From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v4 05/15] KVM: s390: enable/disable AP interpretive execution Date: Mon, 16 Apr 2018 13:13:52 +0200 Message-ID: <15bb0c9b-e605-232b-4dd2-826b6ee0d045@linux.vnet.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> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <15b60572-40d6-0f03-11f9-c50cb7eb00e8@linux.vnet.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: 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 List-ID: On 16/04/2018 12:51, 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? > > 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 If I misunderstood and FEAT_AP really mean AP instructions available in the guest, same question: is this function called if AP instructions are not available in the guest? > >> +        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? sorry, I should have written AP instructions here: is this function called if AP instructions are not available in the guest? > >> +        vcpu->arch.sie_block->eca |= ECA_APIE; >> + >> + >>       if (!test_kvm_facility(vcpu->kvm, 76)) >>           return; >> > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany