Re: [PATCH v11 25/26] KVM: s390: CPU model support for AP virtualization

David Hildenbrand
2018-09-26T07:15:31Z

On 26/09/2018 01:16, Tony Krowiak wrote:
> From: Tony Krowiak <akrowiak@linux.ibm.com>
>
> Introduces two new CPU model facilities to support
> AP virtualization for KVM guests:
>
> 1. AP Query Configuration Information (QCI) facility is installed.
>
> This is indicated by setting facilities bit 12 for
> the guest. The kernel will not enable this facility
> for the guest if it is not set on the host.
>
> If this facility is not set for the KVM guest, then only
> APQNs with an APQI less than 16 will be used by a Linux
> guest regardless of the matrix configuration for the virtual
> machine. This is a limitation of the Linux AP bus.
>
> 2. AP Facilities Test facility (APFT) is installed.
>
> This is indicated by setting facilities bit 15 for
> the guest. The kernel will not enable this facility for
> the guest if it is not set on the host.
>
> If this facility is not set for the KVM guest, then no
> AP devices will be available to the guest regardless of
> the guest's matrix configuration for the virtual
> machine. This is a limitation of the Linux AP bus.
>
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> Tested-by: Farhan Ali <alifm@linux.ibm.com>
> ---
> arch/s390/kvm/kvm-s390.c | 1 +
> arch/s390/tools/gen_facilities.c | 2 ++
> 2 files changed, 3 insertions(+)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 81fd82f7626d..444965e78010 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -371,6 +371,7 @@ static void kvm_s390_cpu_feat_init(void)
>
> if (MACHINE_HAS_ESOP)
> allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP);
> +

This unrelated change should be dropped.

(can maybe be fixed when applying)

Apart from that looks good!

--

Thanks,

David / dhildenb