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=-9.3 required=3.0 tests=DATE_IN_PAST_12_24, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT 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 AC794C35280 for ; Mon, 30 Sep 2019 12:18:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 76DDA218AC for ; Mon, 30 Sep 2019 12:18:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="sBs8dYRs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730803AbfI3MSY (ORCPT ); Mon, 30 Sep 2019 08:18:24 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:45316 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730350AbfI3MSX (ORCPT ); Mon, 30 Sep 2019 08:18:23 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x8UC8lFD186153; Mon, 30 Sep 2019 12:16:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2019-08-05; bh=ok7TwckJtagMaTdSnPLHiT1FwV6KoE8abg0uZFfBZOg=; b=sBs8dYRsEv+nvg0WQV7EHqa4qRzaYsTdya87rOdvIgz+nWTixBsisLisrQNMp/SMLFVE 3y6uMMCDpD+pxS/5ik5BtI+3nsia283zURAC4N8agXBmaBf4pvSzQE/fhldronXOVcXg YZyLQDzEr+WRLYyHUFWhb1vN5IzynQDKmyKQxSnSZn73cHiLr/khEcdbAG82g0bVKrCe ijynTO+ofODHNBCGh7wSg7t1vItRi6mTctwLZ1Ue2JFnytbHfPAwRCrcc9Lagm7e1APr SDcnCiTF5S0Jv6RF5qWwca+jd6x9ztl0xRiYad/Q6DM6g4KnxC/IohHV38Ty3C+CohF0 aA== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 2va05reny9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 30 Sep 2019 12:16:36 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x8UC8sKj152652; Mon, 30 Sep 2019 12:16:35 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 2vahngjd9c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 30 Sep 2019 12:16:35 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x8UCGUaX023518; Mon, 30 Sep 2019 12:16:30 GMT Received: from z2.cn.oracle.com (/10.182.71.205) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 30 Sep 2019 05:16:29 -0700 From: Zhenzhong Duan To: linux-kernel@vger.kernel.org Cc: Zhenzhong Duan , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Paolo Bonzini , Radim Krcmar , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Peter Zijlstra , Will Deacon Subject: [PATCH 1/3] KVM: X86: Add "nopvspin" parameter to disable PV spinlocks Date: Sun, 29 Sep 2019 20:21:04 +0800 Message-Id: <1569759666-26904-2-git-send-email-zhenzhong.duan@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1569759666-26904-1-git-send-email-zhenzhong.duan@oracle.com> References: <1569759666-26904-1-git-send-email-zhenzhong.duan@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9395 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1909300130 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9395 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1909300130 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are cases where a guest tries to switch spinlocks to bare metal behavior (e.g. by setting "xen_nopvspin" on XEN platform and "hv_nopvspin" on HYPER_V). That feature is missed on KVM, add a new parameter "nopvspin" to disable PV spinlocks for KVM guest. This new parameter is also intended to replace "xen_nopvspin" and "hv_nopvspin" in the future. The global variable pvspin isn't defined as __initdata as it's used at runtime by XEN guest. Refactor the print stuff with pr_* which is preferred. Signed-off-by: Zhenzhong Duan Cc: Jonathan Corbet Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Paolo Bonzini Cc: Radim Krcmar Cc: Sean Christopherson Cc: Vitaly Kuznetsov Cc: Wanpeng Li Cc: Jim Mattson Cc: Joerg Roedel Cc: Peter Zijlstra Cc: Will Deacon --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ arch/x86/include/asm/qspinlock.h | 1 + arch/x86/kernel/kvm.c | 27 ++++++++++++++++--------- kernel/locking/qspinlock.c | 7 +++++++ 4 files changed, 30 insertions(+), 9 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c7ac2f3..4b956d8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5330,6 +5330,10 @@ as generic guest with no PV drivers. Currently support XEN HVM, KVM, HYPER_V and VMWARE guest. + nopvspin [X86,KVM] Disables the qspinlock slow path + using PV optimizations which allow the hypervisor to + 'idle' the guest on lock contention. + xirc2ps_cs= [NET,PCMCIA] Format: ,,,,,[,[,[,]]] diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h index 444d6fd..34a4484 100644 --- a/arch/x86/include/asm/qspinlock.h +++ b/arch/x86/include/asm/qspinlock.h @@ -32,6 +32,7 @@ static __always_inline u32 queued_fetch_set_pending_acquire(struct qspinlock *lo extern void __pv_init_lock_hash(void); extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val); extern void __raw_callee_save___pv_queued_spin_unlock(struct qspinlock *lock); +extern bool pvspin; #define queued_spin_unlock queued_spin_unlock /** diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index e820568..7b8cf0d 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -7,6 +7,8 @@ * Authors: Anthony Liguori */ +#define pr_fmt(fmt) "KVM: " fmt + #include #include #include @@ -286,7 +288,7 @@ static void kvm_register_steal_time(void) return; wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED)); - pr_info("kvm-stealtime: cpu %d, msr %llx\n", + pr_info("stealtime: cpu %d, msr %llx\n", cpu, (unsigned long long) slow_virt_to_phys(st)); } @@ -321,7 +323,7 @@ static void kvm_guest_cpu_init(void) wrmsrl(MSR_KVM_ASYNC_PF_EN, pa); __this_cpu_write(apf_reason.enabled, 1); - printk(KERN_INFO"KVM setup async PF for cpu %d\n", + pr_info("setup async PF for cpu %d\n", smp_processor_id()); } @@ -347,7 +349,7 @@ static void kvm_pv_disable_apf(void) wrmsrl(MSR_KVM_ASYNC_PF_EN, 0); __this_cpu_write(apf_reason.enabled, 0); - printk(KERN_INFO"Unregister pv shared memory for cpu %d\n", + pr_info("Unregister pv shared memory for cpu %d\n", smp_processor_id()); } @@ -509,7 +511,7 @@ static void kvm_setup_pv_ipi(void) { apic->send_IPI_mask = kvm_send_ipi_mask; apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself; - pr_info("KVM setup pv IPIs\n"); + pr_info("setup pv IPIs\n"); } static void kvm_smp_send_call_func_ipi(const struct cpumask *mask) @@ -639,11 +641,11 @@ static void __init kvm_guest_init(void) !kvm_para_has_hint(KVM_HINTS_REALTIME) && kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) { smp_ops.send_call_func_ipi = kvm_smp_send_call_func_ipi; - pr_info("KVM setup pv sched yield\n"); + pr_info("setup pv sched yield\n"); } if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online", kvm_cpu_online, kvm_cpu_down_prepare) < 0) - pr_err("kvm_guest: Failed to install cpu hotplug callbacks\n"); + pr_err("failed to install cpu hotplug callbacks\n"); #else sev_map_percpu_data(); kvm_guest_cpu_init(); @@ -746,7 +748,7 @@ static __init int kvm_setup_pv_tlb_flush(void) zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, cpu), GFP_KERNEL, cpu_to_node(cpu)); } - pr_info("KVM setup pv remote TLB flush\n"); + pr_info("setup pv remote TLB flush\n"); } return 0; @@ -842,6 +844,13 @@ void __init kvm_spinlock_init(void) if (num_possible_cpus() == 1) return; + if (!pvspin) { + pr_info("PV spinlocks disabled\n"); + static_branch_disable(&virt_spin_lock_key); + return; + } + pr_info("PV spinlocks enabled\n"); + __pv_init_lock_hash(); pv_ops.lock.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath; pv_ops.lock.queued_spin_unlock = @@ -872,8 +881,8 @@ static void kvm_enable_host_haltpoll(void *i) void arch_haltpoll_enable(unsigned int cpu) { if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) { - pr_err_once("kvm: host does not support poll control\n"); - pr_err_once("kvm: host upgrade recommended\n"); + pr_err_once("host does not support poll control\n"); + pr_err_once("host upgrade recommended\n"); return; } diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 2473f10..945b510 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -580,4 +580,11 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) #include "qspinlock_paravirt.h" #include "qspinlock.c" +bool pvspin = true; +static __init int parse_nopvspin(char *arg) +{ + pvspin = false; + return 0; +} +early_param("nopvspin", parse_nopvspin); #endif -- 1.8.3.1