From patchwork Tue Jun 11 19:40:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 10988259 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 E42FE1708 for ; Tue, 11 Jun 2019 19:42:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D319A28779 for ; Tue, 11 Jun 2019 19:42:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C79E42877F; Tue, 11 Jun 2019 19:42:38 +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=unavailable 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 10D3428783 for ; Tue, 11 Jun 2019 19:42:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405039AbfFKTmd (ORCPT ); Tue, 11 Jun 2019 15:42:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55698 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391080AbfFKTmd (ORCPT ); Tue, 11 Jun 2019 15:42:33 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DB6073092641; Tue, 11 Jun 2019 19:42:32 +0000 (UTC) Received: from amt.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1814B1001B01; Tue, 11 Jun 2019 19:42:30 +0000 (UTC) Received: from amt.cnet (localhost [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 97AC2105152; Tue, 11 Jun 2019 16:42:14 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.7/8.14.7/Submit) id x5BJgEYL011941; Tue, 11 Jun 2019 16:42:14 -0300 Message-Id: <20190611194107.269706590@amt.cnet> User-Agent: quilt/0.60-1 Date: Tue, 11 Jun 2019 16:40:55 -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 , linux-pm@vger.kernel.org Subject: [patch 1/3] drivers/cpuidle: add cpuidle-haltpoll driver References: <20190611194054.878923294@amt.cnet> Content-Disposition: inline; filename=01-cpuidle-haltpoll X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Tue, 11 Jun 2019 19:42:33 +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 The cpuidle_haltpoll driver allows the guest vcpus to poll for a specified amount of time before halting. This provides the following benefits to host side polling: 1) The POLL flag is set while polling is performed, which allows a remote vCPU to avoid sending an IPI (and the associated cost of handling the IPI) when performing a wakeup. 2) The HLT VM-exit cost can be avoided. The downside of guest side polling is that polling is performed even with other runnable tasks in the host. Results comparing halt_poll_ns and server/client application where a small packet is ping-ponged: host --> 31.33 halt_poll_ns=300000 / no guest busy spin --> 33.40 (93.8%) halt_poll_ns=0 / guest_halt_poll_ns=300000 --> 32.73 (95.7%) For the SAP HANA benchmarks (where idle_spin is a parameter of the previous version of the patch, results should be the same): hpns == halt_poll_ns idle_spin=0/ idle_spin=800/ idle_spin=0/ hpns=200000 hpns=0 hpns=800000 DeleteC06T03 (100 thread) 1.76 1.71 (-3%) 1.78 (+1%) InsertC16T02 (100 thread) 2.14 2.07 (-3%) 2.18 (+1.8%) DeleteC00T01 (1 thread) 1.34 1.28 (-4.5%) 1.29 (-3.7%) UpdateC00T03 (1 thread) 4.72 4.18 (-12%) 4.53 (-5%) --- Documentation/virtual/guest-halt-polling.txt | 96 +++++++++++++++++ arch/x86/kernel/process.c | 2 drivers/cpuidle/Kconfig | 9 + drivers/cpuidle/Makefile | 1 drivers/cpuidle/cpuidle-haltpoll.c | 145 +++++++++++++++++++++++++++ 5 files changed, 252 insertions(+), 1 deletion(-) Index: linux-2.6.git/Documentation/virtual/guest-halt-polling.txt =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.git/Documentation/virtual/guest-halt-polling.txt 2019-06-11 16:38:55.072877644 -0300 @@ -0,0 +1,96 @@ +Guest halt polling +================== + +The cpuidle_haltpoll driver allows the guest vcpus to poll for a specified +amount of time before halting. This provides the following benefits +to host side