On Fri, Jul 23 2021, Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > On 22.07.21 19:02, Pierre Morel wrote: >> We add a KVM extension KVM_CAP_S390_CPU_TOPOLOGY to tell the >> userland hypervisor it is safe to activate the CPU Topology facility. > > I think the old variant of using the CPU model was actually better. > It was just the patch description that was wrong. I thought we wanted a cap that userspace can enable to get ptf intercepts? I'm confused. > >> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx> >> --- >> 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 b655a7d82bf0..8c695ee79612 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -568,6 +568,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> case KVM_CAP_S390_VCPU_RESETS: >> case KVM_CAP_SET_GUEST_DEBUG: >> case KVM_CAP_S390_DIAG318: >> + case KVM_CAP_S390_CPU_TOPOLOGY: >> r = 1; >> break; >> case KVM_CAP_SET_GUEST_DEBUG2: >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index d9e4aabcb31a..081ce0cd44b9 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -1112,6 +1112,7 @@ struct kvm_ppc_resize_hpt { >> #define KVM_CAP_BINARY_STATS_FD 203 >> #define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204 >> #define KVM_CAP_ARM_MTE 205 >> +#define KVM_CAP_S390_CPU_TOPOLOGY 206 >> >> #ifdef KVM_CAP_IRQ_ROUTING >> >> Regardless of what we end up with: we need documentation for any new cap :)