[PATCH v6 01/12] PCI: liveupdate: Set up FLB handler for the PCI core

[Pasha Tatashin]

On 2026-06-15 22:22:08+00:00, David Matlack wrote:
> On 2026-06-12 05:15 AM, Pasha Tatashin wrote:
> 
> > On Fri, 22 May 2026 20:23:59 +0000, David Matlack <dmatlack at google.com> wrote:
> 
> 
> 
> > > + * PCI device preservation across Live Update is built on top of the Live Update
> > 
> > I prefer to just use acronyms FLB, and LUO, but have links to the actual 
> > documentations about them.
> > 
> > So, something like this:
> > 
> >   * :ref:`FLB <flb>` Data
> >   * =====================
> >   *
> >   * PCI device preservation across Live Update is built on top of the
> >   * :ref:`LUO <luo>` support for file preservation across kexec. Drivers
> > 
> > And also add _luo and _flb to Documentation/core-api/liveupdate.rst
> > 
> > .. _luo:
> > 
> >  ========================
> >  Live Update Orchestrator
> >  ========================
> > 
> > .. _flb:
> 
> Will do.
> 
> I guess I will need to add another patch to add the link references to
> liveupdate.rst?

Yes, it can be a separate patch, but adding to this patch is also, OK.

> >  LUO File Lifecycle Bound Global Data
> >  ====================================
> > 
> > 
> > Nit, may be:
> 
> Did you have a suggestion here that got lost?

Yeah, I meant:
#define pr_fmt(fmt) "PCI: " KBUILD_BASENAME ": " fmt

> 
> > Please sort alphabetically.
> 
> Will do.
> 
> > I think, we want to use kho_block [1] (it is in liveupdate/next branch) 
> > to allow number of supported devices to be dynamic.
> > 
> > To support this, we would redefine the ABI and tracking structures like 
> > so:
> > 
> > /* include/linux/kho/abi/pci.h */
> > struct pci_ser {
> > 	u64 devices;      /* Phys address of the first block header of kho_block_set */
> > 	u64 nr_devices;   /* Total count of active preserved devices */
> > } __packed;
> > 
> > /* drivers/pci/liveupdate.c */
> > struct pci_flb_outgoing {
> > 	struct pci_ser *ser;            /* Points to the FDT/KHO-allocated ABI struct */
> > 	struct kho_block_set block_set;  /* Controls the active blocks on the fly */
> > };
> > 
> > In  __pci_liveupdate_preserve_device() , we would search for 
> > and reuse any inactive  pci_dev_ser  slot first, and only call 
> > kho_block_set_grow() to expand if no inactive slots are available.
> > 
> > In pci_liveupdate_unpreserve_device(), we would simply 
> > mark the  pci_dev_ser as inactive.
> 
> Makes sense at a high level. I'll work on switching kho_block for v7 and
> get back to you if I hit any issues.