Re: [PATCH v3 02/24] PCI: Add API to track PCI devices preserved across Live Update

[Chris Li]

On Thu, Apr 2, 2026 at 2:29 PM Yanjun.Zhu <yanjun.zhu@xxxxxxxxx> wrote:
> > +config PCI_LIVEUPDATE
> > +     bool "PCI Live Update Support (EXPERIMENTAL)"
> > +     depends on PCI && LIVEUPDATE
> > +     help
> > +       Support for preserving PCI devices across a Live Update. This option
> > +       should only be enabled by developers working on implementing this
> > +       support. Once enough support as landed in the kernel, this option
> > +       will no longer be marked EXPERIMENTAL.
> > +
> > +       If unsure, say N.
>
> Currently, it only supports 'n' or 'y'. Is it possible to add 'm'
> (modular support)?
>
> This would allow the feature to be built as a kernel module. For
> development
>
> purposes, modularization means we only need to recompile a single module
>
> for testing, rather than rebuilding the entire kernel. Compiling a
> module should
>
> be significantly faster than a full kernel build.

Building as a module has extra complexity to handle, e.g. the callback
can happen when the module hasn't been loaded. Then the user space can
take an arbitrarily long time to load the module.

It needs more infrastructure to support the liveupdate as a module.

Chris