I am looking for a way to inform userspace about the lack of an implementation in KVM HV for single stepping of instructions (KVM_GUESTDGB_SINGLESTEP bit from SET_GUEST_DEBUG ioctl). This will be used by QEMU to decide whether to attempt a call to the set_guest_debug ioctl (for BookE, KVM PR) or fallback to a QEMU only implementation (for KVM HV). QEMU thread: http://patchwork.ozlabs.org/cover/1049811/ My current proposal is to introduce a ppc-specific capability for this. However I'm not sure if this would be better as a cap common for all architectures or even if it should report on all of the possible set_guest_debug flags to cover for the future. Please comment. Thanks. Fabiano Rosas (1): KVM: PPC: Report single stepping capability arch/powerpc/kvm/powerpc.c | 5 +++++ include/uapi/linux/kvm.h | 1 + 2 files changed, 6 insertions(+) -- 2.20.1