Messages in this thread | | | Subject | Re: [PATCH v4 05/15] KVM: s390: enable/disable AP interpretive execution | From | Tony Krowiak <> | Date | Tue, 17 Apr 2018 11:02:06 -0400 |
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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.
> > > 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.
> >> + 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.
> >> + vcpu->arch.sie_block->eca |= ECA_APIE; >> + >> + >> if (!test_kvm_facility(vcpu->kvm, 76)) >> return; >> >
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