[patch 08/12] [PATCH] kvm-s390-ucontrol: disable sca

[Carsten Otte]

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 <co...@de.ibm.com>
---
Index: linux-2.5-cecsim/arch/s390/kvm/kvm-s390.c
===================================================================
--- linux-2.5-cecsim.orig/arch/s390/kvm/kvm-s390.c
+++ linux-2.5-cecsim/arch/s390/kvm/kvm-s390.c
@@ -234,10 +234,13 @@ 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))
@@ -374,12 +377,19 @@ struct kvm_vcpu *kvm_arch_vcpu_create(st
                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);

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