On 13.12.2017 02:33, Wanpeng Li wrote: > From: Wanpeng Li <wanpeng...@hotmail.com> > > This patch reuses the preempted field in kvm_steal_time, and will export > the vcpu running/pre-empted information to the guest from host. This will > enable guest to intelligently send ipi to running vcpus and set flag for > pre-empted vcpus. This will prevent waiting for vcpus that are not running. > > Cc: Paolo Bonzini <pbonz...@redhat.com> > Cc: Radim Krčmář <rkrc...@redhat.com> > Cc: Peter Zijlstra <pet...@infradead.org> > Signed-off-by: Wanpeng Li <wanpeng...@hotmail.com> > --- > arch/x86/include/uapi/asm/kvm_para.h | 3 +++ > arch/x86/kernel/kvm.c | 2 +- > arch/x86/kvm/x86.c | 4 ++-- > 3 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/uapi/asm/kvm_para.h > b/arch/x86/include/uapi/asm/kvm_para.h > index 09cc064..763b692 100644 > --- a/arch/x86/include/uapi/asm/kvm_para.h > +++ b/arch/x86/include/uapi/asm/kvm_para.h > @@ -51,6 +51,9 @@ struct kvm_steal_time { > __u32 pad[11]; > }; > > +#define KVM_VCPU_NOT_PREEMPTED (0 << 0) > +#define KVM_VCPU_PREEMPTED (1 << 0)
Is it really helpful to have two flags? Just use KVM_VCPU_PREEMPTED and clear that one in record_steal_time() -- Thanks, David / dhildenb