Re: [PATCH v9 00/13] PCI: liveupdate: PCI core support for Live Update

[David Matlack]

On Tue, Sep 22, 2026 at 11:36 AM Zhu Yanjun <yanjun.zhu@xxxxxxxxx> wrote:
> 在 2026/9/18 13:06, David Matlack 写道:
> > Future Work
> > -----------
> >
> > Following this series, we expect to make further improvements to the PCI
> > core support for Live Update:
> >
> >    - Allow P2P across Live Update by avoiding resizing or moving
> >      preserved device BARs and preserving all upstream bridge windows.
> >
> >    - Support preserving Virtual Functions by preserving SR-IOV
> >      configuration on PFs and enumerating VFs after Live Update.
>
> Preserving the PCIe topology, bus numbers, ACS, and Bus Mastering across
> kexec is a foundational step for minimizing downtime.
>
> As we look toward complete end-to-end support for DMA preservation
> across Live Update—especially for VFIO device passthrough and dma-buf
> sharing scenarios—IOMMU table/domain preservation becomes crucial to
> prevent IOMMU page faults when devices continue performing DMA during kexec.
>
> I would like to ask about the current status and roadmap regarding IOMMU
> Live Update / KHO (Kexec Handover) support:
>
> Is there an ongoing effort or RFC series for IOMMU handover / page-table
> preservation currently in development or under discussion?
>
> How is the coordination between the PCI core Live Update mechanisms and
> the IOMMU subsystem being envisioned for preserving IOVA mappings (e.g.,
> restoring domains or handing over root tables)?
>
> Any pointers to active discussion threads, RFCs, or future plans
> regarding IOMMU participation in Live Update would be greatly appreciated.

The first IOMMU series to support Live update, can be found here:

  https://lore.kernel.org/linux-iommu/20260921004834.2601285-1-skhawaja@xxxxxxxxxx/

The IOMMU series builds on top of the PCI core support (this series)
and the VFIO series linked further up in the cover letter.