From patchwork Tue Mar 3 00:14:05 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 9613 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n230FrqB017207 for ; Tue, 3 Mar 2009 00:15:54 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759289AbZCCAPY (ORCPT ); Mon, 2 Mar 2009 19:15:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759313AbZCCAPX (ORCPT ); Mon, 2 Mar 2009 19:15:23 -0500 Received: from mx2.redhat.com ([66.187.237.31]:45128 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759117AbZCCAPU (ORCPT ); Mon, 2 Mar 2009 19:15:20 -0500 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n230F3oZ025989; Mon, 2 Mar 2009 19:15:03 -0500 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n230F3Un012726; Mon, 2 Mar 2009 19:15:03 -0500 Received: from amt.cnet (vpn-10-58.str.redhat.com [10.32.10.58]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n230Evek004856; Mon, 2 Mar 2009 19:15:01 -0500 Received: from amt.cnet (amt.cnet [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id EADF368021E; Mon, 2 Mar 2009 21:14:13 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.3/8.14.3/Submit) id n230E5LK006282; Mon, 2 Mar 2009 21:14:05 -0300 Date: Mon, 2 Mar 2009 21:14:05 -0300 From: Marcelo Tosatti To: kvm@vger.kernel.org Cc: Gleb Natapov , Ingo Molnar , Peter Zijlstra Subject: KVM: x86: use smp_send_reschedule in kvm_vcpu_kick Message-ID: <20090303001405.GA5889@amt.cnet> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM uses a function call IPI to cause the exit of a guest running on a physical cpu. For virtual interrupt notification there is no need to wait on IPI receival, or to execute any function. This is exactly what the reschedule IPI does, without the overhead of function IPI. So use it instead of smp_call_function_single in kvm_vcpu_kick. Also change the "guest_mode" variable to a bit in vcpu->requests, and use that to collapse multiple IPI's that would be issued between the first one and zeroing of guest mode. This allows kvm_vcpu_kick to called from interrupt context. --- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b556b6a..c68168c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3133,6 +3133,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) local_irq_disable(); + clear_bit(KVM_REQ_KICK, &vcpu->requests); + smp_mb__after_clear_bit(); + if (vcpu->requests || need_resched() || signal_pending(current)) { local_irq_enable(); preempt_enable(); @@ -3140,13 +3143,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) goto out; } - vcpu->guest_mode = 1; - /* - * Make sure that guest_mode assignment won't happen after - * testing the pending IRQ vector bitmap. - */ - smp_wmb(); - if (vcpu->arch.exception.pending) __queue_exception(vcpu); else if (irqchip_in_kernel(vcpu->kvm)) @@ -3188,7 +3184,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) set_debugreg(vcpu->arch.host_dr6, 6); set_debugreg(vcpu->arch.host_dr7, 7); - vcpu->guest_mode = 0; + set_bit(KVM_REQ_KICK, &vcpu->requests); local_irq_enable(); ++vcpu->stat.exits; @@ -4429,28 +4425,19 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) || vcpu->arch.nmi_pending; } -static void vcpu_kick_intr(void *info) -{ -#ifdef DEBUG - struct kvm_vcpu *vcpu = (struct kvm_vcpu *)info; - printk(KERN_DEBUG "vcpu_kick_intr %p \n", vcpu); -#endif -} - void kvm_vcpu_kick(struct kvm_vcpu *vcpu) { - int ipi_pcpu = vcpu->cpu; - int cpu = get_cpu(); + int me = get_cpu(); + int cpu = vcpu->cpu; if (waitqueue_active(&vcpu->wq)) { wake_up_interruptible(&vcpu->wq); ++vcpu->stat.halt_wakeup; } - /* - * We may be called synchronously with irqs disabled in guest mode, - * So need not to call smp_call_function_single() in that case. - */ - if (vcpu->guest_mode && vcpu->cpu != cpu) - smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0); + + if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) + if (!test_and_set_bit(KVM_REQ_KICK, &vcpu->requests)) + smp_send_reschedule(cpu); + put_cpu(); } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 3832243..ef7c239 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -38,6 +38,7 @@ #define KVM_REQ_UNHALT 6 #define KVM_REQ_MMU_SYNC 7 #define KVM_REQ_KVMCLOCK_UPDATE 8 +#define KVM_REQ_KICK 9 #define KVM_USERSPACE_IRQ_SOURCE_ID 0 @@ -72,7 +73,6 @@ struct kvm_vcpu { struct mutex mutex; int cpu; struct kvm_run *run; - int guest_mode; unsigned long requests; unsigned long guest_debug; int fpu_active;