Re: [PATCH v9 15/15] s390x: Add unpack facility feature to GA1

[Cornelia Huck]

On Wed, 11 Mar 2020 09:21:51 -0400
Janosch Frank <address@hidden> wrote:

> From: Christian Borntraeger <address@hidden>
> 
> The unpack facility is an indication that diagnose 308 subcodes 8-10
> are available to the guest. That means, that the guest can put itself
> into protected mode.
> 
> Once it is in protected mode, the hardware stops any attempt of VM
> introspection by the hypervisor.
> 
> Some features are currently not supported in protected mode:
>      * Passthrough devices

s/Passthrough/vfio/ ?

>      * Migration
>      * Huge page backings
> 
> Signed-off-by: Christian Borntraeger <address@hidden>
> Reviewed-by: David Hildenbrand <address@hidden>

Btw: please add your s-o-b if you're passing on patches from others.

> ---
>  target/s390x/gen-features.c | 1 +
>  target/s390x/kvm.c          | 5 +++++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
> index 6278845b12b8dee8..8ddeebc54419a3e2 100644
> --- a/target/s390x/gen-features.c
> +++ b/target/s390x/gen-features.c
> @@ -562,6 +562,7 @@ static uint16_t full_GEN15_GA1[] = {
>      S390_FEAT_GROUP_MSA_EXT_9,
>      S390_FEAT_GROUP_MSA_EXT_9_PCKMO,
>      S390_FEAT_ETOKEN,
> +    S390_FEAT_UNPACK,
>  };
>  
>  /* Default features (in order of release)
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index ff6027036ec2f14a..e11e895a3d9038bb 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -2403,6 +2403,11 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
> Error **errp)
>          clear_bit(S390_FEAT_BPB, model->features);
>      }
>  
> +    /* we do have the IPL enhancements */

I'm more confused by that comment than educated :) Not sure what 'IPL
enhancements' means in this context.

> +    if (cap_protected) {
> +        set_bit(S390_FEAT_UNPACK, model->features);
> +    }
> +
>      /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
>      set_bit(S390_FEAT_ZPCI, model->features);
>      set_bit(S390_FEAT_ADAPTER_EVENT_NOTIFICATION, model->features);