Messages in this thread | | | Subject | Re: [PATCH v4 05/15] KVM: s390: enable/disable AP interpretive execution | From | Pierre Morel <> | Date | Tue, 17 Apr 2018 18:13:57 +0200 |
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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 <akrowiak@linux.vnet.ibm.com> >>> --- >>> 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
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