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 X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76C8EC433E6 for ; Fri, 5 Mar 2021 12:02:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 365D16501B for ; Fri, 5 Mar 2021 12:02:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229783AbhCEMC0 (ORCPT ); Fri, 5 Mar 2021 07:02:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:54296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229723AbhCEMCY (ORCPT ); Fri, 5 Mar 2021 07:02:24 -0500 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AEBD36501B; Fri, 5 Mar 2021 12:02:23 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lI99x-00HSga-Gi; Fri, 05 Mar 2021 12:02:21 +0000 Date: Fri, 05 Mar 2021 12:02:20 +0000 Message-ID: <87h7lpzu43.wl-maz@kernel.org> From: Marc Zyngier To: Yejune Deng Cc: james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org Subject: Re: [PATCH] KVM: arm64: Add big.LITTLE architecture support for vcpu In-Reply-To: <20210305103425.73380-1-yejune.deng@gmail.com> References: <20210305103425.73380-1-yejune.deng@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: yejune.deng@gmail.com, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 05 Mar 2021 10:34:25 +0000, Yejune Deng wrote: > > In big.LITTLE architecture,the application layer calls KVM_ARM_VCPU_INIT > several times.Sometimes the thread will run on the big core, sometimes > will run on the little core.The big core and the little core has always > different cpuid, but the init target is fixed. and that leads to > init->target != phys_target. So modify phys target from the current core > to all cpu online. This is done on purpose, and it is userspace's responsibility to pin its vcpu threads to a certain type of CPUs if it cares at all. Thanks, M. -- Without deviation from the norm, progress is not possible.