From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v2] KVM: x86: Inject pending interrupt even if pending nmi exist Date: Wed, 23 Mar 2016 14:18:31 +0100 Message-ID: <56F297A7.1030309@redhat.com> References: <7CC7D3013F4B10479273CE019E6A8C7A3ED90C@BPXM15GP.gisp.nec.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 8bit Cc: "kvm@vger.kernel.org" , Jan Kiszka , Nobuo Yoshida To: Yuki Shibuya Return-path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:34000 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754652AbcCWNSf (ORCPT ); Wed, 23 Mar 2016 09:18:35 -0400 Received: by mail-wm0-f65.google.com with SMTP id p65so4271971wmp.1 for ; Wed, 23 Mar 2016 06:18:34 -0700 (PDT) In-Reply-To: <7CC7D3013F4B10479273CE019E6A8C7A3ED90C@BPXM15GP.gisp.nec.co.jp> Sender: kvm-owner@vger.kernel.org List-ID: On 23/03/2016 06:08, Yuki Shibuya wrote: > + /* If nmi pending > 0 and injectable interrupts exist, > + * nmi pending counter is cleared to prevent skipping > + * injectable pending interrupts. > + */ > + if (vcpu->arch.nmi_pending && kvm_cpu_has_injectable_intr(vcpu) > + && kvm_x86_ops->interrupt_allowed(vcpu)) > + vcpu->arch.nmi_pending = 0; I am not sure I understand this. Why is it safe to drop nmi_pending? Can we instead do something like this in vcpu_enter_guest? It would be nice to have a testcase for this in kvm-unit-tests. Paolo diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7236bd3a4c3d..6c73cbc8e19a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6561,10 +6561,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (inject_pending_event(vcpu, req_int_win) != 0) req_immediate_exit = true; /* enable NMI/IRQ window open exits if needed */ - else if (vcpu->arch.nmi_pending) - kvm_x86_ops->enable_nmi_window(vcpu); - else if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win) - kvm_x86_ops->enable_irq_window(vcpu); + else { + if (vcpu->arch.nmi_pending) + kvm_x86_ops->enable_nmi_window(vcpu); + if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win) + kvm_x86_ops->enable_irq_window(vcpu); + } if (kvm_lapic_enabled(vcpu)) { update_cr8_intercept(vcpu); Paolo