KVM: s390: Fix user triggerable bug in dead code

In the early days, we had some special handling for the
KVM_EXIT_S390_SIEIC exit, but this was gone in 2009 with commit
d7b0b5eb3000 (KVM: s390: Make psw available on all exits, not
just a subset).

Now this switch statement is just a sanity check for userspace
not messing with the kvm_run structure. Unfortunately, this
allows userspace to trigger a kernel BUG. Let's just remove
this switch statement.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org

1 files changed, 0 insertions, 13 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index ce81eb2ab76a..81b0e11521e4 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1317,19 +1317,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 return -EINVAL;
         }
 
-        switch (kvm_run->exit_reason) {
-        case KVM_EXIT_S390_SIEIC:
-        case KVM_EXIT_UNKNOWN:
-        case KVM_EXIT_INTR:
-        case KVM_EXIT_S390_RESET:
-        case KVM_EXIT_S390_UCONTROL:
-        case KVM_EXIT_S390_TSCH:
-        case KVM_EXIT_DEBUG:
-                break;
-        default:
-                BUG();
-        }
-
         vcpu->arch.sie_block->gpsw.mask = kvm_run->psw_mask;
         vcpu->arch.sie_block->gpsw.addr = kvm_run->psw_addr;
         if (kvm_run->kvm_dirty_regs & KVM_SYNC_PREFIX) {