Re: [Qemu-devel] [PATCH/RFC 2/3] s390x/ais: enable ais when migration is available

[David Hildenbrand]

On 22.09.2017 10:38, Christian Borntraeger wrote:
> Instead of unconditionally enabling the KVM AIS capability
> in the kvm arch init function, do this in the flic realize function
> when we know if migration is available. This requires to initialize
> flic before the CPUs.
> 
> Signed-off-by: Christian Borntraeger <address@hidden>
> ---
>  hw/intc/s390_flic.c          | 11 +++++++++--
>  hw/intc/s390_flic_kvm.c      |  8 +++++++-
>  hw/s390x/s390-virtio-ccw.c   |  8 ++++++--
>  include/hw/s390x/s390_flic.h |  1 +
>  target/s390x/cpu_models.c    |  6 ++++++
>  target/s390x/kvm.c           |  8 +-------
>  6 files changed, 30 insertions(+), 12 deletions(-)
> 
> diff --git a/hw/intc/s390_flic.c b/hw/intc/s390_flic.c
> index 6eaf178..08040fe 100644
> --- a/hw/intc/s390_flic.c
> +++ b/hw/intc/s390_flic.c
> @@ -1,7 +1,7 @@
>  /*
>   * QEMU S390x floating interrupt controller (flic)
>   *
> - * Copyright 2014 IBM Corp.
> + * Copyright 2014,2017 IBM Corp.
>   * Author(s): Jens Freimann <address@hidden>
>   *            Cornelia Huck <address@hidden>
>   *
> @@ -49,6 +49,13 @@ void s390_flic_init(void)
>      qdev_init_nofail(dev);
>  }
>  
> +void s390_flic_enable_ais(void)
> +{
> +    S390FLICState *fs = s390_get_flic();
> +
> +    fs->ais_supported = true;

Can we simply replace all ais_supported checks by
s390_has_feat(S390_FEAT_ADAPTER_INT_SUPPRESSION) and drop ais_supported?

Then, s390_flic_enable_ais() should not be needed.

As far as I understand, we will unlock kvm_vm_enable_cap(kvm_state,
KVM_CAP_S390_AIS, 0); only if we have migration support.

Therefore, CPU model init should see S390_FEAT_ADAPTER_INT_SUPPRESSION
only if migration support is available.


-- 

Thanks,

David