RE: [PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method

From: Dexuan Cui
Date: Mon Feb 13 2017 - 02:49:51 EST

> From: Thomas Gleixner [mailto:tglx@xxxxxxxxxxxxx]
> Sent: Saturday, February 11, 2017 02:02
> ...
> That's important if the stuff happens cross CPU. If the update happens on
> the same CPU then this is a different story and as there are VMexits
> involved they might provide the required ordering already. But I can't tell
> as I have no idea how that host side thing is done.
> tglx

IMO Hyper-V TSC page clocksource here seems pretty similar to KVM's pvclock,
So I would guess "the structure is only updated just before reentering the guest
after some VM event" (,
that is, the update should happen on the same CPU, I guess.

-- Dexuan