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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS 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 6652DC43381 for ; Fri, 29 Mar 2019 01:19:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D0E12183E for ; Fri, 29 Mar 2019 01:19:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728643AbfC2BTe (ORCPT ); Thu, 28 Mar 2019 21:19:34 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:5198 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727668AbfC2BTe (ORCPT ); Thu, 28 Mar 2019 21:19:34 -0400 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 20DFAD095CD29989F7E6; Fri, 29 Mar 2019 09:19:32 +0800 (CST) Received: from [127.0.0.1] (10.177.31.55) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.408.0; Fri, 29 Mar 2019 09:19:23 +0800 Subject: Re: Unexpected interrupt received in Guest OS when booting after "system_reset" To: Marc Zyngier , Christoffer Dall References: <9a6ece7e-9984-dc9e-8fa2-df9736393dd2@arm.com> CC: , , , wanghaibin 00208455 From: Heyi Guo Message-ID: <9694b5f2-80bd-b85c-8fc5-bd1d917e1b33@huawei.com> Date: Fri, 29 Mar 2019 09:19:22 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <9a6ece7e-9984-dc9e-8fa2-df9736393dd2@arm.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.31.55] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/3/29 1:18, Marc Zyngier wrote: > [Please do not send HTML emails] Sorry; will keep in mind next time :) > > On 28/03/2019 15:44, Heyi Guo wrote: >> Hi Marc and Christoffer, >> >> When we issue "system_reset" from qemu monitor to a running VM, guest >> Linux will occasionally get "Unexpected interrupt" after rebooting, with >> kernel message at the bottom. >> >> After some investigation, we found it might be caused by the >> preservation of virtual LPI during system reset: it seems the virtual >> LPI remains in the ap_list during VM reset, as well as its "enabled" and >> "pending_latch" status, and this causes the virtual LPI to be injected >> wrongly after VCPU reboots and enables interrupt. >> >> We propose to clear "enabled" flag of virtual LPI when PROPBASER (or >> GICR_CTRL) of virtual GICR is written to 0, and update virtual LPI >> properties when GICR_CTRL.enableLPIs is set to 1 again. >> >> Any advice? Or did we miss something? > We're clearly missing a trick here, but I'm not convinced of your > approach. To be honest, we were not fully convinced by ourselves either. I was worrying about guest switching GICR_CTRL or GICR_PROPBASER at runtime which probably causes issue for our rough approach. > What should happend is that the redistributors should be reset > as well, and that this should recall any LPI that has been made pending. > Unfortunately, we don't seem to have such code in place, which is > embarrassing. > > Can you give the following, untested patch a go? It isn't right either, > but it should have the right effect. If you confirm that it solves your > problem, we can look at adding the right hooks... Thanks, I'll test this and get back to you. Heyi > Thanks, > > M. > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index ab3f47745d9c..bd9a9250f323 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -2403,8 +2403,32 @@ static int vgic_its_commit_v0(struct vgic_its *its) > return 0; > } > > +static void vgic_nuke_pending_lpis(struct kvm_vcpu *vcpu) > +{ > + struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; > + struct vgic_irq *irq, *tmp; > + unsigned long flags; > + > + raw_spin_lock_irqsave(&vcpu->arch.vgic_cpu.ap_list_lock, flags); > + > + list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) { > + if (irq->intid >= VGIC_MIN_LPI) { > + list_del(&irq->ap_list); > + vgic_put_irq(vcpu->kvm, irq); > + } > + } > + > + raw_spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags); > +} > + > static void vgic_its_reset(struct kvm *kvm, struct vgic_its *its) > { > + struct kvm_vcpu *vcpu; > + int c; > + > + kvm_for_each_vcpu(c, vcpu, kvm) > + vgic_nuke_pending_lpis(vcpu); > + > /* We need to keep the ABI specific field values */ > its->baser_coll_table &= ~GITS_BASER_VALID; > its->baser_device_table &= ~GITS_BASER_VALID; >