KVM: s390: Fix user triggerable bug in dead code
authorChristian Borntraeger <borntraeger@de.ibm.com>
Wed, 6 Aug 2014 14:17:58 +0000 (16:17 +0200)
committerChristian Borntraeger <borntraeger@de.ibm.com>
Mon, 25 Aug 2014 12:35:15 +0000 (14:35 +0200)
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
arch/s390/kvm/kvm-s390.c

index ce81eb2ab76a207128069119acaac4e92918fa99..81b0e11521e444501ff5b1fc723965374ea3bd7e 100644 (file)
@@ -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) {