From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76AD2C4332F for ; Fri, 4 Nov 2022 09:13:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231307AbiKDJNe (ORCPT ); Fri, 4 Nov 2022 05:13:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230045AbiKDJNX (ORCPT ); Fri, 4 Nov 2022 05:13:23 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 89902291; Fri, 4 Nov 2022 02:13:20 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D87C61FB; Fri, 4 Nov 2022 02:13:25 -0700 (PDT) Received: from [10.1.27.15] (e122027.cambridge.arm.com [10.1.27.15]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0AAE83F703; Fri, 4 Nov 2022 02:13:16 -0700 (PDT) Message-ID: <55b704b7-0a44-8f34-e22f-d60b58db610f@arm.com> Date: Fri, 4 Nov 2022 09:13:14 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH] arm64: paravirt: remove conduit check in has_pv_steal_clock To: Usama Arif , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux@armlinux.org.uk, yezengruan@huawei.com, catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, mark.rutland@arm.com Cc: fam.zheng@bytedance.com, liangma@liangbit.com, punit.agrawal@bytedance.com References: <20221104061659.4116508-1-usama.arif@bytedance.com> Content-Language: en-GB From: Steven Price In-Reply-To: <20221104061659.4116508-1-usama.arif@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/11/2022 06:16, Usama Arif wrote: > arm_smccc_1_1_invoke() which is called later on in the function > will return failure if there's no conduit (or pre-SMCCC 1.1), > hence the check is unnecessary. > > Suggested-by: Steven Price > Signed-off-by: Usama Arif Reviewed-by: Steven Price > --- > arch/arm64/kernel/paravirt.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c > index 57c7c211f8c7..aa718d6a9274 100644 > --- a/arch/arm64/kernel/paravirt.c > +++ b/arch/arm64/kernel/paravirt.c > @@ -141,10 +141,6 @@ static bool __init has_pv_steal_clock(void) > { > struct arm_smccc_res res; > > - /* To detect the presence of PV time support we require SMCCC 1.1+ */ > - if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) > - return false; > - > arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, > ARM_SMCCC_HV_PV_TIME_FEATURES, &res); >