On Thu, 9 Nov 2017 10:04:04 +0100 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > The AIS capability was introduced in 4.12, while the interface > to migrate the state was added in 4.13. Let's add a new capability > that tells userspace that AIS states can be migrated. I think that needs a bit more explanation (i.e., why can't userspace check for the migration interface?) Also, it would be good to mention the cap under Documentation/. [It's very likely that we will have forgotten the history of this in in a few month's time...] > > Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> > --- > arch/s390/kvm/kvm-s390.c | 1 + > include/uapi/linux/kvm.h | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index de6a5b7..8f4b655 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -395,6 +395,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_S390_USER_INSTR0: > case KVM_CAP_S390_CMMA_MIGRATION: > case KVM_CAP_S390_AIS: > + case KVM_CAP_S390_AIS_MIGRATION: > r = 1; > break; > case KVM_CAP_S390_MEM_OP: > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 8388875..b605956 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -930,6 +930,7 @@ struct kvm_ppc_resize_hpt { > #define KVM_CAP_PPC_SMT_POSSIBLE 147 > #define KVM_CAP_HYPERV_SYNIC2 148 > #define KVM_CAP_HYPERV_VP_INDEX 149 > +#define KVM_CAP_S390_AIS_MIGRATION 150 > > #ifdef KVM_CAP_IRQ_ROUTING >