KVM: s390/cpacf: Enable/disable protected key functions for kvm guest

Created new KVM device attributes for indicating whether the AES and
DES/TDES protected key functions are available for programs running
on the KVM guest.  The attributes are used to set up the controls in
the guest SIE block that specify whether programs running on the
guest will be given access to the protected key functions available
on the s390 hardware.

Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[split MSA4/protected key into two patches]

1 files changed, 75 insertions, 0 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 9cf899e9a5d4..b2371c0fd1f8 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -22,6 +22,7 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <linux/module.h>
+#include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/timer.h>
 #include <asm/asm-offsets.h>
@@ -342,6 +343,53 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att
 	return ret;
 }
 
+static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu);
+
+static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+	struct kvm_vcpu *vcpu;
+	int i;
+
+	if (!test_vfacility(76))
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+	switch (attr->attr) {
+	case KVM_S390_VM_CRYPTO_ENABLE_AES_KW:
+		get_random_bytes(
+			kvm->arch.crypto.crycb->aes_wrapping_key_mask,
+			sizeof(kvm->arch.crypto.crycb->aes_wrapping_key_mask));
+		kvm->arch.crypto.aes_kw = 1;
+		break;
+	case KVM_S390_VM_CRYPTO_ENABLE_DEA_KW:
+		get_random_bytes(
+			kvm->arch.crypto.crycb->dea_wrapping_key_mask,
+			sizeof(kvm->arch.crypto.crycb->dea_wrapping_key_mask));
+		kvm->arch.crypto.dea_kw = 1;
+		break;
+	case KVM_S390_VM_CRYPTO_DISABLE_AES_KW:
+		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));
+		break;
+	case KVM_S390_VM_CRYPTO_DISABLE_DEA_KW:
+		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));
+		break;
+	default:
+		mutex_unlock(&kvm->lock);
+		return -ENXIO;
+	}
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		kvm_s390_vcpu_crypto_setup(vcpu);
+		exit_sie(vcpu);
+	}
+	mutex_unlock(&kvm->lock);
+	return 0;
+}
+
 static int kvm_s390_set_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
 {
 	u8 gtod_high;
@@ -460,6 +508,9 @@ static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr)
 	case KVM_S390_VM_TOD:
 		ret = kvm_s390_set_tod(kvm, attr);
 		break;
+	case KVM_S390_VM_CRYPTO:
+		ret = kvm_s390_vm_set_crypto(kvm, attr);
+		break;
 	default:
 		ret = -ENXIO;
 		break;
@@ -515,6 +566,19 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
 			break;
 		}
 		break;
+	case KVM_S390_VM_CRYPTO:
+		switch (attr->attr) {
+		case KVM_S390_VM_CRYPTO_ENABLE_AES_KW:
+		case KVM_S390_VM_CRYPTO_ENABLE_DEA_KW:
+		case KVM_S390_VM_CRYPTO_DISABLE_AES_KW:
+		case KVM_S390_VM_CRYPTO_DISABLE_DEA_KW:
+			ret = 0;
+			break;
+		default:
+			ret = -ENXIO;
+			break;
+		}
+		break;
 	default:
 		ret = -ENXIO;
 		break;
@@ -602,6 +666,10 @@ static int kvm_s390_crypto_init(struct kvm *kvm)
 	kvm->arch.crypto.crycbd = (__u32) (unsigned long) kvm->arch.crypto.crycb |
 				  CRYCB_FORMAT1;
 
+	/* Disable AES/DEA protected key functions by default */
+	kvm->arch.crypto.aes_kw = 0;
+	kvm->arch.crypto.dea_kw = 0;
+
 	return 0;
 }
 
@@ -823,6 +891,13 @@ static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)
 	if (!test_vfacility(76))
 		return;
 
+	vcpu->arch.sie_block->ecb3 &= ~(ECB3_AES | ECB3_DEA);
+
+	if (vcpu->kvm->arch.crypto.aes_kw)
+		vcpu->arch.sie_block->ecb3 |= ECB3_AES;
+	if (vcpu->kvm->arch.crypto.dea_kw)
+		vcpu->arch.sie_block->ecb3 |= ECB3_DEA;
+
 	vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
 }