EXPORT_SYMBOL(kvm_ap_interpret_instructions); >>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >>> index 55cd897..1dc8566 100644 >>> --- a/arch/s390/kvm/kvm-s390.c >>> +++ b/arch/s390/kvm/kvm-s390.c >>> @@ -1901,6 +1901,9 @@ static void kvm_s390_crypto_init(struct kvm *kvm) >>>       kvm->arch.crypto.crycb = &kvm->arch.sie_page2->crycb; >>>       kvm_ap_build_crycbd(kvm); >>> >>> +    /* Default setting indicating SIE shall interpret AP >>> instructions */ >>> +    kvm->arch.crypto.apie = 1; >>> + >>>       if (!test_kvm_facility(kvm, 76)) >>>           return; >>> >>> @@ -2434,6 +2437,12 @@ static void kvm_s390_vcpu_crypto_setup(struct >>> kvm_vcpu *vcpu) >>>   { >>>       vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd; >>> >>> +    vcpu->arch.sie_block->eca &= ~ECA_APIE; >>> +    if (vcpu->kvm->arch.crypto.apie && >>> +        test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP)) >> >> Do we call xxx_crypto_setup() if KVM does not support AP interpretation? > > Yes, kvm_s390_vcpu_crypto_setup(vcpu) is called by > kvm_arch_vcpu_setup(vcpu) > as well as from kvm_s390_vcpu_crypto_reset_all(kvm). Calling it has > nothing > to do with whether AP interpretation is supported or not as it does much > more than that, including setting up of wrapping keys and the CRYCBD. Sorry, still the same error I made about CPU_FEAT_AP meaning AP instructions in the guest and not AP interpretation available. Could apie be set if AP instruction are not supported? > >> >>> +        vcpu->arch.sie_block->eca |= ECA_APIE; >>> + >>> + >>>       if (!test_kvm_facility(vcpu->kvm, 76)) >>>           return; >>> >> > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany