[PATCH v10 24/26] KVM: s390: device attrs to enable/disable AP interpretation

[Tony Krowiak]

From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
---
 arch/s390/include/asm/kvm_host.h |    1 +
 arch/s390/include/uapi/asm/kvm.h |    2 ++
 arch/s390/kvm/kvm-s390.c         |   27 +++++++++++++++++++++++----
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index b32bd1b..36d3531 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -719,6 +719,7 @@ struct kvm_s390_crypto {
 	__u32 crycbd;
 	__u8 aes_kw;
 	__u8 dea_kw;
+	__u8 apie;
 };
 
 #define APCB0_MASK_SIZE 1
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index 8c23afc..a8dbd90 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -161,6 +161,8 @@ 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 2cdd980..286c2e0 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 +877,31 @@ 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:
+		kvm->arch.crypto.apie = 0;
+		break;
 	default:
 		mutex_unlock(&kvm->lock);
 		return -ENXIO;
@@ -1493,6 +1508,8 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
 		case KVM_S390_VM_CRYPTO_ENABLE_DEA_KW:
 		case KVM_S390_VM_CRYPTO_DISABLE_AES_KW:
 		case KVM_S390_VM_CRYPTO_DISABLE_DEA_KW:
+		case KVM_S390_VM_CRYPTO_ENABLE_APIE:
+		case KVM_S390_VM_CRYPTO_DISABLE_APIE:
 			ret = 0;
 			break;
 		default:
@@ -2062,6 +2079,7 @@ 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))
@@ -2602,8 +2620,9 @@ 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 (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP))
+	if (vcpu->kvm->arch.crypto.apie)
 		vcpu->arch.sie_block->eca |= ECA_APIE;
 
 	/* Set up protected key support */
-- 
1.7.1