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 94314C433FE for ; Mon, 23 May 2022 15:00:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237553AbiEWPAn (ORCPT ); Mon, 23 May 2022 11:00:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237427AbiEWPAk (ORCPT ); Mon, 23 May 2022 11:00:40 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47EEB5B8B8; Mon, 23 May 2022 08:00:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=keKJrvyQ/+r75XOnYYRl19FO+VGyiPJcwICfZxDBkqs=; b=O+C3jDB0Vwu4Y/gkTmW/RCmTwy kNqD2emzzlOs/8A7J1xO/TSH5qapt6sCckUwfqeKLJwoCrpUi4pUQfOKCsbI70QtSFMdfNTmFr+H0 NXT6Oh9iPuG4hVKz84ZvxHpmEirVLNSMQMza54o3VmB+D23FpdTtf7JnpYZ61zk10z8NLp053Dtmb 5G5TvLT8W+VF+imYpIQccZx+LAQHhkmqjWgwAULVFomENEWSpKhN5UeAVPt+Y1vZC04/4FyRoMtUE OHqcld4S4ftUjXzRb6CJS95k+7T+FIlHKMRNj13Qcs75Xk/j3Ix2WaTpEwsP72+2bzr+hEFsSu6v0 WUJ5ifAA==; Received: from 200-161-159-120.dsl.telesp.net.br ([200.161.159.120] helo=[192.168.1.60]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1nt9XQ-00GTti-N1; Mon, 23 May 2022 17:00:05 +0200 Message-ID: <0fac8c71-6f18-d15c-23f5-075dbc45f3f9@igalia.com> Date: Mon, 23 May 2022 11:56:12 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list Content-Language: en-US To: Scott Branden , Petr Mladek , Sebastian Reichel , Florian Fainelli , Desmond yan Cc: David Gow , Evan Green , Julius Werner , bcm-kernel-feedback-list@broadcom.com, linux-pm@vger.kernel.org, akpm@linux-foundation.org, bhe@redhat.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Alexander Gordeev , Andrea Parri , Ard Biesheuvel , Benjamin Herrenschmidt , Brian Norris , Christian Borntraeger , Christophe JAILLET , "David S. Miller" , Dexuan Cui , Doug Berger , Haiyang Zhang , Hari Bathini , Heiko Carstens , Justin Chen , "K. Y. Srinivasan" , Lee Jones , Markus Mayer , Michael Ellerman , Mihai Carabas , Nicholas Piggin , Paul Mackerras , Pavel Machek , Shile Zhang , Stephen Hemminger , Sven Schnelle , Thomas Bogendoerfer , Tianyu Lan , Vasily Gorbik , Wang ShaoBo , Wei Liu , zhenwei pi References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-20-gpiccoli@igalia.com> <81878a67-21f1-fee8-1add-f381bc8b05df@broadcom.com> From: "Guilherme G. Piccoli" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/05/2022 16:20, Scott Branden wrote: > [...] >> Hi Scott / Desmond, thanks for the detailed answer! Is this adapter >> designed to run in x86 only or you have other architectures' use cases? > The adapter may be used in any PCIe design that supports DMA. > So it may be possible to run in arm64 servers. >> >> [...] >> With that said, and given this is a lightweight notifier that ideally >> should run ASAP, I'd keep this one in the hypervisor list. We can >> "adjust" the semantic of this list to include lightweight notifiers that >> reset adapters. > Sounds the best to keep system operating as tested today. >> >> With that said, Petr has a point - not always such list is going to be >> called before kdump. So, that makes me think in another idea: what if we >> have another list, but not on panic path, but instead in the custom >> crash_shutdown()? Drivers could add callbacks there that must execute >> before kexec/kdump, no matter what. > It may be beneficial for some other drivers but for our use we would > then need to register for the panic path and the crash_shutdown path. > We notify the VK card for 2 purposes: one to stop DMA so memory stop > changing during a kdump. And also to get the card into a good state so > resets happen cleanly. Thanks Scott! With that, I guess it's really better to keep this notifier in this hypervisor/early list - I'm planning to do that for V2. Unless Petr or somebody has strong feelings against that, of course. Cheers, Guilherme