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

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Message-Id: <20251118080656.2012805-4-maobibo@loongson.cn>
Date: Tue, 18 Nov 2025 16:06:56 +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 3/3] LoongArch: Add paravirt preempt hint print prompt

Add paravirt preempt hint print prompt together with steal timer
information, so that it is easy to check whether paravirt preempt hint
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 b99404b6b13f..b7ea511c288b 100644
--- a/arch/loongarch/kernel/paravirt.c
+++ b/arch/loongarch/kernel/paravirt.c
@@ -294,6 +294,7 @@ 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;
@@ -316,8 +317,10 @@ int __init pv_time_init(void)
 		return r;
 	}
 
-	if (kvm_para_has_feature(KVM_FEATURE_PREEMPT_HINT))
+	if (kvm_para_has_feature(KVM_FEATURE_PREEMPT_HINT)) {
 		mp_ops.vcpu_is_preempted = pv_vcpu_is_preempted;
+		pv_preempted = true;
+	}
 #endif
 
 	static_call_update(pv_steal_clock, paravt_steal_clock);
@@ -328,7 +331,10 @@ 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