[PATCH v11 24/26] KVM: s390: device attrs to enable/disable AP interpretation

Tony Krowiak
2018-09-25T23:16:39Z

From: Tony Krowiak <akrowiak@linux.ibm.com>

Introduces two new VM crypto device attributes (KVM_S390_VM_CRYPTO)
to enable or disable AP instruction interpretation from userspace
via the KVM_SET_DEVICE_ATTR ioctl:

* The KVM_S390_VM_CRYPTO_ENABLE_APIE attribute enables hardware
interpretation of AP instructions executed on the guest.

* The KVM_S390_VM_CRYPTO_DISABLE_APIE attribute disables hardware
interpretation of AP instructions executed on the guest. In this
case the instructions will be intercepted and pass through to
the guest.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
---
arch/s390/include/uapi/asm/kvm.h | 2 ++
arch/s390/kvm/kvm-s390.c | 31 ++++++++++++++++++++++++++++---
2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index 9a50f02b9894..16511d97e8dc 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -160,6 +160,8 @@ struct kvm_s390_vm_cpu_subfunc {
#define KVM_S390_VM_CRYPTO_ENABLE_DEA_KW 1
#define KVM_S390_VM_CRYPTO_DISABLE_AES_KW 2
#define KVM_S390_VM_CRYPTO_DISABLE_DEA_KW 3
+#define KVM_S390_VM_CRYPTO_ENABLE_APIE 4
+#define KVM_S390_VM_CRYPTO_DISABLE_APIE 5

/* kvm attributes for migration mode */
#define KVM_S390_VM_MIGRATION_STOP 0
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index c94ef2d0dbe4..81fd82f7626d 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -856,12 +856,11 @@ void kvm_s390_vcpu_crypto_reset_all(struct kvm *kvm)

static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
{
- if (!test_kvm_facility(kvm, 76))
- return -EINVAL;
-
mutex_lock(&kvm->lock);
switch (attr->attr) {
case KVM_S390_VM_CRYPTO_ENABLE_AES_KW:
+ if (!test_kvm_facility(kvm, 76))
+ return -EINVAL;
get_random_bytes(
kvm->arch.crypto.crycb->aes_wrapping_key_mask,
sizeof(kvm->arch.crypto.crycb->aes_wrapping_key_mask));
@@ -869,6 +868,8 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
VM_EVENT(kvm, 3, "%s", "ENABLE: AES keywrapping support");
break;
case KVM_S390_VM_CRYPTO_ENABLE_DEA_KW:
+ if (!test_kvm_facility(kvm, 76))
+ return -EINVAL;
get_random_bytes(
kvm->arch.crypto.crycb->dea_wrapping_key_mask,
sizeof(kvm->arch.crypto.crycb->dea_wrapping_key_mask));
@@ -876,17 +877,35 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
VM_EVENT(kvm, 3, "%s", "ENABLE: DEA keywrapping support");
break;
case KVM_S390_VM_CRYPTO_DISABLE_AES_KW:
+ if (!test_kvm_facility(kvm, 76))
+ return -EINVAL;
kvm->arch.crypto.aes_kw = 0;
memset(kvm->arch.crypto.crycb->aes_wrapping_key_mask, 0,
sizeof(kvm->arch.crypto.crycb->aes_wrapping_key_mask));
VM_EVENT(kvm, 3, "%s", "DISABLE: AES keywrapping support");
break;
case KVM_S390_VM_CRYPTO_DISABLE_DEA_KW:
+ if (!test_kvm_facility(kvm, 76))
+ return -EINVAL;
kvm->arch.crypto.dea_kw = 0;
memset(kvm->arch.crypto.crycb->dea_wrapping_key_mask, 0,
sizeof(kvm->arch.crypto.crycb->dea_wrapping_key_mask));
VM_EVENT(kvm, 3, "%s", "DISABLE: DEA keywrapping support");
break;
+ case KVM_S390_VM_CRYPTO_ENABLE_APIE:
+ if (!ap_instructions_available()) {
+ mutex_unlock(&kvm->lock);
+ return -EOPNOTSUPP;
+ }
+ 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:
mutex_unlock(&kvm->lock);
return -ENXIO;
@@ -1495,6 +1514,10 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
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 = ap_instructions_available() ? 0 : -ENXIO;
+ break;
default:
ret = -ENXIO;
break;
@@ -2062,6 +2085,7 @@ static u64 kvm_s390_get_initial_cpuid(void)
static void kvm_s390_crypto_init(struct kvm *kvm)
{
kvm->arch.crypto.crycb = &kvm->arch.sie_page2->crycb;
+ kvm->arch.crypto.apie = 0;
kvm_s390_set_crycb_format(kvm);

if (!test_kvm_facility(kvm, 76))
@@ -2601,6 +2625,7 @@ 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->arch.sie_block->eca &= ~ECA_APIE;

if (vcpu->kvm->arch.crypto.apie)
vcpu->arch.sie_block->eca |= ECA_APIE;
--
2.19.0.221.g150f307