From patchwork Thu Mar 8 07:01:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Shunyong Yang X-Patchwork-Id: 10267081 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AD7E76016D for ; Thu, 8 Mar 2018 07:16:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8E2EA29721 for ; Thu, 8 Mar 2018 07:16:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 818C6297C0; Thu, 8 Mar 2018 07:16:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, T_DKIM_INVALID autolearn=no version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id C09DC29721 for ; Thu, 8 Mar 2018 07:16:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=mhGDmxYUbJhFa0hvFHt2FCOjZx7viMQiOOZXMDQjksM=; b=bjDt8eR9u/IjFC ZAVp9buQBBRJeBhWi+XY34oKMQ2HTyuliXhRWxz+yIf3Ck4RUMXv80jjlxGwphkXcxNsFVNdBPkeW 1/QRD589k15uNEwXNthuoNHjCv3vi1z1vyCi0TopC4DEKVci0EOOfCv8sgIK51rrpdUVpdL6WtDHN zllTxEHY92aXq8uYxnhBeFXX24zWVv1CaRFIMaEOds/XiLcBkRh7oLwVmkIuCOanoxmDuFGh4XOnw +KTIqpD4zBm2l5AP9xFy8eh/nEh/IX25tOoTJ1YEP1unv3t3wIybN0Ws54DJ9LJihkz11fPk3NcKg kgP2GpZ6JJZcDd7PBNjA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.89 #1 (Red Hat Linux)) id 1etpmh-0007zt-5x; Thu, 08 Mar 2018 07:16:15 +0000 Received: from [223.203.96.7] (helo=barracuda.hxt-semitech.com) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1etpma-0007yA-He for linux-arm-kernel@lists.infradead.org; Thu, 08 Mar 2018 07:16:12 +0000 X-ASG-Debug-ID: 1520492651-093b7e4ca910d00001-tbGyMd Received: from HXTBJIDCEMVIW01.hxtcorp.net ([10.128.0.14]) by barracuda.hxt-semitech.com with ESMTP id RSX4kDqpwnuBAGmB (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 08 Mar 2018 15:04:11 +0800 (CST) X-Barracuda-Envelope-From: shunyong.yang@hxt-semitech.com Received: from y.localdomain (10.5.21.109) by HXTBJIDCEMVIW01.hxtcorp.net (10.128.0.14) with Microsoft SMTP Server (TLS) id 15.0.847.32; Thu, 8 Mar 2018 15:04:10 +0800 From: Shunyong Yang To: Subject: [RFC PATCH] KVM: arm/arm64: vgic: change condition for level interrupt resampling Date: Thu, 8 Mar 2018 15:01:30 +0800 X-ASG-Orig-Subj: [RFC PATCH] KVM: arm/arm64: vgic: change condition for level interrupt resampling Message-ID: <1520492490-7943-1-git-send-email-shunyong.yang@hxt-semitech.com> X-Mailer: git-send-email 1.8.3.1 MIME-Version: 1.0 X-Originating-IP: [10.5.21.109] X-ClientProxiedBy: HXTBJIDCEMVIW01.hxtcorp.net (10.128.0.14) To HXTBJIDCEMVIW01.hxtcorp.net (10.128.0.14) X-Barracuda-Connect: UNKNOWN[10.128.0.14] X-Barracuda-Start-Time: 1520492651 X-Barracuda-Encrypted: ECDHE-RSA-AES256-SHA X-Barracuda-URL: https://192.168.50.101:443/cgi-mod/mark.cgi X-Virus-Scanned: by bsmtpd at hxt-semitech.com X-Barracuda-BRTS-Status: 1 X-Barracuda-Bayes: INNOCENT GLOBAL 0.7508 1.0000 1.7796 X-Barracuda-Spam-Score: 1.78 X-Barracuda-Spam-Status: No, SCORE=1.78 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.48719 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180307_231608_942113_A065458C X-CRM114-Status: GOOD ( 11.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Shunyong Yang , david.daney@cavium.com, marc.zyngier@arm.com, ard.biesheuvel@linaro.org, will.deacon@arm.com, linux-kernel@vger.kernel.org, Joey Zheng , eric.auger@redhat.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP When resampling irqfds is enabled, level interrupt should be de-asserted when resampling happens. On page 4-47 of GIC v3 specification IHI0069D, it said, "When the PE acknowledges an SGI, a PPI, or an SPI at the CPU interface, the IRI changes the status of the interrupt to active and pending if: • It is an edge-triggered interrupt, and another edge has been detected since the interrupt was acknowledged. • It is a level-sensitive interrupt, and the level has not been deasserted since the interrupt