polling: + + 1) The POLL flag is set while polling is performed, which allows + a remote vCPU to avoid sending an IPI (and the associated + cost of handling the IPI) when performing a wakeup. + + 2) The VM-exit cost can be avoided. + +The downside of guest side polling is that polling is performed +even with other runnable tasks in the host. + +The basic logic as follows: A global value, guest_halt_poll_ns, +is configured by the user, indicating the maximum amount of +time polling is allowed. This value is fixed. + +Each vcpu has an adjustable guest_halt_poll_ns +("per-cpu guest_halt_poll_ns"), which is adjusted by the algorithm +in response to events (explained below). + +Module Parameters +================= + +The cpuidle_haltpoll module has 5 tunable module parameters: + +1) guest_halt_poll_ns: + +Maximum amount of time, in nanoseconds, that polling is +performed before halting. + +Default: 0 + +2) guest_halt_poll_shrink: + +Division factor used to shrink per-cpu guest_halt_poll_ns when +wakeup event occurs after the global guest_halt_poll_ns. + +Default: 2 + +3) guest_halt_poll_grow: + +Multiplication factor used to grow per-cpu guest_halt_poll_ns +when event occurs after per-cpu guest_halt_poll_ns +but before global guest_halt_poll_ns. + +Default: 2 + +4) guest_halt_poll_grow_start: + +The per-cpu guest_halt_poll_ns eventually reaches zero +in case of an idle system. This value sets the initial +per-cpu guest_halt_poll_ns when growing. This can +be increased from 10000, to avoid misses during the initial +growth stage: + +10000, 20000, 40000, ... (example assumes guest_halt_poll_grow=2). + +Default: 10000 + +5) guest_halt_poll_allow_shrink: + +Bool parameter which allows shrinking. Set to N +to avoid it (per-cpu guest_halt_poll_ns will remain +high once achieves global guest_halt_poll_ns value). + +Default: Y + +The module parameters can be set from the debugfs files in: + + /sys/module/cpuidle_haltpoll/parameters/ + +Host and guest polling +====================== + +KVM also performs host side polling (that is, it can poll for a certain +amount of time before halting) on behalf of guest vcpus. + +Modern hosts support poll control MSRs, which are used by +cpuidle_haltpoll to disable host side polling on a per-VM basis. + +If the KVM host does not support this interface, then both guest side +and host side polling can be performed, which can incur extra CPU and +energy consumption. One might consider disabling host side polling +manually if upgrading to a new host is not an option. + +Further Notes +============= + +Care should be taken when setting the guest_halt_poll_ns parameter +as a large value has the potential to drive the cpu usage to 100% on a +machine which would be almost entirely idle otherwise. + Index: linux-2.6.git/arch/x86/kernel/process.c =================================================================== --- linux-2.6.git.orig/arch/x86/kernel/process.c 2019-06-11 12:14:37.731286353 -0300 +++ linux-2.6.git/arch/x86/kernel/process.c 2019-06-11 12:14:44.699424799 -0300 @@ -580,7 +580,7 @@ safe_halt(); trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } -#ifdef CONFIG_APM_MODULE +#if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE) EXPORT_SYMBOL(default_idle); #endif Index: linux-2.6.git/drivers/cpuidle/Kconfig =================================================================== --- linux-2.6.git.orig/drivers/cpuidle/Kconfig 2019-06-11 12:14:37.731286353 -0300 +++ linux-2.6.git/drivers/cpuidle/Kconfig 2019-06-11 16:38:13.984060707 -0300 @@ -51,6 +51,15 @@ source "drivers/cpuidle/Kconfig.powerpc" endmenu +config HALTPOLL_CPUIDLE + tristate "Halt poll cpuidle driver" + depends on X86 + default y + help + This option enables halt poll cpuidle driver, which allows to poll + before halting in the guest (more efficient than polling in the + host via halt_poll_ns for some scenarios). + endif config ARCH_NEEDS_CPU_IDLE_COUPLED Index: linux-2.6.git/drivers/cpuidle/Makefile =================================================================== --- linux-2.6.git.orig/drivers/cpuidle/Makefile 2019-06-11 12:14:37.731286353 -0300 +++ linux-2.6.git/drivers/cpuidle/Makefile 2019-06-11 12:14:44.700424819 -0300 @@ -7,6 +7,7 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o obj-$(CONFIG_DT_IDLE_STATES) += dt_idle_states.o obj-$(CONFIG_ARCH_HAS_CPU_RELAX) += poll_state.o +obj-$(CONFIG_HALTPOLL_CPUIDLE) += cpuidle-haltpoll.o ################################################################################## # ARM SoC drivers Index: linux-2.6.git/drivers/cpuidle/cpuidle-haltpoll.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.git/drivers/cpuidle/cpuidle-haltpoll.c 2019-06-11 16:37:23.328053569 -0300 @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * cpuidle driver for halt polling. + * + * Copyright 2019 Red Hat, Inc. and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + * Authors: Marcelo Tosatti + */ + +#include +#include +#include +#include +#include + +static unsigned int guest_halt_poll_ns __read_mostly = 200000; +module_param(guest_halt_poll_ns, uint, 0644); + +/* division factor to shrink halt_poll_ns */ +static unsigned int guest_halt_poll_shrink __read_mostly = 2; +module_param(guest_halt_poll_shrink, uint, 0644); + +/* multiplication factor to grow per-cpu halt_poll_ns */ +static unsigned int guest_halt_poll_grow __read_mostly = 2; +module_param(guest_halt_poll_grow, uint, 0644); + +/* value in ns to start growing per-cpu halt_poll_ns */ +static unsigned int guest_halt_poll_grow_start __read_mostly = 10000; +module_param(guest_halt_poll_grow_start, uint, 0644); + +/* value in ns to start growing per-cpu halt_poll_ns */ +static bool guest_halt_poll_allow_shrink __read_mostly = true; +module_param(guest_halt_poll_allow_shrink, bool, 0644); + +static DEFINE_PER_CPU(unsigned int, halt_poll_ns); + +static void adjust_haltpoll_ns(unsigned int block_ns, + unsigned int *cpu_halt_poll_ns) +{ + unsigned int val; + + /* Grow cpu_halt_poll_ns if + * cpu_halt_poll_ns < block_ns < guest_halt_poll_ns + */ + if (block_ns > *cpu_halt_poll_ns && block_ns <= guest_halt_poll_ns) { + val = *cpu_halt_poll_ns * guest_halt_poll_grow; + + if (val < guest_halt_poll_grow_start) + val = guest_halt_poll_grow_start; + if (val > guest_halt_poll_ns) + val = guest_halt_poll_ns; + + *cpu_halt_poll_ns = val; + } else if (block_ns > guest_halt_poll_ns && + guest_halt_poll_allow_shrink) { + unsigned int shrink = guest_halt_poll_shrink; + + val = *cpu_halt_poll_ns; + if (shrink == 0) + val = 0; + else + val /= shrink; + *cpu_halt_poll_ns = val; + } +} + +static int haltpoll_enter_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) +{ + unsigned int *cpu_halt_poll_ns; + unsigned long long start, now, block_ns; + int cpu = smp_processor_id(); + + cpu_halt_poll_ns = per_cpu_ptr(&halt_poll_ns, cpu); + + if (current_set_polling_and_test()) { + local_irq_enable(); + goto out; + } + + start = sched_clock(); + local_irq_enable(); + for (;;) { + if (need_resched()) { + current_clr_polling(); + goto out; + } + + now = sched_clock(); + if (now - start > *cpu_halt_poll_ns) + break; + + cpu_relax(); + } + + local_irq_disable(); + if (current_clr_polling_and_test()) { + local_irq_enable(); + goto out; + } + + default_idle(); + block_ns = sched_clock() - start; + adjust_haltpoll_ns(block_ns, cpu_halt_poll_ns); + +out: + return index; +} + +static struct cpuidle_driver haltpoll_driver = { + .name = "haltpoll_idle", + .owner = THIS_MODULE, + .states = { + { /* entry 0 is for polling */ }, + { + .enter = haltpoll_enter_idle, + .exit_latency = 0, + .target_residency = 0, + .power_usage = -1, + .name = "Halt poll", + .desc = "Halt poll idle", + }, + }, + .safe_state_index = 0, + .state_count = 2, +}; + +static int __init haltpoll_init(void) +{ + return cpuidle_register(&haltpoll_driver, NULL); +} + +static void __exit haltpoll_exit(void) +{ + cpuidle_unregister(&haltpoll_driver); +} + +module_init(haltpoll_init); +module_exit(haltpoll_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Marcelo Tosatti "); + From patchwork Tue Jun 11 19:40:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 10988253 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 A8CD413AF for ; Tue, 11 Jun 2019 19:42:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 981CA28783 for ; Tue, 11 Jun 2019 19:42:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8C76228789; Tue, 11 Jun 2019 19:42:36 +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 0DE442877F for ; Tue, 11 Jun 2019 19:42:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405705AbfFKTme (ORCPT ); Tue, 11 Jun 2019 15:42:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45168 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389150AbfFKTmd (ORCPT ); Tue, 11 Jun 2019 15:42:33 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D48823082B15; Tue, 11 Jun 2019 19:42:32 +0000 (UTC) Received: from amt.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 181AC1001B03; Tue, 11 Jun 2019 19:42:30 +0000 (UTC) Received: from amt.cnet (localhost [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 3811A105153; Tue, 11 Jun 2019 16:42:15 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.7/8.14.7/Submit) id x5BJgE7h011942; Tue, 11 Jun 2019 16:42:14 -0300 Message-Id: <20190611194107.343397521@amt.cnet> User-Agent: quilt/0.60-1 Date: Tue, 11 Jun 2019 16:40:56 -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 , linux-pm@vger.kernel.org, Marcelo Tosatti Subject: [patch 2/3] kvm: x86: add host poll control msrs References: <20190611194054.878923294@amt.cnet> Content-Disposition: inline; filename=02-pollcontrol-host.patch X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Tue, 11 Jun 2019 19:42:32 +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 Add an MSRs which allows the guest to disable host polling (specifically the cpuidle-haltpoll, when performing polling in the guest, disables host side polling). Signed-off-by: Marcelo Tosatti --- Documentation/virtual/kvm/msr.txt | 9 +++++++++ arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/include/uapi/asm/kvm_para.h | 2 ++ arch/x86/kvm/Kconfig | 1 + arch/x86/kvm/cpuid.c | 3 ++- arch/x86/kvm/x86.c | 22 ++++++++++++++++++++++ 6 files changed, 38 insertions(+), 1 deletion(-) Index: linux-2.6.git/Documentation/virtual/kvm/msr.txt =================================================================== --- linux-2.6.git.orig/Documentation/virtual/kvm/msr.txt 2019-06-11 15:54:16.500695464 -0300 +++ linux-2.6.git/Documentation/virtual/kvm/msr.txt 2019-06-11 16:04:09.917453903 -0300 @@ -273,3 +273,12 @@ guest must both read the least significant bit in the memory area and clear it using a single CPU instruction, such as test and clear, or compare and exchange. + +MSR_KVM_POLL_CONTROL: 0x4b564d05 + Control host side polling. + + data: Bit 0 enables (1) or disables (0) host halt poll + logic. + KVM guests can disable