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 <maob...@loongson.cn> 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 <maob...@loongson.cn>
---
  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