[PATCH v6 04/12] PCI: liveupdate: Document driver binding responsibilities

[Samiullah Khawaja]

On Fri, May 22, 2026 at 08:24:02PM +0000, David Matlack wrote:
>Document how driver binding works during a Live Update and what the PCI
>core expects of drivers and users. Note that this is only a description
>of the current division of responsibilities. These can change in the
>future if we decide.
>
>Signed-off-by: David Matlack <dmatlack at google.com>
>---
> drivers/pci/liveupdate.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
>diff --git a/drivers/pci/liveupdate.c b/drivers/pci/liveupdate.c
>index 96c43b84532c..4f2ec6ffdd16 100644
>--- a/drivers/pci/liveupdate.c
>+++ b/drivers/pci/liveupdate.c
>@@ -70,6 +70,22 @@
>  * preserved. These may be relaxed in the future:
>  *
>  *  * The device cannot be a Virtual Function (VF).
>+ *
>+ * Driver Binding
>+ * ==============
>+ *
>+ * In the outgoing kernel, it is the driver's responsibility to ensure that it
>+ * does not release a device between pci_liveupdate_preserve() and
>+ * pci_liveupdate_unpreserve().
>+ *
>+ * In the incoming kernel, it is the driver's responsibility to ensure that it
>+ * does not release a preserved device between probe() and
>+ * pci_liveupdate_finish().
>+ *
>+ * It is the user's responsibility to ensure that incoming preserved devices are
>+ * bound to the correct driver. i.e. The PCI core does not protect against a
>+ * device getting preserved by driver A in the outgoing kernel and then getting
>+ * bound to driver B in the incoming kernel.
>  */
>
> #define pr_fmt(fmt) "PCI: liveupdate: " fmt
>-- 
>2.54.0.746.g67dd491aae-goog
>

Reviewed-by: Samiullah Khawaja <skhawaja at google.com>