Re: [PATCH v8 08/12] PCI: liveupdate: Adopt ACS controls in incoming preserved devices

[David Matlack <dmatlack@google.com>]

On 2026-09-10 06:51 PM, Bjorn Helgaas wrote:

> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 77b17b13ee61..22001bdf4c97 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -34,6 +34,8 @@
> >  #include <linux/aer.h>
> >  #include <linux/bitfield.h>
> >  #include <linux/suspend.h>
> > +
> > +#include "liveupdate.h"
> >  #include "pci.h"
> >  
> >  DEFINE_MUTEX(pci_slot_mutex);
> > @@ -1008,6 +1010,9 @@ void pci_enable_acs(struct pci_dev *dev)
> >  	bool enable_acs = false;
> >  	int pos;
> >  
> > +	if (!pci_liveupdate_enable_adopted_acs_controls(dev))
> > +		return;
> 
> Ugh.  The asymmetry between pci_save_state(), which does nothing
> ACS-related, and pci_restore_state(), which enables it, is sort of
> sketchy to begin with.
> 
> The command-line parsing in this path feels like kind of a wart (not
> that you're touching it).
> 
> It just seems like this path is already hard to analyze, and
> liveupdate is making it harder.
> 
> If we could save/restore the ACS state around the reset, wouldn't that
> solve this without any liveupdate specials here?

Yeah that would simplify the liveupdate support greatly. Let me work on
that for v9.