KVM: async_pf: Exploit one reg interface for pfault

To enable pfault after live migration we need to expose pfault_token,
pfault_select and pfault_compare, as one reg registers to userspace.

So that qemu is able to transfer this between the source and the target.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/uapi/asm/kvm.h

@@ -73,4 +73,7 @@ struct kvm_sync_regs {
 #define KVM_REG_S390_EPOCHDIFF	(KVM_REG_S390 | KVM_REG_SIZE_U64 | 0x2)
 #define KVM_REG_S390_CPU_TIMER  (KVM_REG_S390 | KVM_REG_SIZE_U64 | 0x3)
 #define KVM_REG_S390_CLOCK_COMP (KVM_REG_S390 | KVM_REG_SIZE_U64 | 0x4)
+#define KVM_REG_S390_PFTOKEN	(KVM_REG_S390 | KVM_REG_SIZE_U64 | 0x5)
+#define KVM_REG_S390_PFCOMPARE	(KVM_REG_S390 | KVM_REG_SIZE_U64 | 0x6)
+#define KVM_REG_S390_PFSELECT	(KVM_REG_S390 | KVM_REG_SIZE_U64 | 0x7)
 #endif

arch/s390/kvm/kvm-s390.c

@@ -561,6 +561,18 @@ static int kvm_arch_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu,
 		r = put_user(vcpu->arch.sie_block->ckc,
 			     (u64 __user *)reg->addr);
 		break;
+	case KVM_REG_S390_PFTOKEN:
+		r = put_user(vcpu->arch.pfault_token,
+			     (u64 __user *)reg->addr);
+		break;
+	case KVM_REG_S390_PFCOMPARE:
+		r = put_user(vcpu->arch.pfault_compare,
+			     (u64 __user *)reg->addr);
+		break;
+	case KVM_REG_S390_PFSELECT:
+		r = put_user(vcpu->arch.pfault_select,
+			     (u64 __user *)reg->addr);
+		break;
 	default:
 		break;
 	}
@@ -590,6 +602,18 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,
 		r = get_user(vcpu->arch.sie_block->ckc,
 			     (u64 __user *)reg->addr);
 		break;
+	case KVM_REG_S390_PFTOKEN:
+		r = get_user(vcpu->arch.pfault_token,
+			     (u64 __user *)reg->addr);
+		break;
+	case KVM_REG_S390_PFCOMPARE:
+		r = get_user(vcpu->arch.pfault_compare,
+			     (u64 __user *)reg->addr);
+		break;
+	case KVM_REG_S390_PFSELECT:
+		r = get_user(vcpu->arch.pfault_select,
+			     (u64 __user *)reg->addr);
+		break;
 	default:
 		break;
 	}