host halt polling when performing + polling themselves. + Index: linux-2.6.git/arch/x86/include/asm/kvm_host.h =================================================================== --- linux-2.6.git.orig/arch/x86/include/asm/kvm_host.h 2019-06-11 15:54:16.500695464 -0300 +++ linux-2.6.git/arch/x86/include/asm/kvm_host.h 2019-06-11 16:04:09.917453903 -0300 @@ -755,6 +755,8 @@ struct gfn_to_hva_cache data; } pv_eoi; + u64 msr_kvm_poll_control; + /* * Indicate whether the access faults on its page table in guest * which is set when fix page fault and used to detect unhandeable Index: linux-2.6.git/arch/x86/include/uapi/asm/kvm_para.h =================================================================== --- linux-2.6.git.orig/arch/x86/include/uapi/asm/kvm_para.h 2019-06-11 15:54:16.500695464 -0300 +++ linux-2.6.git/arch/x86/include/uapi/asm/kvm_para.h 2019-06-11 16:04:09.917453903 -0300 @@ -29,6 +29,7 @@ #define KVM_FEATURE_PV_TLB_FLUSH 9 #define KVM_FEATURE_ASYNC_PF_VMEXIT 10 #define KVM_FEATURE_PV_SEND_IPI 11 +#define KVM_FEATURE_POLL_CONTROL 12 #define KVM_HINTS_REALTIME 0 @@ -47,6 +48,7 @@ #define MSR_KVM_ASYNC_PF_EN 0x4b564d02 #define MSR_KVM_STEAL_TIME 0x4b564d03 #define MSR_KVM_PV_EOI_EN 0x4b564d04 +#define MSR_KVM_POLL_CONTROL 0x4b564d05 struct kvm_steal_time { __u64 steal; Index: linux-2.6.git/arch/x86/kvm/Kconfig =================================================================== --- linux-2.6.git.orig/arch/x86/kvm/Kconfig 2019-06-11 15:54:16.500695464 -0300 +++ linux-2.6.git/arch/x86/kvm/Kconfig 2019-06-11 16:04:09.917453903 -0300 @@ -41,6 +41,7 @@ select PERF_EVENTS select HAVE_KVM_MSI select HAVE_KVM_CPU_RELAX_INTERCEPT + select HAVE_KVM_NO_POLL select KVM_GENERIC_DIRTYLOG_READ_PROTECT select KVM_VFIO select SRCU Index: linux-2.6.git/arch/x86/kvm/cpuid.c =================================================================== --- linux-2.6.git.orig/arch/x86/kvm/cpuid.c 2019-06-11 15:54:16.500695464 -0300 +++ linux-2.6.git/arch/x86/kvm/cpuid.c 2019-06-11 16:04:09.918453923 -0300 @@ -643,7 +643,8 @@ (1 << KVM_FEATURE_PV_UNHALT) | (1 << KVM_FEATURE_PV_TLB_FLUSH) | (1 << KVM_FEATURE_ASYNC_PF_VMEXIT) | - (1 << KVM_FEATURE_PV_SEND_IPI); + (1 << KVM_FEATURE_PV_SEND_IPI) | + (1 << KVM_FEATURE_POLL_CONTROL); if (sched_info_on()) entry->eax |= (1 << KVM_FEATURE_STEAL_TIME); Index: linux-2.6.git/arch/x86/kvm/x86.c =================================================================== --- linux-2.6.git.orig/arch/x86/kvm/x86.c 2019-06-11 15:54:16.500695464 -0300 +++ linux-2.6.git/arch/x86/kvm/x86.c 2019-06-11 16:04:48.002209329 -0300 @@ -1177,6 +1177,7 @@ MSR_IA32_POWER_CTL, MSR_K7_HWCR, + MSR_KVM_POLL_CONTROL, }; static unsigned num_emulated_msrs; @@ -2628,6 +2629,14 @@ return 1; break; + case MSR_KVM_POLL_CONTROL: + /* only enable bit supported */ + if (data & (-1ULL << 1)) + return 1; + + vcpu->arch.msr_kvm_poll_control = data; + break; + case MSR_IA32_MCG_CTL: case MSR_IA32_MCG_STATUS: case MSR_IA32_MC0_CTL ... MSR_IA32_MCx_CTL(KVM_MAX_MCE_BANKS) - 1: @@ -2877,6 +2886,9 @@ case MSR_KVM_PV_EOI_EN: msr_info->data = vcpu->arch.pv_eoi.msr_val; break; + case MSR_KVM_POLL_CONTROL: + msr_info->data = vcpu->arch.msr_kvm_poll_control; + break; case MSR_IA32_P5_MC_ADDR: case MSR_IA32_P5_MC_TYPE: case MSR_IA32_MCG_CAP: @@ -8874,6 +8886,10 @@ msr.host_initiated = true; kvm_write_tsc(vcpu, &msr); vcpu_put(vcpu); + + /* poll control enabled by default */ + vcpu->arch.msr_kvm_poll_control = 1; + mutex_unlock(&vcpu->mutex); if (!kvmclock_periodic_sync) @@ -9948,6 +9964,12 @@ } EXPORT_SYMBOL_GPL(kvm_vector_hashing_enabled); +bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) +{ + return (vcpu->arch.msr_kvm_poll_control & 1) == 0; +} +EXPORT_SYMBOL_GPL(kvm_arch_no_poll); + EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_fast_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq); From patchwork Tue Jun 11 19:40:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 10988247 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 564631708 for ; Tue, 11 Jun 2019 19:42:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4651F2877F for ; Tue, 11 Jun 2019 19:42:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 39F4428783; Tue, 11 Jun 2019 19:42:35 +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 AED322877F for ; Tue, 11 Jun 2019 19:42:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391554AbfFKTmd (ORCPT ); Tue, 11 Jun 2019 15:42:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35966 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391042AbfFKTmd (ORCPT ); Tue, 11 Jun 2019 15:42:33 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E22E859474; Tue, 11 Jun 2019 19:42:32 +0000 (UTC) Received: from amt.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 18205614D9; Tue, 11 Jun 2019 19:42:30 +0000 (UTC) Received: from amt.cnet (localhost [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id C8BFC105157; Tue, 11 Jun 2019 16:42:15 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.7/8.14.7/Submit) id x5BJgFEK011943; Tue, 11 Jun 2019 16:42:15 -0300 Message-Id: <20190611194107.423384855@amt.cnet> User-Agent: quilt/0.60-1 Date: Tue, 11 Jun 2019 16:40:57 -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 , linux-pm@vger.kernel.org, Marcelo Tosatti Subject: [patch 3/3] cpuidle-haltpoll: disable host side polling when kvm virtualized References: <20190611194054.878923294@amt.cnet> Content-Disposition: inline; filename=03-pollcontrol-guest.patch X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 11 Jun 2019 19:42:33 +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 --- arch/x86/Kconfig | 7 +++++ arch/x86/include/asm/cpuidle_haltpoll.h | 8 ++++++ arch/x86/kernel/kvm.c | 42 ++++++++++++++++++++++++++++++++ drivers/cpuidle/cpuidle-haltpoll.c | 9 ++++++ include/linux/cpuidle_haltpoll.h | 16 ++++++++++++ 5 files changed, 81 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 2019-06-11 16:05:13.024705702 -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 2019-06-11 16:04:02.000000000 -0300 +++ linux-2.6.git/drivers/cpuidle/cpuidle-haltpoll.c 2019-06-11 16:05:41.711274798 -0300 @@ -15,6 +15,7 @@ #include #include #include +#include static unsigned int guest_halt_poll_ns __read_mostly = 200000; module_param(guest_halt_poll_ns, uint, 0644); @@ -130,11 +131,17 @@ 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 2019-06-11 16:05:13.025705722 -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 2019-06-11 15:53:31.000000000 -0300 +++ linux-2.6.git/arch/x86/Kconfig 2019-06-11 16:05:13.026705742 -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 2019-06-11 15:53:31.000000000 -0300 +++ linux-2.6.git/arch/x86/kernel/kvm.c 2019-06-11 16:05:13.026705742 -0300 @@ -853,3 +853,45 @@ } #endif /* CONFIG_PARAVIRT_SPINLOCKS */ + +#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL + +static void kvm_disable_host_haltpoll(void *i) +{ + wrmsrl(MSR_KVM_POLL_CONTROL, 0); +} + +static 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)) { + printk(KERN_ERR "kvm: host does not support poll control\n"); + printk(KERN_ERR "kvm: host upgrade recommended\n"); + return; + } + + preempt_disable(); + /* Enable 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(); + /* Enable 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