From patchwork Tue Nov 3 16:21:02 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Stabellini X-Patchwork-Id: 7545631 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id E18429F36A for ; Tue, 3 Nov 2015 16:23:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EAE802065A for ; Tue, 3 Nov 2015 16:23:50 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DED06204A7 for ; Tue, 3 Nov 2015 16:23:49 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZteLI-0004pp-3D; Tue, 03 Nov 2015 16:21:52 +0000 Received: from smtp02.citrix.com ([66.165.176.63]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZteL2-0004YY-4C for linux-arm-kernel@lists.infradead.org; Tue, 03 Nov 2015 16:21:37 +0000 X-IronPort-AV: E=Sophos;i="5.20,239,1444694400"; d="scan'208";a="315347531" From: Stefano Stabellini To: Subject: [PATCH v10 3/5] arm: introduce CONFIG_PARAVIRT, PARAVIRT_TIME_ACCOUNTING and pv_time_ops Date: Tue, 3 Nov 2015 16:21:02 +0000 Message-ID: <1446567664-11890-3-git-send-email-stefano.stabellini@eu.citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: MIME-Version: 1.0 X-DLP: MIA2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151103_082136_437992_10E1BF9B X-CRM114-Status: GOOD ( 16.11 ) X-Spam-Score: -4.2 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux@arm.linux.org.uk, Ian Campbell , arnd@arndb.de, Stefano Stabellini , marc.zyngier@arm.com, catalin.marinas@arm.com, konrad.wilk@oracle.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, Christopher Covington , olof@lixom.net, nico@linaro.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Introduce CONFIG_PARAVIRT and PARAVIRT_TIME_ACCOUNTING on ARM. The only paravirt interface supported is pv_time_ops.steal_clock, so no runtime pvops patching needed. This allows us to make use of steal_account_process_tick for stolen ticks accounting. Signed-off-by: Stefano Stabellini Acked-by: Christopher Covington Acked-by: Ian Campbell CC: linux@arm.linux.org.uk CC: will.deacon@arm.com CC: nico@linaro.org CC: marc.zyngier@arm.com CC: cov@codeaurora.org CC: arnd@arndb.de CC: olof@lixom.net --- Changes in v10: - replace "---help---" with "help" Changes in v7: - ifdef CONFIG_PARAVIRT the content of paravirt.h. Changes in v3: - improve commit description and Kconfig help text; - no need to initialize pv_time_ops; - add PARAVIRT_TIME_ACCOUNTING. --- arch/arm/Kconfig | 20 ++++++++++++++++++++ arch/arm/include/asm/paravirt.h | 20 ++++++++++++++++++++ arch/arm/kernel/Makefile | 1 + arch/arm/kernel/paravirt.c | 25 +++++++++++++++++++++++++ 4 files changed, 66 insertions(+) create mode 100644 arch/arm/include/asm/paravirt.h create mode 100644 arch/arm/kernel/paravirt.c diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 639411f..8dfdaa6 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1819,6 +1819,25 @@ config SWIOTLB config IOMMU_HELPER def_bool SWIOTLB +config PARAVIRT + bool "Enable paravirtualization code" + help + This changes the kernel so it can modify itself when it is run + under a hypervisor, potentially improving performance significantly + over full virtualization. + +config PARAVIRT_TIME_ACCOUNTING + bool "Paravirtual steal time accounting" + select PARAVIRT + default n + help + Select this option to enable fine granularity task steal time + accounting. Time spent executing other tasks in parallel with + the current vCPU is discounted from the vCPU power. To account for + that, there can be a small performance impact. + + If in doubt, say N here. + config XEN_DOM0 def_bool y depends on XEN @@ -1832,6 +1851,7 @@ config XEN select ARCH_DMA_ADDR_T_64BIT select ARM_PSCI select SWIOTLB_XEN + select PARAVIRT help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. diff --git a/arch/arm/include/asm/paravirt.h b/arch/arm/include/asm/paravirt.h new file mode 100644 index 0000000..8435ff59 --- /dev/null +++ b/arch/arm/include/asm/paravirt.h @@ -0,0 +1,20 @@ +#ifndef _ASM_ARM_PARAVIRT_H +#define _ASM_ARM_PARAVIRT_H + +#ifdef CONFIG_PARAVIRT +struct static_key; +extern struct static_key paravirt_steal_enabled; +extern struct static_key paravirt_steal_rq_enabled; + +struct pv_time_ops { + unsigned long long (*steal_clock)(int cpu); +}; +extern struct pv_time_ops pv_time_ops; + +static inline u64 paravirt_steal_clock(int cpu) +{ + return pv_time_ops.steal_clock(cpu); +} +#endif + +#endif diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index af9e59b..3e6e937 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -81,6 +81,7 @@ obj-$(CONFIG_VDSO) += vdso.o ifneq ($(CONFIG_ARCH_EBSA110),y) obj-y += io.o endif +obj-$(CONFIG_PARAVIRT) += paravirt.o head-y := head$(MMUEXT).o obj-$(CONFIG_DEBUG_LL) += debug.o diff --git a/arch/arm/kernel/paravirt.c b/arch/arm/kernel/paravirt.c new file mode 100644 index 0000000..53f371e --- /dev/null +++ b/arch/arm/kernel/paravirt.c @@ -0,0 +1,25 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Copyright (C) 2013 Citrix Systems + * + * Author: Stefano Stabellini + */ + +#include +#include +#include +#include + +struct static_key paravirt_steal_enabled; +struct static_key paravirt_steal_rq_enabled; + +struct pv_time_ops pv_time_ops; +EXPORT_SYMBOL_GPL(pv_time_ops);