From: Jason Gunthorpe <jgg@nvidia.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: David Matlack <dmatlack@google.com>,
Alex Williamson <alex@shazbot.org>,
Adithya Jayachandran <ajayachandra@nvidia.com>,
Alex Mastro <amastro@fb.com>,
Alistair Popple <apopple@nvidia.com>,
Andrew Morton <akpm@linux-foundation.org>,
Bjorn Helgaas <bhelgaas@google.com>, Chris Li <chrisl@kernel.org>,
David Rientjes <rientjes@google.com>,
Jacob Pan <jacob.pan@linux.microsoft.com>,
Josh Hilke <jrhilke@google.com>,
Kevin Tian <kevin.tian@intel.com>,
kvm@vger.kernel.org, Leon Romanovsky <leonro@nvidia.com>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-pci@vger.kernel.org, Mike Rapoport <rppt@kernel.org>,
Parav Pandit <parav@nvidia.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Philipp Stanner <pstanner@redhat.com>,
Pratyush Yadav <pratyush@kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>,
Samiullah Khawaja <skhawaja@google.com>,
Shuah Khan <shuah@kernel.org>,
Tomita Moeko <tomitamoeko@gmail.com>,
Vipin Sharma <vipinsh@google.com>, William Tu <witu@nvidia.com>,
Yi Liu <yi.l.liu@intel.com>, Yunxiang Li <Yunxiang.Li@amd.com>,
Zhu Yanjun <yanjun.zhu@linux.dev>
Subject: Re: [PATCH 02/21] PCI: Add API to track PCI devices preserved across Live Update
Date: Sat, 29 Nov 2025 20:51:13 -0400 [thread overview]
Message-ID: <20251130005113.GB760268@nvidia.com> (raw)
In-Reply-To: <aSrMSRd8RJn2IKF4@wunner.de>
On Sat, Nov 29, 2025 at 11:34:49AM +0100, Lukas Wunner wrote:
> On Wed, Nov 26, 2025 at 07:35:49PM +0000, David Matlack wrote:
> > Add an API to enable the PCI subsystem to track all devices that are
> > preserved across a Live Update, including both incoming devices (passed
> > from the previous kernel) and outgoing devices (passed to the next
> > kernel).
> >
> > Use PCI segment number and BDF to keep track of devices across Live
> > Update. This means the kernel must keep both identifiers constant across
> > a Live Update for any preserved device.
>
> While bus numbers will *usually* stay the same across next and previous
> kernel, there are exceptions. E.g. if "pci=assign-busses" is specified
> on the command line, the kernel will re-assign bus numbers on every boot.
Stuff like this has to be disabled for this live update stuff, if the
bus numbers are changed it will break the active use of the iommu
across the kexec.
So while what you say is all technically true, I'm not sure this is
necessary.
Jason
next prev parent reply other threads:[~2025-11-30 0:51 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-26 19:35 [PATCH 00/21] vfio/pci: Base support to preserve a VFIO device file across Live Update David Matlack
2025-11-26 19:35 ` [PATCH 01/21] liveupdate: luo_flb: Prevent retrieve() after finish() David Matlack
2025-11-26 19:35 ` [PATCH 02/21] PCI: Add API to track PCI devices preserved across Live Update David Matlack
2025-11-29 10:34 ` Lukas Wunner
2025-11-29 20:10 ` Pasha Tatashin
2025-11-30 0:51 ` Jason Gunthorpe [this message]
2025-11-30 1:20 ` Pasha Tatashin
2025-12-01 13:29 ` Jason Gunthorpe
2025-12-01 18:54 ` David Matlack
2025-12-02 6:20 ` Lukas Wunner
2025-12-02 14:59 ` Jason Gunthorpe
2025-12-02 16:36 ` Chris Li
2025-12-02 18:19 ` Jason Gunthorpe
