From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5997BC2EA; Mon, 24 Nov 2025 07:12:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763968366; cv=none; b=N5VZY+U/WaqXG384oUIcVDWn1K5OXeRDtXbcF4zrXS0VaJhAEE99y7WW/J4dBDZ6iVdHwPUh1jqDQlFDFwIGkTTEs1kucGYM9Zkna2yLsvWozzhqcRQtszjp+oxAyuWFD4oYEALLgtCWozF4DmlGNtjA6ThEqaofqKdowoOyDHU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763968366; c=relaxed/simple; bh=juKN0XshDUgOwCgjd883BKYK8bpksKuyneFk+bQxMRk=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=X2KSNinJvKuPTvj0wveHERn6VmXSQweEdpFzgUupC/i3X9YbQ6HddEOzyOP/81j30z0buoYnszRQuzYjua/6imX3F5TN8bhPc55lggeTmXDFVRhwLrLQrm6NfByEczSbOF2hry9t4xlOs2N2TZL9PMD9EhdHebJU5qpB6GagJdI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [10.20.42.62]) by gateway (Coremail) with SMTP id _____8Cxf9NnBSRpuGgnAA--.18721S3; Mon, 24 Nov 2025 15:12:39 +0800 (CST) Received: from [10.20.42.62] (unknown [10.20.42.62]) by front1 (Coremail) with SMTP id qMiowJAxVORkBSRpdHg9AQ--.43654S3; Mon, 24 Nov 2025 15:12:38 +0800 (CST) Subject: Re: [PATCH v2 3/3] LoongArch: Add paravirt preempt print prompt To: Huacai Chen Cc: Paolo Bonzini , Juergen Gross , Ajay Kaher , Alexey Makhalov , Broadcom internal kernel review list , WANG Xuerui , kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, x86@kernel.org References: <20251124035402.3817179-1-maobibo@loongson.cn> <20251124035402.3817179-4-maobibo@loongson.cn> From: Bibo Mao Message-ID: Date: Mon, 24 Nov 2025 15:10:10 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID:qMiowJAxVORkBSRpdHg9AQ--.43654S3 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoW7WrWxCr13tF1ftFWrGFWUKFX_yoW8CFW7p3 yfAFZa9a1xGay8Ca9xtrs5Wrn8JrWkK3Z7uF9rWa45AasrZrn7Jr18CrWYvF1q9rWxWF10 grn5Wrs09FsrG3cCm3ZEXasCq-sJn29KB7ZKAUJUUUU7529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUPab4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r106r15M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVW8Jr0_Cr1UM2kKe7AKxVWUXVWUAwAS0I0E0xvYzxvE52x082IY62kv0487Mc804VCY07 AIYIkI8VC2zVCFFI0UMc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWU tVWrXwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI4 8JMxk0xIA0c2IEe2xFo4CEbIxvr21lc7CjxVAaw2AFwI0_JF0_Jw1l42xK82IYc2Ij64vI r41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxYO2xFxVAFwI0_JF0_Jw1lx2IqxVAqx4xG67 AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIY rxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0I7IYx2IY6xkF7I0E14 v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWx JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUxxhLUU UUU On 2025/11/24 下午2:33, Huacai Chen wrote: > Hi, Bibo, > > On Mon, Nov 24, 2025 at 11:54 AM Bibo Mao 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 >> --- >> 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(¶virt_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 >>