From patchwork Wed Jan 12 07:40:31 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 473171 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p0C8XI2n022364 for ; Wed, 12 Jan 2011 08:33:45 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932074Ab1ALHkf (ORCPT ); Wed, 12 Jan 2011 02:40:35 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:60200 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755730Ab1ALHkd (ORCPT ); Wed, 12 Jan 2011 02:40:33 -0500 Received: from tang.cn.fujitsu.com (tang.cn.fujitsu.com [10.167.250.3]) by song.cn.fujitsu.com (Postfix) with ESMTP id 0B46717003F; Wed, 12 Jan 2011 15:40:30 +0800 (CST) Received: from mailserver.fnst.cn.fujitus.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id p0C7ZJt6000618; Wed, 12 Jan 2011 15:35:19 +0800 Received: from eric.localdomain ([10.167.225.99]) by mailserver.fnst.cn.fujitus.com (Lotus Domino Release 8.5.1FP4) with ESMTP id 2011011215400448-151494 ; Wed, 12 Jan 2011 15:40:04 +0800 Message-ID: <4D2D5AEF.1070006@cn.fujitsu.com> Date: Wed, 12 Jan 2011 15:40:31 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Thunderbird/3.1.7 MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , LKML , KVM Subject: [PATCH v3 2/3] KVM: send IPI to vcpu only when it's in guest mode References: <4D2D5AA6.9080804@cn.fujitsu.com> In-Reply-To: <4D2D5AA6.9080804@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-01-12 15:40:04, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-01-12 15:40:04, Serialize complete at 2011-01-12 15:40:04 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Wed, 12 Jan 2011 08:33:45 +0000 (UTC) diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c index 70d224d..8213efe 100644 --- a/arch/ia64/kvm/kvm-ia64.c +++ b/arch/ia64/kvm/kvm-ia64.c @@ -662,6 +662,7 @@ again: goto vcpu_run_fail; srcu_read_unlock(&vcpu->kvm->srcu, idx); + vcpu->mode = IN_GUEST_MODE; kvm_guest_enter(); /* @@ -683,6 +684,7 @@ again: */ barrier(); kvm_guest_exit(); + vcpu->mode = OUTSIDE_GUEST_MODE; preempt_enable(); idx = srcu_read_lock(&vcpu->kvm->srcu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0b77e9c..434363e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5213,14 +5213,18 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_load_guest_fpu(vcpu); kvm_load_guest_xcr0(vcpu); - atomic_set(&vcpu->guest_mode, 1); - smp_wmb(); + vcpu->mode = IN_GUEST_MODE; + + /* We should set ->mode before check ->requests, + * see the comment in make_all_cpus_request. + */ + smp_mb(); local_irq_disable(); - if (!atomic_read(&vcpu->guest_mode) || vcpu->requests + if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests || need_resched() || signal_pending(current)) { - atomic_set(&vcpu->guest_mode, 0); + vcpu->mode = OUTSIDE_GUEST_MODE; smp_wmb(); local_irq_enable(); preempt_enable(); @@ -5256,7 +5260,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_get_msr(vcpu, MSR_IA32_TSC, &vcpu->arch.last_guest_tsc); - atomic_set(&vcpu->guest_mode, 0); + vcpu->mode = OUTSIDE_GUEST_MODE; smp_wmb(); local_irq_enable(); @@ -6157,7 +6161,7 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu) me = get_cpu(); if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) - if (atomic_xchg(&vcpu->guest_mode, 0)) + if (kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE) smp_send_reschedule(cpu); put_cpu(); } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index b5021db..b99eacd 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -98,19 +98,26 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #endif +enum { + OUTSIDE_GUEST_MODE, + IN_GUEST_MODE, + EXITING_GUEST_MODE +}; + struct kvm_vcpu { struct kvm *kvm; #ifdef CONFIG_PREEMPT_NOTIFIERS struct preempt_notifier preempt_notifier; #endif + int cpu; int vcpu_id; - struct mutex mutex; - int cpu; - atomic_t guest_mode; - struct kvm_run *run; + int srcu_idx; + int mode; unsigned long requests; unsigned long guest_debug; - int srcu_idx; + + struct mutex mutex; + struct kvm_run *run; int fpu_active; int guest_fpu_loaded, guest_xcr0_loaded; @@ -140,6 +147,11 @@ struct kvm_vcpu { struct kvm_vcpu_arch arch; }; +static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu) +{ + return cmpxchg(&vcpu->mode, IN_GUEST_MODE, EXITING_GUEST_MODE); +} + /* * Some of the bitops functions do not support too long bitmaps. * This number must be determined not to exceed such limits. diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index b1b6cbb..71a4eaf 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -153,7 +153,12 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req) if (kvm_make_check_request(req, vcpu)) continue; cpu = vcpu->cpu; - if (cpus != NULL && cpu != -1 && cpu != me) + + /* Set ->requests bit before we read ->mode */ + smp_mb(); + + if (cpus != NULL && cpu != -1 && cpu != me && + kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE) cpumask_set_cpu(cpu, cpus); } if (unlikely(cpus == NULL))