KVM: s390: ucontrol: disable sca

This patch makes sure user controlled virtual machines do not use a
system control area (sca). This is needed in order to create
virtual machines with more cpus than the size of the sca [64].

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 20 insertions, 10 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 8489edf80c89..abf784d8c680 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -228,10 +228,13 @@ out_err:
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
         VCPU_EVENT(vcpu, 3, "%s", "free cpu");
-        clear_bit(63 - vcpu->vcpu_id, (unsigned long *) &vcpu->kvm->arch.sca->mcn);
-        if (vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sda ==
-                (__u64) vcpu->arch.sie_block)
-                vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sda = 0;
+        if (!kvm_is_ucontrol(vcpu->kvm)) {
+                clear_bit(63 - vcpu->vcpu_id,
+                          (unsigned long *) &vcpu->kvm->arch.sca->mcn);
+                if (vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sda ==
+                    (__u64) vcpu->arch.sie_block)
+                        vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sda = 0;
+        }
         smp_mb();
 
         if (kvm_is_ucontrol(vcpu->kvm))
@@ -368,12 +371,19 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
                 goto out_free_cpu;
 
         vcpu->arch.sie_block->icpua = id;
-        BUG_ON(!kvm->arch.sca);
-        if (!kvm->arch.sca->cpu[id].sda)
-                kvm->arch.sca->cpu[id].sda = (__u64) vcpu->arch.sie_block;
-        vcpu->arch.sie_block->scaoh = (__u32)(((__u64)kvm->arch.sca) >> 32);
-        vcpu->arch.sie_block->scaol = (__u32)(__u64)kvm->arch.sca;
-        set_bit(63 - id, (unsigned long *) &kvm->arch.sca->mcn);
+        if (!kvm_is_ucontrol(kvm)) {
+                if (!kvm->arch.sca) {
+                        WARN_ON_ONCE(1);
+                        goto out_free_cpu;
+                }
+                if (!kvm->arch.sca->cpu[id].sda)
+                        kvm->arch.sca->cpu[id].sda =
+                                (__u64) vcpu->arch.sie_block;
+                vcpu->arch.sie_block->scaoh =
+                        (__u32)(((__u64)kvm->arch.sca) >> 32);
+                vcpu->arch.sie_block->scaol = (__u32)(__u64)kvm->arch.sca;
+                set_bit(63 - id, (unsigned long *) &kvm->arch.sca->mcn);
+        }
 
         spin_lock_init(&vcpu->arch.local_int.lock);
         INIT_LIST_HEAD(&vcpu->arch.local_int.list);