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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 725ACC433F5 for ; Sat, 23 Apr 2022 06:51:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233674AbiDWGyT (ORCPT ); Sat, 23 Apr 2022 02:54:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233589AbiDWGyS (ORCPT ); Sat, 23 Apr 2022 02:54:18 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8DE55F8CA; Fri, 22 Apr 2022 23:51:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6C6F6B80022; Sat, 23 Apr 2022 06:51:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FAACC385A5; Sat, 23 Apr 2022 06:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650696680; bh=K/et5AaKBRLTBYtnLXvvukZr52M2pfPjJy2F2k300V8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=coRHeWIRmnAV7xb3syQDjEUvW8vLdNM4I37T4uJOt7KEdtkyq1AFj1lQiS/OuH9vg yzNIpqqmJklkc1i/xvekGW7Bcff9m9lSqzayeV+RjrA6idcxYQ9OlhPCq1Frr5uron oBXFiZrspQR8fSjShC1uMylq4Zm7xCEAhgKilsT8= Date: Sat, 23 Apr 2022 08:51:16 +0200 From: Greg Kroah-Hartman To: Sebastian Ene Cc: Rob Herring , Arnd Bergmann , Dragan Cvetic , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, maz@kernel.org, will@kernel.org, qperret@google.com Subject: Re: [PATCH v2 0/2] Detect stalls on guest vCPUS Message-ID: References: <20220422141949.3456505-1-sebastianene@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220422141949.3456505-1-sebastianene@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 22, 2022 at 02:19:48PM +0000, Sebastian Ene wrote: > This adds a mechanism to detect stalls on the guest vCPUS by creating a > per CPU hrtimer which periodically 'pets' the host backend driver. > > This device driver acts as a soft lockup detector by relying on the host > backend driver to measure the elapesed time between subsequent 'pet' events. > If the elapsed time doesn't match an expected value, the backend driver > decides that the guest vCPU is locked and resets the guest. The host > backend driver takes into account the time that the guest is not > running. The communication with the backend driver is done through MMIO > and the register layout of the virtual watchdog is described as part of > the backend driver changes. > > The host backend driver is implemented as part of: > https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3548817 > > Changelog v2: > - move the driver to misc as this does not cope with watchdog core > subsystem Wait, why does it not cope with it? That's not documented anywhere in your patch that adds the driver. In fact, most of the text here needs to be in the changelog for the driver submission, not thrown away in the 00/XX email that will never end up in the kernel tree. thanks, greg k-h