On Thu, 06 Oct 2022 22:29:59 -0700, Haren Myneni wrote:

The hypervisor assigns VAS (Virtual Accelerator Switchboard)
windows depends on cores configured in LPAR. The kernel uses
OF reconfig notifier to reconfig VAS windows for DLPAR CPU event.
In the case of shared CPU mode partition, the hypervisor assigns
VAS windows depends on CPU entitled capacity, not based on vcpus.
When the user changes CPU entitled capacity for the partition,
drmgr uses /proc/ppc64/lparcfg interface to notify the kernel.

[...]

Applied to powerpc/fixes.

[1/1] powerpc/pseries: Use lparcfg to reconfig VAS windows for DLPAR CPU
      https://git.kernel.org/powerpc/c/2147783d6bf0b7ca14c72a25527dc5135bd17f65

cheers