KVM: s390: allow user space to handle instr 0x0000

We will use illegal instruction 0x0000 for handling 2 byte sw breakpoints
from user space. As it can be enabled dynamically via a capability,
let's move setting of ICTL_OPEREXC to the post creation step, so we avoid
any races when enabling that capability just while adding new cpus.

Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 850be47c4cc9..7a2f1551bc39 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -359,6 +359,9 @@ static int handle_operexc(struct kvm_vcpu *vcpu)
             test_kvm_facility(vcpu->kvm, 74))
                 return handle_sthyi(vcpu);
 
+        if (vcpu->arch.sie_block->ipa == 0 && vcpu->kvm->arch.user_instr0)
+                return -EOPNOTSUPP;
+
         return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
 }