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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 E9835C282CE for ; Tue, 4 Jun 2019 12:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBA3F20665 for ; Tue, 4 Jun 2019 12:24:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727597AbfFDMYk (ORCPT ); Tue, 4 Jun 2019 08:24:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12051 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727495AbfFDMYk (ORCPT ); Tue, 4 Jun 2019 08:24:40 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 507569F759; Tue, 4 Jun 2019 12:24:29 +0000 (UTC) Received: from amt.cnet (ovpn-112-8.gru2.redhat.com [10.97.112.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id B6850194A2; Tue, 4 Jun 2019 12:24:23 +0000 (UTC) Received: from amt.cnet (localhost [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 633F0105157; Tue, 4 Jun 2019 09:24:09 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.7/8.14.7/Submit) id x54CO4rb019151; Tue, 4 Jun 2019 09:24:04 -0300 Date: Tue, 4 Jun 2019 09:24:04 -0300 From: Marcelo Tosatti To: kvm-devel Cc: Paolo Bonzini , Radim Krcmar , Andrea Arcangeli , "Rafael J. Wysocki" , Peter Zijlstra , Wanpeng Li , Konrad Rzeszutek Wilk , Raslan KarimAllah , Boris Ostrovsky , Ankur Arora , Christian Borntraeger Subject: [patch v2 3/3] cpuidle-haltpoll: disable host side polling when kvm virtualized Message-ID: <20190604122404.GA18979@amt.cnet> References: <20190603225242.289109849@amt.cnet> <20190603225254.360289262@amt.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190603225254.360289262@amt.cnet> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 04 Jun 2019 12:24:40 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org When performing guest side polling, it is not necessary to also perform host side polling. So disable host side polling, via the new MSR interface, when loading cpuidle-haltpoll driver. Signed-off-by: Marcelo Tosatti --- v2: remove extra "}" arch/x86/Kconfig | 7 +++++ arch/x86/include/asm/cpuidle_haltpoll.h | 8 ++++++ arch/x86/kernel/kvm.c | 40 ++++++++++++++++++++++++++++++++ drivers/cpuidle/cpuidle-haltpoll.c | 9 ++++++- include/linux/cpuidle_haltpoll.h | 16 ++++++++++++ 5 files changed, 79 insertions(+), 1 deletion(-) Index: linux-2.6.git/arch/x86/include/asm/cpuidle_haltpoll.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.git/arch/x86/include/asm/cpuidle_haltpoll.h 2019-06-03 19:38:42.328718617 -0300 @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ARCH_HALTPOLL_H +#define _ARCH_HALTPOLL_H + +void arch_haltpoll_enable(void); +void arch_haltpoll_disable(void); + +#endif Index: linux-2.6.git/drivers/cpuidle/cpuidle-haltpoll.c =================================================================== --- linux-2.6.git.orig/drivers/cpuidle/cpuidle-haltpoll.c 2019-06-03 19:38:12.376619124 -0300 +++ linux-2.6.git/drivers/cpuidle/cpuidle-haltpoll.c 2019-06-03 19:38:42.328718617 -0300 @@ -15,6 +15,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include "cpuidle-haltpoll-trace.h" @@ -157,11 +158,17 @@ static int __init haltpoll_init(void) { - return cpuidle_register(&haltpoll_driver, NULL); + int ret = cpuidle_register(&haltpoll_driver, NULL); + + if (ret == 0) + arch_haltpoll_enable(); + + return ret; } static void __exit haltpoll_exit(void) { + arch_haltpoll_disable(); cpuidle_unregister(&haltpoll_driver); } Index: linux-2.6.git/include/linux/cpuidle_haltpoll.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.git/include/linux/cpuidle_haltpoll.h 2019-06-03 19:41:57.293366260 -0300 @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _CPUIDLE_HALTPOLL_H +#define _CPUIDLE_HALTPOLL_H + +#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL +#include +#else +static inline void arch_haltpoll_enable(void) +{ +} + +static inline void arch_haltpoll_disable(void) +{ +} +#endif +#endif Index: linux-2.6.git/arch/x86/Kconfig =================================================================== --- linux-2.6.git.orig/arch/x86/Kconfig 2019-06-03 19:38:12.376619124 -0300 +++ linux-2.6.git/arch/x86/Kconfig 2019-06-03 19:42:34.478489868 -0300 @@ -787,6 +787,7 @@ bool "KVM Guest support (including kvmclock)" depends on PARAVIRT select PARAVIRT_CLOCK + select ARCH_CPUIDLE_HALTPOLL default y ---help--- This option enables various optimizations for running under the KVM @@ -795,6 +796,12 @@ underlying device model, the host provides the guest with timing infrastructure such as time of day, and system time +config ARCH_CPUIDLE_HALTPOLL + def_bool n + prompt "Disable host haltpoll when loading haltpoll driver" + help + If virtualized under KVM, disable host haltpoll. + config PVH bool "Support for running PVH guests" ---help--- Index: linux-2.6.git/arch/x86/kernel/kvm.c =================================================================== --- linux-2.6.git.orig/arch/x86/kernel/kvm.c 2019-06-03 19:38:12.376619124 -0300 +++ linux-2.6.git/arch/x86/kernel/kvm.c 2019-06-03 19:40:14.359024312 -0300 @@ -853,3 +853,43 @@ } #endif /* CONFIG_PARAVIRT_SPINLOCKS */ + +#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL + +void kvm_disable_host_haltpoll(void *i) +{ + wrmsrl(MSR_KVM_POLL_CONTROL, 0); +} + +void kvm_enable_host_haltpoll(void *i) +{ + wrmsrl(MSR_KVM_POLL_CONTROL, 1); +} + +void arch_haltpoll_enable(void) +{ + if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) + return; + + preempt_disable(); + /* Enabling guest halt poll disables host halt poll */ + kvm_disable_host_haltpoll(NULL); + smp_call_function(kvm_disable_host_haltpoll, NULL, 1); + preempt_enable(); +} +EXPORT_SYMBOL_GPL(arch_haltpoll_enable); + +void arch_haltpoll_disable(void) +{ + if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) + return; + + preempt_disable(); + /* Enabling guest halt poll disables host halt poll */ + kvm_enable_host_haltpoll(NULL); + smp_call_function(kvm_enable_host_haltpoll, NULL, 1); + preempt_enable(); +} + +EXPORT_SYMBOL_GPL(arch_haltpoll_disable); +#endif