Re: [PATCH] x86/hyperv: Disable preemption while setting reenlightenment vector

Vitaly Kuznetsov
2019-06-14T21:44:44Z

Peter Zijlstra <peterz@infradead.org> writes:

>
> I know you probably can't change the HV interface, but I'm thinking its
> rather daft you have to specify a CPU at all for this. The HV can just
> pick one and send the notification there, who cares.

Generally speaking, hypervisor can't know if the CPU is offline (or
e.g. 'isolated') from guest's perspective so I think having an option to
specify affinity for reenlightenment notification is rather a good
thing, not bad.

(Actually, I don't remember if I tried specifying 'HV_ANY' (U32_MAX-1)
here to see what happens. But then I doubt it'll notice the fact that we
offlined some CPU so we may get a totally unexpected IRQ there).

--
Vitaly