Messages in this thread |  | | Subject | Re: [PATCH v3 04/14] KVM: s390: device attribute to set AP interpretive execution | From | Tony Krowiak <> | Date | Mon, 2 Apr 2018 14:55:46 -0400 |
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On 03/20/2018 06:48 PM, Halil Pasic wrote: > > On 03/20/2018 06:58 PM, Tony Krowiak wrote: >> I spoke with Christian this morning and he made a suggestion which I think would provide the best solution here. >> This is my proposal: >> 1. Get rid of the KVM_S390_VM_CRYPTO_INTERPRET_AP device attribute and return to setting ECA.28 from the >> mdev device open callback. >> 2. Since there may be vcpus online at the time the mdev device open is called, we must first take all running vcpus out of >> SIE and block them. Christian suggested the kvm_s390_vcpu_block_all(struct kvm *kvm) function will do the trick. So I >> propose introducing a function like the following to be called during mdev open: > There is one thing you missed, otherwise I'm *very* satisfied with this > proposal. > > What you have missed IMHO is vcpu hottplug. So IMHO you should keep > kvm->arch.crypto.apie, and update it accordingly ... I agree, I will fix it. > > >> int kvm_ap_set_interpretive_exec(struct kvm *kvm, bool enable) >> { >> int i; >> struct kvm_vcpu *vcpu; >> >> if (!test_kvm_cpu_feat(kvm, KVM_S390_VM_CPU_FEAT_AP)) >> return -EOPNOTSUPP; >> >> mutex_lock(&kvm->lock); >> >> kvm_s390_vcpu_block_all(kvm); > ... let's say here. Yep > >> kvm_for_each_vcpu(i, vcpu, kvm) { > And here you can call kvm_s390_vcpu_crypto_setup(vcpu) (the changes to > this function will be required for hotplug) if you like Sounds good to me. > >> if (enable) >> vcpu->arch.sie_block->eca |= ECA_APIE; >> else >> vcpu->arch.sie_block->eca &= ~ECA_APIE; > or keep this stuff, it does not really matter to me. I'll call the kvm_s390_vcpu_crypto_setup(vcpu) to set ECA_APIE. > >> } >> >> kvm_s390_vcpu_unblock_all(kvm); >> >> mutex_unlock(&kvm->lock); >> >> return 0; >> } >> >> This interface allows us to set ECA.28 even if vcpus are running > I tend to agree. I will give it a proper review when this gets more > formal (e.g. v4 (preferably) or patches to be fixed up to this series). > > Please don't forget to revisit the discussion on kvm_s390_vm_set_crypto: > if the mechanism there isn't right for ECA.28 I think you should tell > us why it's OK for the other attributes if it's OK. If it is not then > I guess you will want to do a stand alone patch for that. That will no longer be a part of this patch series. We can revisit that as a separate issue at a future time. >
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