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 <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
---
 target/s390x/kvm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 720cb1d..ebb75ca 100644
--- 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);
 
-- 
2.9.4

On 22.09.2017 10:38, Christian Borntraeger wrote:
> 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 <borntraeger@de.ibm.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> ---
>  target/s390x/kvm.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index 720cb1d..ebb75ca 100644
> --- 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);
>  
> 

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 

Thanks,

David