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=-4.5 required=3.0 tests=DKIM_ADSP_NXDOMAIN, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no 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 E3A7BC433FF for ; Wed, 31 Jul 2019 10:59:07 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 6E5F720651 for ; Wed, 31 Jul 2019 10:59:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E5F720651 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kermel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id BCA664A54F; Wed, 31 Jul 2019 06:59:06 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id n8vF6aE3Xe71; Wed, 31 Jul 2019 06:59:05 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id AC96C4A51F; Wed, 31 Jul 2019 06:59:05 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 92C4B4A535 for ; Tue, 30 Jul 2019 16:58:07 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 0PvW3KzmV-6W for ; Tue, 30 Jul 2019 16:58:06 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 78DE14A52E for ; Tue, 30 Jul 2019 16:58:06 -0400 (EDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ED6EF28; Tue, 30 Jul 2019 13:58:05 -0700 (PDT) Received: from why (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 518253F575; Tue, 30 Jul 2019 13:58:03 -0700 (PDT) Date: Tue, 30 Jul 2019 21:57:59 +0100 From: Marc Zyngier To: Julien Thierry Subject: Re: [PATCH v4 7/9] arm/arm64: kvm: pmu: Make overflow handler NMI safe Message-ID: <20190730215759.5b54e45d@why> In-Reply-To: <1563351432-55652-8-git-send-email-julien.thierry@arm.com> References: <1563351432-55652-1-git-send-email-julien.thierry@arm.com> <1563351432-55652-8-git-send-email-julien.thierry@arm.com> Organization: ARM Ltd X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-Mailman-Approved-At: Wed, 31 Jul 2019 06:59:05 -0400 Cc: peterz@infradead.org, liwei391@huawei.com, will.deacon@arm.com, acme@kernel.org, alexander.shishkin@linux.intel.com, mingo@redhat.com, namhyung@kernel.org, sthotton@marvell.com, jolsa@redhat.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Wed, 17 Jul 2019 09:17:10 +0100 Julien Thierry wrote: > When using an NMI for the PMU interrupt, taking any lock might cause a > deadlock. The current PMU overflow handler in KVM takes locks when > trying to wake up a vcpu. > > When overflow handler is called by an NMI, defer the vcpu waking in an > irq_work queue. > > Signed-off-by: Julien Thierry > Cc: Christoffer Dall > Cc: Marc Zyngier > Cc: Will Deacon > Cc: Mark Rutland > Cc: James Morse > Cc: Suzuki K Pouloze > Cc: kvmarm@lists.cs.columbia.edu Acked-by: Marc Zyngier M. -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm