On 16/01/2020 13.50, Cornelia Huck wrote:
> On Thu, 16 Jan 2020 13:20:26 +0100
> Thomas Huth <th...@redhat.com> wrote:
>
>> The AIS feature has been disabled late in the v2.10 development
>> cycle since there were some issues with migration (see commit
>> 3f2d07b3b01ea61126b - "s390x/ais: for 2.10 stable: disable ais
>> facility"). We originally wanted to enable it again for newer
>> machine types, but apparently we forgot to do this so far. Let's
>> do it for the new s390-ccw-virtio-5.0 machine now.
>>
>> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1756946
>> Signed-off-by: Thomas Huth <th...@redhat.com>
>> ---
>> hw/s390x/s390-virtio-ccw.c | 4 ++++
>> include/hw/s390x/s390-virtio-ccw.h | 4 ++++
>> target/s390x/kvm.c | 11 ++++++++---
>> 3 files changed, 16 insertions(+), 3 deletions(-)
>>
>
>> @@ -365,10 +367,13 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>> /*
>> * 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.
>> + * support is considered necessary we only enable this for newer
>
> s/necessary we only enable this/necessary, we only try to enable this/
>
>> + * machine types and if KVM_CAP_S390_AIS_MIGRATION is available.
>
> maybe s/and if/if/
Sure ... could you fix it up when picking up the patch (in case I don't
have to respin), or do you want me to send a v2?
>> */
>> - /* kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); */
>> + if (smc->kvm_ais_allowed &&
>> + kvm_check_extension(s, KVM_CAP_S390_AIS_MIGRATION)) {
>> + kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0);
>> + }
>>
>> kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES);
>> return 0;
>
> Looks good.
>
> Remind me again: ais only made a difference for pci devices, right? Is
> it enough to give this a quick whirl with virtio-pci devices?
I don't remember the details, Christian, could you please answer this
question?
Thomas
