From patchwork Wed Mar 1 22:15:43 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Stabellini X-Patchwork-Id: 9599153 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 2590B60414 for ; Wed, 1 Mar 2017 22:17:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1762727F90 for ; Wed, 1 Mar 2017 22:17:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0BCAE284E7; Wed, 1 Mar 2017 22:17:49 +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=-3.7 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RCVD_IN_SORBS_SPAM autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9D2AD27F90 for ; Wed, 1 Mar 2017 22:17:48 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cjCXI-00035X-D7; Wed, 01 Mar 2017 22:15:52 +0000 Received: from mail6.bemta6.messagelabs.com ([193.109.254.103]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cjCXH-00035I-AO for xen-devel@lists.xenproject.org; Wed, 01 Mar 2017 22:15:51 +0000 Received: from [85.158.143.35] by server-2.bemta-6.messagelabs.com id 22/5A-19731-61847B85; Wed, 01 Mar 2017 22:15:50 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrNLMWRWlGSWpSXmKPExsVybKJsh66Yx/Y Ig9vTmSy+b5nM5MDocfjDFZYAxijWzLyk/IoE1oyJrfPYC15wVmzsWM3ewHicvYuRi0NIYCqj xJrtB1ggnINMEo/u7QFyODnYBAwl/j7ZxAZiiwhISGxqWMEEYjMLWEvce/ODHcQWFgiRWDv5E pjNIqAqMbX1OJjNK+AmsWf/P1YQW0JATuLksclgNqeAj8T3w81gc4QEvCXW/X3NBlGTITGvZw 5UvZfEohuXoGw1iavnNjFPYORbwMiwilGjOLWoLLVI18hML6koMz2jJDcxM0fX0MBMLze1uDg xPTUnMalYLzk/dxMjMFAYgGAH45kFgYcYJTmYlER5d6/aFiHEl5SfUpmRWJwRX1Sak1p8iFGG g0NJgjfQfXuEkGBRanpqRVpmDjBkYdISHDxKIrzXXYHSvMUFibnFmekQqVOMilLivLfdgBICI ImM0jy4NlicXGKUlRLmZQQ6RIinILUoN7MEVf4VozgHo5IwrzLIdp7MvBK46a+AFjMBLX6hsh VkcUkiQkqqgbGo7v2nPl3dpOYkxf+1W6T6RXXXxd+TVljWuzU5/MEWcymvW4595ZffBB6a2vn B0fXGsUOlnLsNY+Lvxot/esVr81AqoGnGFbXGqu6sohCvhxIrpU+HzFwfz9STZJCvri5ULmQh un3f9ZojASua2/bse6f34578sgdzhK7tOt2yYdI0njUOMUosxRmJhlrMRcWJADvwIS+OAgAA X-Env-Sender: sstabellini@kernel.org X-Msg-Ref: server-13.tower-21.messagelabs.com!1488406548!54315744!1 X-Originating-IP: [198.145.29.136] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 9.4.3; banners=-,-,- X-VirusChecked: Checked Received: (qmail 6399 invoked from network); 1 Mar 2017 22:15:49 -0000 Received: from mail.kernel.org (HELO mail.kernel.org) (198.145.29.136) by server-13.tower-21.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 1 Mar 2017 22:15:49 -0000 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 79A2F20398; Wed, 1 Mar 2017 22:15:47 +0000 (UTC) Received: from sstabellini-ThinkPad-X260.hsd1.ca.comcast.net (96-82-76-110-static.hfc.comcastbusiness.net [96.82.76.110]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8800420397; Wed, 1 Mar 2017 22:15:46 +0000 (UTC) From: Stefano Stabellini To: julien.grall@arm.com Date: Wed, 1 Mar 2017 14:15:43 -0800 Message-Id: <1488406545-26164-1-git-send-email-sstabellini@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: References: X-Virus-Scanned: ClamAV using ClamSMTP Cc: xen-devel@lists.xenproject.org, sstabellini@kernel.org Subject: [Xen-devel] [PATCH v5 1/3] arm: remove irq from inflight, then change physical affinity X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP This patch fixes a potential race that could happen when gic_update_one_lr and vgic_vcpu_inject_irq run simultaneously. When GIC_IRQ_GUEST_MIGRATING is set, we must make sure that the irq has been removed from inflight before changing physical affinity, to avoid concurrent accesses to p->inflight, as vgic_vcpu_inject_irq will take a different vcpu lock. Signed-off-by: Stefano Stabellini --- xen/arch/arm/gic.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c index 9522c6c..16bb150 100644 --- a/xen/arch/arm/gic.c +++ b/xen/arch/arm/gic.c @@ -503,6 +503,11 @@ static void gic_update_one_lr(struct vcpu *v, int i) gic_raise_guest_irq(v, irq, p->priority); else { list_del_init(&p->inflight); + /* Remove from inflight, then change physical affinity. It + * makes sure that when a new interrupt is received on the + * next pcpu, inflight is already cleared. No concurrent + * accesses to inflight. */ + smp_mb(); if ( test_and_clear_bit(GIC_IRQ_GUEST_MIGRATING, &p->status) ) { struct vcpu *v_target = vgic_get_target_vcpu(v, irq);