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.
