Re: [PATCH v2 07/15] KVM: s390: Interfaces to configure/deconfigure guest's AP matrix

[Tony Krowiak]

On 02/28/2018 11:15 AM, Pierre Morel wrote:
> On 27/02/2018 15:28, Tony Krowiak wrote:
> > Provides interfaces to assign AP adapters, usage domains
> > and control domains to a KVM guest.
> >
> > A KVM guest is started by executing the Start Interpretive Execution 
> > (SIE)
> > instruction. The SIE state description is a control block that 
> > contains the
> > state information for a KVM guest and is supplied as input to the SIE
> > instruction. The SIE state description has a satellite structure 
> > called the
> > Crypto Control Block (CRYCB). The CRYCB contains three bitmask fields
> > identifying the adapters, queues (domains) and control domains 
> > assigned to
> > the KVM guest:
> >
> > * The AP Adapter Mask (APM) field identifies the AP adapters assigned to
> >    the KVM guest
> >
> > * The AP Queue Mask (AQM) field identifies the AP queues assigned to
> >    the KVM guest. Each AP queue is connected to a usage domain within
> >    an AP adapter.
> >
> > * The AP Domain Mask (ADM) field identifies the control domains
> >    assigned to the KVM guest.
> >
> > Each adapter, queue (usage domain) and control domain are identified by
> > a number from 0 to 255. The bits in each mask, from most significant to
> > least significant bit, correspond to the numbers 0-255. When a bit is
> > set, the corresponding adapter, queue (usage domain) or control domain
> > is assigned to the KVM guest.
>
> ...snip...
>
> >   static int kvm_ap_apxa_installed(void)
> >   {
> >       int ret;
> > @@ -50,3 +170,140 @@ void kvm_ap_set_crycb_format(struct kvm *kvm, 
> > __u32 *crycbd)
> >               *crycbd |= CRYCB_FORMAT1;
> >       }
> >   }
> > +
> > +static int kvm_ap_matrix_apm_create(struct kvm_ap_matrix *ap_matrix, 
> > int apxa)
> > +{
> > +    if (apxa)
> > +        ap_matrix->apm_max = 256;
>
> AFAIK the number of possible bits in the masks for a system is not a 
> generic value but is
> returned by the QCI instruction.
> Is there a reason to use a fix value?
Right you are! I'll initialize the value based on what is returned from 
the QCI call.
> > +    else
> > +        ap_matrix->apm_max = 64;
> > +
> > +    ap_matrix->apm = kzalloc(KVM_AP_MASK_BYTES(ap_matrix->apm_max),
> > +                 GFP_KERNEL);
> > +    if (!ap_matrix->apm)
> > +        return -ENOMEM;
> > +
> > +    return 0;
> > +}
> > +
> > +static int kvm_ap_matrix_aqm_create(struct kvm_ap_matrix *ap_matrix, 
> > int apxa)
> > +{
> > +    if (apxa)
> > +        ap_matrix->aqm_max = 256;
>
> same here
ditto
> > +    else
> > +        ap_matrix->aqm_max = 16;
> > +
> > +    ap_matrix->aqm = kzalloc(KVM_AP_MASK_BYTES(ap_matrix->aqm_max),
> > +                 GFP_KERNEL);
> > +    if (!ap_matrix->aqm)
> > +        return -ENOMEM;
> > +
> > +    return 0;
> > +}
> > +
> > +static int kvm_ap_matrix_adm_create(struct kvm_ap_matrix *ap_matrix, 
> > int apxa)
> > +{
> > +    if (apxa)
> > +        ap_matrix->adm_max = 256;
>
> and here
ditto
> Pierre