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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6DDF9F46C69 for ; Mon, 6 Apr 2026 18:10:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=85/sv/Jd+nnLebgu7yOJ82/6JMUXxVcSgRKO3WW/KJM=; b=tpRHoF6yea485rAIAa7y/anA6l rM+w1mOnskZiZ+ebFOxER99kExRQq8ilEx8ZR7F1HdNgXY+A4vqgkai26whmxOUzm1p35RNXaqq9+ FjSCHqxgUesHMWXfaBJdmDFRpKWsDbmVco7Z0D/gqoQstT0GLqGDiUz5bDGP67H0Kr6Ki70Ww5BS4 b3K9GTKcwfc5dD6ZXgqs0pEmtfPz+J/+G02/3zPFkW7Yaa7ysXjceHmnPQg+Ao4j5ni7VVT9LC0SH +XM9ok1aIn6jPKJmcMt8ZKllewebmQB/+k9DYDapOUZ113Yi6s5q2vSMWYSKUWdG3t/BEj4E2ovvl pDX/8qAA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w9oPB-00000005Nq4-0vEo; Mon, 06 Apr 2026 18:10:33 +0000 Received: from out-177.mta1.migadu.com ([95.215.58.177]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w9oP5-00000005NoO-2NIX for kexec@lists.infradead.org; Mon, 06 Apr 2026 18:10:29 +0000 Message-ID: <1c5fd907-f610-48e4-89cc-4040aaef2674@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1775498991; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=85/sv/Jd+nnLebgu7yOJ82/6JMUXxVcSgRKO3WW/KJM=; b=HrKy4i01v27KUFcXt/1w2kf+yZsl5MXCFBmMdpuBla2c4B2kFG8UdHSH93UsEojRTPjWIJ RVbUZS7qtBOUTvf1Fe92L2hJ6/CpkB4KYvevqVhozqjWCBottlm/LzMr5DomESqDJznrrj NsvzlhYZFx9aBwmc2y/0M9aHDJw9o8k= Date: Mon, 6 Apr 2026 11:09:37 -0700 MIME-Version: 1.0 Subject: Re: [PATCH v3 02/24] PCI: Add API to track PCI devices preserved across Live Update To: David Matlack , Zhu Yanjun Cc: Alex Williamson , Bjorn Helgaas , Adithya Jayachandran , Alexander Graf , Alex Mastro , Andrew Morton , Ankit Agrawal , Arnd Bergmann , Askar Safin , "Borislav Petkov (AMD)" , Chris Li , Dapeng Mi , David Rientjes , Feng Tang , Jacob Pan , Jason Gunthorpe , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Kees Cook , Kevin Tian , kexec@lists.infradead.org, kvm@vger.kernel.org, Leon Romanovsky , Leon Romanovsky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Li RongQing , Lukas Wunner , Marco Elver , =?UTF-8?Q?Micha=C5=82_Winiarski?= , Mike Rapoport , Parav Pandit , Pasha Tatashin , "Paul E. 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From: "Yanjun.Zhu" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260406_111027_760421_53C547AB X-CRM114-Status: GOOD ( 14.93 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 4/6/26 9:06 AM, David Matlack wrote: > On Sun, Apr 5, 2026 at 9:56 AM Zhu Yanjun wrote: >> 在 2026/4/3 14:58, David Matlack 写道: >>> On Thu, Apr 2, 2026 at 2:29 PM Yanjun.Zhu wrote: >>>> On 3/23/26 4:57 PM, David Matlack wrote: >>>>> +config PCI_LIVEUPDATE >>>>> + bool "PCI Live Update Support (EXPERIMENTAL)" >>>>> + depends on PCI && LIVEUPDATE >>>>> + help >>>>> + Support for preserving PCI devices across a Live Update. This option >>>>> + should only be enabled by developers working on implementing this >>>>> + support. Once enough support as landed in the kernel, this option >>>>> + will no longer be marked EXPERIMENTAL. >>>>> + >>>>> + If unsure, say N. >>>> Currently, it only supports 'n' or 'y'. Is it possible to add 'm' >>>> (modular support)? >>>> >>>> This would allow the feature to be built as a kernel module. For >>>> development >>>> >>>> purposes, modularization means we only need to recompile a single module >>>> >>>> for testing, rather than rebuilding the entire kernel. Compiling a >>>> module should >>>> >>>> be significantly faster than a full kernel build. >>> I don't think it is possible for CONFIG_PCI_LIVEUPDATE to support 'm'. >>> pci_setup_device() (which is under CONFIG_PCI) needs to call >>> pci_liveupdate_setup_device(), and CONFIG_PCI cannot be built as a >>> module. This call is necessary so the PCI core knows whether a device >>> being enumerated was preserved across a previous Live Update. >> After the following changes, the liveupdate.ko can be generated >> successfully. > Sure but you've broken the feature. Now devices can be probed before > liveupdate.ko is loaded and the PCI core will have an incorrect view From this perspective, I think it makes sense. Zhu Yanjun > of which devices were preserved by the previous kernel.