Re: [PATCH v2 3/3] LoongArch: Add paravirt preempt print prompt

[Bibo Mao]

On 2025/11/24 下午2:33, Huacai Chen wrote:
> Hi, Bibo,
>
> On Mon, Nov 24, 2025 at 11:54 AM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> > Add paravirt preempt print prompt together with steal timer information,
> > so that it is easy to check whether paravirt preempt feature is enabled
> > or not.
> >
> > Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> > ---
> >   arch/loongarch/kernel/paravirt.c | 10 ++++++++--
> >   1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
> > index d4163679adc4..ffe1cf284c41 100644
> > --- a/arch/loongarch/kernel/paravirt.c
> > +++ b/arch/loongarch/kernel/paravirt.c
> > @@ -300,6 +300,7 @@ static struct notifier_block pv_reboot_nb = {
> >   int __init pv_time_init(void)
> >   {
> >          int r;
> > +       bool pv_preempted = false;
> >
> >          if (!kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
> >                  return 0;
> > @@ -322,8 +323,10 @@ int __init pv_time_init(void)
> >                  return r;
> >          }
> >
> > -       if (kvm_para_has_feature(KVM_FEATURE_PREEMPT))
> > +       if (kvm_para_has_feature(KVM_FEATURE_PREEMPT)) {
> >                  static_branch_enable(&virt_preempt_key);
> > +               pv_preempted = true;
> > +       }
> >   #endif
> >
> >          static_call_update(pv_steal_clock, paravt_steal_clock);
> > @@ -334,7 +337,10 @@ int __init pv_time_init(void)
> >                  static_key_slow_inc(&paravirt_steal_rq_enabled);
> >   #endif
> >
> > -       pr_info("Using paravirt steal-time\n");
> > +       if (pv_preempted)
> No pv_preempted needed, you can just use
> static_key_enabled(&virt_preempt_key) and merge this patch to Patch-2.
yes, good idea.
Will do in next version with these two points.

Regards
Bibo Mao
> Huacai
>
> > +               pr_info("Using paravirt steal-time with preempt hint enabled\n");
> > +       else
> > +               pr_info("Using paravirt steal-time with preempt hint disabled\n");
> >
> >          return 0;
> >   }
> > --
> > 2.39.3