On 2025/11/1 07:58, Jakub Kicinski wrote:

On Thu, 30 Oct 2025 20:13:13 +0800 Wen Gu wrote:

quoted

This adds a driver for Alibaba CIPU PTP clock. The CIPU, an underlying
infrastructure of Alibaba Cloud, synchronizes time with atomic clocks
via the network and provides microsecond or sub-microsecond precision
timestamps for VMs and bare metals on cloud.

User space processes, such as chrony, running in VMs or on bare metals
can get the high precision time through the PTP device exposed by this
driver.

As mentioned on previous revisions this is a pure clock device which has
nothing to do with networking and PTP.

I don't quite agree that this has nothing to do with PTP.

What is the difference between this CIPU PTP driver and other PTP drivers
under drivers/ptp? such as ptp_s390, ptp_vmw, ptp_pch, and others. Most of
these PTP drivers do not directly involve IEEE 1588 or networking as well.

There should be a separate class
for "hypervisor clocks", if not a common driver.

'hypervisor clock' is not very accurate. CIPU PTP can be used in VM and
bare metal scenarios, and bare metals do not need hypervisors.

Regards.