[PATCH v8 06/12] PCI: liveupdate: Auto-preserve upstream bridges across Live Update

[Pranjal Shrivastava]

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 <pasha.tatashin at soleen.com>
> Signed-off-by: David Matlack <dmatlack at google.com>

Reviewed-by: Pranjal Shrivastava <praan at google.com>

Thanks,
Praan