On Wed, May 20, 2026, at 15:46, Michael Kelley wrote:
> From: Arnd Bergmann <[email protected]> Sent: Wednesday, May 20, 2026 12:40 AM
>>
>> When the vmbus driver is not part of the kernel, the mvhv_root
>> driver now fails to link:
>>
>> ERROR: modpost: "hv_vmbus_exists" [drivers/hv/mshv_root.ko] undefined!
>>
>> Avoid this by adding an explicit Kconfig dependency. Note that
>> stubbing out the hv_vmbus_exists() based on configuration would
>> also work for some cases, but not with MSHV_ROOT=y and HYPERV_VMBUS=m.
>
> Conceptually, the MSHV root code should not have a dependency on
> VMBus. The "does VMBus exist?" question should handled differently
> by setting up a boolean in the core Hyper-V code that defaults to "false".
> If the VMBus driver loads, it would set the boolean to "true". MSHV
> root code would query the boolean.
That makes sense to me, but it's outside of my area for a drive-by
build fix. Please treat my patch as a 'Reported-by' then, I expect
this can easily be addressed by Jork or someone else in the
hyperv team.
Arnd
