[GIT PULL 1/2] KVM: s390: Fix user triggerable bug in dead code

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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@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
 arch/s390/kvm/kvm-s390.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index ce81eb2..81b0e11 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) {
-- 
1.8.4.2

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