s390x/ais: for 2.10 stable: disable ais facility

The migration interface for ais was introduced with kernel 4.13
but the capability itself had been active since 4.12. As migration
support is considered necessary lets disable ais in the 2.10
stable version. A proper fix and re-enablement will be done
for qemu 2.11.

Signed-off-by: Christian Borntraeger <[email protected]>
Message-Id: <20170921140834[email protected]>
Signed-off-by: Cornelia Huck <[email protected]>

diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 720cb1d83385cef8f7f32b17ae564ea7353e4098..ebb75cafaaea6b8a19aeadb5590e94540d8f93a8 100644 (file)
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -311,8 +311,13 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
         }
     }
 
-    /* Try to enable AIS facility */
-    kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0);
+    /*
+     * The migration interface for ais was introduced with kernel 4.13
+     * but the capability itself had been active since 4.12. As migration
+     * support is considered necessary let's disable ais in the 2.10
+     * machine.
+     */
+    /* kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); */
 
     qemu_mutex_init(&qemu_sigp_mutex);