From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Krowiak Subject: Re: [PATCH v10 24/26] KVM: s390: device attrs to enable/disable AP interpretation Date: Mon, 24 Sep 2018 14:42:48 -0400 Message-ID: <1c0c5a2e-3ef4-e5f5-52b8-7aeddca1f472@linux.ibm.com> References: <1536781396-13601-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1536781396-13601-25-git-send-email-akrowiak@linux.vnet.ibm.com> <9263b698-1827-1b7f-28bf-75b44657dea2@redhat.com> <18a21cda-1da9-3bfb-7b34-80415b5457f9@linux.ibm.com> <172560fb-2c54-ea43-3401-f108cf2a0595@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: 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 List-ID: On 09/24/2018 12:25 PM, Tony Krowiak wrote: > On 09/24/2018 07:23 AM, David Hildenbrand wrote: (...) >> Will you also fixup this patch to expose KVM_S390_VM_CRYPTO_ENABLE_APIE >> only if supported by HW? (ap_instructions_available) > > Given that this patch DOES expose KVM_S390_VM_CRYPTO_ENABLE_APIE only if > supported by HW, I assume you are talking about > KVM_S390_VM_CRYPTO_DISABLE_APIE. I didn't check > ap_instructions_available() for disabling APIE because I didn't > think it necessary given that ECA.28 will be set to 0 (intercept) by > default, whether AP instructions are installed or not; so why not allow > disabling apie. I suppose from the perspective of consistency, since the > kvm_s390_vm_has_attr() function checks ap_instructions_available() for > both attributes, then it probably makes sense to add that check to > KVM_S390_VM_CRYPTO_DISABLE_APIE here. Then again, we could make a change > in ap_instructions_available() to allow KVM_S390_VM_CRYPTO_DISABLE_APIE > regardless of whether AP instructions are available. It boils down to > whether APIE needs to be dynamically disabled at some point when it has > been enabled. The only case I can think of where that may be necessary > is if a guest is migrated to a system without AP instructions. I don't > think that can happen and may even be protected against precisely > because the VM attributes won't be available on the target system due to > no AP instructions. What say you? > David, I'm sorry, I misinterpreted what you were asking for. Check out the fixup! patch below and let me know if that is what you are looking for. If so, I will integrate that change and post v11 tomorrow (Tuesday 9/24). -----------------------------------8<----------------------------------- From: Tony Krowiak Date: Mon, 24 Sep 2018 14:18:37 -0400 Subject: [FIXUP v10] fixup! KVM: s390: device attrs to enable/disable AP interpretation --- arch/s390/kvm/kvm-s390.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 6654bb1fc26a..a528558baa78 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -901,6 +901,10 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr) kvm->arch.crypto.apie = 1; break; case KVM_S390_VM_CRYPTO_DISABLE_APIE: + if (!ap_instructions_available()) { + mutex_unlock(&kvm->lock); + return -EOPNOTSUPP; + } kvm->arch.crypto.apie = 0; break; default: @@ -1509,9 +1513,11 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr) case KVM_S390_VM_CRYPTO_ENABLE_DEA_KW: case KVM_S390_VM_CRYPTO_DISABLE_AES_KW: case KVM_S390_VM_CRYPTO_DISABLE_DEA_KW: + ret = 0; + break; case KVM_S390_VM_CRYPTO_ENABLE_APIE: case KVM_S390_VM_CRYPTO_DISABLE_APIE: - ret = 0; + ret = ap_instructions_available(); break; default: ret = -ENXIO; @@ -2620,6 +2626,7 @@ 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->ecb3 &= ~(ECB3_AES | ECB3_DEA); + vcpu->kvm->arch.crypto.apie &= ~ECA_APIE; if (vcpu->kvm->arch.crypto.apie) vcpu->arch.sie_block->eca |= ECA_APIE; -- 2.19.0.221.g150f307 >> >