Re: [Xen-devel] [PATCH v6 16/18] vmx: Add some scheduler hooks for VT-d posted interrupts

["Wu, Feng" <feng.wu@xxxxxxxxx>]

> >> Thanks for the comments!
> >>
> >> From my understanding, __sync_local_execstate() can only get called
> >> in the following two cases:
> >> #1) this_cpu(curr_vcpu) == current, in this case, __context_switch() is
> >> not called.
> >> #2) this_cpu(curr_vcpu) != current, and current == idle_vcpu, that means
> >> we just switched from a non-idle vCPU to idle vCPU, so here we need to
> >> call __context_switch() to copy things to the original vcpu struct.
> >>
> >> Please correct me if the above understanding is wrong or incomplete?
> >
> > Hi George / Dario,
> >
> > Could you please confirm the above understanding is correct? (In fact, it is
> > Related to lazy context switch, right?) if so I can continue with the
> > pi_context_switch() way George suggested.
> 
> Yes, that's the general idea.  Normally, you can access the registers of
> a non-running vcpu from the vcpu struct.  But if we've done a lazy
> context switch, that's not true -- so to access those registers properly
> we need to go through and do the full context switch *on that pcpu*.

Thanks for the clarification!

Thanks,
Feng
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