From patchwork Tue Jun 4 12:24:04 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 10974873 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 67C0F13AD for ; Tue, 4 Jun 2019 12:24:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5531E2886C for ; Tue, 4 Jun 2019 12:24:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 494A5288C6; Tue, 4 Jun 2019 12:24:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CA0AF2886C 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-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 X-Virus-Scanned: ClamAV using ClamSMTP 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