was acknowledged." GIC v2 specification IHI0048B.b has similar description on page 3-42 for state machine transition. When some VFIO device, like mtty(8250 VFIO mdev emulation driver in samples/vfio-mdev) triggers a level interrupt, the status transition in LR is pending-->active-->active and pending. Then it will wait resampling to de-assert the interrupt. Current design of lr_signals_eoi_mi() will return false if state in LR is not invalid(Inactive). It causes resampling will not happen in mtty case. This will cause interrupt fired continuously to guest even 8250 IIR has no interrupt. When 8250's interrupt is configured in shared mode, it will pass interrupt to other drivers to handle. However, there is no other driver involved. Then, a "nobody cared" kernel complaint occurs. / # cat /dev/ttyS0 [ 4.826836] random: crng init done [ 6.373620] irq 41: nobody cared (try booting with the "irqpoll" option) [ 6.376414] CPU: 0 PID: 1307 Comm: cat Not tainted 4.16.0-rc4 #4 [ 6.378927] Hardware name: linux,dummy-virt (DT) [ 6.380876] Call trace: [ 6.381937] dump_backtrace+0x0/0x180 [ 6.383495] show_stack+0x14/0x1c [ 6.384902] dump_stack+0x90/0xb4 [ 6.386312] __report_bad_irq+0x38/0xe0 [ 6.387944] note_interrupt+0x1f4/0x2b8 [ 6.389568] handle_irq_event_percpu+0x54/0x7c [ 6.391433] handle_irq_event+0x44/0x74 [ 6.393056] handle_fasteoi_irq+0x9c/0x154 [ 6.394784] generic_handle_irq+0x24/0x38 [ 6.396483] __handle_domain_irq+0x60/0xb4 [ 6.398207] gic_handle_irq+0x98/0x1b0 [ 6.399796] el1_irq+0xb0/0x128 [ 6.401138] _raw_spin_unlock_irqrestore+0x18/0x40 [ 6.403149] __setup_irq+0x41c/0x678 [ 6.404669] request_threaded_irq+0xe0/0x190 [ 6.406474] univ8250_setup_irq+0x208/0x234 [ 6.408250] serial8250_do_startup+0x1b4/0x754 [ 6.410123] serial8250_startup+0x20/0x28 [ 6.411826] uart_startup.part.21+0x78/0x144 [ 6.413633] uart_port_activate+0x50/0x68 [ 6.415328] tty_port_open+0x84/0xd4 [ 6.416851] uart_open+0x34/0x44 [ 6.418229] tty_open+0xec/0x3c8 [ 6.419610] chrdev_open+0xb0/0x198 [ 6.421093] do_dentry_open+0x200/0x310 [ 6.422714] vfs_open+0x54/0x84 [ 6.424054] path_openat+0x2dc/0xf04 [ 6.425569] do_filp_open+0x68/0xd8 [ 6.427044] do_sys_open+0x16c/0x224 [ 6.428563] SyS_openat+0x10/0x18 [ 6.429972] el0_svc_naked+0x30/0x34 [ 6.431494] handlers: [ 6.432479] [<000000000e9fb4bb>] serial8250_interrupt [ 6.434597] Disabling IRQ #41 This patch changes the lr state condition in lr_signals_eoi_mi() from invalid(Inactive) to active and pending to avoid this. I am not sure about the original design of the condition of invalid(active). So, This RFC is sent out for comments. Cc: Joey Zheng Signed-off-by: Shunyong Yang --- virt/kvm/arm/vgic/vgic-v2.c | 4 ++-- virt/kvm/arm/vgic/vgic-v3.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c index e9d840a75e7b..740ee9a5f551 100644 --- a/virt/kvm/arm/vgic/vgic-v2.c +++ b/virt/kvm/arm/vgic/vgic-v2.c @@ -46,8 +46,8 @@ void vgic_v2_set_underflow(struct kvm_vcpu *vcpu) static bool lr_signals_eoi_mi(u32 lr_val) { - return !(lr_val & GICH_LR_STATE) && (lr_val & GICH_LR_EOI) && - !(lr_val & GICH_LR_HW); + return !((lr_val & GICH_LR_STATE) ^ GICH_LR_STATE) && + (lr_val & GICH_LR_EOI) && !(lr_val & GICH_LR_HW); } /* diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c index 6b329414e57a..43111bba7af9 100644 --- a/virt/kvm/arm/vgic/vgic-v3.c +++ b/virt/kvm/arm/vgic/vgic-v3.c @@ -35,8 +35,8 @@ void vgic_v3_set_underflow(struct kvm_vcpu *vcpu) static bool lr_signals_eoi_mi(u64 lr_val) { - return !(lr_val & ICH_LR_STATE) && (lr_val & ICH_LR_EOI) && - !(lr_val & ICH_LR_HW); + return !((lr_val & ICH_LR_STATE) ^ ICH_LR_STATE) && + (lr_val & ICH_LR_EOI) && !(lr_val & ICH_LR_HW); } void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)