Re: [PATCH v16 2/2] Documentation: add debugfs description for vfio

[Alex Williamson]

On Tue, 26 Sep 2023 17:33:56 +0800
liulongfang <liulongfang@xxxxxxxxxx> wrote:

> From: Longfang Liu <liulongfang@xxxxxxxxxx>
> 
> 1.Add an debugfs document description file to help users understand
> how to use the accelerator live migration driver's debugfs.
> 2.Update the file paths that need to be maintained in MAINTAINERS
> 
> Signed-off-by: Longfang Liu <liulongfang@xxxxxxxxxx>
> ---
>  Documentation/ABI/testing/debugfs-vfio | 25 +++++++++++++++++++++++++
>  MAINTAINERS                            |  1 +
>  2 files changed, 26 insertions(+)
>  create mode 100644 Documentation/ABI/testing/debugfs-vfio
> 
> diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
> new file mode 100644
> index 000000000000..7959ec5ac445
> --- /dev/null
> +++ b/Documentation/ABI/testing/debugfs-vfio
> @@ -0,0 +1,25 @@
> +What:		/sys/kernel/debug/vfio
> +Date:		Sep 2023
> +KernelVersion:  6.7
> +Contact:	Longfang Liu <liulongfang@xxxxxxxxxx>
> +Description:	This debugfs file directory is used for debugging
> +		of vfio devices, it's a common directory for all vfio devices.
> +		Vfio core will create a device subdirectory under this
> +		directory.
> +
> +What:		/sys/kernel/debug/vfio/<device>/migration
> +Date:		Sep 2023
> +KernelVersion:  6.7
> +Contact:	Longfang Liu <liulongfang@xxxxxxxxxx>
> +Description:	This debugfs file directory is used for debugging
> +		of vfio devices that support live migration.
> +		The debugfs of each vfio device that supports live migration
> +		could be created under this directory.
> +
> +What:		/sys/kernel/debug/vfio/<device>/migration/state
> +Date:		Sep 2023
> +KernelVersion:  6.7
> +Contact:	Longfang Liu <liulongfang@xxxxxxxxxx>
> +Description:	Read the live migration status of the vfio device.
> +		The status of these live migrations includes:
> +		ERROR, RUNNING, STOP, STOP_COPY, RESUMING.

This is another area that's doomed to be out of sync, it's already not
updated for P2P states.  Better to avoid the problem and say something
like "The contents of the state file reflects the migration state
relative to those defined in the vfio_device_mig_state enum".

Also, as suggested last time, October is a more realistic date.  Thanks,

Alex

> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7b1306615fc0..bd01ca674c60 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22304,6 +22304,7 @@ L:	kvm@xxxxxxxxxxxxxxx
>  S:	Maintained
>  T:	git https://github.com/awilliam/linux-vfio.git
>  F:	Documentation/ABI/testing/sysfs-devices-vfio-dev
> +F:	Documentation/ABI/testing/debugfs-vfio
>  F:	Documentation/driver-api/vfio.rst
>  F:	drivers/vfio/
>  F:	include/linux/vfio.h