Re: [PATCH v8 03/12] PCI: liveupdate: Track incoming preserved PCI devices

[Samiullah Khawaja]

On Tue, Jul 28, 2026 at 10:09:57PM +0000, David Matlack wrote:
> During PCI enumeration, the previous kernel might have passed state about
> devices that were preserved across kexec. The PCI core needs to fetch
> this state to identify which devices are "incoming" and require special
> handling.
>
> Add pci_liveupdate_setup_device() which is called during device setup
> to fetch the serialized state (struct pci_ser) from the Live Update
> Orchestrator. The first time this happens, pci_flb_retrieve() will run
> and convert the array of pci_dev_ser structs into an xarray so that it
> can be looked up efficiently.
>
> If a device is found in the xarray, the PCI core stores a pointer to its
> state in dev->liveupdate_incoming until pci_liveupdate_finish() is
> called by the driver. This pointer allows the PCI core and drivers to
> apply Live Update-specific logic to incoming devices in subsequent
> commits.
>
> Drivers can check if a device is an incoming preserved device (e.g.
> during probe) by calling pci_liveupdate_is_incoming().
>
> CONFIG_64BIT is now required to enable CONFIG_PCI_LIVEUPDATE so that the
> domain and bdf can be guaranteed to fit in an unsigned long and be used
> as the xarray key.
>
> Reviewed-by: Pranjal Shrivastava <praan@xxxxxxxxxx>
> Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> ---
> MAINTAINERS                    |   1 +
> drivers/pci/Kconfig            |   2 +-
> drivers/pci/liveupdate.c       | 256 ++++++++++++++++++++++++++++++++-
> drivers/pci/liveupdate.h       |   5 +
> drivers/pci/probe.c            |   3 +
> include/linux/pci_liveupdate.h |  13 ++
> 6 files changed, 277 insertions(+), 3 deletions(-)

[snip]

> static void pci_flb_finish(struct liveupdate_flb_op_args *args)
> {
> +	struct pci_flb_incoming *incoming = args->obj;
> +
> 	pr_debug("Finished struct pci_ser (0x%llx)\n", args->data);
> -	kho_restore_free(args->obj);
> +	pci_check_all_devices_finished(incoming);

This should handle FLB/FD lifecycle nicely. Thanks for adding this.
> +
> +	xa_destroy(&incoming->xa);
> +	kho_block_set_destroy(&incoming->block_set);
> +	kho_restore_free(incoming->ser);
> +	kfree(incoming);
> }

Reviewed-by: Samiullah Khawaja <skhawaja@xxxxxxxxxx>