RE: [PATCH v6 18/19] x86: Add support for generic vDSO

[Michael Kelley]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Sent: Sunday, June 23, 2019 3:13 PM
> 
> I have no objections if you collect hyper-v stuff, quite the contrary, but
> changes which touch other subsystems need to be coordinated upfront. That's
> all I'm asking for.
> 
> Btw, that clocksource stuff looks good code wise, just the change logs need
> some care and after the VDSO stuff hits next we need to sort out the
> logistics. I hope these changes are completely self contained. If not we'll
> find a solution.
>

In my view, the only thing that potentially needs a solution is where the
Hyper-V clock code used by VDSO ends up in the code tree.  I think the
right long term place is include/clocksource/hyperv_timer.h.   That location
is architecture neutral, and the same Hyper-V clock code will be shared by
the Hyper-V on ARM64 support that's in process.

Vincenzo's patch set creates a new file arch/x86/include/asm/mshyperv-tsc.h,
which I will want to move when creating the separate Hyper-V clocksource
driver.   If you're OK with that file existing for a release and then going away,
that's fine.  Alternatively, put the code in include/clocksource/hyperv_timer.h
now as part of the VDSO patch set so it's in the right place from the start.  My
subsequent patch set will add a few additional tweaks to remove x86-isms
and fully integrate with the separate Hyper-V clocksource driver.

Michael