KVM: s390: bail out early on fatal signal in dirty logging

A KVM_GET_DIRTY_LOG ioctl might take a long time.
This can result in fatal signals seemingly being ignored.
Lets bail out during the dirty bit sync, if a fatal signal
is pending.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/kvm/kvm-s390.c

@@ -281,6 +281,8 @@ static void kvm_s390_sync_dirty_log(struct kvm *kvm,
 
 		if (gmap_test_and_clear_dirty(address, gmap))
 			mark_page_dirty(kvm, cur_gfn);
+		if (fatal_signal_pending(current))
+			return;
 		cond_resched();
 	}
 }