KVM: s390: vsie: support intervention-bypass

We can easily enable intervention bypass for guest 2, so it can use it
for guest 3.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

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

@@ -103,6 +103,7 @@ struct kvm_s390_vm_cpu_machine {
 #define KVM_S390_VM_CPU_FEAT_SIIF	3
 #define KVM_S390_VM_CPU_FEAT_GPERE	4
 #define KVM_S390_VM_CPU_FEAT_GSLS	5
+#define KVM_S390_VM_CPU_FEAT_IB		6
 struct kvm_s390_vm_cpu_feat {
 	__u64 feat[16];
 };

arch/s390/kvm/kvm-s390.c

@@ -273,6 +273,8 @@ static void kvm_s390_cpu_feat_init(void)
 		allow_cpu_feat(KVM_S390_VM_CPU_FEAT_GPERE);
 	if (sclp.has_gsls)
 		allow_cpu_feat(KVM_S390_VM_CPU_FEAT_GSLS);
+	if (sclp.has_ib)
+		allow_cpu_feat(KVM_S390_VM_CPU_FEAT_IB);
 }
 
 int kvm_arch_init(void *opaque)

arch/s390/kvm/vsie.c

@@ -322,6 +322,8 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 		scb_s->ecb3 |= scb_o->ecb3 & 0x01U;
 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF))
 		scb_s->eca |= scb_o->eca & 0x00000001U;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB))
+		scb_s->eca |= scb_o->eca & 0x40000000U;
 
 	prepare_ibc(vcpu, vsie_page);
 	rc = shadow_crycb(vcpu, vsie_page);