On Mon, 2 Jul 2018 18:20:55 +0200 Halil Pasic <pasic@xxxxxxxxxxxxx> wrote: > On 07/02/2018 06:11 PM, Cornelia Huck wrote: > > On Mon, 2 Jul 2018 11:54:28 -0400 > > Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > > > >> On 07/02/2018 11:41 AM, Cornelia Huck wrote: > >>> On Mon, 2 Jul 2018 11:37:11 -0400 > >>> Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > >>> > >>>> On 07/02/2018 10:38 AM, Christian Borntraeger wrote: > >>>>> On 06/29/2018 11:11 PM, Tony Krowiak wrote: > >>>>>> Introduces a new CPU model feature and two CPU model > >>>>>> facilities to support AP virtualization for KVM guests. > >>>>>> > >>>>>> CPU model feature: > >>>>>> > >>>>>> The KVM_S390_VM_CPU_FEAT_AP feature indicates that > >>>>>> AP instructions are available on the guest. This > >>>>>> feature will be enabled by the kernel only if the AP > >>>>>> instructions are installed on the linux host. This feature > >>>>>> must be specifically turned on for the KVM guest from > >>>>>> userspace to use the VFIO AP device driver for guest > >>>>>> access to AP devices. > >>>>>> > >>>>>> CPU model facilities: > >>>>>> > >>>>>> 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. This facility > >>>>>> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP > >>>>>> feature is not installed. > >>>>>> > >>>>>> If this facility is not set for the KVM guest, then only > >>>>>> APQNs with an APQI less than 16 will be available to the > >>>>>> guest regardless of the guest's matrix configuration. This > >>>>>> is a limitation of the AP bus running on the guest. > >>>>>> > >>>>>> 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. This facility > >>>>>> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP > >>>>>> feature is not installed. > >>>>>> > >>>>>> 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. This is a limitation > >>>>>> of the AP bus running under the guest. > >>>>>> > >>>>>> Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> > >>>>>> Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx> > >>>>>> Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx> > >>>>> I think it probably should be at the end of the series, other than that its good. > >>>> If I move this to the end of the series, the very next patch checks the > >>>> > >>>> KVM_S390_VM_CPU_FEAT_AP feature? > >>> Introduce it here, offer it only with the last patch? > >> > >> I apologize, but I don't know what you mean by this. Are you suggesting > >> this patch > >> should only include the #define for KVM_S390_VM_CPU_FEAT_AP? > > > > Yes, just introduce the definition here (so code later in the series > > can refer to it) and flip the switch (offer the bit) as the final > > patch. > > > > The other features introduced and exposed here are no different. For > KVM_S390_VM_CPU_FEAT_AP defer exposing means defer allow_cpu_feat(); > for the STFLE features, defer adding to FACILITIES_KVM_CPUMODEL. > > Anyway, I think the definition should be squashed into #6. Expose the > features after patch #6 is in place or expose them at the end of the > series is IMHO a matter of taste -- and I lean towards expose at the > end of the series. Squashing with patch 6 and enabling at the end of the series sounds good to me as well.
