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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 4C904C433E6 for ; Thu, 11 Mar 2021 12:33:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F24E864FE7 for ; Thu, 11 Mar 2021 12:33:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233239AbhCKMco (ORCPT ); Thu, 11 Mar 2021 07:32:44 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:13594 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232730AbhCKMcU (ORCPT ); Thu, 11 Mar 2021 07:32:20 -0500 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4Dx7ZX3jllz16Hkl; Thu, 11 Mar 2021 20:30:28 +0800 (CST) Received: from [10.174.184.135] (10.174.184.135) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.498.0; Thu, 11 Mar 2021 20:32:07 +0800 Subject: Re: [PATCH v3 3/4] KVM: arm64: GICv4.1: Restore VLPI's pending state to physical side To: Marc Zyngier CC: Eric Auger , Will Deacon , , , , , Alex Williamson , Cornelia Huck , "Lorenzo Pieralisi" , , References: <20210127121337.1092-1-lushenming@huawei.com> <20210127121337.1092-4-lushenming@huawei.com> <87tupif3x3.wl-maz@kernel.org> From: Shenming Lu Message-ID: <0820f429-4c29-acd6-d9e0-af9f6deb68e4@huawei.com> Date: Thu, 11 Mar 2021 20:32:07 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.2.2 MIME-Version: 1.0 In-Reply-To: <87tupif3x3.wl-maz@kernel.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.184.135] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/3/11 17:14, Marc Zyngier wrote: > On Wed, 27 Jan 2021 12:13:36 +0000, > Shenming Lu wrote: >> >> From: Zenghui Yu >> >> When setting the forwarding path of a VLPI (switch to the HW mode), >> we could also transfer the pending state from irq->pending_latch to >> VPT (especially in migration, the pending states of VLPIs are restored >> into kvm’s vgic first). And we currently send "INT+VSYNC" to trigger >> a VLPI to pending. >> >> Signed-off-by: Zenghui Yu >> Signed-off-by: Shenming Lu >> --- >> arch/arm64/kvm/vgic/vgic-v4.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c >> index ac029ba3d337..a3542af6f04a 100644 >> --- a/arch/arm64/kvm/vgic/vgic-v4.c >> +++ b/arch/arm64/kvm/vgic/vgic-v4.c >> @@ -449,6 +449,20 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq, >> irq->host_irq = virq; >> atomic_inc(&map.vpe->vlpi_count); >> >> + /* Transfer pending state */ >> + if (irq->pending_latch) { >> + ret = irq_set_irqchip_state(irq->host_irq, >> + IRQCHIP_STATE_PENDING, >> + irq->pending_latch); >> + WARN_RATELIMIT(ret, "IRQ %d", irq->host_irq); >> + >> + /* >> + * Let it be pruned from ap_list later and don't bother >> + * the List Register. >> + */ >> + irq->pending_latch = false; > > NAK. If the interrupt is on the AP list, it must be pruned from it > *immediately*. The only case where it can be !pending and still on the > AP list is in interval between sync and prune. If we start messing > with this, we can't reason about the state of this list anymore. > > Consider calling vgic_queue_irq_unlock() here. Thanks for giving a hint, but it seems that vgic_queue_irq_unlock() only queues an IRQ after checking, did you mean vgic_prune_ap_list() instead? Thanks a lot for the comments! :-) Shenming > > Thanks, > > M. >