linux-kernel - [PATCH v2 3/3] LoongArch: Add paravirt preempt print prompt

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Message-Id: <20251124035402.3817179-4-maobibo@loongson.cn>
Date: Mon, 24 Nov 2025 11:54:01 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Paolo Bonzini <pbonzini@...hat.com>,
	Huacai Chen <chenhuacai@...nel.org>,
	Juergen Gross <jgross@...e.com>,
	Ajay Kaher <ajay.kaher@...adcom.com>,
	Alexey Makhalov <alexey.makhalov@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	WANG Xuerui <kernel@...0n.name>
Cc: kvm@...r.kernel.org,
	loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	virtualization@...ts.linux.dev,
	x86@...nel.org
Subject: [PATCH v2 3/3] LoongArch: Add paravirt preempt print prompt

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@...ngson.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)
+		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