Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755664AbaGQJOF (ORCPT ); Thu, 17 Jul 2014 05:14:05 -0400 Received: from mga14.intel.com ([192.55.52.115]:40733 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754507AbaGQJOB convert rfc822-to-8bit (ORCPT ); Thu, 17 Jul 2014 05:14:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,676,1400050800"; d="scan'208";a="563115092" From: "Zhang, Yang Z" To: Paolo Bonzini , Wanpeng Li , Jan Kiszka CC: Marcelo Tosatti , Gleb Natapov , Bandan Das , "Hu, Robert" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH 2/3] KVM: nVMX: Fix fail to get nested ack intr's vector during nested vmexit Thread-Topic: [PATCH 2/3] KVM: nVMX: Fix fail to get nested ack intr's vector during nested vmexit Thread-Index: AQHPoZw7RcQZK/akI06lbOFGhVZ6iZuj+mTA Date: Thu, 17 Jul 2014 09:13:56 +0000 Message-ID: References: <1405573011-41330-1-git-send-email-wanpeng.li@linux.intel.com> <1405573011-41330-2-git-send-email-wanpeng.li@linux.intel.com> <53C78E37.5090807@redhat.com> In-Reply-To: <53C78E37.5090807@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paolo Bonzini wrote on 2014-07-17: > Il 17/07/2014 06:56, Wanpeng Li ha scritto: >> && nested_exit_intr_ack_set(vcpu)) { >> int irq = kvm_cpu_get_interrupt(vcpu); >> + >> + if (irq < 0 && kvm_apic_vid_enabled(vcpu->kvm)) >> + irq = kvm_get_apic_interrupt(vcpu); > > There's something weird in this patch. If you "inline" > kvm_cpu_get_interrupt, what you get is this: > > int irq; > /* Beginning of kvm_cpu_get_interrupt... */ > if (!irqchip_in_kernel(v->kvm)) > irq = v->arch.interrupt.nr; > else { > irq = kvm_cpu_get_extint(v); /* PIC */ > if (!kvm_apic_vid_enabled(v->kvm) && irq == -1) > irq = kvm_get_apic_interrupt(v); /* APIC */ > } > > /* kvm_cpu_get_interrupt done. */ > if (irq < 0 && kvm_apic_vid_enabled(vcpu->kvm)) > irq = kvm_get_apic_interrupt(vcpu); > > There are just two callers of kvm_cpu_get_interrupt, and the other is > protected by kvm_cpu_has_injectable_intr so it won't be executed if > virtual interrupt delivery is enabled. So you patch is effectively the same as this: > > diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c index > bd0da43..a1ec6a5 100644 --- a/arch/x86/kvm/irq.c +++ > b/arch/x86/kvm/irq.c @@ -108,7 +108,7 @@ int > kvm_cpu_get_interrupt(struct kvm_vcpu *v) > > vector = kvm_cpu_get_extint(v); > - if (kvm_apic_vid_enabled(v->kvm) || vector != -1) > + if (vector != -1) > return vector; /* PIC */ > > return kvm_get_apic_interrupt(v); /* APIC */ > But in kvm_get_apic_interrupt I have just added this comment: > > /* Note that we never get here with APIC virtualization > * enabled. */ > > because kvm_get_apic_interrupt calls apic_set_isr, and apic_set_isr > must never be called with APIC virtualization enabled either. With > APIC virtualization enabled, isr_count is always 1, and > highest_isr_cache is always -1, and apic_set_isr breaks both of these invariants. > You are right. kvm_lapic_find_highest_irr should be the right one. > Paolo Best regards, Yang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/