KVM: s390: epoch difference and TOD programmable field

This patch makes vcpu epoch difference and the TOD programmable
field accessible from userspace. This is needed in order to
implement a couple of instructions that deal with the time of
day clock on s390, such as SET CLOCK and for migration.
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/s390/include/asm/kvm.h

@@ -52,4 +52,7 @@ struct kvm_sync_regs {
 	__u32 acrs[16];	/* access registers */
 	__u64 crs[16];	/* control registers */
 };
+
+#define KVM_REG_S390_TODPR	(KVM_REG_S390 | KVM_REG_SIZE_U32 | 0x1)
+#define KVM_REG_S390_EPOCHDIFF	(KVM_REG_S390 | KVM_REG_SIZE_U64 | 0x2)
 #endif

arch/s390/kvm/kvm-s390.c

@@ -446,6 +446,14 @@ static int kvm_arch_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu,
 	int r = -EINVAL;
 
 	switch (reg->id) {
+	case KVM_REG_S390_TODPR:
+		r = put_user(vcpu->arch.sie_block->todpr,
+			     (u32 __user *)reg->addr);
+		break;
+	case KVM_REG_S390_EPOCHDIFF:
+		r = put_user(vcpu->arch.sie_block->epoch,
+			     (u64 __user *)reg->addr);
+		break;
 	default:
 		break;
 	}
@@ -459,6 +467,14 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,
 	int r = -EINVAL;
 
 	switch (reg->id) {
+	case KVM_REG_S390_TODPR:
+		r = get_user(vcpu->arch.sie_block->todpr,
+			     (u32 __user *)reg->addr);
+		break;
+	case KVM_REG_S390_EPOCHDIFF:
+		r = get_user(vcpu->arch.sie_block->epoch,
+			     (u64 __user *)reg->addr);
+		break;
 	default:
 		break;
 	}