Re: [PATCH v6 04/27] vfio/pci: Register a file handler with Live Update Orchestrator

[Samiullah Khawaja]

On Mon, Nov 02, 2026 at 07:36:33AM -0800, Vipin Sharma wrote:
> Register a live update file handler for vfio-pci device files. Add stub
> implementations of all required callbacks so that registration does not
> fail. Register it with both live update framework and PCI subsystem.
>
> This file handler will be extended in subsequent commits to enable a
> device bound to vfio-pci to run without interruption while the host is
> going through a kexec Live Update.
>
> Put this support behind a new Kconfig VFIO_PCI_LIVEUPDATE. Initial
> support is added for no-iommu model vfio-pci devices.
>
> Co-developed-by: David Matlack <dmatlack@xxxxxxxxxx>
> Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> Signed-off-by: Vipin Sharma <vipinsh@xxxxxxxxxx>
> ---
> MAINTAINERS                            |  1 +
> drivers/vfio/pci/Kconfig               | 11 ++++
> drivers/vfio/pci/Makefile              |  1 +
> drivers/vfio/pci/vfio_pci.c            | 11 +++-
> drivers/vfio/pci/vfio_pci_liveupdate.c | 75 ++++++++++++++++++++++++++
> drivers/vfio/pci/vfio_pci_priv.h       | 14 +++++
> include/linux/kho/abi/vfio_pci.h       | 28 ++++++++++
> 7 files changed, 140 insertions(+), 1 deletion(-)
> create mode 100644 drivers/vfio/pci/vfio_pci_liveupdate.c
> create mode 100644 include/linux/kho/abi/vfio_pci.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5d1b58271989..167aa9d66ce8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -28662,6 +28662,7 @@ F:	Documentation/ABI/testing/debugfs-vfio
> F:	Documentation/ABI/testing/sysfs-devices-vfio-dev
> F:	Documentation/driver-api/vfio.rst
> F:	drivers/vfio/
> +F:	include/linux/kho/abi/vfio_pci.h
> F:	include/linux/vfio.h
> F:	include/linux/vfio_pci_core.h
> F:	include/uapi/linux/vfio.h
> diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig
> index 296bf01e185e..e8285ad93a69 100644
> --- a/drivers/vfio/pci/Kconfig
> +++ b/drivers/vfio/pci/Kconfig
> @@ -42,6 +42,17 @@ config VFIO_PCI_IGD
> 	  and LPC bridge config space.
>
> 	  To enable Intel IGD assignment through vfio-pci, say Y.
> +
> +config VFIO_PCI_LIVEUPDATE
> +	bool "VFIO PCI support for Live Update in no-iommu mode"
> +	depends on PCI_LIVEUPDATE && VFIO_NOIOMMU

Can we handle this dependency in code instead of doing through
configs? Are there any build dependencies on noiommu?
> +	help
> +	  Support for preserving devices bound to vfio-pci in no-iommu mode
> +	  across a Live Update. It enables a device to continue working (DMA)
> +	  while host kernel is going through a kexec live update.
> +
> +	  If you don't know what to do here, say N.
> +
> endif

Thanks,
Sami