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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C9829C5DF81 for ; Mon, 24 Aug 2026 13:42:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A431E6B008C; Mon, 24 Aug 2026 09:42:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9F40C6B0092; Mon, 24 Aug 2026 09:42:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8E2FE6B0095; Mon, 24 Aug 2026 09:42:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 691EA6B008C for ; Mon, 24 Aug 2026 09:42:03 -0400 (EDT) Received: from smtpin01.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id DF4EB1A0111 for ; Mon, 24 Aug 2026 13:42:02 +0000 (UTC) X-FDA: 85136276484.01.791AE25 Received: from mail-pl1-f173.google.com (mail-pl1-f173.google.com [209.85.214.173]) by imf05.hostedemail.com (Postfix) with ESMTP id 1B04110000C for ; Mon, 24 Aug 2026 13:42:00 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=Tp6MMWCc; spf=pass (imf05.hostedemail.com: domain of praan@google.com designates 209.85.214.173 as permitted sender) smtp.mailfrom=praan@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787578921; b=7RwIDSJQZffoe/m+wtmdOgZ1gQGWh9FpvPXJeC+H3a0bmHyIhIAMDiq4DnnUcWNvHx5I4P fkIbgzHP5qSuOYmlJf/CG9x6cEd+mzugwQ3RINF7JQrq8KzKtbP5YgJnKMA3uITaHCN3Yd afl6x63a7u8mg5droxIrVIiq1v3kuX4= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=Tp6MMWCc; spf=pass (imf05.hostedemail.com: domain of praan@google.com designates 209.85.214.173 as permitted sender) smtp.mailfrom=praan@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787578921; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=MXklq75Z4X2qA44rayjTFnITvL4DP/DDkWPkbOCUBY0=; b=ZFSy3XguWV7lxqJxdN/ip0X36ffGvaeigv9kyfehyVOOVUCbnpZ86hcm966FCihpJ3o0yv OVml0uY8eRmjhQCzVaAZvN1rbiYMWZisM29uRC1s3TiYPzr6dSV4nkFzxHjzrA1pF7iBgU 0ZUe/GigP5kNUeIBtkDIqYoDqyHIDhA= Received: by mail-pl1-f173.google.com with SMTP id d9443c01a7336-2d3b440b97aso155445ad.1 for ; Mon, 24 Aug 2026 06:42:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787578920; x=1788183720; darn=kvack.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=MXklq75Z4X2qA44rayjTFnITvL4DP/DDkWPkbOCUBY0=; b=Tp6MMWCcAiDb31oYwI94KGXkfa6AUryTYts1LD35YAfdXL3Yb209mz/ncaX5k0ZT1N JoRJnl96Jcl/6InvXzcXLJxYwTtrayQhltLBs4LNAsIL46M8w1XMcP9mNtpW8OnXKFhP 5476JTWdx1locHr1oFVI2UUHuebWSq8yvj6hhh96J1M9qL+Ucr2qpwmYv+jF1L7d0sAf VwxZ8UU609x/DHzzJG8pcyNrIZzZ82ba7Oh5pFYY5RMnP749yRTzraBUzBBRdV+EixPU sTpaKFP36wp1QFV7aSE+6XCFrT1NoNTk8xpN4KJimfbYArJrLFuCwM2FQP9uEpT53mdm jqxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787578920; x=1788183720; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=MXklq75Z4X2qA44rayjTFnITvL4DP/DDkWPkbOCUBY0=; b=Bdmt08PMk5QDq+3knFx4URIExlXxFQqk2NOcqxyVk/hIYuGV4IZL1exeJxwUjC/W3E VRX4BSrsWkNv/JK69a51buXhmsDlbLdPinG2zVFi2OqlT9QX90YNvkCzkwAYFDLbrK1i Xwh5z0jLmqJIrNT5XjI5rlJVQMlalWafdYJHPpzYar0e+9mMT8bRZ/eo5PPKuln1pWjn 2HEOgRVghzu4dZmywI6YoLDNBkEYyL6Aj6qNMDHtQzueFU+Rvds6gf5PCTqotnzQLg3B OpmbQOGZdkHjWLZRMc9lPVQ9Em9DDuKgj7AEi42eRNIxIn3vdj9foWMd6R7LDVKaYUhi NLow== X-Forwarded-Encrypted: i=1; AHgh+Rp9CBrvsocO2wMScQ/Zw8Nb4+HlmXNvGecIyCSdbcwP/GDQ6BkU+pVVJ/7d+tYpcaBw6F9cnhycXw==@kvack.org X-Gm-Message-State: AFuF++mBPiSIEKpxhbl2ekFwigqg83hs4pnxl65lrT21zfbwIV+MklaA DFaWyuUneIftA+06kvCfnnQlddeSb7D9tN+4xWxtulNPU4kyV7D2ECksz+JV0wkgRA== X-Gm-Gg: AR+sD12sfzmv+UIlCGuWK4pwU63cgwN8aIYovbjDeus66vWNz1tykJi2e8tBd5SiERc EAkOjn+npbxOiN2iLFSoL/rdUgIU4tpwXRUKS435QL2/WVVmUP5YhlVQaSQghCVw8WlCTzyUriu 1s18GwY5ZPbQOYj+W8XUoBvbB+tiifNLushjk45QoPTPKLd5HKMGqDccmmuVYiYPDzHRcMN2CJp Jj96Jp+ULMg5gXlXwAxzOXDRNa5AP7djlsQ/aVrdaZ029vXaLwn0egEKOIRhqrdsVS0UDRAWXSF FZc+xuvDnQ5KmVfjxQqoYadVexsP3W6RwNrZpy7dWBL7FdBsptGnrtc7XDv5J8gwGRoflhZ7r3R U4dnKgdk15y/4O1lNAMUVKWMFZiZhPi3r7K6TQR699Wm30XdGVjM8sZJVXEck5OZeonEZt0X1Aj FZ7Ox/Da/aOMVjbzM0zwAwXSML2U4T8ZR6JnLiPlnV70Hy9aTCClKmvCYKQEzxOfhlxSwQGA7dd J+PwpyOP2mF9IhRuS+UrMjsoQ== X-Received: by 2002:a17:903:1b4e:b0:2ca:cbe5:c3af with SMTP id d9443c01a7336-2d673b9e9ccmr8380625ad.7.1787578919029; Mon, 24 Aug 2026 06:41:59 -0700 (PDT) Received: from google.com (164.210.142.34.bc.googleusercontent.com. [34.142.210.164]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d676761c35sm18347475ad.15.2026.08.24.06.41.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Aug 2026 06:41:58 -0700 (PDT) Date: Mon, 24 Aug 2026 13:41:50 +0000 From: Pranjal Shrivastava To: David Matlack Cc: kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Adithya Jayachandran , Alexander Graf , Alex Williamson , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Leon Romanovsky , Lukas Wunner , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pratyush Yadav , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Vipin Sharma , William Tu , Yi Liu Subject: Re: [PATCH v8 06/12] PCI: liveupdate: Auto-preserve upstream bridges across Live Update Message-ID: References: <20260728221007.2098560-1-dmatlack@google.com> <20260728221007.2098560-7-dmatlack@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260728221007.2098560-7-dmatlack@google.com> X-Rspamd-Queue-Id: 1B04110000C X-Rspam-User: X-Stat-Signature: 5zmbumq9rrs4ktudx8y4zi3paok1a51c X-Rspamd-Server: rspam06 X-HE-Tag: 1787578920-263851 X-HE-Meta: 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 CRhYQjgk BIQFbfgdxDaJKRH1O2hcXM6mk/XH/bydf6O85YzPJBMbPiPK6QimSZ7+6zkniVqLtLxmFHdwuT08ea75yRDB0um9ywCdn4r4sFsbqDFtjYYs623tzSLM7rsr4uFIWMPSXkTcIxq4R67ScYEi2D2ugZMklJS07vzQignpbH3gBcbUjx9vyRLmT4g1zY79iKvM6L991OYBIt3m9H0pUecJtvp2yt8viK5m3qBPwJtOKY2dFiUw2U88ghy09ChdACuinyGp7J3nLclFrZQqh75Brh7B5QDaq5jT5Z9KDUmwY2fTUg9N6kT7QYnUM4NfDdzaJCQfkGVEAYPT+oC7YZy3JbRClSh27Omv3aYHMgo7cj8PK6tbRd97tinV5RG2X4bDyyvHxO0Rqu6wpsEP1hqjDnsL+FdfqJTU1EdyZ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jul 28, 2026 at 10:10:00PM +0000, David Matlack wrote: > When a PCI device is preserved across a Live Update, all of its upstream > bridges up to the root port must also be preserved. This enables the PCI > core and any drivers bound to the bridges to manage bridges correctly > across a Live Update. > > Notably, this will be used in subsequent commits to ensure that > preserved devices can continue performing memory transactions without a > disruption or change in routing. > > To preserve bridges, the PCI core tracks the number of downstream > devices preserved under each bridge using a reference count in struct > pci_dev_ser. This allows a bridge to remain preserved until all its > downstream preserved devices are unpreserved or finish their > participation in the Live Update. > > Reviewed-by: Pasha Tatashin > Signed-off-by: David Matlack Reviewed-by: Pranjal Shrivastava Thanks, Praan