2025-12-02 21:20 ` Chris Li
2025-12-03 5:44 ` Lukas Wunner
2025-12-01 21:23 ` Pasha Tatashin
2025-11-29 20:15 ` Pasha Tatashin
2025-12-01 18:07 ` David Matlack
2025-11-26 19:35 ` [PATCH 03/21] PCI: Require driver_override for incoming Live Update preserved devices David Matlack
2025-12-02 21:16 ` David Matlack
2025-12-02 21:24 ` Chris Li
2025-11-26 19:35 ` [PATCH 04/21] vfio/pci: Register a file handler with Live Update Orchestrator David Matlack
2025-11-26 19:35 ` [PATCH 05/21] vfio/pci: Preserve vfio-pci device files across Live Update David Matlack
2025-11-26 19:35 ` [PATCH 06/21] vfio/pci: Retrieve preserved device files after " David Matlack
2025-12-03 12:55 ` Alex Mastro
2025-12-03 15:45 ` Pasha Tatashin
2025-12-03 17:29 ` David Matlack
2025-12-04 10:30 ` Alex Mastro
2025-11-26 19:35 ` [PATCH 07/21] vfio/pci: Notify PCI subsystem about devices preserved across " David Matlack
2025-11-26 19:35 ` [PATCH 08/21] vfio: Enforce preserved devices are retrieved via LIVEUPDATE_SESSION_RETRIEVE_FD David Matlack
2025-11-26 19:35 ` [PATCH 09/21] vfio/pci: Store Live Update state in struct vfio_pci_core_device David Matlack
2025-11-26 19:35 ` [PATCH 10/21] vfio/pci: Skip reset of preserved device after Live Update David Matlack
2025-11-26 19:35 ` [PATCH 11/21] selftests/liveupdate: Move luo_test_utils.* into a reusable library David Matlack
2025-11-26 19:35 ` [PATCH 12/21] selftests/liveupdate: Add helpers to preserve/retrieve FDs David Matlack
2025-11-26 19:36 ` [PATCH 13/21] vfio: selftests: Build liveupdate library in VFIO selftests David Matlack
2025-11-26 19:36 ` [PATCH 14/21] vfio: selftests: Add Makefile support for TEST_GEN_PROGS_EXTENDED David Matlack
2025-11-26 19:36 ` [PATCH 15/21] vfio: selftests: Add vfio_pci_liveupdate_uapi_test David Matlack
2025-11-26 19:36 ` [PATCH 16/21] vfio: selftests: Initialize vfio_pci_device using a VFIO cdev FD David Matlack
2025-11-26 19:36 ` [PATCH 17/21] vfio: selftests: Add vfio_pci_liveupdate_kexec_test David Matlack
2025-11-26 19:36 ` [PATCH 18/21] vfio: selftests: Expose iommu_modes to tests David Matlack
2025-11-26 19:36 ` [PATCH 19/21] vfio: selftests: Expose low-level helper routines for setting up struct vfio_pci_device David Matlack
2025-12-28 4:03 ` Zhu Yanjun
2026-01-05 17:54 ` David Matlack
2026-01-06 0:07 ` Yanjun.Zhu
2026-01-06 0:19 ` David Matlack
2025-11-26 19:36 ` [PATCH 20/21] vfio: selftests: Verify that opening VFIO device fails during Live Update David Matlack
2025-11-26 19:36 ` [PATCH 21/21] vfio: selftests: Add continuous DMA to vfio_pci_liveupdate_kexec_test David Matlack
2025-11-28 4:56 ` [PATCH 00/21] vfio/pci: Base support to preserve a VFIO device file across Live Update Zhu Yanjun
2025-12-01 15:49 ` Zhu Yanjun
2025-12-01 17:10 ` David Matlack
2025-12-01 17:16 ` Zhu Yanjun
2025-12-01 17:32 ` David Matlack
2025-12-01 17:36 ` David Matlack
2025-12-01 17:44 ` Pasha Tatashin
2025-12-01 21:45 ` Yanjun.Zhu
2025-12-01 21:48 ` David Matlack
2025-12-01 21:56 ` Yanjun.Zhu
2025-12-02 5:50 ` Zhu Yanjun
2025-12-01 21:59 ` Pasha Tatashin
2025-12-02 14:10 ` Pratyush Yadav
2025-12-02 21:29 ` David Matlack
2025-12-02 21:41 ` Pasha Tatashin
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