Hi,
On 6/25/25 4:18 PM, Pasha Tatashin wrote:
> diff --git a/Documentation/ABI/testing/sysfs-kernel-liveupdate b/Documentation/ABI/testing/sysfs-kernel-liveupdate
> new file mode 100644
> index 000000000000..4cd4a4fe2f93
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-kernel-liveupdate
> @@ -0,0 +1,51 @@
> +What: /sys/kernel/liveupdate/
> +Date: May 2025
> +KernelVersion: 6.16.0
> +Contact: pasha.tatashin@xxxxxxxxxx
> +Description: Directory containing interfaces to query the live
> + update orchestrator. Live update is the ability to reboot the
> + host kernel (e.g., via kexec, without a full power cycle) while
> + keeping specifically designated devices operational ("alive")
> + across the transition. After the new kernel boots, these devices
> + can be re-attached to their original workloads (e.g., virtual
> + machines) with their state preserved. This is particularly
> + useful, for example, for quick hypervisor updates without
> + terminating running virtual machines.
> +
> +
> +What: /sys/kernel/liveupdate/state
> +Date: May 2025
> +KernelVersion: 6.16.0
> +Contact: pasha.tatashin@xxxxxxxxxx
> +Description: Read-only file that displays the current state of the live
> + update orchestrator as a string. Possible values are:
> +
> + "normal": No live update operation is in progress. This is
> + the default operational state.
Just an opinion, but the ':'s after each possible value aren't needed
and just add noise.
You could just drop the ':'s -- or you could make a table here, like
Documentation/ABI/testing/sysfs-hypervisor-xen does, by adding
=========== ================================================
> + "prepared": The live update preparation phase has completed
> + successfully (e.g., triggered via the
> + /dev/liveupdate event). Kernel subsystems have
> + been notified via the %LIVEUPDATE_PREPARE
> + event/callback and should have initiated state
> + saving. User workloads (e.g., VMs) are generally
> + still running, but some operations (like device
> + unbinding or new DMA mappings) might be
> + restricted. The system is ready for the reboot
> + trigger.
> +
> + "frozen": The final reboot notification has been sent
> + (e.g., triggered via the 'reboot()' syscall),
> + corresponding to the %LIVEUPDATE_REBOOT kernel
> + event. Subsystems have had their final chance to
> + save state. User workloads must be suspended.
> + The system is about to execute the reboot into
> + the new kernel (imminent kexec). This state
> + corresponds to the "blackout window".
> +
> + "updated": The system has successfully rebooted into the
> + new kernel via live update. Restoration of
> + preserved resources can now occur (typically via
> + ioctl commands). The system is awaiting the
> + final 'finish' signal after user space completes
> + restoration tasks.
and
=========== ================================================
Or just disagree or ignore. :)
--
~Randy
