On Wed, 29 May 2019 at 20:28, Liran Alon <liran.alon@xxxxxxxxxx> wrote:
>
>
>
> > On 28 May 2019, at 3:53, Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
> >
> > From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> >
> > The target vCPUs are in runnable state after vcpu_kick and suitable
> > as a yield target. This patch implements the sched yield hypercall.
> >
> > 17% performace increase of ebizzy benchmark can be observed in an
> > over-subscribe environment. (w/ kvm-pv-tlb disabled, testing TLB flush
> > call-function IPI-many since call-function is not easy to be trigged
> > by userspace workload).
> >
> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> > Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> > ---
> > arch/x86/kvm/x86.c | 24 ++++++++++++++++++++++++
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index e7e57de..2ceef51 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -7172,6 +7172,26 @@ void kvm_vcpu_deactivate_apicv(struct kvm_vcpu *vcpu)
> > kvm_x86_ops->refresh_apicv_exec_ctrl(vcpu);
> > }
> >
> > +void kvm_sched_yield(struct kvm *kvm, u64 dest_id)
> > +{
> > + struct kvm_vcpu *target;
> > + struct kvm_apic_map *map;
> > +
> > + rcu_read_lock();
> > + map = rcu_dereference(kvm->arch.apic_map);
> > +
> > + if (unlikely(!map))
> > + goto out;
> > +
>
> We should have a bounds-check here on “dest_id”.
Yeah, fix it in v3.
Regards,
Wanpeng Li
