On 26/10/19 05:23, Zhenzhong Duan wrote: > vcpu->halt_poll_ns could be zeroed in certain cases (e.g. by > halt_poll_ns_shrink). If halt_poll_ns_grow_start is zero, > vcpu->halt_poll_ns will never be larger than zero. > > Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx> > --- > virt/kvm/kvm_main.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 2ca2979..1b6fe3b 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2266,6 +2266,13 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) > goto out; > > val *= grow; > + > + /* > + * vcpu->halt_poll_ns needs a nonzero start point to grow if it's zero. > + */ > + if (!grow_start) > + grow_start = 1; > + > if (val < grow_start) > val = grow_start; > > Zeroing grow_start will simply disable halt polling. Is that a problem? Paolo
