From: Bjorn Helgaas <helgaas@kernel.org>
To: David Matlack <dmatlack@google.com>
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 <ajayachandra@nvidia.com>,
Alexander Graf <graf@amazon.com>,
Alex Williamson <alex@shazbot.org>,
Bjorn Helgaas <bhelgaas@google.com>, Chris Li <chrisl@kernel.org>,
David Rientjes <rientjes@google.com>,
Jacob Pan <jacob.pan@linux.microsoft.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Jonathan Corbet <corbet@lwn.net>, Josh Hilke <jrhilke@google.com>,
Leon Romanovsky <leonro@nvidia.com>,
Lukas Wunner <lukas@wunner.de>, Mike Rapoport <rppt@kernel.org>,
Parav Pandit <parav@nvidia.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Pranjal Shrivastava <praan@google.com>,
Pratyush Yadav <pratyush@kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>,
Samiullah Khawaja <skhawaja@google.com>,
Shuah Khan <skhan@linuxfoundation.org>,
Vipin Sharma <vipinsh@google.com>, William Tu <witu@nvidia.com>,
Yi Liu <yi.l.liu@intel.com>
Subject: Re: [PATCH v8 06/12] PCI: liveupdate: Auto-preserve upstream bridges across Live Update
Date: Thu, 10 Sep 2026 18:51:26 -0500 [thread overview]
Message-ID: <20260910235126.GA367952@bhelgaas> (raw)
In-Reply-To: <20260728221007.2098560-7-dmatlack@google.com>
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.
This seems to hint that we're going to allow bridge reconfiguration in
some cases, e.g., for hot-adds. The simplest case is "leave config of
all bridges the same", and I thought that was what the previous patch
commit log said.
What's the benefit added by this patch?
next prev parent reply other threads:[~2026-09-10 23:51 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-28 22:09 [PATCH v8 00/12] PCI: liveupdate: PCI core support for Live Update David Matlack
2026-07-28 22:09 ` [PATCH v8 01/12] PCI: liveupdate: Set up FLB handler for the PCI core David Matlack
2026-07-28 22:19 ` sashiko-bot
2026-08-17 21:12 ` Samiullah Khawaja
2026-09-10 23:48 ` Bjorn Helgaas
2026-09-11 16:44 ` David Matlack
2026-07-28 22:09 ` [PATCH v8 02/12] PCI: liveupdate: Track outgoing preserved PCI devices David Matlack
2026-07-28 22:19 ` sashiko-bot
2026-08-24 20:14 ` Samiullah Khawaja
2026-08-27 21:47 ` Bjorn Helgaas
2026-07-28 22:09 ` [PATCH v8 03/12] PCI: liveupdate: Track incoming " David Matlack
2026-07-28 22:22 ` sashiko-bot
2026-07-28 23:37 ` David Matlack
2026-08-24 20:13 ` Samiullah Khawaja
2026-09-10 23:49 ` Bjorn Helgaas
2026-09-11 16:45 ` David Matlack
2026-07-28 22:09 ` [PATCH v8 04/12] PCI: liveupdate: Document driver binding responsibilities David Matlack
2026-07-28 22:12 ` sashiko-bot
2026-09-10 23:50 ` Bjorn Helgaas
2026-07-28 22:09 ` [PATCH v8 05/12] PCI: liveupdate: Preserve bus numbers during Live Update David Matlack
2026-07-28 22:19 ` sashiko-bot
2026-09-10 23:51 ` Bjorn Helgaas
2026-09-11 18:30 ` David Matlack
2026-09-12 17:31 ` David Matlack
2026-07-28 22:10 ` [PATCH v8 06/12] PCI: liveupdate: Auto-preserve upstream bridges across " David Matlack
2026-07-28 22:18 ` sashiko-bot
2026-08-24 13:41 ` Pranjal Shrivastava
2026-09-10 23:51 ` Bjorn Helgaas [this message]
2026-09-11 17:00 ` David Matlack
2026-07-28 22:10 ` [PATCH v8 07/12] PCI: Refactor matching logic for pci_dev_acs_ops David Matlack
2026-07-28 22:18 ` sashiko-bot
2026-07-28 22:10 ` [PATCH v8 08/12] PCI: liveupdate: Adopt ACS controls in incoming preserved devices David Matlack
2026-07-28 22:22 ` sashiko-bot
2026-08-24 13:42 ` Pranjal Shrivastava
2026-09-10 23:51 ` Bjorn Helgaas
2026-09-11 18:31 ` David Matlack
2026-07-28 22:10 ` [PATCH v8 09/12] PCI: liveupdate: Adopt ARI Forwarding Enable on preserved bridges David Matlack
2026-07-28 22:19 ` sashiko-bot
2026-08-24 13:43 ` Pranjal Shrivastava
2026-07-28 22:10 ` [PATCH v8 10/12] PCI: liveupdate: Freeze preservation status during shutdown David Matlack
2026-07-28 22:21 ` sashiko-bot
2026-08-24 20:07 ` Samiullah Khawaja
2026-07-28 22:10 ` [PATCH v8 11/12] PCI: liveupdate: Do not disable bus mastering on preserved devices during kexec David Matlack
2026-07-28 22:18 ` sashiko-bot
2026-08-24 20:02 ` Samiullah Khawaja
2026-07-28 22:10 ` [PATCH v8 12/12] Documentation: PCI: Add documentation for Live Update David Matlack
2026-07-28 22:19 ` sashiko-bot
2026-08-24 20:01 ` Samiullah Khawaja
2026-08-18 17:01 ` [PATCH v8 00/12] PCI: liveupdate: PCI core support " David Matlack
2026-09-10 21:37 ` Pasha Tatashin
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