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=-9.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 18ECEC4727E for ; Wed, 30 Sep 2020 12:38:19 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AEC752071E for ; Wed, 30 Sep 2020 12:38:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="2WZJSHh/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEC752071E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RCbBoTMegVlheasHfeJOIa0F3ISVPMDEFWgD93+CmFI=; b=2WZJSHh/HKWCjVsXsllYfns+G e8oNHXrdhmJ9/ozw8IREqkme6TKlhE1q/YWn7IVC7E0lH4E8i1qbDxmo55fQtsfl++d7zkbwJ5Fde j/RFlDi6smgSTURo+L4snXHvvnu5COjlpiq7rKiajuOFk1eqrqKAcPojuc182HIP8JN/78SdvF6dz 2c2zdUu+nS9QTG54umAVToW1hvjtZRH9xH9pI1cpWVWUY9VwjItsRQBTlZ0uTmgRVf3xwIwxqQws6 ID4QTzjXuvmYgXqJ8EoCSurf2AJSjRSGHzjnWGL2a28JUITgAbiWdBCiQF954GmmFvpvT+Uo6ktHp ObV35MsLA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNbLq-0007QG-Ef; Wed, 30 Sep 2020 12:36:54 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNbLn-0007Os-Hh for linux-arm-kernel@lists.infradead.org; Wed, 30 Sep 2020 12:36:52 +0000 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 5FFC530E; Wed, 30 Sep 2020 05:36:49 -0700 (PDT) Received: from [192.168.0.110] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6EF553F6CF; Wed, 30 Sep 2020 05:36:47 -0700 (PDT) Subject: Re: [PATCH v7 5/7] KVM: arm64: pmu: Make overflow handler NMI safe To: Will Deacon References: <20200924110706.254996-1-alexandru.elisei@arm.com> <20200924110706.254996-6-alexandru.elisei@arm.com> <20200928175725.GB11792@willie-the-truck> From: Alexandru Elisei Message-ID: <6b1ecdef-3a42-c428-2309-753b1470e3de@arm.com> Date: Wed, 30 Sep 2020 13:37:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200928175725.GB11792@willie-the-truck> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200930_083651_643695_E2052488 X-CRM114-Status: GOOD ( 20.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, sumit.garg@linaro.org, kvm@vger.kernel.org, Julien Thierry , Marc Zyngier , maz@kernel.org, Suzuki K Pouloze , Will Deacon , linux-kernel@vger.kernel.org, swboyd@chromium.org, James Morse , Julien Thierry , catalin.marinas@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Will, On 9/28/20 6:57 PM, Will Deacon wrote: > On Thu, Sep 24, 2020 at 12:07:04PM +0100, Alexandru Elisei wrote: >> From: Julien Thierry >> >> kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from >> NMI context, defer waking the vcpu to an irq_work queue. >> >> A vcpu can be freed while it's not running by kvm_destroy_vm(). Prevent >> running the irq_work for a non-existent vcpu by calling irq_work_sync() on >> the PMU destroy path. >> >> Cc: Julien Thierry >> Cc: Marc Zyngier >> Cc: Will Deacon >> Cc: Mark Rutland >> Cc: Catalin Marinas >> Cc: James Morse >> Cc: Suzuki K Pouloze >> Cc: kvm@vger.kernel.org >> Cc: kvmarm@lists.cs.columbia.edu >> Signed-off-by: Julien Thierry >> Tested-by: Sumit Garg (Developerbox) >> [Alexandru E.: Added irq_work_sync()] >> Signed-off-by: Alexandru Elisei >> --- >> I suggested in v6 that I will add an irq_work_sync() to >> kvm_pmu_vcpu_reset(). It turns out it's not necessary: a vcpu reset is done >> by the vcpu being reset with interrupts enabled, which means all the work >> has had a chance to run before the reset takes place. > I don't understand this ^^ Marc had the same comment, I replied in his email. I thought about it and you're right, it doesn't make much sense. > > But the patch itself looks good, so I'm going to queue this lot anyway! Thank you for picking up the series! Thanks, Alex _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel